A workpiece clamping device for air tightness testing

Abstract

The invention discloses a workpiece clamping device for air tightness testing, which relates to the technical field of workpiece clamping. The workpiece includes an air inlet and an air outlet, and the clamping device includes: a first clamping component, which at least includes a first chuck capable of position adjustment, the first chuck can be moved to a first station and a second station, and the first chuck is used to position the air outlet; a second clamping component, which corresponds to the second station and includes: a second base frame, on which a slide seat is slidably arranged, and the slide seat is driven by a second telescopic cylinder; a second rotating cylinder, which is rotatably arranged in the slide seat, and one end of the second rotating cylinder extends out of the slide seat and extends to form a second chuck; an air supply head, which is sealingly slidably arranged in the second rotating cylinder, and one end of the air supply head extends out of the second rotating cylinder so as to be connected to an external air tightness detector; the positioning and clamping process of the workpiece by the clamping device is highly automated, manual operations are reduced, and testing efficiency and accuracy are improved.

Description

Technical Field

[0001] The invention relates to the technical field of workpiece clamping, in particular to a workpiece clamping device for air tightness testing. Background Art

[0002] In industrial production, air tightness testing is a key link to ensure the sealing performance of products, and it is of certain importance. On the one hand, air tightness testing can directly evaluate the sealing performance of products and ensure that there will be no leakage problems during the design, manufacturing and use of products. This is especially important for products that need to withstand pressure, liquid or gas flow, such as pressure-maintaining valves, pipe connectors, etc. In addition, leakage will not only lead to a decline in product performance, but may also cause safety accidents. For example, in a high-pressure system, if the pressure-maintaining valve is not sealed tightly, it may cause pressure to run away, and then cause an explosion or fire. Therefore, through air tightness testing, potential leaks can be discovered and repaired in a timely manner to improve product safety.

[0003] There are many methods for air tightness testing. According to the different characteristics of the product and the test requirements, you can choose the appropriate test method. Common air tightness test methods include pressure decay method. Specifically, by filling a certain pressure of gas into the tested product, and then observing the change of gas pressure over time to judge the sealing performance of the product. If the pressure drops quickly, it means that the product has a leakage problem.

[0004] However, when conducting air tightness tests, the workpiece clamping device is a key component that connects the test equipment and the workpiece, and its performance directly affects the accuracy and reliability of the test.

[0005] At present, the workpiece clamping devices available on the market generally face some shortcomings in the process of air tightness testing. First of all, poor sealing is one of the main factors restricting the test accuracy. Traditional clamping devices often find it difficult to form a stable and reliable seal between the workpiece and the test interface, which may cause gas to leak from the gap during the test, making it impossible to accurately evaluate the airtightness of the workpiece. Secondly, the low degree of automation is also a significant problem with existing clamping devices. Many clamping devices still rely on manual operation to complete the steps of loading and unloading, positioning and clamping of the workpiece, which not only increases the labor intensity, but also easily introduces human errors. For example, manual positioning may not be precise enough, resulting in inaccurate alignment between the workpiece and the test interface; manual adjustment of the clamping force may also cause the clamping to be too tight or too loose due to improper operation, thus affecting the smooth progress of the test.

[0006] Therefore, it is necessary to provide a workpiece clamping device for air tightness testing to solve the above problems. Summary of the invention

[0007] In order to solve the above problems, the present invention provides the following technical solutions: a workpiece clamping device for air tightness testing, used for clamping a workpiece, the workpiece comprising an air inlet and an air outlet, the clamping device comprising:

[0008] A first clamping assembly, which at least includes a first chuck capable of position adjustment, the first chuck can be moved to a first station and a second station, and the first chuck is used to locate the air outlet of the workpiece;

[0009] A second clamping assembly, corresponding to the second station, comprises:

[0010] A second base frame, on which a slide is slidably disposed, the slide being driven by a second telescopic cylinder, and the second telescopic cylinder being fixed to the second base frame;

[0011] A second rotating cylinder is rotatably disposed in the slide seat, and one end of the second rotating cylinder extends out of the slide seat and extends to form a second chuck, and the second chuck is in a cone shape;

[0012] The air supply head is sealingly and slidably arranged in the second rotating cylinder, and one end of the air supply head extends out of the second rotating cylinder so as to be connected to an external airtightness detector.

