Rapid gas sampling module of gas tank vehicle

Abstract

The utility model discloses a gas sampling fast module of a gas tank vehicle, which belongs to the technical field of gas sampling detection devices and comprises a valve body, the upper end of the valve body is open, the lower end of the valve body is closed, the valve body is provided with a valve body hole, a gas receiving component is assembled and disassembled on the valve body hole, and the side part of the valve body is provided with a notch, a locking piece and a lock pin. The locking piece swings on the outer side of the valve body, the inner end of the locking piece enters or leaves the interior of the valve body through the notch during swinging, and the lock pin elastically moves on the side portion of the valve body and locks or unlocks the locking piece. According to the structure, the assembly stability between the gas sampling quick module and the gas tank vehicle can be improved, the problem of leakage of liquefied gas is effectively avoided, after the gas sampling quick module is connected with the gas tank vehicle, a user can connect the sampling steel cylinder with the gas receiving assembly, then the liquefied gas can be sampled, the whole operation process does not need any tool assistance, and the working efficiency is improved. The fast gas sampling module is fast and convenient, and the modularized fast gas sampling module is simple and reasonable in overall structure and high in practicability.

Description

Technical Field

[0001] The utility model relates to the technical field of gas sampling detection devices, in particular to a gas sampling fast module of a gas tank truck. Background Art

[0002] The liquefied gas raw material is transported to the loading and unloading platform by a gas tank truck, and then unloaded into the raw material spherical tank through a pipeline. After the gas tank truck arrives at the company, the gas needs to be sampled and tested before unloading, and the product can only be unloaded after it is qualified. The operation is generally that the analyst brings the sampling cylinder to the site. The two ends of the sampling cylinder are equipped with two sampling hand valves. One end is connected to the liquid phase of the tank truck through a quick connector, and the liquefied gas on the other end is directly discharged into the air, thereby achieving the purpose of replacing the sampler. When the sampler is fully replaced, close the exhaust root valve at the end of the sampler for sampling. After the sampling is completed, close the front valve of the sampler and the outlet valve of the tank truck in turn, disconnect the quick connector connected to the tank truck, and bring the sampling cylinder back to the analysis room for analysis.

[0003] Since liquefied gas is an extremely dangerous, volatile, flammable and explosive chemical, the connection reliability requirements for quick connectors are very high.

[0004] For example, a dry quick connector disclosed in the utility model patent with Chinese patent application number CN201620519312.8 is composed of a female valve body and a male valve body that are spirally connected. A thread is arranged on the outer surface of the male valve body and a push pin matching the thread is arranged at the end of the female valve body. A valve flap is arranged in the valve cavity of the male valve body through a bracket. One end of the valve flap is sealed with one end of the valve cavity of the male valve body and a guide rod matching the guide hole on the bracket is arranged on the other end of the valve flap. A spring is arranged on the guide rod between the valve flap and the bracket.

[0005] For example, the utility model patent with Chinese patent application number CN201820035480.9 discloses a hydraulic quick connector for loading and unloading liquefied hydrocarbons, which includes a male part and a female part. The male part includes a male head, a male inner tube and a slot; the female part includes a female head, a locking claw, a restraining spring, a female inner tube and a sealing ring. The locking claw is located inside the female part and outside the female inner tube, and is connected to the restraining spring. There is a sealing ring outside the female inner tube mouth. The sealing ring is arranged between the restraining springs and can be used in the loading and unloading process of liquefied hydrocarbons.

[0006] The above quick connectors are matched by threads, which can ensure the reliability of use, but the structure is relatively complex and requires the assistance of tools to achieve disassembly and assembly during use, which is inconvenient to operate.

[0007] Therefore, further improvement is necessary. Utility Model Content

[0008] The utility model aims to provide a gas sampling quick module for a gas tank truck to overcome the shortcomings of the prior art.

[0009] A gas sampling rapid module for a gas tank truck designed for this purpose includes a valve body, the upper end of the valve body is open, the lower end is closed and a valve body hole is provided, the valve body hole is provided with a detachable gas connection component, the side of the valve body is provided with a notch, a locking piece and a locking pin, the locking piece is swingably arranged on the outside of the valve body, and the inner end of the locking piece enters or leaves the inside of the valve body through the notch when swinging, and the locking pin elastically moves on the side of the valve body to lock or unlock the locking piece.

