A robot casting air tightness testing device and method

Abstract

The present application belongs to the technical field of industrial robot testing, and particularly relates to a robot casting air tightness testing device and method. The device is used for air tightness testing of a small arm casting. The small arm casting has an end interface at one end and an upper sealing interface and a lower sealing interface for connecting with a wrist shaft at the other end. The robot casting air tightness testing device comprises a static sealing zone assembly, a dynamic sealing zone assembly and a gas supply system. The dynamic sealing zone assembly is used for sealing the upper sealing interface and the lower sealing interface of the small arm casting. The static sealing zone assembly is used for sealing the end interface of the small arm casting. The static sealing zone assembly is provided with an air tightness interface connected with the gas supply system. The gas supply system supplies gas to the inner cavity of the small arm casting to realize air tightness testing. The present application can effectively detect air leakage sand holes in the casting hole wall, solve the problem of missed detection of traditional end face sealing air tightness testing, accurately identify leakage defects, prevent defective castings from flowing into subsequent processes, and reduce production costs.

Description

Technical Field

[0001] This invention belongs to the field of industrial robot testing technology, and specifically relates to a device and method for testing the airtightness of robot castings. Background Technology

[0002] Air tightness testing must be conducted on industrial robot castings before they leave the foundry, which is a core step in the quality control of mass production of industrial robots. If castings have leakage defects such as sand holes and air holes, once they flow into subsequent processing and assembly processes, the material and labor costs of subsequent processing and assembly will continue to increase, and the resource losses caused by defective products will be significantly amplified. Therefore, it is necessary to accurately identify leakage defects at the casting leaving the factory stage.

[0003] Current airtightness testing methods typically use sealing gaskets to press against the machined end faces of castings for sealing and inspection. This method has a significant drawback: relying solely on end-face sealing gaskets cannot effectively detect air leakage pinholes located in the casting's hole walls. Some pinholes are distributed on the machined end faces and inner hole sidewalls, areas that the end-face sealing gaskets cannot cover, leading to missed defects during inspection. Castings with leakage defects are then passed on to downstream processes as qualified products, resulting in significant production waste. Traditional inspection methods struggle to simultaneously detect defects at both the end faces and hole sidewalls; the industry urgently needs an airtightness testing method capable of simultaneously identifying airtightness leaks at both the casting's end faces and hole walls. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide a robot casting airtightness testing device and method to solve the problem that the existing airtightness testing method, which uses a sealing gasket to press the machined end face of the casting, cannot effectively detect air leakage sand holes at the machined end face and hole wall of the casting, is prone to missed detection, and causes defective castings to flow into subsequent processes, resulting in resource waste.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention provides a robot casting airtightness testing device for testing the airtightness of a forearm casting. One end of the forearm casting has an end interface, and the other end has an upper sealing interface and a lower sealing interface for connection to a wrist axis. The robot casting airtightness testing device includes a static sealing zone assembly, a dynamic sealing zone assembly, and an air supply system. The dynamic sealing zone assembly seals the upper and lower sealing ports of the forearm casting; the static sealing zone assembly seals the end interface of the forearm casting; and the static sealing zone assembly has an airtight interface connected to the air supply system, which supplies air to the inner cavity of the forearm casting to achieve airtightness testing.

[0007] The dynamic sealing zone assembly includes a central support assembly, an upper sealing shaft, and a lower sealing shaft. The upper and lower sealing shafts are respectively inserted into the upper and lower sealing interfaces of the forearm casting, and upper and lower O-rings for sealing are respectively fitted on the upper and lower sealing shafts. Three upper sealing shaft shoulders are provided circumferentially at the outer end of the upper sealing shaft, and three lower sealing shaft shoulders are provided circumferentially at the outer end of the lower sealing shaft. The upper and lower sealing shaft shoulders are respectively in contact with the machined end faces of the corresponding sealing interfaces. The central support assembly is supported between the upper and lower sealing shafts.

[0008] The central support assembly includes a central threaded sleeve and upper and lower hexagonal head bolts connected to both ends of the central threaded sleeve. The ends of the upper and lower hexagonal head bolts are in contact with the upper and lower sealing shafts, respectively, and the upper and lower hexagonal head bolts are locked by upper and lower nuts, respectively.

