Air spring with air nozzle nylon piston air tightness automatic detection equipment and detection method

Abstract

The present application relates to the field of nylon piston air tightness detection, in particular to air spring with air nozzle nylon piston air tightness automatic detection equipment and detection method, including water pool, lifting whole board and a plurality of pressure charging components, the lifting whole board is equipped with lifting single board for the installation of the pressure charging component, the pressure charging component includes movable mold and sealing gasket, the lifting single board is equipped with first fixed plate and second fixed plate, the movable mold is equipped with mold cavity, the air nozzle of the piston is connected with air pipe, the free end of the air pipe is closed structure, the first fixed plate is equipped with push-pull cylinder, the second fixed plate is equipped with pressure charging nozzle. The present application supports the piston through the mold cavity of movable mold, then the sealing gasket is pressed under the action of push-pull cylinder, the open end of the piston is sealed and communicated with the pressure charging nozzle, at the same time, the air pipe is limited by the top clamping groove of the mold cavity, ensures that the air nozzle is upward, the leakage bubble is vertically upward when immersed, which is convenient for accurate identification.

Description

Technical Field

[0001] This invention relates to the field of air tightness testing of nylon pistons, specifically to an automatic air tightness testing device and method for nylon pistons with air springs and valves. Background Technology

[0002] In the manufacturing process of air springs, the airtightness of the nylon piston with a valve is a key indicator to ensure product performance and service life. Currently, the commonly used testing method is to seal the piston, fill it with compressed air through the air valve and connecting pipe, spray detergent solution at the interface between the air valve and the pipe, and rely on visual inspection to see if bubbles are generated to determine if there is a leak.

[0003] However, this method has significant drawbacks: firstly, it is difficult to fully cover the detection area; secondly, detergent residue may affect subsequent assembly or product cleanliness. Furthermore, this method cannot achieve automated detection, making it difficult to meet the demands of high-precision, high-efficiency quality inspection in mass production.

[0004] Therefore, there is a need for an automatic air tightness testing device for nylon pistons with air springs and air nozzles. After sealing, the entire piston can be directly immersed in water for inflation testing, which can cover the entire testing area and improve testing sensitivity and reliability. Summary of the Invention

[0005] To address the problems existing in the current technology, an automatic air tightness testing device for an air spring with a nozzle and a nylon piston is provided. The piston is supported by the cavity of the movable mold, and then the sealing gasket is pressed under the action of the push-pull cylinder to seal the piston opening and connect it to the pressurizing nozzle. At the same time, the air pipe is limited by the slot at the top of the mold cavity to ensure that the nozzle faces upward. When immersed in water, the leaking air bubbles rise vertically, which is convenient for accurate identification.

[0006] To address the problems of existing technologies, this invention provides an automatic air tightness testing device for an air spring with a nylon piston and air valve, comprising a water tank for holding testing water, a lifting plate horizontally positioned above the water tank and capable of vertically lifting as a whole, and multiple pressurization components equally spaced along the length of the lifting plate. The lifting plate has a single lifting plate for mounting the pressurization components. Each pressurization component includes a movable mold and a sealing gasket. The movable mold is movable relative to the sealing gasket. A first fixed plate and a second fixed plate are symmetrically arranged on the single lifting plate along the width of the lifting plate. The movable mold is mounted on the first fixed plate, and the sealing gasket is mounted on the second fixed plate. The movable mold faces... A mold cavity matching the piston shape is provided on one side of the sealing gasket. The matching gap between the mold cavity and the piston shape is <0.05mm. An air pipe is connected to the piston's air nozzle. The free end of the air pipe is a closed structure. The air pipe is a rigid PU tube with an outer diameter of 8-12mm. The closed end is heat-sealed. A push-pull cylinder for driving the movable mold is provided on the first fixed plate. A pressurizing nozzle extending outward through the sealing gasket is provided on the second fixed plate. When the movable mold pushes the piston so that its open end presses against the sealing gasket, the piston's inner cavity communicates with the pressurizing nozzle to form a sealed, pressurized state. This allows the piston as a whole to be immersed 5-10cm below the water surface in the pool for airtightness testing.

[0007] Preferably, the top of the mold cavity is provided with a groove that matches the air pipe, which is used to keep the piston nozzle facing upward when the air pipe is inserted. The fitting gap between the groove and the air pipe is 0.02-0.03mm, and the depth of the groove is 1 / 2-2 / 3 of the outer diameter of the air pipe.

[0008] Preferably, a feeding mechanism is provided directly above the water tank. The feeding mechanism includes a feeding tray and a clamp. A clamp is provided on the feeding tray for each movable mold. The feeding tray is positioned between the sealing gasket and the movable mold and can move vertically to cooperate with the movable mold to send the piston into the mold cavity.

[0009] Preferably, the top of the feeding tray is provided with a strip plate corresponding to the position of each clamp, the strip plate extends toward the direction of the movable mold, and the strip plate has a groove for engaging the air pipe at its extended end.