[0010] The locking member is provided with a locking hole. When the locking member swings toward the valve body, the inner end of the locking member enters into the interior of the valve body through the notch, and the locking pin acts on the locking hole.

[0011] The valve body is also provided with a transfer piece, a transfer elastic piece is provided on the transfer piece, and the transfer elastic piece elastically moves on the side of the valve body, the lock pin is provided on the transfer piece, and the locking piece is swingably provided on the outside of the valve body through the transfer piece.

[0012] The inner end position of the locking member entering the valve body is arranged in an arc shape.

[0013] A boss is provided on the valve body, the boss is protruding from the outside of the notch, and a first locking pin hole and a first adapter hole are provided on the boss, the locking pin is passed through the first locking pin hole, and a second adapter hole is provided on the locking member, the first adapter hole and the second adapter hole correspond to each other, and an adapter is passed therebetween, and the locking member is swingably set on the boss through the adapter.

[0014] The locking member is provided with a locking hole, the locking hole is located at one side of the second adapter hole, and the locking pin is locked with or separated from the locking hole when the locking member swings.

[0015] The adapter is provided with a convex ring, a transfer elastic member, and a second locking pin hole. The convex ring is provided at one end of the adapter, and the transfer elastic member is positioned on the adapter. One end of the transfer elastic member elastically acts with the convex ring, and the other end elastically acts with the boss. The second locking pin hole is provided at the other end of the adapter, and the locking pin is penetrated through the second locking pin hole, bent toward the direction of the boss and penetrated through the first locking pin hole.

[0016] The air connecting component includes a connecting piece, an air connecting seat, an air connecting elastic piece, a valve core, and an air connecting nozzle. The connecting piece is detachably matched with the valve body hole and the air connecting seat, respectively. The air connecting elastic piece and the valve core are sequentially arranged in the air connecting seat. The air connecting elastic piece elastically acts on the connecting piece and the valve core, respectively. The end of the valve core extends out of the air connecting seat and is detachably matched with the air connecting nozzle. The valve core is elastically extended and retracted on the air connecting seat by the air connecting elastic piece, and communication or blocking between the valve body hole and the air connecting nozzle is achieved during extension and retraction.

[0017] The air receiving seat passes through from top to bottom and is provided with an air receiving positioning step inside the seat, a large inner diameter area and a small inner diameter area are formed inside the air receiving seat by the air receiving positioning step, an air outlet is provided at the bottom of the valve core, and an air inlet connected to the air outlet is provided on the side, a valve core positioning step, a first seal and a second seal are further provided on the side of the valve core, the valve core positioning step is located above the air inlet, the first seal is positioned between the valve core positioning step and the air inlet, the second seal is positioned below the air inlet, a third seal is provided on the air receiving nozzle, and is sealed and disassembled with the air outlet through the third seal, the valve core positioning step and the air receiving positioning step are sealed and positioned by the first seal, the valve core is sealed and cooperated with the inner wall of the small inner diameter area through the second seal, and the air inlet reciprocates between the large inner diameter area and the small inner diameter area when the valve core elastically expands and contracts.

[0018] The connecting piece includes a first connecting piece and a second connecting piece, one end of the first connecting piece is detachably matched with the valve body hole, and the other end is detachably matched with one end of the second connecting piece. A positioning portion is also provided on the valve core, and the positioning portion is located above the valve core positioning step. The air-connecting elastic piece is positioned in the second connecting piece and positioned on the positioning portion. One end of the air-connecting elastic piece elastically acts on the second connecting piece, and the other end elastically acts on the valve core positioning step.

[0019] The utility model improves the above structure and utilizes the connecting male head of the valve body and the loading and unloading port of the gas tank truck to connect in place, and then through the swing of the locking piece, the inner end of the locking piece enters into the interior of the valve body through the notch and is crimped and positioned with the connecting male head. At this time, the locking pin locks the position of the locking piece through elastic force, thereby preventing the locking piece and the connecting male head from being separated due to vibration or excessive air pressure, so as to improve the assembly stability between the gas sampling rapid module and the gas tank truck and effectively avoid the leakage of liquefied gas. When the gas sampling rapid module is connected to the gas tank truck, the user can connect the sampling cylinder with the gas connecting component, and the liquefied gas in the gas tank truck can enter the sampling cylinder from the valve body and the gas connecting component to complete the sampling of the liquefied gas. The entire operation process does not require any tool assistance, is quick and convenient, and the overall structure of the modularly arranged gas sampling rapid module is simple and reasonable, and has strong practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the assembly structure of an embodiment of the utility model.

