ball valve

Abstract

The application relates to the technical field of valves, in particular to a ball valve. The ball valve comprises a valve body, an end cover and a connecting pipe, the valve body is provided with a valve cavity, the end cover is arranged between the valve body and the connecting pipe and is connected with the valve body and the connecting pipe respectively, the end cover is provided with a flow-through hole, and the flow-through hole is connected with the valve cavity and the connecting pipe respectively. A welding groove is arranged at the position where the end cover is connected with the valve body, the welding groove comprises a first taper surface arranged on the end cover, and / or the welding groove comprises a second taper surface arranged on the valve body, and the end cover and the valve body are welded and fixed through the welding groove. The ball valve provided by the application solves the problems of poor welding quality and poor welding stability of the welding structure of the existing ball valve.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of valves, in particular to a ball valve. BACKGROUND

[0002] Ball valves are often used in air conditioning systems to achieve the cut-off and conduction of refrigerant flow. At present, the ball valve usually comprises a valve body, an end cover and a connecting pipe, and the connecting pipe is connected to the valve body through the end cover.

[0003] In the related art, the connection between the valve body and the end cover is achieved by directly abutting and then fixed by welding. However, the welding structure has poor quality and stability after welding, which reduces the service life of the ball valve. CONTENT OF THE UTILITY MODEL

[0004] Therefore, it is necessary to provide a ball valve to solve the problem of poor welding quality and stability of the existing ball valve welding structure.

[0005] The present application provides a ball valve, which comprises a valve body, an end cover and a connecting pipe, a valve cavity is formed in the valve body, the end cover is arranged between the valve body and the connecting pipe and connected with the valve body and the connecting pipe respectively, and a flow-through hole is formed in the end cover, which communicates with the valve cavity and the connecting pipe respectively; wherein, a welding groove is arranged at the position where the end cover and the valve body are connected, the welding groove comprises a first taper surface arranged on the end cover, and / or the welding groove comprises a second taper surface arranged on the valve body, and the end cover and the valve body are fixed by welding through the welding groove.

[0006] In one of the embodiments, the end cover is fixed by laser welding with the valve body, and / or the end cover is fixed by high-frequency welding with the connecting pipe.

[0007] In one of the embodiments, the end cover comprises a main body part and a first connecting part, the first connecting part protrudes and is connected to one end of the main body part along the axial direction; wherein, the first connecting part is inserted into the valve cavity and connected with the valve body.

[0008] In one of the embodiments, the outer surface of the valve body is provided with a solder spreading area, the solder spreading area is arranged close to the welding groove and communicates with the welding groove; and / or the outer surface of the valve body is protruded radially to form a boss, and the end of the boss close to the welding groove is formed with a avoiding area.

[0009] In one of the embodiments, the inner diameter of the valve cavity is b, the outer diameter of the first connecting portion is E, wherein b-E≤0.5mm; and / or, the outer diameter of the valve body at the solder spreading area is a, the outer diameter of the main body portion is D, wherein |D-a|≤1mm; and / or, the width of the solder spreading area is d, and d≥1mm; and / or, the depth of the solder groove is f, and the wall thickness of the valve body is g, wherein 0.1≤f / g≤0.5; and / or, the solder groove comprises the first taper surface and the second taper surface, and the included angle formed by the first taper surface and the second taper surface is e, and 70°≤e≤120°.

[0010] In one of the embodiments, the flow-through hole comprises a first hole section, which is arranged at one end of the flow-through hole close to the valve cavity; the ball valve further comprises a valve core and a sealing member, the valve core is rotatably installed in the valve cavity, and the sealing member is installed in the first hole section to seal the valve core and the end cover.

[0011] In one of the embodiments, the bottom wall of the first hole section protrudes axially to form a limiting portion, and the limiting portion is in abutting engagement with the sealing member.

[0012] In one of the embodiments, the limiting portion is configured as a limiting protruding ring, which extends in a ring shape; or, the limiting portion is configured as a plurality of limiting protrusions, which are arranged at intervals in the circumferential direction of the end cover.