[0013] Further, preferably, an elastic outer coating is attached to the outer surface of the second clamp.

[0014] Further, as a preference, the outer fixed sleeve of the second drum is provided with a gear;

[0015] A mounting cylinder is fixed on one side of the slide seat for slidingly mounting the rack, and a clearance groove is provided on the mounting cylinder and the slide seat so that the rack can mesh with the gear;

[0016] The rack is also driven by a fourth telescopic cylinder, and the fourth telescopic cylinder is fixed on the slide.

[0017] Further, as a preference, the other end of the air supply head is fixedly connected to a wedge-shaped head, the wedge-shaped head is located in the second chuck, the wedge-shaped head has an outer wedge surface, the end of the second chuck also extends to form a sealing wedge head, the sealing wedge head has an inner wedge surface, and the inner wedge surface cooperates with the outer wedge surface.

[0018] Further, preferably, the sealing wedge is made of elastic material.

[0019] Further, as a preference, a mounting seat is fixed to one side of the slide seat for mounting a third telescopic cylinder, and a telescopic end of the third telescopic cylinder is connected to the air supply head.

[0020] Further, as a preference, the first clamping assembly further comprises:

[0021] A first base frame, on which a base cylinder is fixed;

[0022] A first rotating drum, which is rotatably disposed in the base drum and driven by a driving member;

[0023] A square rod, which vertically limits and slides through the first rotating cylinder, and the top of the square rod is connected to the first clamping head by an arm body, and the bottom of the square rod is connected to the telescopic end of the first telescopic cylinder, and the first telescopic cylinder is fixed on the first base frame.

[0024] Further, preferably, the first chuck comprises:

[0025] An inner chuck made of elastic material;

[0026] An outer chuck is sleeved on the outside of the inner chuck, and a plurality of clamping columns extending downward are arranged at the bottom of the outer chuck;

[0027] a sensor embedded in the inner chuck;

[0028] Wherein, the outer diameter of the inner chuck is larger than the diameter of the air outlet of the workpiece.

[0029] Compared with the prior art, the present invention provides a workpiece clamping device for air tightness testing, which has the following beneficial effects:

[0030] The clamping device achieves a high degree of automation in the positioning and clamping process of the workpiece, reduces manual operation, and improves test efficiency and accuracy. The first chuck and the second chuck ensure the precise positioning and stable clamping of the workpiece, which is conducive to improving the accuracy of the test. In addition, the first chuck can be adjusted in position and can be moved between different workstations, which increases the flexibility of the device.

[0031] In the present invention, in the second clamping assembly, the use of the outer coating and the screw-in positioning method together improve the sealing between the second clamp and the workpiece air inlet, reduce gas leakage, and improve the reliability of the test. The elastic outer coating can also buffer the impact force during the clamping process and reduce damage to the edge of the workpiece air inlet. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the main structure of a workpiece clamping device for air tightness testing;

[0033] Figure 2 It is a schematic diagram of the top view of a workpiece clamping device for air tightness testing;

[0034] Figure 3 A schematic diagram of the three-dimensional structure of a workpiece clamping device for air tightness testing Figure 1 ;

[0035] Figure 4 A schematic diagram of the three-dimensional structure of a workpiece clamping device for air tightness testing Figure 2 ;

[0036] Figure 5 for Figure 1 AA cross-sectional structural diagram;

[0037] Figure 6 It is a schematic cross-sectional structural diagram of a second clamping assembly in a workpiece clamping device for air tightness testing;

[0038] Figure 7 for Figure 2 BB cross-sectional structure diagram;

[0039] In the figure: C, first station; D, second station; 1, workpiece; 2, first clamping assembly; 3, second clamping assembly; 21, first base frame; 22, base cylinder; 23, first rotating cylinder; 24, square rod; 25, arm body; 26, first chuck; 27, first telescopic cylinder; 28, driving member; 261, inner chuck; 262, outer chuck; 263, sensor; 31, second base frame; 32, slide seat; 33, second telescopic cylinder; 34, second rotating cylinder; 35, second chuck; 351, sealing wedge head; 36, air supply head; 37, wedge head; 38, mounting seat; 39, third telescopic cylinder; 310, gear; 311, mounting cylinder; 312, rack; 313, fourth telescopic cylinder. DETAILED DESCRIPTION

[0040] The terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned description of the drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances, which is merely a way of distinguishing the objects of the same attributes when describing them in the embodiments of the present application. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, so that the process, method, system, product or equipment comprising a series of units need not be limited to those units, but may include other units that are not clearly listed or inherent to these processes, methods, products or equipment.