[0021] Figure 2 This is a schematic diagram of the assembly structure from another perspective of an embodiment of the utility model.

[0022] Figure 3 It is a schematic diagram of the structure after the locking pin and the locking piece are locked.

[0023] Figure 4 This is a schematic diagram of the exploded structure of the gas connection component. DETAILED DESCRIPTION

[0024] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below.

[0025] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0026] See also Figure 1-Figure 4 The gas sampling rapid module of the gas tank truck includes a valve body 1, the upper end of the valve body 1 is open, the lower end is closed and a valve body hole is provided, the valve body hole is provided with a gas connection component, the side of the valve body 1 is provided with a notch 2, a locking piece 3 and a locking pin 4, the locking piece 3 is swingably arranged on the outside of the valve body 1, and its inner end enters or leaves the inside of the valve body 1 through the notch 2 when swinging, and the locking pin 4 elastically moves on the side of the valve body 1 and locks or unlocks the locking piece 3.

[0027] In this embodiment, the valve body 1 is connected to the male connector of the loading and unloading port of the gas tank truck, and then the inner end of the locking member 3 is swung to allow the inner end of the locking member 3 to enter the interior of the valve body 1 through the notch 2 and be crimped into position with the male connector. At this time, the locking pin 4 locks the position of the locking member 3 through an elastic force, thereby preventing the locking member 3 from being separated from the male connector due to vibration or excessive air pressure, so as to improve the assembly stability between the gas sampling rapid module and the gas tank truck and effectively avoid the leakage of liquefied gas. When the gas sampling rapid module is connected to the gas tank truck, the user can connect the sampling cylinder to the gas connecting component, and the liquefied gas in the gas tank truck can enter the sampling cylinder from the valve body 1 and the gas connecting component to complete the sampling of the liquefied gas. The entire operation process does not require any tool assistance, is quick and convenient, and the overall structure of the modularly arranged gas sampling rapid module is simple and reasonable, and has strong practicality.

[0028] In order to achieve the locking of the locking pin 4 and the locking member 3, a locking hole 5 is provided on the locking member 3. When the locking member 3 swings toward the valve body 1, the inner end of the locking member 3 enters the inside of the valve body 1 through the notch 2, and the locking pin 4 locks on the locking hole 5. When the inner end of the locking member 3 enters the inside of the valve body 1, it will be crimped onto the male connector, and the position of the locking member 3 will be locked by the locking pin 4.

[0029] An adapter 6 is also provided on the valve body 1, and a adapter elastic member 7 is provided on the adapter 6, and the adapter 6 elastically moves on the side of the valve body 1 through the adapter elastic member 7. The lock pin 4 is provided on the adapter 6, and the locking member 3 is swingably provided on the outside of the valve body 1 through the adapter 6, thereby, the lock pin 4 and the adapter 6 can realize synchronous movement through the adapter elastic member 7, and the locking member 3 can realize stable swing through the adapter 6.

[0030] The inner end of the locking member 3 entering the valve body 1 is arranged in an arc shape, thereby improving the smoothness of crimping between the inner end of the locking member 3 and the connecting male head, while also reducing the wear problem caused by the crimping between the two, thereby increasing the service life of the product.

[0031] A boss 8 is provided on the valve body 1, which is protruding from the outside of the notch 2 and is provided with a first lock pin hole and a first adapter hole. The lock pin 4 is passed through the first lock pin hole, and a second adapter hole is provided on the locking member 3. The first adapter hole and the second adapter hole correspond to each other, and an adapter 6 is passed therebetween. The locking member 3 is swingably set on the boss 8 through the adapter 6.