[0013] In one of the embodiments, the outer diameter of the main body portion is D, and the thickness of the main body portion is G, and G≥D / 20.

[0014] In one of the embodiments, the flow-through hole further comprises a second hole section, which is arranged at one end of the flow-through hole close to the connecting pipe, and the connecting pipe is inserted into the second hole section and in abutting engagement with the bottom wall of the second hole section.

[0015] In one of the embodiments, the end cover further comprises a second connecting portion, which protrudes from one end of the main body portion away from the first connecting portion, and the second hole section is at least partially arranged in the second connecting portion; wherein the wall thickness of the connecting pipe is T, the inner diameter of the second hole section is A, and 0.05mm≤A-T≤0.5mm; and / or, the wall thickness of the second connecting portion is B, and 1≤B / T≤2; and / or, the depth of the second hole section is C, and C / T≥0.8; and / or, the outer diameter of the main body portion is D, the height of the second connecting portion protruding from the main body portion is F, and F≥D / 15.

[0016] Compared with the prior art, the welding groove can increase the actual welding area between the valve body and the end cover, thereby improving the welding strength and stability. After welding is completed, the welding groove is filled with the molten solder or the valve body and the end cover, so that the joint between the valve body and the end cover is a flat structure, the structural stability is improved, the welding strength can be avoided from being damaged by vibration and other working conditions, and the structure is visually more beautiful. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0018] Figure 1 Structure schematic view of the ball valve of an embodiment provided by the present application;

[0019] Figure 2 Structure schematic view of the ball valve of an embodiment provided by the present application;

[0020] Figure 3 Structure schematic view of the ball valve of an embodiment provided by the present application;

[0021] Figure 4 Structure schematic view of the ball valve of an embodiment provided by the present application;

[0022] The meanings of the symbols in the drawings are as follows:

[0023] 100, ball valve; 1001, welding groove; 10, valve body; 101, valve cavity; 102, second conical surface; 11, solder spreading area; 12, boss; 121, avoiding area; 20, end cover; 201, flow-through hole; 2011, first hole section; 2012, second hole section; 202, first conical surface; 21, main body part; 22, first connecting part; 23, second connecting part; 24, limiting part; 30, connecting pipe; 40, valve core; 50, sealing element; 60, valve rod. DETAILED DESCRIPTION

[0024] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the drawings. In the following description, many specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the spirit of the present application, so the present application is not limited to the specific embodiments disclosed below.

[0025] It is to be noted that when a component is referred to as being "on" or "disposed on" another component, it can be directly on the other component or intervening components can also be present. When a component is referred to as being "connected" to another component, it can be directly connected to the other component or intervening components can also be present. The terms "vertical", "horizontal", "upper", "lower", "left", "right", and similar terms as used in the description of the present application are used for explanation purposes only and are not intended to be limiting.

[0026] In addition, the terms "first", "second", etc. are used herein only to describe various conditions, and are not to be construed as indicating or implying relative importance or a specific number of features indicated. Thus, the features with "first", "second", etc. can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.

[0027] In the present application, unless otherwise explicitly specified and limited, the "on", "under", "above" and "over" of the first feature to the second feature can be that the first feature is in direct contact with the second feature, or the first feature is indirectly in contact with the second feature through an intermediate medium. Moreover, the "on", "above" and "over" of the first feature to the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the first feature is higher in horizontal height than the second feature. The "under", "below" and "under" of the first feature to the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the first feature is lower in horizontal height than the second feature.

[0028] Unless otherwise defined, all technical and scientific terms used in the specification of the present application have the same meaning as commonly understood by one skilled in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used in the specification of the present application includes any and all combinations of one or more related listed items.

[0029] Ball valves are often used in air conditioning systems to achieve the cut-off and conduction of refrigerant flow. At present, the ball valve often includes a valve body, an end cover and a connecting pipe, and the connecting pipe is connected to the valve body through the end cover.

[0030] In the related art, the connection between the valve body and the end cover is achieved by directly abutting and then fixed by welding. However, the quality and stability of the welding structure after welding are poor, which reduces the service life of the ball valve.