[0009] The leak detection method for the machined end face is as follows: spray a leak detection agent onto the machined end face, and determine whether there are air leaks or pinholes by observing whether bubbles are generated; rotate the upper sealing shoulder and the lower sealing shoulder to detect the airtightness of the blocked part of the machined end face.

[0010] The upper sealing interface and the lower sealing interface include a lip seal ring sealing hole section and a bearing positioning section; when the forearm casting is in use, the lip seal ring sealing hole section and the bearing positioning section are respectively equipped with a lip seal ring and a bearing, and the lip seal ring can compensate for the air leakage defect of the lip seal ring sealing hole section.

[0011] The gas supply system includes a gas supply pipeline and a hand valve and a pressure gauge arranged sequentially along the gas supply direction. One end of the gas supply pipeline is connected to the airtight interface on the static sealing zone assembly, and the other end is provided with a quick-connect fitting.

[0012] The static sealing zone assembly includes a first static sealing gasket, a first sealing plate, a first screw, a second static sealing gasket, a second sealing plate, and a second screw. The first static sealing gasket and the first sealing plate are disposed on the end interface of the forearm casting from the inside out, and are connected to the first threaded hole on the forearm casting by a number of first screws. The second static sealing gasket and the second sealing plate are disposed on the outer side of the first sealing plate from the inside out, and are connected to the first sealing plate by a number of second screws to form a multi-layer sealing structure.

[0013] Another aspect of the present invention provides a method for testing the airtightness of robot castings using the apparatus described above, comprising the following steps:

[0014] S1. Clamping and sealing: Assemble the dynamic sealing zone assembly between the upper and lower sealing interfaces of the forearm casting, so that the upper and lower sealing shoulder stops are respectively in contact with the machined end faces of the corresponding sealing interfaces; install the static sealing zone assembly on the end interface of the forearm casting to complete the sealing of both ends of the forearm casting.

[0015] S2, Pipeline Connection: Connect the gas supply pipeline of the gas supply system to the airtight interface of the static sealing zone component;

[0016] S3. Internal Cavity Air Supply: Open the hand valve of the air supply system to introduce test gas into the internal cavity of the forearm casting. The gas pressure is 30 kPa. After the pressure gauge reading stabilizes for 3 minutes, close the hand valve and then disconnect the quick-connect connector. Perform a pressure holding test for 10 minutes. If the pressure gauge maintains 30 kPa, the test is over. If the pressure is released, proceed to the next step of the test.

[0017] S4. Sand hole leak detection: Spray leak test agent onto the machined end face and observe whether air bubbles are generated at the machined end face. Rotate the upper and lower sealing shoulder stops to test the airtightness of the blocked part of the machined end face. If air bubbles are present, it is determined that there is a sand hole defect in the machined end face. Seal the sand hole with sealant and then repeat steps S2-S3 or S2-S4. If there are no air bubbles, the sealing performance of the machined end face is qualified.

[0018] S5. Observe whether there are air bubbles at the joint between the sealing hole section of the lip seal and the machined end face. If there are air bubbles, it indicates that there is a sand hole defect in the sealing hole section of the lip seal. Record it and consider it as qualified.

[0019] The aforementioned method for testing the air tightness of robot castings also includes an assembly verification step: After the test is completed, lip seals and bearings are assembled at both ends of the wrist shaft, and then the wrist shaft is arranged between the upper and lower sealing interfaces of the forearm casting, so that the lip seals at both ends of the wrist shaft are respectively embedded in the corresponding lip seal sealing hole sections, and the bearings at both ends of the wrist shaft are respectively embedded in the corresponding bearing positioning sections. The lip seals compensate for the air leakage defects in the lip seal sealing hole sections, simulating the sealing performance of the forearm casting under actual product use conditions.

[0020] The present invention has the following beneficial effects and advantages:

[0021] 1. Eliminate the problem of missed detection of sand holes in the hole wall: Unlike the traditional inspection method that only seals the machined end face with a sealing gasket, the side wall of the hole section is sealed by a lip seal ring. With the addition of a rotating shoulder stop of the sealing plate, the inspection can be carried out in two stages, which can effectively identify the air leakage sand holes distributed in the hole wall of the casting and greatly reduce the probability of missed detection.