[0010] Preferably, the clamp includes a fixed post and inner support plates evenly distributed around it. Each inner support plate has a guide plate on its outer side. Each inner support plate has two insert rods that extend outward through the guide plate and slide with it. A spring is fixedly connected between the inner support plate and the guide plate. The spring has an elastic coefficient of 150-250 N / m, and the sliding accuracy of the insert rods is ±0.02 mm.

[0011] Preferably, the outer side of one end of the inner support plate extending toward the movable mold is provided with a rubber pad, and the end of the rubber pad is provided with a guide slope. All the inner support plates and their rubber pads together constitute an inner support positioning structure for inserting into the piston cavity and performing radial positioning.

[0012] Preferably, the fixed column is a hollow structure. When the piston on the fixture is aligned with the movable mold, the fixed column and the pressurizing nozzle are coaxial, forming an airflow passage connecting the piston cavity and the external air source.

[0013] Preferably, fixed electromagnets are provided around the fixed column, and a movable electromagnet is provided at the end of each insertion rod that is fixedly connected to the inner support plate. When the piston is inserted into the mold cavity, the clamp is in the inner support retraction state under the electromagnetic attraction. The attraction force between the fixed electromagnet and the movable electromagnet is 50-80N, and the retraction distance of the inner support plate after energization is 3-5mm.

[0014] Preferably, the feeding mechanism further includes a replenishing tray aligned with the feeding tray at a high position. The replenishing tray is capable of moving horizontally relative to the feeding tray, and a tray with the same structure as the movable mold is provided on the replenishing tray at the position corresponding to each clamp.

[0015] This invention also provides an automatic method for detecting the air tightness of an air spring with a valve nylon piston, comprising the following steps:

[0016] S1. Place the piston with the closed-end air pipe into the mold cavity of the movable mold, and make the air pipe lock into the slot at the top of the mold cavity, so that the piston nozzle faces upward.

[0017] S2. The movable mold is driven to move towards the sealing gasket by the push-pull cylinder, so that the piston opening end presses against the sealing gasket, and at the same time the piston inner cavity forms a closed air passage through the pressurized nozzle.

[0018] S3. Start the lifting plate to drive the sealed piston down and completely immerse it in the water of the pool;

[0019] S4. Inject gas at the set pressure into the piston cavity through the pressurizing nozzle. The set pressure is 0.3-0.6 MPa compressed air. Hold the pressure for 10-20 seconds. Observe whether bubbles are generated at the connection between the air nozzle and the air pipe in water to determine whether the air tightness is qualified. If the number of bubbles generated is <1 / 5s, the air tightness is qualified; otherwise, it is unqualified. If the pressure drop rate is >0.01 MPa / s during the pressurization process, the air tightness is directly determined to be unqualified, the pressure holding is stopped and an alarm is triggered.

[0020] The advantages of this application compared to the prior art are:

[0021] 1. In this invention, the piston is supported by the mold cavity in the movable mold. Then, the push-pull cylinder drives the movable mold to move horizontally towards the sealing gasket, pressing the open end of the piston against the sealing gasket to form a sealed cavity. At the same time, the inner cavity of the piston is connected to the pressurizing nozzle passing through the sealing gasket to construct a sealed inflation channel.

[0022] Subsequently, the lifting cylinder lowers the entire lifting plate, fully immersing the sealed piston in the water tank. Guide rods around the lifting plate slide against the support to ensure smooth vertical movement. Through holes on the lifting plate and its individual components effectively reduce fluid resistance during underwater movement. Underwater, an adjustable pressure air source inflates the piston's interior through a pressurizing nozzle, and leaks at the air nozzle connections are detected using bubble visualization. This collaborative process achieves comprehensive, high-precision, automated airtightness testing.

[0023] 2. The present invention provides a slot at the top of the active mold cavity that precisely matches the outer diameter of the air pipe. When the piston is installed into the mold cavity and the closed air pipe connected to its air nozzle end is embedded in the slot, the slot limits the air pipe, so that the piston air nozzle is positioned in a vertically upward posture.

[0024] Subsequently, after the piston is submerged in water, it is ensured that the air nozzle is at its highest point when the piston is submerged in water for testing. This allows the leaking air bubbles to rise vertically along the shortest path, improving the clarity and response sensitivity of the air bubbles captured by manual observation or visual recognition systems, thereby improving the accuracy, consistency and reliability of airtightness determination.

[0025] 3. This invention utilizes a feeding tray that descends smoothly along a column guide under the drive of a downward-moving cylinder, precisely delivering the piston carried by the fixture between the movable mold and the sealing gasket. The fixture employs an inner support plate with a guide beveled rubber pad and a spring structure to achieve flexible self-centering clamping of the piston. The strip groove on the plate is pre-positioned with the air pipe, ensuring its accurate embedding into the mold cavity slot.