[0041] Example: Please refer to Figure 1-Figure 7 In an embodiment of the present invention, a workpiece clamping device for air tightness testing is provided, which is used to clamp a workpiece 1, wherein the workpiece 1 includes an air inlet and an air outlet, and the workpiece 1 may be a safety valve or a pressure-maintaining valve. In this case, the air inlet and the air outlet are distributed perpendicularly to each other;

[0042] The clamping device comprises:

[0043] A first clamping assembly 2, which at least includes a first chuck 26 capable of position adjustment, the first chuck 26 can be moved to a first station C and a second station D, and the first chuck 26 is used to locate the air outlet of the workpiece 1;

[0044] The second clamping assembly 3, which corresponds to the second station D, comprises:

[0045] A second base frame 31 on which a slide 32 is slidably disposed, the slide 32 being driven by a second telescopic cylinder 33, and the second telescopic cylinder 33 being fixed on the second base frame 31;

[0046] A second rotating cylinder 34 is rotatably disposed in the slide seat 32, and one end of the second rotating cylinder 34 extends out of the slide seat 32 and extends to form a second chuck 35, the second chuck 35 is a cone-shaped cylinder, and is used to locate the air inlet of the workpiece 1 and cooperate with the first chuck 26 to clamp the workpiece 1;

[0047] The air supply head 36 is sealingly and slidably disposed in the second rotating cylinder 34, and one end of the air supply head 36 extends out of the second rotating cylinder 34 so as to be connected to an external airtightness detector.

[0048] The first station C is a loading and unloading station, and the second station D is a testing station. When the first chuck 26 moves to the first station C, an external manipulator can be used to cooperate with the first chuck 26 to load the workpiece 1. Then the first chuck 26 moves to the second station D. At this time, the slide 32 and the second chuck 35 are used to cooperate to locate the air inlet of the workpiece 1. The air supply head 36 is connected to the air inlet of the workpiece 1, and the air supply head 36 is also connected to an external air tightness detector, so as to realize the air tightness test of the workpiece 1.

[0049] More specifically, in the loading stage, the first chuck 26 first moves to the first station C (loading and unloading station), where an external manipulator or other automated equipment is used in conjunction with the first chuck 26 to place the workpiece 1 to be tested on the first chuck 26 and preliminarily locate the air outlet of the workpiece 1.

[0050] During the workpiece transfer stage, the first chuck 26 moves with the workpiece 1 to the second station D (testing station).

[0051] In the clamping and positioning stage, at the second station D, the second clamping assembly 3 starts to work. Driven by the second telescopic cylinder 33, the slide 32 drives the second rotating cylinder 34 and the second chuck 35 to move toward the air inlet of the workpiece 1. The second chuck 35 (conical) locates the air inlet of the workpiece 1 and cooperates with the first chuck 26 to achieve complete clamping and fixation of the workpiece 1.

[0052] During the air tightness test stage, one end of the air supply head 36 is connected to an external air tightness detector, which evaluates the air tightness performance of the workpiece 1 by supplying air to the inside of the workpiece 1 and detecting its pressure changes. The test data is collected and analyzed by the external air tightness detector to determine whether the workpiece 1 meets the air tightness requirements.

[0053] In the unloading and resetting stage, after the test is completed, the second clamping assembly 3 is first reset to release the positioning of the workpiece 1, and the first chuck 26 moves the workpiece 1 to the first station C again. At the first station C, an external manipulator or other automated equipment cooperates with the first chuck 26 to remove the tested workpiece 1 and prepare to load the next workpiece 1 to be tested.

[0054] That is to say, the positioning and clamping process of the workpiece 1 of the clamping device is highly automated, which reduces manual operations and improves test efficiency and accuracy. The first clamp 26 and the second clamp 35 ensure the precise positioning and stable clamping of the workpiece 1, which is conducive to improving the accuracy of the test. In addition, the first clamp 26 can be adjusted in position and can be moved between different workstations, which increases the flexibility of the device.