[0032] In this embodiment, there are two notches 2, which are symmetrically arranged on the side of the valve body 1, and four bosses 8 are provided, which are symmetrically arranged in a group of two on the outside of the valve body 1. The two bosses 8 are spaced apart, and the spacing between them corresponds to the size of the notch 2, that is, the two bosses 8 are respectively protruded at the left and right positions of the outside of the notch 2, and there are two corresponding locking pieces 3 symmetrically arranged on the left and right. The left-right symmetrical locking pieces 3 are respectively crimped with the left and right positions of the connecting male head, which can further improve the assembly stability between the gas sampling rapid module and the gas tank truck.

[0033] The locking hole 5 is located at one side of the second adapter hole, and the locking pin 4 is locked with or separated from the locking hole 5 when the locking member 3 swings.

[0034] The adapter 6 is provided with a convex ring 9, a transfer elastic member 7 and a second lock pin hole. The convex ring 9 is arranged at one end of the adapter 6. The transfer elastic member 7 is positioned on the adapter 6. One end of the transfer elastic member 7 elastically acts on the convex ring 9, and the other end elastically acts on the boss 8. The second lock pin hole is arranged at the other end of the adapter 6. The lock pin 4 is penetrated through the second lock pin hole, bent toward the direction of the boss 8 and penetrated through the first lock pin hole.

[0035] In this embodiment, the convex ring 9 and the adapter 6 can be assembled and disassembled by means of threads. The lock pin 4 is inserted into the second lock pin hole and bent into an L shape in the direction of the boss 8, and then inserted into the first lock pin hole. The adapter elastic member 7 is a compression spring. The adapter 6 always moves elastically in the direction of the convex ring 9 through the elastic force of the adapter elastic member 7, so that the lock pin 4 can be locked on the locking hole 5 in a natural state. The user can drive the adapter 6 to overcome the elastic force of the adapter elastic member 7 by pressing on the boss 8, so that the lock pin 4 and the locking hole 5 are separated from each other. At this time, the locking member 3 can swing freely on the boss 8. In addition, since the convex ring 9 and the lock pin 4 are located at both ends of the adapter 6, the adapter 6 can be limited to prevent the adapter 6 from falling off from the first adapter hole and the second adapter hole, so as to ensure the assembly stability of the valve body 1, the adapter 6, the lock member 3, and the adapter elastic member 7.

[0036] The air connecting component includes a connecting piece, an air connecting seat 10, an air connecting elastic piece 11, a valve core 12, and an air connecting nozzle 13. The connecting piece is detachably matched with the valve body hole and the air connecting seat 10 respectively. The air connecting elastic piece 11 and the valve core 12 are sequentially arranged in the air connecting seat 10. The air connecting elastic piece 11 elastically acts on the connecting piece and the valve core 12 respectively. The end of the valve core 12 extends out of the air connecting seat 10 and is detachably matched with the air connecting nozzle 13. The valve core 12 is elastically extended and retracted on the air connecting seat 10 by the air connecting elastic piece 11, and realizes conduction or blocking between the valve body hole and the air connecting nozzle 13 when extending and retracting.

[0037] The air receiving seat 10 is penetrated from top to bottom, and an air receiving positioning step is arranged inside the air receiving seat 10. The air receiving positioning step forms a large inner diameter area and a small inner diameter area inside the air receiving seat 10. An air outlet 14 is arranged at the bottom of the valve core 12, and an air inlet 15 connected to the air outlet 14 is arranged at the side. A valve core positioning step 16, a first sealing member 17, and a second sealing member 18 are also arranged at the side of the valve core 12. The valve core positioning step 16 is located above the air inlet 15, and the first sealing member 17 is positioned on the valve core positioning step. 16 and the air inlet 15, the second seal 18 is positioned below the air inlet 15, the air nozzle 13 is provided with a third seal, and is sealed and disassembled with the air outlet 14 through the third seal, the valve core positioning step 16 and the air receiving positioning step are sealed and positioned by the first seal 17, the valve core 12 is sealed with the inner wall of the small inner diameter area through the second seal 18, and the air inlet 15 reciprocates between the large inner diameter area and the small inner diameter area when the valve core 12 elastically expands and contracts.