[0031] Please refer to Figures 1-4To address the poor welding quality and stability of existing ball valve welding structures, this application provides a ball valve 100. The ball valve 100 includes a valve body 10, a valve core 40, an end cap 20, a sealing element 50, and a connecting pipe 30. A valve cavity 101 is formed within the valve body 10, and the valve core 40 is rotatably mounted within the valve cavity 101. The end cap 20 is located between the valve body 10 and the connecting pipe 30, and is connected to both the valve body 10 and the connecting pipe 30. A flow hole 201 is formed within the end cap 20, connecting the valve cavity 101 and the connecting pipe 30. The sealing element 50 is installed between the valve core 40 and the end cap 20 to seal the connection between them. A welding groove 1001 is provided at the connection between the end cap 20 and the valve body 10. The welding groove 1001 includes a first conical surface 202 on the end cap 20, and / or a second conical surface 102 on the valve body 10. The end cap 20 and the valve body 10 are welded and fixed together through the welding groove 1001. Thus, the welding groove 1001 increases the actual welding area between the valve body 10 and the end cap 20, thereby improving welding strength and stability. Furthermore, after welding, the melted solder or partial melting of the valve body 10 and the end cap 20 fills the welding groove 1001, ensuring that the joint between the valve body 10 and the end cap 20 is a planar structure. This improves structural stability, prevents damage to welding strength due to vibration or other operating conditions, and also enhances the visual appeal.

[0032] Specifically, in this embodiment, such as Figure 3 As shown, the welding groove 1001 is configured as a V-shaped groove, that is, the welding groove 1001 is formed by the first conical surface 202 on the end cover 20 and the second conical surface 102 on the valve body 10.

[0033] In other embodiments, the welding groove 1001 can also be formed by the first conical surface 202 on the end cap 20 surrounding the end face of the valve body 10, or by the second conical surface 102 on the valve body 10 surrounding the end face of the main body 21, forming a semi-V-shaped structure. The specific arrangement can be reasonably set according to the actual situation. Here, both the first conical surface 202 and the second conical surface 102 can be formed by machining.

[0034] In one embodiment, the end cap 20 is welded to the valve body 10 by laser welding, and the end cap 20 is welded to the connecting pipe 30 by high-frequency welding.

[0035] Understandably, the high-frequency welding method used to connect the end cap 20 and the connecting pipe 30 ensures uniform heating of the end cap 20, preventing heat deformation and guaranteeing the concentricity of the end cap 20 and valve body 10. Furthermore, traditional welding methods can lead to reduced strength of connected components due to "over-aging" in the heat-affected zone. High-frequency welding, with its uniform heat distribution, effectively strengthens the components during the welding process, mitigating strength loss and ensuring material strength. Simultaneously, the laser welding method connecting the end cap 20 and valve body 10 effectively reduces the impact of welding heat on the valve body 10 and its internal components due to its high energy density, small heat-affected zone, and fast welding speed. This ensures the normal operation of the ball valve 100. Moreover, this welding method allows for a more compact and lightweight design of the ball valve 100.

[0036] For example, the welding heat can have an adverse effect on the components inside the valve body 10 (such as the seal 50), which can easily cause thermal deformation of the seal 50, thereby causing the seal 50 to fail.

[0037] In other embodiments, the valve body 10, end cap 20, and connecting pipe 30 can also be fixed by welding methods such as furnace welding or flame welding. It should be noted that when laser welding is used, no welding rod is needed. The welding groove 1001 is filled by the partial melting of the valve body 10 and end cap 20. In this case, the connection between the valve body 10 and end cap 20 can form a flat surface, ensuring welding strength and improving aesthetics. When other welding methods are used, welding rods can be used. After the welding rods melt, they fill the welding groove 1001. In this case, the solder will protrude from the welding groove 1001 and accumulate around it, for example, it will accumulate in the solder spreading area 11 described below.

[0038] In one embodiment, the ball valve 100 is made of aluminum alloy. Compared to traditional valve-making materials (such as brass), aluminum alloy is not only lighter but also cheaper, effectively reducing the cost of the ball valve 100. Furthermore, for the same weight, the aluminum ball valve 100 can have a greater wall thickness than the brass ball valve 100, thereby effectively improving the structural stability of the ball valve 100. Of course, in other embodiments, the ball valve 100 may also be made of brass.