[0026] During the loading process, the movable mold, in conjunction with the electromagnetically controlled inner support plate, retracts, allowing the fixture to exit without interference after releasing the piston. Simultaneously, the replenishing tray, via a translation cylinder and slide rail, achieves high-level replenishment, completing automatic piston replenishment. This collaborative process enables parallel piston positioning and loading / unloading operations, improving detection cycle time, repeatability, and automation efficiency. Attached Figure Description

[0027] Figure 1 This is a three-dimensional structural schematic diagram of the automatic air tightness detection device for an air spring with a nozzle and a nylon piston according to the present invention.

[0028] Figure 2 This is a partial three-dimensional structural cross-sectional view of the automatic air tightness detection device for an air spring with a nozzle and a nylon piston according to the present invention.

[0029] Figure 3 This is the invention Figure 2The enlarged schematic diagram at point A shows the connection structure between the pressurizing nozzle and the piston cavity, as well as the limiting state of the slot on the air tube.

[0030] Figure 4 This is a three-dimensional structural diagram of the lifting plate and pressurization assembly of the automatic air tightness detection device for the air spring with air nozzle nylon piston of the present invention.

[0031] Figure 5 This is an exploded three-dimensional structural diagram of the lifting plate and pressurization assembly of the automatic air tightness detection device for the air spring with air nozzle and nylon piston of the present invention.

[0032] Figure 6 This is a three-dimensional structural diagram of the feeding tray in the feeding mechanism of the automatic air tightness testing equipment for air springs with air nozzles and nylon pistons of the present invention.

[0033] Figure 7 This is an exploded three-dimensional structural diagram of the loading tray and clamp of the automatic air tightness testing device for the air spring with air nozzle nylon piston of the present invention.

[0034] Figure 8 This is the invention Figure 2 The enlarged schematic diagram at point B shows the positioning of the piston by the clamp on the loading pallet.

[0035] Figure 9 This is a three-dimensional structural diagram of the feeding tray in the feeding mechanism of the automatic airtightness testing device for air springs with nozzles and nylon pistons of the present invention.

[0036] Figure 10 This is the invention Figure 2 The enlarged diagram at point C shows the positioning of the piston by the support on the feeding tray.

[0037] Figure 11 This is a three-dimensional structural schematic diagram of the air spring with nozzle nylon piston of the present invention from a first perspective.

[0038] Figure 12 This is a three-dimensional structural schematic diagram of the air spring with nozzle nylon piston of the present invention from a second perspective.

[0039] The diagram is labeled as follows: 1. Piston; 11. Air nozzle; 12. Air pipe; 2. Water tank; 3. Lifting plate; 31. Lifting single plate; 311. Through hole; 32. First fixed plate; 321. Push-pull cylinder; 33. Second fixed plate; 331. Pressurizing nozzle; 332. Pressurizing air passage; 4. Pressurizing assembly; 41. Movable mold; 411. Mold cavity; 412. Slot; 42. Sealing gasket; 5. Support; 51. Lifting cylinder; 52. Guide rod; 6. Feeder 61. Feeding tray; 611. Side plate; 62. Clamp; 621. Fixed column; 6211. Fixed electromagnet; 6212. Movable electromagnet; 622. Inner support plate; 6221. Rubber pad; 623. Guide plate; 6231. Insert rod; 6232. Spring; 63. Strip plate; 631. Strip groove; 64. Feeding tray; 641. Support; 7. Bracket; 71. Downward movement cylinder; 72. Column; 73. Slide rail; 74. Translation cylinder. Detailed Implementation

[0040] To further understand the features, technical means, and specific objectives and functions achieved by the present invention, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0041] See Figures 1 to 5 As shown, the automatic air tightness testing device for an air spring with a nozzle and a nylon piston includes a water tank 2 for holding testing water. A lifting plate 3 is horizontally positioned above the water tank 2 and can be raised and lowered vertically as a whole. Multiple pressurizing components 4 are arranged at equal intervals along the length of the lifting plate 3, and the lifting plate 3 is provided with a lifting single plate 31 for mounting the pressurizing components 4. The pressurizing component 4 includes a movable mold 41 and a sealing gasket 42, and the movable mold 41 can move relative to the sealing gasket 42. A first fixed plate 32 and a second fixed plate 33 are symmetrically arranged on the lifting single plate 31 along the width direction of the lifting plate 3. The movable mold 41 is mounted on the first fixed plate 32, and the sealing gasket 42 is mounted on the second fixed plate 33. The movable mold 41 has a cavity 411 on the side facing the sealing gasket 42 that matches the shape of the piston 1, and the matching gap between the cavity 411 and the shape of the piston 1 is <0.05mm. Piston 1 has an air nozzle 11 connected to an air pipe 12. The free end of the air pipe 12 is a closed structure. The air pipe 12 is a rigid PU tube with an outer diameter of 8-12mm, and the closed end is heat-sealed. The first fixed plate 32 is equipped with a push-pull cylinder 321 for driving the movable mold 41 to move. The second fixed plate 33 is equipped with a pressurizing nozzle 331 extending outward through the sealing gasket 42. When the movable mold 41 pushes piston 1 so that its open end presses against the sealing gasket 42, the inner cavity of piston 1 communicates with the pressurizing nozzle 331 to form a sealed pressurized state, allowing piston 1 to be immersed 5-10cm below the water surface of the water tank 2 for airtightness testing.