[0038] The connecting piece includes a first connecting piece 19 and a second connecting piece 20. One end of the first connecting piece 19 is detachably matched with the valve body hole, and the other end is detachably matched with one end of the second connecting piece 20. A positioning portion 21 is also provided on the valve core 12. The positioning portion 21 is located above the valve core positioning step 16. The air-connecting elastic piece 11 is positioned in the second connecting piece 20 and positioned on the positioning portion 21. One end of the air-connecting elastic piece 11 elastically acts on the second connecting piece 20, and the other end elastically acts on the valve core positioning step 16.

[0039] In this embodiment, the valve body hole, the first connecting piece 19, the second connecting piece 20, and the air receiving seat 10 are disassembled and assembled with each other by means of threads, and the air nozzle 13 and the air outlet 14 are disassembled and assembled with each other by means of threads. The setting of the air nozzle 13 can limit the position of the valve core 12 extending into the air receiving seat 10, and the setting of the first seal 17, the second seal 18, and the third seal can improve the sealing between the valve core 12 and the air receiving seat 10 and the air nozzle 13.

[0040] The air receiving elastic member 11 is a compression spring, and the valve core 12 is elastically movable toward the air receiving seat 10 through the air receiving elastic member 11, so that the lower end of the valve core 12 is always extended out of the air receiving seat 10. At this time, the valve core positioning step 16 is sealed and positioned on the air receiving positioning step through the first sealing member 17, and the air inlet 15 is located in the small inner diameter area. At the same time, the second sealing member 18 is sealed with the inner wall of the small inner diameter area, and the valve body hole and the air receiving nozzle 13 are blocked and not conductive, so there will be no leakage of liquefied gas. When the sampling cylinder acts on the air receiving nozzle 13, the valve core 12 can be driven to move toward the valve body 1 and overcome the elastic force of the air receiving elastic member 11. When the valve core positioning step 16 leaves the gas receiving positioning step, the air inlet 15 is located in the large inner diameter area. At this time, the valve body hole and the air receiving nozzle 13 are connected to each other, and the liquefied gas in the valve body 1 enters the first connecting piece 19, the second connecting piece 20, and the interior of the air receiving seat 10 from the valve body hole in sequence. The liquefied gas located in the air receiving seat 10 enters the air receiving nozzle 13 from the air inlet 15 and the air outlet 14 in sequence, and finally enters the sampling cylinder to complete the sampling. In addition, the second sealing member 18 is always sealed with the inner wall of the small inner diameter area, so that when the valve core 12 is telescopic, the liquefied gas in the air receiving seat 10 will never leak from the gap between the valve core 12 and the air receiving seat 10.

[0041] The above is a preferred embodiment of the utility model, which shows and describes the basic principle, main features and advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principle of the utility model. The utility model may have various changes and improvements without departing from the spirit and scope of the utility model, and these changes and improvements fall within the scope of the utility model to be protected, and the scope of protection of the utility model is defined by the attached claims and their equivalents.

Claims

1. A gas sampling quick module for a gas tank truck, comprising a valve body (1), characterized in that: The valve body (1) is open at the upper end and closed at the lower end and is provided with a valve body hole. A gas connection assembly is detachably mounted on the valve body hole. A notch (2), a locking piece (3) and a locking pin (4) are provided on the side of the valve body (1). The locking piece (3) is swingably arranged on the outside of the valve body (1), and its inner end enters or leaves the inside of the valve body (1) through the notch (2) when swinging. The locking pin (4) is elastically movable on the side of the valve body (1) and locks or unlocks the locking piece (3).

2. The gas sampling rapid module of the gas tank truck according to claim 1, characterized in that: The locking member (3) is provided with a locking hole (5). When the locking member (3) swings in the direction of the valve body (1), the inner end of the locking member (3) enters the interior of the valve body (1) through the notch (2), and the locking pin (4) acts on the locking hole (5) to lock.

3. The gas sampling quick module of the gas tank truck according to claim 1, characterized in that: The valve body (1) is further provided with a transition piece (6), the transition piece (6) is provided with a transition elastic piece (7), and the transition elastic piece (7) elastically moves on the side of the valve body (1), the lock pin (4) is provided on the transition piece (6), and the locking piece (3) is swingably provided on the outside of the valve body (1) through the transition piece (6).