[0022] 2. High reliability of detection: It can be used with leak detection agent to intuitively determine the location of leaks, accurately locate gas leakage defects, and facilitate subsequent sealing and repair of casting defects.

[0023] 3. Pre-processing quality control saves production costs: Precisely screen for leak-defective workpieces during the airtightness testing of castings before they leave the factory, preventing castings with sand hole defects from flowing into subsequent processing and assembly processes, thus reducing the loss of a large amount of materials and time resources in the later stages.

[0024] 4. Reasonable and fault-tolerant testing logic: When testing the assembled lip seal, if the outer cylindrical surface of the lip seal can seal the sand hole and form a seal, the test is deemed qualified. This takes into account the practical working conditions of the casting, and the testing and judgment standards are in line with the actual use scenarios of robot castings.

[0025] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0026] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0027] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0028] Figure 1 This is an isometric view of the sealing of the forearm of an industrial robot using a robot casting airtightness testing device according to the present invention.

[0029] Figure 2 This is a schematic diagram of the test state of a robot casting airtightness testing device according to the present invention;

[0030] Figure 3 for Figure 2 Enlarged view of a portion of point A in the middle;

[0031] Figure 4 for Figure 3 Enlarged view of a section at point C;

[0032] Figure 5 for Figure 2 Enlarged view of a section at point B in the middle;

[0033] Figure 6 This is an assembly verification test diagram of the industrial robot forearm in this invention;

[0034] Figure 7 for Figure 6 Enlarged view of a section at point D;

[0035] Figure 8 for Figure 6 Enlarged view of a section at point E in the middle.

[0036] In the diagram: 1. Forearm casting; 101. Machined end face; 102. Lip seal ring sealing hole section; 103. Bearing positioning section; 104. First threaded hole; 105. First mounting surface; 2. Left forearm cover; 3. Right forearm cover; 4. Static sealing zone assembly; 401. First layer static sealing gasket; 402. First layer sealing plate; 403. First layer screw; 404. Second layer static sealing gasket; 405. Second layer sealing plate; 406. Second layer screw; 407. Airtight interface; 5. Dynamic sealing zone assembly; 501. 502. Center threaded sleeve; 503. Lower nut; 504. Lower hex head bolt; 505. Lower sealing shaft shoulder; 506. Lower O-ring seal; 507. Upper nut; 508. Upper hex head bolt; 509. Upper sealing shaft shoulder; 510. Upper sealing shaft; 511. Upper O-ring seal; 6. Right side sealing gasket; 7. Rear boom cylinder; 701. Sealing surface; 8. Wrist shaft; 9. Lip seal; 10. Bearing; 11. Left side sealing gasket; 12. Pressure gauge; 13. Hand valve; 14. Quick-connect coupling. Detailed Implementation

[0037] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0038] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0039] See Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a robot casting airtightness testing device for testing the airtightness of a forearm casting 1. The forearm casting 1 has an end interface at one end and an upper sealing interface and a lower sealing interface at the other end for connection with the wrist axis. The robot casting airtightness testing device includes a static sealing zone component 4, a dynamic sealing zone component 5, and an air supply system. The dynamic sealing zone component 5 is used to seal the upper sealing port and the lower sealing port of the forearm casting 1. The static sealing zone component 4 is used to seal the end interface of the forearm casting 1. The static sealing zone component 4 is provided with an airtight interface 407 connected to the air supply system. The air supply system supplies air to the inner cavity of the forearm casting 1 to realize airtightness detection.

[0040] In an embodiment of the present invention, the left side of the forearm casting 1 is provided with a left sealing gasket 11 and a left forearm cover 2, and the right side is provided with a right sealing gasket 6 and a right forearm cover 3.

[0041] See Figure 2 As shown, in an embodiment of the present invention, the gas supply system includes a gas supply pipeline and a hand valve 13 and a pressure gauge 12 arranged sequentially along the gas supply direction. One end of the gas supply pipeline is connected to the airtight interface 407 on the static sealing zone assembly 4, and the other end is provided with a quick-connect connector 14.