[0042] The top of the second fixed plate 33 is provided with a pressurizing air passage 332 that communicates with the pressurizing nozzle 331, and the pressurizing air passage 332 is connected to an external air source.

[0043] The lifting plate 3 and the lifting single plate 31 are respectively provided with through holes 311, which are used to reduce the fluid resistance encountered by the lifting plate 3 when it rises and falls in water, and improve the stability and efficiency of immersion and lifting.

[0044] The top of the pool 2 is symmetrically provided with two supports 5 along its length. Each support 5 is provided with a lifting cylinder 51 that is connected to the lifting plate 3. The lifting plate 3 is provided with guide rods 52 that pass vertically upward through the support 5 and slide with it.

[0045] The air pressure of the pressurizing nozzle 331 is adjustable, and the pressure and time are adjustable. The pressurizing pressure adjustment range of the pressurizing nozzle 331 is 0.1-3.0MPa, and the pressure holding time can be adjusted within 5-90s.

[0046] In the automatic air tightness testing process of the air spring with air nozzle nylon piston, the testing process begins by placing the piston to be tested 1 into the mold cavity 411 of the movable mold 41, wherein the air nozzle 11 end of the piston 1 is connected to an air pipe 12 with its free end closed. The slot 412 opened at the top of the mold cavity 411 ensures that the air pipe 12 remains stable during the testing process and that the air nozzle 11 of the piston 1 faces upward.

[0047] Once piston 1 is in place, the push-pull cylinder 321 mounted on the first fixed plate 32 is activated, driving the movable mold 41 to move horizontally along the width of the pool 2, approaching the sealing gasket 42 fixed on the second fixed plate 33. As the movable mold 41 advances, the open end of piston 1 is pressed against the sealing gasket 42, forming a reliable sealing interface. At this time, the internal cavity of piston 1 is connected through the pressurizing nozzle 331 provided on the second fixed plate 33. The pressurizing nozzle 331 passes through the sealing gasket 42 and extends outward, its internal channel connecting with the pressurizing air passage 332 opened at the top of the second fixed plate 33, which in turn connects to an external adjustable air source system.

[0048] Thus, the inner cavity of piston 1, the pressurizing nozzle 331, the pressurizing air passage 332, and the external air source form a complete closed air path, allowing piston 1 to enter a sealed, pressurized state. Subsequently, the lifting cylinder 51 operates synchronously, driving the lifting plate 3, which is connected to it, to descend smoothly in the vertical direction. The lifting plate 3 is equipped with vertically extending guide rods 52 around its perimeter, effectively limiting swaying during the lifting process and ensuring motion accuracy and stability. As the lifting plate 3 moves downward, the multiple lifting plates 31 and each pressurizing component 4 mounted on it together drive the sealed piston 1 to slowly immerse itself in the test water in the water tank 2 until piston 1 is completely submerged below the water surface.

[0049] To reduce fluid resistance and water hammer effect caused by the large-area water displacement of the plate during lifting, multiple through holes 311 are provided on the entire lifting plate 3 and each individual lifting plate 31, allowing water to flow quickly through the upper and lower spaces of the plate, improving the smoothness and response speed of the lifting action. After the piston 1 is completely submerged, an external air source injects compressed gas into the inner cavity of the piston 1 through the pressurization air passage 332 and the pressurization nozzle 331. The air source system connected to the pressurization nozzle 331 in this device has adjustable pressure and adjustable holding time, which can flexibly set the inflation pressure value and holding time according to the test standards of different models of piston 1, thereby realizing standardized and parameterized airtightness testing.

[0050] During the pressure holding period, operators or the accompanying vision system can visually and accurately determine whether there is a leakage defect in the piston 1 by observing whether continuous or intermittent bubbles are generated at the connection between the underwater piston 1's nozzle 11 and the sealed air pipe 12. The entire detection process relies on the coordinated operation of the above-mentioned structure to achieve integrated automatic detection from seal establishment and precise immersion to controllable pressurization, effectively avoiding the pollution, blind spots, and inefficiency problems of traditional detergent spraying methods.

[0051] See Figures 3 to 5 , Figure 11 and Figure 12 As shown, the top of the mold cavity 411 is provided with a slot 412 that matches the air pipe 12, which is used to keep the piston 1 air nozzle 11 in an upward position when the air pipe 12 is inserted. The fitting gap between the slot 412 and the air pipe 12 is 0.02-0.03mm, and the depth of the slot 412 is 1 / 2-2 / 3 of the outer diameter of the air pipe 12.

[0052] During the testing process, the nylon piston 1 under test has a gas tube 12 with its free end closed pre-connected to its gas nozzle 11. When the piston 1 is placed in the mold cavity 411 of the movable mold 41, the gas tube 12 is aligned and embedded into the slot 412 provided at the top of the mold cavity 411. The cross-sectional shape of the slot 412 precisely matches the outer diameter of the gas tube 12, which can limit the position of the gas tube 12.