[0055] The outer fixed sleeve of the second rotating drum 34 is provided with a gear 310;

[0056] A mounting cylinder 311 is fixed on one side of the slide seat 32 for slidingly mounting a rack 312. A clearance groove is provided on the mounting cylinder 311 and the slide seat 32 so that the rack 312 can mesh with the gear 310.

[0057] The rack 312 is also driven by a fourth telescopic cylinder 313 , and the fourth telescopic cylinder 313 is fixed on the slide 32 .

[0058] Furthermore, an elastic outer coating is attached to the outer surface of the second clamp 35 .

[0059] Then, in the initial stage, the second chuck 35 (with an elastic outer coating) is initially located at a position not in contact with the air inlet of the workpiece 1 , and its approximate feeding direction is controlled by the second telescopic cylinder 33 .

[0060] The rack 312 is driven by the fourth telescopic cylinder 313 to be in an initial meshing position with the gear 310 , at which time the rotation angle of the second rotating drum 34 (and the second clamping head 35 ) is a preset or initial one.

[0061] When the second telescopic cylinder 33 starts to work, it drives the slide 32 (and all components mounted thereon, including the second rotating cylinder 34 and the second chuck 35 ) to move toward the air inlet of the workpiece 1 .

[0062] At the same time, the fourth telescopic cylinder 313 drives the rack 312 to slide in the mounting cylinder 311, and the rack 312 meshes with the gear 310 and drives it to rotate. Since the gear 310 is fixedly sleeved outside the second rotating cylinder 34, the second rotating cylinder 34 (and the second clamp 35) also rotates accordingly.

[0063] Under the feeding of the second telescopic cylinder 33 and the rotation drive of the fourth telescopic cylinder 313, the second chuck 35 is gradually inserted into the air inlet of the workpiece 1 in a screw-in manner. This screw-in manner not only helps to more accurately locate the air inlet, but also enhances the stability of positioning through the friction force generated by the rotation.

[0064] The outer coating plays a key role in the screwing process. It can adapt to the slight irregularities of the edge of the air inlet, provide a better sealing effect, and reduce damage to the workpiece 1 caused by over-tightening.

[0065] As the second chuck 35 penetrates deeper and rotates, the sealing between it and the gas inlet of the workpiece 1 is gradually enhanced. The presence of the elastic outer coating further ensures the reliability of the seal and reduces the possibility of gas leakage.

[0066] In this embodiment, the other end of the air supply head 36 is fixedly connected to a wedge head 37, and the wedge head 37 is located in the second chuck 35. The wedge head 37 has an outer wedge surface. The end of the second chuck 35 also extends to form a sealing wedge head 351, and the sealing wedge head 351 has an inner wedge surface. The inner wedge surface cooperates with the outer wedge surface.

[0067] In addition, the sealing wedge 351 is made of elastic material.

[0068] A mounting seat 38 is fixed to one side of the slide seat 32 for mounting a third telescopic cylinder 39 , and a telescopic end of the third telescopic cylinder 39 is connected to the air supply head 36 .

[0069] Among them, elastic materials refer to materials that have the ability to recover deformation. Such materials can produce elastic deformation after being acted upon by external forces, and return to their original shape after the external forces are removed. For example:

[0070] Rubber: Rubber is a high molecular polymer material with excellent elasticity and recovery ability, as well as good tensile, tear and wear resistance.

[0071] Elastomeric plastics: Elastomeric plastics are a class of plastic materials with high elasticity, whose elasticity is changed by adjusting the structure of the polymer and the type of additives. They usually have the characteristics of resistance to pressure, tension and wear.

[0072] Polyurethane (PU): Polyurethane is a material with excellent elasticity, good wear resistance and shaping memory.

[0073] Then, during implementation, when the second chuck 35 is screwed into the air inlet of the workpiece 1, the third telescopic cylinder 39 drives the air supply head 36 away from the air inlet of the workpiece 1, and the wedge head 37 locks the sealing wedge head 351 and drives it to move outward, thereby cooperating with the second chuck 35 to further seal and lock the air inlet of the workpiece 1.