[0042] See Figure 3 and Figure 4 As shown in the embodiment of the present invention, the dynamic sealing zone assembly 5 includes a central support assembly, an upper sealing shaft 510, and a lower sealing shaft 505. The upper sealing shaft 510 and the lower sealing shaft 505 are respectively inserted into the upper sealing interface and the lower sealing interface of the forearm casting 1. An upper O-ring 511 and a lower O-ring 506, which serve a sealing function, are respectively fitted onto the upper sealing shaft 510 and the lower sealing shaft 505. The upper O-ring 511 and the lower O-ring 506 respectively seal the upper... The sealing interface and the lower sealing interface are separated into a lip seal ring sealing hole section 102 and a bearing positioning section 103; three upper sealing shaft shoulders 509 are provided circumferentially at the outer end of the upper sealing shaft 510, and three lower sealing shaft shoulders 504 are provided circumferentially at the outer end of the lower sealing shaft 505; the upper sealing shaft shoulders 509 and the lower sealing shaft shoulders 504 respectively fit against the machined end face 101 of the corresponding sealing interface; the central support assembly is supported between the upper sealing shaft 510 and the lower sealing shaft 505.

[0043] Furthermore, annular sealing grooves are provided on the outer circumference of the upper sealing shaft 510 and the lower sealing shaft 505, and the upper O-ring 511 and the lower O-ring 506 are respectively embedded in the annular sealing grooves of the upper sealing shaft 510 and the lower sealing shaft 505. In this embodiment, all sealing rings and gaskets are made of fluororubber.

[0044] In an embodiment of the present invention, the central support assembly includes a central threaded sleeve 501 and an upper hexagonal head bolt 508 and a lower hexagonal head bolt 503 connected to both ends of the central threaded sleeve 501. The ends of the upper hexagonal head bolt 508 and the lower hexagonal head bolt 503 are in contact with the upper sealing shaft 510 and the lower sealing shaft 505, respectively, ensuring that the upper sealing shaft 510 and the lower sealing shaft 505 can rotate. The upper hexagonal head bolt 508 and the lower hexagonal head bolt 503 are locked by the upper nut 507 and the lower nut 502, respectively.

[0045] Furthermore, the center threaded sleeve 501 is an external hexagonal hollow cylinder structure with internal threads.

[0046] Specifically, the leak detection method for the machined end face 101 is as follows: spray a leak detection agent onto the machined end face 101, and determine whether there are air leaks or pinholes by observing whether bubbles are generated; rotate the upper sealing shoulder stop 509 and the lower sealing shoulder stop 504 to test the airtightness of the blocked part of the machined end face 101.

[0047] See Figure 5 As shown, in an embodiment of the present invention, the static sealing zone assembly 4 includes a first static sealing gasket 401, a first sealing plate 402, a first screw 403, a second static sealing gasket 404, a second sealing plate 405, and a second screw 406. The first static sealing gasket 401 and the first sealing plate 402 are disposed from the inside to the outside on the first mounting surface 105 of the end interface of the forearm casting 1, and are connected to the first threaded hole 104 opened on the forearm casting 1 by a plurality of first screws 403. The second static sealing gasket 404 and the second sealing plate 405 are disposed from the inside to the outside on the outer side of the first sealing plate 402, and are connected to the first sealing plate 402 by a plurality of second screws 406 to form a multi-layer sealing structure.

[0048] Specifically, the first static sealing gasket 401 and the second static sealing gasket 404 are preferably made of fluororubber. The first sealing plate 402 has a countersunk hexagonal head hole; the first screw 403 passes through the countersunk hexagonal head hole on the first sealing plate 402 and the hole in the first static sealing gasket 401, and is threadedly connected to the first threaded hole 104 on the forearm casting 1. The first threaded hole 104 is a through-hole. The second sealing plate 405 has a countersunk hexagonal head hole; the second screw 406 passes through the countersunk hexagonal head hole on the second sealing plate 405 and the hole in the second static sealing gasket 404, and is connected to the threaded hole in the first sealing plate 402. The second sealing plate 405 is provided with an airtight interface 407, which has an internal thread, preferably an Rc1 / 8 sealing thread.