[0053] Once the air tube 12 is fully inserted, it restricts the position of the air nozzle 11 on the piston 1, causing the air nozzle 11 on the piston 1 to naturally be in a vertically upward orientation. This orientation ensures that when the piston 1 is fully immersed in water for inflation testing, the air nozzle 11 is located at the highest point of the piston 1. If there is a minor leak, the resulting air bubbles will rise vertically along the shortest path, making them easy to observe or clearly captured by an image recognition system, thereby improving the accuracy and reliability of airtightness assessment.

[0054] See Figures 1 to 7As shown, a feeding mechanism 6 is provided directly above the water tank 2. The feeding mechanism 6 includes a feeding plate 61 and a clamp 62. A clamp 62 is provided on the feeding plate 61 corresponding to the position of each movable mold 41. The feeding plate 61 is located between the sealing gasket 42 and the movable mold 41 and can move vertically to cooperate with the movable mold 41 to send the piston 1 into the mold cavity 411.

[0055] Each of the supports 5 has a bracket 7 at both ends, and each bracket 7 has a downward displacement cylinder 71. The feeding tray 61 has side plates 611 at both ends that are connected to the corresponding two downward displacement cylinders 71.

[0056] The bracket 7 is provided with a column 72 that extends vertically upward through the side plate 611 and slides with it.

[0057] When the piston 1 needs to be fed into the mold cavity 411, the two downward cylinders 71 mounted on the brackets 7 at the ends of the side supports 5 move synchronously, their piston rods extend downward, driving the side plates 611 at both ends of the feeding tray 61 connected to them to descend together. At the same time, the vertical column 72 set on the bracket 7 passes through the guide hole on the side plate 611 and forms a sliding fit with the side plate 611 to ensure that the feeding tray 61 remains horizontal, stable, and free from swaying or jamming during the lifting and lowering process.

[0058] As the loading pallet 61 descends smoothly, the clamp 62 on it carries the piston 1 precisely into the assembly area enclosed by the movable mold 41 and the sealing gasket 42. Subsequently, the push-pull cylinder 321 drives the movable mold 41 towards the sealing gasket 42, pressing the piston 1 from the clamp 62 into the mold cavity 411. This effectively ensures the repeatability of piston 1 positioning and the stability of the testing cycle. Then, the clamp 62 releases the piston 1, and the movable mold 41 pulls the piston 1 out. After the piston 1 is completely removed from the clamp 62, the loading pallet 61 rises, and then the subsequent pressurization and airtightness testing is performed.

[0059] See Figures 6 to 8 As shown, the top of the feeding tray 61 is provided with a strip 63 corresponding to the position of each clamp 62. The strip 63 extends toward the movable mold 41, and the strip 63 has a groove 631 for engaging the air pipe 12 at its extended end.

[0060] When piston 1 is placed in fixture 62, air pipe 12 is simultaneously embedded into the slot 631 on strip plate 63, so that air pipe 12 is limited from above by strip plate 63. This not only prevents air pipe 12 from shaking or shifting during subsequent movement or pressing, but also ensures that the relative position of air pipe 12 and piston 1 nozzle 11 remains stable.

[0061] Because the position of the strip groove 631 is precisely aligned with the slot 412 at the top of the mold cavity 411, when the feeding plate 61 descends and sends the piston 1 into the movable mold 41, the air pipe 12 can smoothly and accurately slide into the slot 412 at the top of the mold cavity 411, achieving seamless connection. Thus, the strip plate 63 and the strip groove 631 together constitute the pre-positioning and transition support structure of the air pipe 12, ensuring the consistency of the air pipe 12's posture during the transfer of the piston 1 from the clamp 62 to the mold cavity 411, laying a key foundation for the subsequent upward orientation of the air nozzle 11, sealing and tightening, and underwater airtightness testing.

[0062] See Figure 7 and Figure 8 As shown, the clamp 62 includes a fixed post 621 and inner support plates 622 evenly distributed around it. Each inner support plate 622 has a guide plate 623 on its outer side. The inner support plate 622 has two insertion rods 6231 that extend outward through the guide plate 623 and slide with it. A spring 6232 is fixedly connected between the inner support plate 622 and the guide plate 623. The elastic coefficient of the spring 6232 is 150-250 N / m. The sliding accuracy of the insertion rod 6231 is ±0.02 mm.

[0063] When piston 1 is inserted into clamp 62 from above, its inner wall presses against the outer ends of each inner support plate 622, overcoming the elastic force of spring 6232 and causing the inner support plates 622 to contract inward synchronously. The insertion rod 6231 slides along guide plate 623, achieving flexible self-adaptation. Once piston 1 is fully in place, the elastic force of spring 6232 causes the rubber pads 6221 on the outer side of inner support plate 622 to press tightly against the inner wall of piston 1, forming uniform radial support and positioning. This ensures that piston 1 is subjected to balanced force and accurate positioning during clamping, and prevents deformation or damage to nylon piston 1 due to rigid clamping, providing a stable and reliable clamping foundation for subsequent airtightness testing.