[0074] More specifically, as mentioned above, the second chuck 35 (with the outer covering) is screwed into the air inlet of the workpiece 1 to achieve preliminary positioning.

[0075] After the second clamp 35 is inserted into place, the third telescopic cylinder 39 starts to work, and its telescopic end pulls the air supply head 36 to move away from the air inlet of the workpiece 1.

[0076] As the air supply head 36 moves, the wedge-shaped head 37 fixedly connected thereto also moves. The outer wedge surface of the wedge-shaped head 37 and the inner wedge surface of the sealing wedge head 351 begin to interact with each other.

[0077] Since the sealing wedge 351 is made of elastic material, when the outer wedge surface and the inner wedge surface cooperate, the sealing wedge 351 is squeezed and shows a tendency to move outwards. This outwards movement further enhances the sealing effect between the second clamp 35 and the air inlet of the workpiece 1.

[0078] That is to say, as the wedge-shaped head 37 continues to move and locks the sealing wedge 351, the sealing between the second chuck 35 and the air inlet of the workpiece 1 reaches the best state. The screwing and embedding of the second chuck 35 and the coordinated use of the wedge-shaped head 37 and the sealing wedge 351 provide double sealing protection, greatly improving the accuracy and reliability of the test. In addition, the sealing wedge 351 made of elastic material moves outward under the action of the outer wedge surface, further enhancing the sealing effect between the air inlet of the workpiece 1 and reducing the possibility of gas leakage.

[0079] In this embodiment, the first clamping assembly 2 further includes:

[0080] A first base frame 21, on which a base cylinder 22 is fixed;

[0081] A first rotating drum 23, which is rotatably disposed in the base drum 22 and driven by a driving member 28;

[0082] The square rod 24 vertically limits the sliding movement through the first rotating cylinder 23 , and the top of the square rod 24 is connected to the first clamp 26 by an arm 25 , and the bottom of the square rod 24 is connected to the telescopic end of the first telescopic cylinder 27 , and the first telescopic cylinder 27 is fixed on the first base frame 21 .

[0083] In this embodiment, the first clamp 26 includes:

[0084] The inner clamp 261 is made of elastic material;

[0085] The outer clamp head 262 is sleeved on the outer part of the inner clamp head 261, and a plurality of clamping columns extending downward are arranged at the bottom of the outer clamp head 262;

[0086] A sensor 263, which is embedded in the inner clamp 261;

[0087] The outer diameter of the inner chuck 261 is larger than the diameter of the air outlet of the workpiece 1 .

[0088] When the workpiece 1 is placed at the designated position, the first telescopic cylinder 27 drives the square rod 24 and the first clamp 26 to move downward. The inner clamp 261 first contacts and adapts to the air outlet of the workpiece 1, and then further positions the workpiece 1 under the action of the outer clamp 262 and the clamping column.

[0089] That is to say, the main function of the external manipulator or other automated equipment is to position the workpiece 1 at the first workstation C, and it cooperates with the first chuck 26 to realize loading or unloading of the workpiece 1. The first chuck 26 mainly uses interference fit to realize the positioning of the workpiece 1.

[0090] The sensor can sense whether there is gas leakage at the outlet of workpiece 1. Taking the air pressure sensor as an example,

[0091] The air pressure sensor can sense the air pressure change at the air outlet of the workpiece 1. When the workpiece 1 is clamped and filled with gas of a certain pressure, the air pressure sensor will continuously monitor the air pressure value at the air outlet of the workpiece 1 to detect whether there is gas leakage.

[0092] Once the air pressure sensor detects an abnormal change in air pressure (such as a sudden increase), it will immediately send a signal indicating that there may be a gas leakage problem in workpiece 1. This signal can be used to trigger an alarm device or stop the subsequent testing process to avoid wasting time and resources on workpiece 1 with obvious defects.

[0093] By using the air pressure sensor to conduct preliminary leak detection, workpieces that do not require further detailed testing can be quickly screened out, thereby reducing the number and time of using the airtightness tester. Although the airtightness tester has high detection accuracy, the detection speed is relatively slow and the cost is high, so it is more reasonable to use it on workpieces that have passed the preliminary screening.