[0039] In one embodiment, such as Figure 3 and Figure 4 As shown, the end cap 20 includes a main body 21 and a first connecting part 22, the first connecting part 22 protruding and connected to one axial end of the main body 21. The first connecting part 22 is inserted into the valve cavity 101 and connected to the valve body 10. The insertion connection between the first connecting part 22 and the valve body 10 improves the coaxiality of the end cap 20 and the valve body 10, thereby enhancing the laser welding effect between the end cap 20 and the valve body 10.

[0040] Further, the inner diameter of the valve cavity 101 is b, and the outer diameter of the first connecting portion 22 is E, where b-E≤0.5mm. In this way, the coaxiality of the end cover 20 and the valve body 10 can be further ensured, thereby improving the laser welding effect between the end cover 20 and the valve body 10. Moreover, the inner wall of the valve cavity 101 and the outer wall of the first connecting portion 22 form a clearance fit or an interference fit, which can reduce the difficulty of insertion or further improve the connection reliability.

[0041] Preferably, b-E≤0.1mm, for example, the value of b-E can be set to 0.02mm, 0.04mm, 0.06mm, 0.08mm or 0.1mm, etc., which are not listed one by one here.

[0042] Further, the included angle formed by the first taper surface 202 and the second taper surface 102 is e, and 70°≤e≤120°. At the same time, the depth of the welding groove 1001 is f, and the wall thickness of the valve body 10 is g, and 0.1≤f / g≤0.5 is satisfied. In this way, the laser welding penetration can be increased, the laser reflection of the aluminum alloy can be reduced, the laser absorption can be improved, the laser welding porosity can be reduced, and the laser welding surface can be increased, thereby effectively improving the welding reliability and reducing the welding difficulty.

[0043] In an embodiment, as shown in Figure 3 The outer surface of the valve body 10 is provided with a solder spreading area 11, which is arranged close to and in communication with the welding groove 1001. The solder spreading area 11 is used to spread the solder, so that the welding has sufficient weld width.

[0044] The width of the solder spreading area 11 is d, and d≥1mm. In this way, the weld width of the laser welding is effectively ensured, thereby improving the weldability. Alternatively, the value of d can be 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm or 2mm, etc., which are not listed one by one here.

[0045] Further, the outer diameter of the valve body 10 at the solder spreading area 11 is a, and the outer diameter of the main body portion 21 is D, where |D-a|≤1mm. That is, the outer diameter of the main body portion 21 can be greater than or less than the outer diameter of the valve body 10 at the solder spreading area 11, but the difference between the two should be within 1mm, so as to reduce the height difference on both sides of the welding groove 1001, thereby improving the weldability of laser welding.

[0046] To ensure the structural strength of the end cover 20, in an embodiment, the thickness of the main body portion 21 is G, and G≥D / 20. In this way, the thickness of the main body portion 21 is ensured, which is beneficial to improve the strength of the main body portion 21 and the connecting pipe 30 of the end cover 20.

[0047] In an embodiment, as shown inFigure 1 As shown, the outer surface of the valve body 10 is radially convexly formed with a boss 12, which can improve the structural strength of the valve body 10 at the joint with the valve rod 60, wherein the valve rod 60 extends into the valve cavity 101 and is connected with the valve core 40 to drive the valve core 40 to rotate in the valve cavity 101 through the rotation of the valve rod 60.

[0048] Further, the boss 12 is formed with a clearance 121 at one end close to the welding groove 1001, so as to prevent the boss 12 from affecting the laser welding wire feeding, thereby reducing the welding difficulty and improving the welding efficiency.

[0049] In an embodiment, as shown in Figure 2 and Figure 3 The flow-through hole 201 includes a first hole section 2011 arranged at one end of the flow-through hole 201 close to the valve cavity 101. The sealing member 50 is installed in the first hole section 2011 to seal the connection between the valve core 40 and the end cover 20. In this way, the assembly of the sealing member 50 is facilitated, and the sealing effect between the valve core 40 and the end cover 20 can be improved.