[0049] See Figures 6 to 8As shown in the embodiment of the present invention, both the upper and lower sealing interfaces of the forearm casting 1 are provided with machined end faces 101. These machined end faces 101 are externally machined surfaces used for axial positioning. The machined end face 101 is a region prone to air leakage because machining disrupts the solidification flow lines inside the casting. Both the upper and lower sealing interfaces include a lip seal ring sealing hole section 102 and a bearing positioning section 103. In the usage state of the forearm casting 1, a wrist shaft 8 is assembled between the upper and lower sealing interfaces. Lip seal rings 9 and bearings 10 are fitted at both ends of the wrist shaft 8. The lip seal rings 9 and bearings 10 are respectively assembled into the corresponding lip seal ring sealing hole section 102 and bearing positioning section 103. The lip seal ring 9 can compensate for the air leakage defect of the lip seal ring sealing hole section 102. The lip seal ring sealing hole section 102 and bearing positioning section 103 are used for radial positioning of the lip seal ring 9 and bearing 10, respectively. The end interface of the forearm casting 1 is sealed to the rear forearm cylinder 7 using an adhesive coating method. Specifically, adhesive A is applied to the sealing surface 701 of the rear forearm cylinder 7, and adhesive B is applied to the first mounting surface 105 of the forearm casting 1. Because the sealant cleaning process is time-consuming, a sealing gasket is used for airtightness testing during mass production. The first threaded hole 104 is a through-hole, and there is a risk of air leakage at the threaded hole and the open hole location; therefore, a multi-layer sealing structure is required.

[0050] This invention provides a robot casting airtightness testing device. A static sealing zone assembly seals the end interface of the forearm casting, while a dynamic sealing zone assembly seals the upper and lower sealing interfaces. A gas supply system introduces testing gas into the inner cavity of the forearm casting to achieve overall airtightness testing. The upper and lower sealing shoulder stops of the dynamic sealing zone assembly are rotatable, allowing for leak detection on areas obscured by the machined end face, eliminating blind spots and facilitating the identification of hidden air leaks. After testing, a wrist shaft, lip seal, and bearing can be assembled to simulate actual product assembly and usage conditions, verifying the lip seal's ability to compensate for air leakage defects in the lip seal's sealing hole section. This device can simultaneously perform casting defect detection and operational sealing performance verification, providing comprehensive testing coverage and results closely reflecting actual usage conditions.

[0051] See Figures 1 to 8 As shown, another embodiment of the present invention provides a method for testing the airtightness of robot castings using the device described above, wherein the test is conducted in a constant temperature environment, and includes the following steps:

[0052] S1. Clamping and sealing: Assemble the dynamic sealing zone assembly 5 between the upper sealing interface and the lower sealing interface of the forearm casting 1, so that the upper sealing shoulder stop 509 and the lower sealing shoulder stop 504 respectively fit against the machined end face 101 of the corresponding sealing interface; install the static sealing zone assembly 4 on the end interface of the forearm casting 1 to complete the sealing and plugging of both ends of the forearm casting 1.

[0053] S2. Pipeline connection: Connect the gas supply pipeline of the gas supply system to the airtight interface 407 of the static sealing zone component 4.

[0054] S3. Internal Cavity Air Supply: Open the hand valve 13 of the air supply system to introduce test gas into the internal cavity of the forearm casting 1. The gas pressure is 30 kPa. After the pressure gauge 12 reading stabilizes for 3 minutes, close the hand valve 13 and then disconnect the quick-connect connector 14. Perform a pressure holding test for 10 minutes. If the pressure gauge 12 maintains 30 kPa, the test is over. If the pressure is released, proceed to the next test.

[0055] S4. Sand hole leak detection: Spray leak test agent onto the machined end face 101 and observe whether air bubbles are generated at the machined end face 101. Rotate the upper sealing shoulder stop 509 and the lower sealing shoulder stop 504 to test the airtightness of the blocked part of the machined end face 101. If air bubbles are present, it is determined that there is a leaking sand hole defect in the machined end face 101. Seal the leaking sand hole with sealant and then repeat steps S2-S3 or steps S2-S4. If there are no air bubbles, the sealing performance of the machined end face 101 is qualified.

[0056] S5. Observe whether there are air bubbles at the joint between the sealing hole section 102 of the lip seal ring and the machined end face 101. If there are air bubbles, it indicates that the sealing hole section 102 of the lip seal ring has a sand hole defect. Record it and consider it as qualified.