4. The gas sampling rapid module of the gas tank truck according to claim 1, characterized in that: The inner end position of the locking member (3) entering the interior of the valve body (1) is arranged in an arc shape.

5. The gas sampling quick module of the gas tank truck according to any one of claims 1 to 4, characterized in that: The valve body (1) is provided with a boss (8), the boss (8) is protruding from the outside of the notch (2), and is provided with a first locking pin hole and a first adapter hole, the locking pin (4) is passed through the first locking pin hole, the locking member (3) is provided with a second adapter hole, the first adapter hole and the second adapter hole correspond to each other, and an adapter (6) is passed therebetween, the locking member (3) is swingably provided on the boss (8) via the adapter (6).

6. The gas sampling quick module of the gas tank truck according to claim 5, characterized in that: The locking member (3) is provided with a locking hole (5), the locking hole (5) being located on one side of the second adapter hole, and the locking pin (4) is locked with or separated from the locking hole (5) when the locking member (3) swings.

7. The gas sampling rapid module of the gas tank truck according to claim 6, characterized in that: The adapter (6) is provided with a convex ring (9), a transfer elastic member (7), and a second lock pin hole. The convex ring (9) is provided at one end of the adapter (6). The transfer elastic member (7) is positioned and sleeved on the adapter (6). One end of the transfer elastic member (7) elastically acts on the convex ring (9), and the other end elastically acts on the boss (8). The second lock pin hole is provided at the other end of the adapter (6). The lock pin (4) is passed through the second lock pin hole, bent in the direction of the boss (8), and passed through the first lock pin hole.

8. The gas sampling rapid module of the gas tank truck according to claim 1, characterized in that: The air connection assembly comprises a connecting piece, an air connection seat (10), an air connection elastic piece (11), a valve core (12), and an air connection nozzle (13); the connecting piece is detachably matched with the valve body hole and the air connection seat (10), respectively; the air connection elastic piece (11) and the valve core (12) are sequentially arranged in the air connection seat (10); the air connection elastic piece (11) elastically acts on the connecting piece and the valve core (12), respectively; an end of the valve core (12) extends out of the air connection seat (10) and is detachably matched with the air connection nozzle (13); the valve core (12) is elastically extended and retracted on the air connection seat (10) by the air connection elastic piece (11), and when extended and retracted, conduction or blocking between the valve body hole and the air connection nozzle (13) is achieved.

9. The gas sampling rapid module of the gas tank truck according to claim 8, characterized in that: The air receiving seat (10) is penetrated from top to bottom and is provided with an air receiving positioning step inside. The air receiving seat (10) forms a large inner diameter area and a small inner diameter area inside through the air receiving positioning step. The bottom of the valve core (12) is provided with an air outlet (14), and the side is provided with an air inlet (15) connected to the air outlet (14). The side of the valve core (12) is also provided with a valve core positioning step (16), a first sealing member (17), and a second sealing member (18). The valve core positioning step (16) is located above the air inlet (15), and the first sealing member (17) is positioned on the valve core positioning step (16). The second sealing member (18) is positioned below the air inlet (15) between the air inlet and the air inlet (15); a third sealing member is provided on the air receiving nozzle (13), and the third sealing member is used for sealing assembly and disassembly cooperation with the air outlet (14); the valve core positioning step (16) and the air receiving positioning step are sealed and positioned by the first sealing member (17); the valve core (12) is sealed and cooperated with the inner wall of the small inner diameter area by the second sealing member (18); and the air inlet (15) reciprocates between the large inner diameter area and the small inner diameter area when the valve core (12) elastically expands and contracts.

10. The gas sampling rapid module of the gas tank truck according to claim 9, characterized in that: The connecting piece comprises a first connecting piece (19) and a second connecting piece (20); one end of the first connecting piece (19) is detachably matched with the valve body hole, and the other end is detachably matched with one end of the second connecting piece (20); a positioning portion (21) is also provided on the valve core (12); the positioning portion (21) is located above the valve core positioning step (16); the air-connecting elastic piece (11) is positioned in the second connecting piece (20) and on the positioning portion (21); one end of the air-connecting elastic piece (11) elastically acts on the second connecting piece (20), and the other end elastically acts on the valve core positioning step (16).

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