[0064] See Figure 7 and Figure 8 As shown, the outer side of one end of the inner support plate 622 extending toward the movable mold 41 is provided with a rubber pad 6221. The end of the rubber pad 6221 is provided with a guide slope. All the inner support plates 622 and their rubber pads 6221 together constitute an inner support positioning structure for inserting into the inner cavity of the piston 1 and for radial positioning.

[0065] When the clamp 62 is inserted into the inner cavity of the piston 1, the guide ramp first contacts the inlet of the inner wall of the piston 1. During the advancement process, the guiding effect of the ramp causes each inner support plate 622 to elastically retract towards the center simultaneously, smoothly entering the inner cavity of the piston 1. Once fully inserted, the spring 6232 pushes the inner support plate 622 to return to its original position outward, causing the rubber pad 6221 to tightly adhere to the inner wall of the piston 1, forming uniform, soft, and reliable radial support and positioning.

[0066] The rubber pad 6221 is made of flexible material, which ensures clamping stability and avoids scratching or damaging the inner surface of the nylon piston 1. All the inner support plates 622 and their rubber pads 6221 work together to form a self-centering and self-adaptive inner support positioning structure, ensuring that the piston 1 maintains axial alignment and stable posture throughout the subsequent transfer, alignment and pressing into the mold cavity 411, providing key clamping guarantees for high-precision sealing and airtightness testing.

[0067] See Figure 3 and Figure 8 As shown, the fixed column 621 is a hollow structure. When the piston 1 on the clamp 62 is aligned with the movable mold 41, the fixed column 621 and the pressurizing nozzle 331 are coaxial, forming an airflow passage connecting the inner cavity of the piston 1 with the external air source.

[0068] When the loading pallet 61 lowers the clamp 62 holding the piston 1 to the predetermined position and precisely aligns it with the movable mold 41, the fixed column 621 at the center of the clamp 62 is coaxially aligned with the pressurizing nozzle 331 on the second fixed plate 33. Since the fixed column 621 adopts a hollow structure, a through hollow channel is formed inside it.

[0069] Subsequently, the push-pull cylinder 321 drives the movable mold 41 forward, fully pressing the piston 1 into the mold cavity 411. At this time, the clamp 62 releases the piston 1, preparing to retract. To prevent the piston 1 from shifting, falling off, or interfering with the clamp 62 due to loss of clamping during the subsequent retraction of the movable mold 41, the pressurizing nozzle 331 activates the air source in advance, supplying air to the inner cavity of the piston 1 through the pressurizing nozzle 331. Compressed air enters the inner cavity of the piston 1 through the hollow channel of the fixed column 621, forming positive pressure inside, so that the piston 1 is firmly pressed into the mold cavity 411 under the action of air pressure, maintaining stable positioning.

[0070] See Figure 5 and Figure 8 As shown, fixed electromagnets 6211 are provided around the fixed column 621, and a movable electromagnet 6212 is provided at the end of each insertion rod 6231 that is fixedly connected to the inner support plate 622. When the piston 1 is inserted into the mold cavity 411, the clamp 62 is in the inner support retraction state under the electromagnetic attraction. The attraction force of the fixed electromagnet 6211 and the movable electromagnet 6212 is 50-80N. After being energized, the inner support plate 622 retracts by 3-5mm.

[0071] The fixed electromagnet 6211 and the movable electromagnet 6212 are energized within 0.5 seconds after the piston 1 is embedded in the mold cavity 411, and remain energized after retraction until the piston 1 seal detection begins.

[0072] During the process of piston 1 being inserted into movable mold 41, in order to avoid interference between clamp 62 and piston 1 or to prevent subsequent actions from being hindered, electromagnetic control unit is activated to simultaneously energize the fixed electromagnets 6211 arranged around the fixed column 621 and the movable electromagnets 6212 installed at the ends of each insertion rod 6231.

[0073] Since the fixed electromagnet 6211 and the movable electromagnet 6212 are arranged opposite each other and their polarities are configured to attract each other, a strong magnetic attraction is generated when energized, pulling the movable electromagnet 6212 and its connected insert rod 6231 towards the center of the fixed column 621. The insert rod 6231 drives the inner support plate 622 to retract synchronously against the elastic force of the spring 6232, causing the rubber pad 6221, which was originally tensioned on the inner wall of the piston 1, to quickly disengage. The entire clamp 62 thus switches to the inner support retraction state. This state ensures that during the retraction of the movable mold 41, the inner support plate 622 completely avoids the inner contour of the piston 1, preventing jamming or accidental removal of the piston 1, thereby achieving reliable retention of the piston 1 in the mold cavity 411.

[0074] See Figure 1 , Figure 2 and Figures 7 to 10 As shown, the feeding mechanism 6 also includes a replenishing tray 64 aligned with the feeding tray 61 at a high position. The replenishing tray 64 can move horizontally relative to the feeding tray 61. The replenishing tray 64 is provided with a tray 641 with the same structure as the movable mold 41 at the position corresponding to each clamp 62.