[0057] The method for observing the leakage of the lip seal ring sealing hole section 102 is as follows: spray a leak test agent on the test position and observe whether there is bubbling at the joint between the lip seal ring sealing hole section 102 and the machined end face 101; rotate the upper sealing shaft 510 and the lower sealing shaft 505, and if bubbling is observed, it can be determined that there is leakage at this position. Record it as qualified, because the leakage defect of the lip seal ring sealing hole section 102 is compensated by the lip seal ring 9 assembled later.

[0058] The method for testing the air tightness of robot castings also includes an assembly verification step: After the test is completed, lip seals 9 and bearings 10 are assembled at both ends of the wrist shaft 8. The wrist shaft 8 is then placed between the upper and lower sealing interfaces of the forearm casting 1, so that the lip seals 9 at both ends of the wrist shaft 8 are respectively embedded in the corresponding lip seal sealing hole sections 102, and the bearings 10 at both ends of the wrist shaft 8 are respectively embedded in the corresponding bearing positioning sections 103. The lip seals 9 compensate for the air leakage defects of the lip seal sealing hole sections 102, simulating the sealing performance of the forearm casting 1 under actual product use conditions.

[0059] This invention provides a method for testing the airtightness of robot castings. After assembling the casting and various sealing components in a constant temperature environment, the overall airtightness of the casting is determined through inflation, pressure stabilization, and pressure holding. Leak detection is carried out by spraying a leak detection agent and rotating the components multiple times, which can effectively check areas prone to leakage, such as machined end faces, as well as blind spots that are obscured, thus improving the defect detection rate. Furthermore, it can simulate the actual assembly conditions of the whole machine to verify the compensation capability of the sealing ring for leakage defects in the casting holes. It can not only identify sand hole leakage defects in the casting body, but also evaluate the sealing adaptation performance under actual use conditions. The test process is clear and controllable, and the test results are closer to the actual service conditions of the product.

[0060] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A device for testing the airtightness of robot castings, used for testing the airtightness of a forearm casting (1), wherein one end of the forearm casting (1) has an end interface, and the other end is provided with an upper sealing interface and a lower sealing interface for connection with a wrist axis, characterized in that, The robot casting airtightness testing device includes a static sealing area component (4), a dynamic sealing area component (5), and an air supply system. The dynamic sealing area component (5) is used to seal the upper and lower sealing ports of the forearm casting (1). The static sealing area component (4) is used to seal the end interface of the forearm casting (1). The static sealing area component (4) is provided with an airtight interface (407) connected to the air supply system. The air supply system supplies air to the inner cavity of the forearm casting (1) to realize airtightness testing.

2. The robot casting airtightness testing device according to claim 1, characterized in that, The dynamic sealing zone assembly (5) includes a central support assembly, an upper sealing shaft (510) and a lower sealing shaft (505), wherein the upper sealing shaft (510) and the lower sealing shaft (505) are respectively inserted into the upper sealing interface and the lower sealing interface of the forearm casting (1), and the upper sealing shaft (510) and the lower sealing shaft (505) are respectively fitted with an upper O-ring (511) and a lower O-ring (506) for sealing. The outer end of the upper sealing shaft (510) is provided with three upper sealing shaft shoulder stops (509) along the circumferential direction, and the outer end of the lower sealing shaft (505) is provided with three lower sealing shaft shoulder stops (504) along the circumferential direction; the upper sealing shaft shoulder stops (509) and the lower sealing shaft shoulder stops (504) respectively fit with the machined end face (101) of the corresponding sealing interface; the central support assembly is supported between the upper sealing shaft (510) and the lower sealing shaft (505).

3. The robot casting airtightness testing device according to claim 2, characterized in that, The central support assembly includes a central threaded sleeve (501) and an upper hexagonal head bolt (508) and a lower hexagonal head bolt (503) connected to both ends of the central threaded sleeve (501). The ends of the upper hexagonal head bolt (508) and the lower hexagonal head bolt (503) are in contact with the upper sealing shaft (510) and the lower sealing shaft (505), respectively. The upper hexagonal head bolt (508) and the lower hexagonal head bolt (503) are locked by an upper nut (507) and a lower nut (502), respectively.

4. The robot casting airtightness testing device according to claim 2, characterized in that, The leak detection method for the machining end face (101) is as follows: spray a leak detection agent onto the machining end face (101), and determine whether there are air leaks or pinholes by observing whether bubbles are generated; rotate the upper sealing shoulder (509) and the lower sealing shoulder (504) to detect the airtightness of the part of the machining end face (101) that is blocked.