[0050] Since the valve core 40 rotates during operation, and the valve core 40 is in close abutment with the sealing member 50 when sealed, there is a risk that the sealing member 50 will be dragged by the valve core 40 due to friction, thereby affecting the sealing effect. Therefore, in an embodiment, the bottom wall of the first hole section 2011 is axially convexly formed with a limiting portion 24, which abuts with the sealing member 50 to increase the contact area between the inner wall of the first hole section 2011 and the sealing member 50, thereby effectively reducing the probability of movement of the sealing member 50.

[0051] Specifically, in an embodiment, the limiting portion 24 is configured as a limiting convex ring extending in a ring shape. In this way, the sealing member 50 can be prevented from being dragged by the valve core 40, and the sealing performance of the sealing member 50 is ensured.

[0052] In another embodiment, the limiting portion 24 can also be configured as a plurality of limiting protrusions arranged at intervals in the circumferential direction of the end cover 20. In this way, the sealing member 50 can also be effectively prevented from being dragged by the valve core 40, and the sealing performance of the sealing member 50 is ensured.

[0053] In an embodiment, as shown in Figure 3 and Figure 4 The flow-through hole 201 also includes a second hole section 2012 arranged at one end of the flow-through hole 201 close to the connecting pipe 30, and the connecting pipe 30 is inserted into the second hole section 2012 and abuts with the bottom wall of the second hole section 2012, which is conducive to improving the connection strength between the connecting pipe 30 and the end cover 20, and facilitating subsequent welding.

[0054] In order to facilitate the insertion of the connecting pipe 30 into the second hole section 2012, in an embodiment, the wall thickness of the connecting pipe 30 is T, the inner diameter of the second hole section 2012 is A, and 0.05mm≤A-T≤0.5mm. In this way, the insertion of the connecting pipe 30 is facilitated and the coaxiality between the connecting pipe 30 and the end cover 20 can be ensured, thereby improving the strength reliability of the high-frequency welding.

[0055] Alternatively, the value of A-T can be 0.05mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm or 0.5mm, and the like, which are not listed one by one here.

[0056] Further, the end cover 20 further comprises a second connecting portion 23, which is protruded and connected to one end of the main body portion 21 away from the first connecting portion 22, and the second hole section 2012 is at least partially arranged in the second connecting portion 23, that is, the outer diameter of the second connecting portion 23 is smaller than the outer diameter of the main body portion 21, which can reduce the material usage of the end cover 20 and reduce the cost.

[0057] In order to ensure the reliability of the connection between the second connecting portion 23 and the second hole section 2012 and the connecting pipe 30, in an embodiment, the wall thickness of the second connecting portion 23 is B, and 1≤B / T≤2, so as to improve the strength of the second connecting portion 23 and prevent it from melting due to heat during the welding process, thereby improving the weldability of the high-frequency welding.

[0058] Further, in an embodiment, the height of the second connecting portion 23 protruding from the main body portion 21 is F, and F≥D / 15. In this way, the height of the second connecting portion 23 is increased, thereby ensuring the strength of the second connecting portion 23 and further preventing it from melting due to heat during the welding process, thereby improving the weldability of the high-frequency welding.

[0059] Still further, in an embodiment, the depth of the second hole section 2012 is C, and C / T≥0.8, so as to ensure the length of the connecting pipe 30 inserted into the end cover 20 and improve the reliability of the connection between the two, thereby being able to improve the welding strength of the high-frequency welding.

[0060] The technical features of the above-described embodiments can be combined in any manner. In order to make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, however, as long as the combinations of the technical features do not exist contradictions, they should be considered as the scope of the present disclosure.

[0061] The above-described embodiments are merely illustrative of several embodiments of the present application, which are described in more detail and in a specific manner, but should not be construed as limiting the scope of the patent application. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the patent protection scope of the present application should be subject to the appended claims.