[0075] Both ends of the feeding tray 64 are provided with slide rails 73 that slide with it. The slide rails 73 are fixedly connected to the bracket 7. Each slide rail 73 is provided with a translation cylinder 74 that is pulsatingly connected to the feeding tray 64.

[0076] The translation of the replenishing pallet 64 is interlocked with the lifting action of the loading pallet 61 to avoid interference.

[0077] To achieve seamless integration of efficient material replenishment and inspection cycles during continuous operation, after the loading pallet 61 carrying piston 1 descends into the inspection station, the replenishment pallet 64 remains in a high position, ready for operation. At this time, the operator or upstream automated equipment can pre-place the next batch of pistons 1 in the holder 641 of the replenishment pallet 64.

[0078] After the current batch of workpieces is inspected and the loading pallet 61 rises and resets, the two translation cylinders 74 mounted on the bracket 7 move synchronously, pushing the replenishing pallet 64 horizontally along the slide rail 73. The replenishing pallet 64 then precisely aligns the piston 1 in the fixture 641 with the clamp 62. Subsequently, the piston 1 is transferred to the clamp 62, and the replenishing pallet 64, driven by the translation cylinders 74, returns to its original position, ready to receive the next batch of workpieces. This achieves parallel operation of inspection and loading, significantly shortening inspection time and improving the overall automation efficiency of the machine.

[0079] An automatic method for detecting the air tightness of an air spring with a valve and a nylon piston, applied to the aforementioned automatic air tightness detection equipment, includes the following steps:

[0080] S1. Place the piston 1 with the closed end air pipe 12 into the mold cavity 411 of the movable mold 41, and make the air pipe 12 snap into the slot 412 at the top of the mold cavity 411, so that the air nozzle 11 of the piston 1 faces upward.

[0081] S2. The movable mold 41 is driven to move towards the sealing gasket 42 by the push-pull cylinder 321, so that the open end of the piston 1 presses the sealing gasket 42, and at the same time, the inner cavity of the piston 1 forms a closed air passage through the pressurizing nozzle 331.

[0082] S3. Start the lifting plate 3 to drive the sealed piston 1 to descend as a whole and be completely immersed in the water of the pool 2;

[0083] S4. Inject gas at a set pressure into the inner cavity of piston 1 through pressurizing nozzle 331. The set pressure is 0.3-0.6MPa compressed air. Hold the pressure for 10-20s. Observe in water whether bubbles are generated at the connection between air nozzle 11 and air pipe 12 to determine whether the air tightness is qualified. If the number of bubbles generated is <1 / 5s, the air tightness is qualified; otherwise, it is unqualified. If the pressure drop rate is >0.01MPa / s during the pressurization process, the air tightness is directly determined to be unqualified, the pressure holding is stopped and an alarm is triggered.

[0084] This invention supports the piston 1 through the cavity 411 of the movable mold 41, and uses a push-pull cylinder 321 to drive the movable mold 41 to press horizontally against the sealing gasket 42, so that the open end of the piston 1 is sealed and connected to the pressurizing nozzle 331 to form a closed air passage. At the same time, the slot 412 provided at the top of the mold cavity 411 limits the sealing air pipe 12 at the air nozzle 11 end of the piston 1, forcing the air nozzle 11 to maintain a vertically upward posture, ensuring that leaking air bubbles rise vertically along the shortest path during water immersion detection, which is convenient for accurate identification.

[0085] Subsequently, the lifting cylinder 51 drives the lifting plate 3 to descend smoothly, so that the piston 1 is fully immersed in the water pool 2. Underwater, the adjustable pressure air source is used to inflate the plate to achieve visual airtightness detection.

[0086] During the loading stage, the loading pallet 61, guided by the downward cylinder 71 and the column 72, sends the clamp 62 into the assembly area. The clamp 62 achieves flexible self-centering clamping of the piston 1 through the inner support plate 622 with guide inclined rubber pad 6221 and spring 6232. The strip groove 631 on the strip plate 63 pre-positions the air pipe 12 to ensure its accurate insertion into the slot 412. After the piston 1 is pressed in, the electromagnetic attraction drives the inner support plate 622 to retract, allowing the clamp 62 to exit without interference. The replenishment pallet 64, through the translation cylinder 74 and the slide rail 73, completes the pre-assembly and horizontal docking of the next batch of pistons 1 at a high position, realizing parallel operation of inspection and loading, and comprehensively improving positioning accuracy, inspection reliability and automation efficiency.