[0094] What is described above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A workpiece clamping device for air tightness testing, used for clamping a workpiece (1), the workpiece (1) comprising an air inlet and an air outlet, characterized in that: The clamping device comprises: A first clamping assembly (2), comprising at least a first chuck (26) capable of being adjusted in position, the first chuck (26) being capable of being moved to a first work position (C) and a second work position (D), the first chuck (26) being used to locate an air outlet of the workpiece (1); The second clamping assembly (3), which corresponds to the second station (D), comprises: a second base frame (31) on which a slide seat (32) is slidably disposed, the slide seat (32) being driven by a second telescopic cylinder (33), and the second telescopic cylinder (33) being fixed on the second base frame (31); a second rotating cylinder (34) rotatably disposed in the slide seat (32), and one end of the second rotating cylinder (34) protrudes from the slide seat (32) and extends to form a second chuck (35), the second chuck (35) being in the shape of a cone, the second chuck (35) being used to locate the air inlet of the workpiece (1) and cooperating with the first chuck (26) to clamp the workpiece (1); an air supply head (36) which is sealingly slidably disposed in the second rotating cylinder (34), and one end of the air supply head (36) extends out of the second rotating cylinder (34) so ​​as to be connected to an external airtightness detector; The first clamping assembly (2) further comprises: A first base frame (21) on which a base cylinder (22) is fixed; A first rotating drum (23) rotatably disposed in the base drum (22) and driven by a driving member (28); a square rod (24) which vertically limits and slides through the first rotating cylinder (23); the top of the square rod (24) is connected to the first clamp (26) by an arm body (25); the bottom of the square rod (24) is connected to the telescopic end of a first telescopic cylinder (27); the first telescopic cylinder (27) is fixed to the first base frame (21); The first station (C) is a loading and unloading station, and the second station (D) is a testing station. When the first chuck (26) moves to the first station (C), an external manipulator is used to cooperate with the first chuck (26) to load the workpiece (1). Then, the first chuck (26) moves to the second station (D). At this time, the slide seat (32) and the second chuck (35) are used to cooperate to position the air inlet of the workpiece (1). The air supply head (36) is connected to the air inlet of the workpiece (1), and the air supply head (36) is also connected to an external air tightness detector, so as to realize the air tightness test of the workpiece (1).

2. A workpiece clamping device for air tightness testing according to claim 1, characterized in that: An elastic outer coating is attached to the outer surface of the second clamp (35).

3. A workpiece clamping device for air tightness testing according to claim 1, characterized in that: The outer fixed sleeve of the second rotating drum (34) is provided with a gear (310); A mounting cylinder (311) is fixed on one side of the slide seat (32) for slidably mounting the rack (312); and a clearance groove is provided on the mounting cylinder (311) and the slide seat (32) so that the rack (312) and the gear (310) can be meshed. The rack (312) is also driven by a fourth telescopic cylinder (313), and the fourth telescopic cylinder (313) is fixed on the slide seat (32).

4. A workpiece clamping device for air tightness testing according to claim 2, characterized in that: The other end of the air supply head (36) is fixedly connected to a wedge head (37), the wedge head (37) being located in the second chuck (35), the wedge head (37) having an outer wedge surface, the end of the second chuck (35) also extending to form a sealing wedge head (351), the sealing wedge head (351) having an inner wedge surface, the inner wedge surface and the outer wedge surface cooperating with each other.

5. A workpiece clamping device for air tightness testing according to claim 4, characterized in that: The sealing wedge head (351) is made of elastic material.

6. A workpiece clamping device for air tightness testing according to claim 4, characterized in that: A mounting seat (38) is also fixed on one side of the slide seat (32) for mounting a third telescopic cylinder (39), wherein the telescopic end of the third telescopic cylinder (39) is connected to the air supply head (36).

7. A workpiece clamping device for air tightness testing according to claim 1, characterized in that: The first chuck (26) comprises: An inner chuck (261) made of elastic material; An outer clamp (262) is sleeved on the outside of the inner clamp (261), and a plurality of clamping columns extending downwards are arranged at the bottom of the outer clamp (262); A sensor (263) embedded in the inner clamp (261); Wherein, the outer diameter of the inner chuck (261) is larger than the diameter of the air outlet of the workpiece (1).

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