Claims

1. A ball valve, characterized in that The valve body (10) is provided with a valve cavity (101), the end cover (20) is arranged between the valve body (10) and the connecting pipe (30) and connected with the valve body (10) and the connecting pipe (30) respectively, and the end cover (20) is provided with a flow-through hole (201) which communicates with the valve cavity (101) and the connecting pipe (30) respectively; The welding groove (1001) is arranged at the position where the end cover (20) and the valve body (10) are connected, the welding groove (1001) comprises a first taper surface (202) arranged on the end cover (20), and / or the welding groove (1001) comprises a second taper surface (102) arranged on the valve body (10), and the end cover (20) and the valve body (10) are welded and fixed through the welding groove (1001).

2. The ball valve according to claim 1, characterized in that The end cover (20) is welded and fixed with the valve body (10) by laser welding, and / or the end cover (20) is welded and fixed with the connecting pipe (30) by high-frequency welding.

3. The ball valve of claim 1, wherein The end cover (20) comprises a main body part (21) and a first connecting part (22), the first connecting part (22) is protruded and connected to one end of the main body part (21) along the axial direction; The first connecting part (22) is inserted into the valve cavity (101) and connected with the valve body (10).

4. The ball valve according to claim 3, characterized in that The outer surface of the valve body (10) is provided with a solder spreading area (11), the solder spreading area (11) is arranged close to the welding groove (1001) and communicates with the welding groove (1001); And / or, the outer surface of the valve body (10) is radially protruded to form a boss (12), one end of the boss (12) close to the welding groove (1001) is formed with a avoiding area (121).

5. The ball valve of claim 4, wherein, The inner diameter of the valve cavity (101) is b, and the outer diameter of the first connecting part (22) is E, wherein b-E≤0.5mm; And / or, the outer diameter of the valve body (10) at the solder spreading area (11) is a, and the outer diameter of the main body part (21) is D, wherein |D-a|≤1mm; And / or, the width of the solder spreading area (11) is d, and d≥1mm; And / or, the depth of the welding groove (1001) is f, and the wall thickness of the valve body (10) is g, wherein 0.1≤f / g≤0.5; And / or, the welding groove (1001) comprises the first taper surface (202) and the second taper surface (102), and the included angle formed by the first taper surface (202) and the second taper surface (102) is e, and 70°≤e≤120°.

6. The ball valve of claim 3, wherein The flow-through hole (201) comprises a first hole section (2011) arranged at one end of the flow-through hole (201) close to the valve cavity (101); The ball valve further comprises a valve core (40) rotatably installed in the valve cavity (101) and a sealing member (50) installed in the first hole section (2011) to seal the valve core (40) and the end cover (20).

7. The ball valve of claim 6, wherein The bottom wall of the first hole section (2011) is axially protruded to form a limiting portion (24) which abuts against the sealing member (50).

8. The ball valve of claim 7, wherein, The limiting portion (24) is configured as a limiting protruding ring extending in a ring shape. Alternatively, the limiting portion (24) is configured as a plurality of limiting protrusions which are arranged in a circumferential direction of the end cover (20).

9. The ball valve of claim 3, wherein The outer diameter of the main body portion (21) is D, the thickness of the main body portion (21) is G, and G≥D / 20.

10. The ball valve of claim 3, wherein The flow-through hole (201) further comprises a second hole section (2012) arranged at one end of the flow-through hole (201) close to the connector (30), and the connector (30) is inserted into the second hole section (2012) and abuts against the bottom wall of the second hole section (2012).

11. The ball valve of claim 10, wherein, The end cover (20) further comprises a second connecting portion (23) protruding from one end of the main body portion (21) away from the first connecting portion (22), and the second hole section (2012) is at least partially arranged in the second connecting portion (23); wherein the wall thickness of the connector (30) is T, the inner diameter of the second hole section (2012) is A, and 0.05mm≤A-T≤0.5mm; and / or, the wall thickness of the second connecting portion (23) is B, and 1≤B / T≤2; and / or, the depth of the second hole section (2012) is C, and C / T≥0.8; and / or, the outer diameter of the main body portion (21) is D, the height of the second connecting portion (23) protruding from the main body portion (21) is F, and F≥D / 15.

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