[0087] The above embodiments only illustrate one or more implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of protection 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 scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. An automatic air tightness testing device for an air spring with a valve and a nylon piston, characterized in that, include: The water tank is used to hold the water for testing. The lifting panel is horizontally positioned above the water tank and can be raised and lowered as a whole in the vertical direction. Multiple pressurization components are arranged at equal intervals along the length of the lifting plate, and the lifting plate is provided with a lifting plate for mounting the pressurization components; The pressurization assembly includes a movable mold and a sealing gasket, wherein the movable mold is movable relative to the sealing gasket; The lifting plate is symmetrically provided with a first fixed plate and a second fixed plate along the width direction of the lifting plate. The movable mold is installed on the first fixed plate and the sealing gasket is installed on the second fixed plate. The movable mold has a mold cavity on the side facing the sealing gasket that matches the shape of the piston, and the matching gap between the mold cavity and the piston shape is <0.05mm; The piston is connected to an air tube at the air nozzle. The free end of the air tube is a closed structure. The air tube is a rigid PU tube with an outer diameter of 8-12mm. The closed end is treated with heat fusion sealing. The first fixed plate is equipped with a push-pull cylinder for driving the movement of the movable mold; The second fixed plate is provided with a pressurizing nozzle that extends outward through the sealing gasket; When the movable mold pushes the piston to press the sealing gasket with its open end, the inner cavity of the piston is connected to the pressurizing nozzle to form a sealed pressurizing state, so that the piston as a whole can be immersed in the water tank 5-10cm below the water surface for air tightness testing. A feeding mechanism is provided directly above the water tank. The feeding mechanism includes a feeding plate and a clamp. A clamp is provided on the feeding plate corresponding to the position of each movable mold. The feeding plate is set between the sealing gasket and the movable mold and can move in the vertical direction to cooperate with the movable mold to send the piston into the mold cavity. The top of the feeding tray is provided with a strip plate corresponding to the position of each clamp. The strip plate extends toward the direction of the movable mold, and the strip plate has a groove for engaging the air pipe at its extended end. The clamp includes a fixed post and inner support plates evenly distributed around it. Each inner support plate has a guide plate on its outer side. Each inner support plate has two insert rods that extend outward through the guide plate and slide with it. A spring is fixedly connected between the inner support plate and the guide plate. The spring has an elastic coefficient of 150-250 N / m, and the sliding accuracy of the insert rods is ±0.02 mm.

2. The automatic air tightness testing device for air springs with valves and nylon pistons according to claim 1, characterized in that, The top of the mold cavity is provided with a slot that matches the air pipe, which is used to keep the piston nozzle facing upward when the air pipe is inserted. The gap between the slot and the air pipe is 0.02-0.03mm, and the depth of the slot is 1 / 2-2 / 3 of the outer diameter of the air pipe.

3. The automatic air tightness testing device for an air spring with a valve and a nylon piston according to claim 1, characterized in that, The inner support plate has a rubber pad on the outer side of one end extending toward the movable mold. The end of the rubber pad has a guide slope. All the inner support plates and their rubber pads together constitute an inner support positioning structure for inserting into the piston cavity and performing radial positioning.

4. The automatic air tightness testing device for air springs with valves and nylon pistons according to claim 1, characterized in that, The fixed column is a hollow structure. When the piston on the fixture is aligned with the movable mold, the fixed column and the pressurizing nozzle are coaxial, forming an airflow passage connecting the piston cavity and the external air source.

5. The automatic air tightness testing device for an air spring with a valve and a nylon piston according to claim 4, characterized in that, Fixed electromagnets are provided around the fixed column, and a movable electromagnet is provided at the end of each insertion rod that is fixedly connected to the inner support plate. When the piston is inserted into the mold cavity, the clamp is in the inner support retraction state under the electromagnetic attraction. The attraction force between the fixed electromagnet and the movable electromagnet is 50-80N, and the retraction distance of the inner support plate after energization is 3-5mm.

6. The automatic air tightness testing device for an air spring with a valve and a nylon piston according to claim 1, characterized in that, The feeding mechanism also includes a replenishing tray that is aligned with the feeding tray at a high position. The replenishing tray can move horizontally relative to the feeding tray. The replenishing tray is provided with a support with the same structure as the movable mold at the position of each clamp.

7. An automatic method for detecting the air tightness of an air spring with a valve nylon piston, applied to the automatic air tightness detection equipment for an air spring with a valve nylon piston as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Place the piston with the closed-end air pipe into the mold cavity of the movable mold, and make the air pipe lock into the slot at the top of the mold cavity, so that the piston nozzle faces upward. S2. The movable mold is driven to move towards the sealing gasket by the push-pull cylinder, so that the piston opening end presses against the sealing gasket, and at the same time the piston inner cavity forms a closed air passage through the pressurized nozzle. S3. Start the lifting plate to drive the sealed piston down and completely immerse it in the water of the pool; S4. Inject gas at the set pressure into the piston cavity through the pressurizing nozzle. The set pressure is 0.3-0.6 MPa compressed air. Hold the pressure for 10-20 seconds. Observe whether bubbles are generated at the connection between the air nozzle and the air pipe in water to determine whether the air tightness is qualified. If the number of bubbles generated is <1 / 5s, the air tightness is qualified; otherwise, it is unqualified. If the pressure drop rate is >0.01 MPa / s during the pressurization process, the air tightness is directly determined to be unqualified, the pressure holding is stopped and an alarm is triggered.

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