5. The robot casting airtightness testing device according to claim 2, characterized in that, The upper sealing interface and the lower sealing interface include a lip seal ring sealing hole section (102) and a bearing positioning section (103); when the forearm casting (1) is in use, the lip seal ring sealing hole section (102) and the bearing positioning section (103) are respectively equipped with a lip seal ring (9) and a bearing (10), and the lip seal ring (9) can compensate for the air leakage defect of the lip seal ring sealing hole section (102).

6. The robot casting airtightness testing device according to claim 2, characterized in that, The gas supply system includes a gas supply pipeline and a hand valve (13) and a pressure gauge (12) arranged sequentially along the gas supply direction. One end of the gas supply pipeline is connected to the airtight interface (407) on the static sealing zone assembly (4), and the other end is provided with a quick-connect connector (14).

7. The robot casting airtightness testing device according to claim 1, characterized in that, The static sealing zone assembly (4) includes a first static sealing gasket (401), a first sealing plate (402), a first screw (403), a second static sealing gasket (404), a second sealing plate (405), and a second screw (406). The first static sealing gasket (401) and the first sealing plate (402) are arranged from the inside to the outside on the end interface of the forearm casting (1), and are connected to the first threaded hole (104) opened on the forearm casting (1) by a number of first screws (403). The second static sealing gasket (404) and the second sealing plate (405) are arranged from the inside to the outside on the outside of the first sealing plate (402), and are connected to the first sealing plate (402) by a number of second screws (406) to form a multi-layer sealing structure.

8. A method for testing the airtightness of robot castings using the device described in claim 6, characterized in that, Includes the following steps: S1. Clamping and sealing: Assemble the dynamic sealing zone assembly (5) between the upper sealing interface and the lower sealing interface of the forearm casting (1), so that the upper sealing shoulder (509) and the lower sealing shoulder (504) fit against the machined end face (101) of the corresponding sealing interface respectively; install the static sealing zone assembly (4) on the end interface of the forearm casting (1) to complete the sealing and plugging of both ends of the forearm casting (1); S2, Pipeline connection: Connect the gas supply pipeline of the gas supply system to the airtight interface (407) of the static sealing zone component (4). S3, Inner cavity air supply: Open the hand valve (13) of the air supply system and introduce test gas into the inner cavity of the forearm casting (1). The gas pressure is 30 kPa. After the pressure gauge (12) reading stabilizes for 3 minutes, close the hand valve (13) and then unplug the quick connector (14); perform a pressure holding test for 10 minutes; if the pressure gauge (12) maintains 30 kPa, the test ends; if the pressure is released, proceed to the next test. S4, Sand hole leak detection: Spray leak test agent onto the machined end face (101), observe whether air bubbles are generated at the machined end face (101), rotate the upper sealing shoulder stop (509) and the lower sealing shoulder stop (504) to test the air tightness of the blocked part of the machined end face (101); if air bubbles appear, it is determined that there is a leaking sand hole defect in the machined end face (101), seal the leaking sand hole with sealant, and then repeat steps S2-S3 or steps S2-S4; if there are no air bubbles, the sealing performance of the machined end face (101) is qualified; S5. Observe whether there are air bubbles at the joint between the sealing hole section (102) of the lip seal ring and the machined end face (101). If there are air bubbles, it indicates that the sealing hole section (102) of the lip seal ring has a sand hole defect. Record it and consider it as qualified.

9. The method for testing the airtightness of robot castings according to claim 8, characterized in that, It also includes an assembly verification step: After the test is completed, lip seals (9) and bearings (10) are assembled at both ends of the wrist shaft (8). Then, the wrist shaft (8) is arranged between the upper sealing interface and the lower sealing interface of the forearm casting (1), so that the lip seals (9) at both ends of the wrist shaft (8) are respectively embedded in the lip seal sealing hole section (102) on the corresponding side, and the bearings (10) at both ends of the wrist shaft (8) are respectively embedded in the bearing positioning section (103) on the corresponding side. The leakage defect of the lip seal sealing hole section (102) is compensated by the lip seals (9), simulating the sealing performance of the forearm casting (1) under the actual use conditions of the product.

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