Reinforced tire lining belt

Abstract

The utility model provides a reinforced tire lining belt which comprises an annular wall main body and two fins connected to the two axial ends of the annular wall main body, the two fins extend outwards in the axial direction and extend outwards in the radial direction, a receiving space is formed by the two fins and the peripheral wall of the annular wall main body, and the receiving space is communicated with the annular wall main body. The receiving space is used for receiving an inner tube of a tire, and the inner peripheral wall of the annular wall main body is used for abutting against a rim; the joints of the two ends of the annular wall body and the two fins are each provided with an arc transition section, and the thickness of each arc transition section is larger than or equal to 12 mm. After the thickness of the arc transition section is increased, the technical problem of stress tearing prevention which can be achieved by two lining belts originally can be solved only by using a single lining belt, and more convenience is achieved in the installation process.

Description

Technical Field

[0001] The utility model relates to a reinforced tire lining. Background Art

[0002] Existing high-load tires generally include a rim, an outer tire, an inner tire, a lining strip and a rim. The rim includes a rim body and a rim snap ring. The rim body includes an intermediate shaft column and a first side wing fixedly connected to one end of the intermediate shaft column. The rim snap ring is sleeved on the other end of the intermediate shaft column by sleeve connection, and a matching gap is formed between the rim snap ring and the intermediate shaft column. During the tire assembly process, the inner tire needs to be placed in the outer tire first, and then the lining strip is placed at the inner annular opening of the outer tire. The assembled outer tire, inner tire and lining strip are installed by aligning the center of the outer tire with the intermediate shaft column, and then the rim snap ring is sleeved on the other end of the intermediate shaft column. The lining strip includes an intermediate ring wall and a first wing and a second wing connected to the axial ends of the intermediate ring wall. After the tire is installed as a whole, the inner side of the intermediate ring wall is pressed against the intermediate shaft column of the rim, and the first wing and the second wing are pressed against the outer tire. The thickness of the connection transition between the middle ring wall and the first wing and the second wing gradually becomes thinner toward the side, and its thickness is between 8 mm and 8.3 mm. When the inner tube is inflated and pressurized or used in a high-load environment, the first wing or the second wing will be squeezed toward the fitting gap under the extrusion of the inner tube, and linear stress concentration will be formed on the first wing and the second wing, thereby causing stress tearing.

[0003] To deal with this problem, a method is to use double lining tapes to increase the overall thickness of the lining tape. When the outer lining tape is damaged, the inner lining tape can still function. However, the problem is that the installation of double lining tapes is more troublesome and takes more time. Utility Model Content

[0004] The utility model aims to overcome the disadvantage of the double-strip lining in the prior art that the installation is troublesome, and to provide a reinforced tire lining, which is thickened at the connection between the annular wall body and the wing to prevent stress concentration tearing.

[0005] In order to solve the above technical problems, the utility model provides a reinforced tire lining belt, comprising an annular wall body and two winglets connected to the two axial ends of the annular wall body, the two winglets extend axially outward and radially outward, the two winglets and the outer peripheral wall of the annular wall body form a receiving space, the receiving space is used to receive the inner tube of the tire, and the inner peripheral wall of the annular wall body is used to abut against the rim;

[0006] The connection between the two ends of the annular wall body and the two fins also includes an arc transition section respectively, and the thickness of the arc transition section is greater than or equal to 12 mm and less than or equal to 16 mm.

[0007] In a more preferred embodiment, the extension length between the axial inner end and the axial outer end of the arc transition section is less than or equal to 50 mm.

[0008] In a more preferred embodiment, the axial arc length interval between the axial inner ends of the two circular arc transition sections is less than or equal to 128 mm;

[0009] The axial arc length interval between the axial outer ends of the two arc transition sections is greater than or equal to 137 mm;

[0010] The extending length between the axial inner end and the axial outer end of the arc transition section is greater than or equal to 9 mm.

[0011] In a more preferred embodiment, the axial arc length interval between the axial inner ends of the two circular arc transition segments is less than or equal to 110 mm;

[0012] The axial arc length interval between the axial outer ends of the two circular arc transition sections is greater than or equal to 150 mm.

[0013] In a more preferred embodiment, the thickness of the arc transition section is uniformly thickened to 14.4 mm from the axial inner end to the axial outer end.

[0014] In a more preferred embodiment, the outer circumferential wall of the wing is provided with a first arc segment and a first straight line segment in sequence along the direction away from the annular wall body, and the inner circumferential wall of the wing is provided with a second arc segment and a second straight line segment in sequence along the direction away from the annular wall body, the first arc segment and the second arc segment correspondingly form the arc transition segment, and the ends of the first straight line segment and the second straight line segment are connected.

[0015] In a more preferred embodiment, the inner circumferential wall of the annular wall body is recessed to form an inner groove, the inner groove extends along the circumferential direction, and a plurality of patterned protrusions arranged in an array are convexly provided on the bottom wall of the inner groove;

[0016] The axial outer side of the inner groove is arranged close to the axial inner end of the circular arc transition section.

[0017] In a more preferred embodiment, the cross-sectional area of ​​the pattern lug gradually decreases in a direction away from the groove bottom wall.

[0018] In a more preferred embodiment, the two axial sides of the inner groove form a full circle of line-surface contact connection with the rim, and the pattern protrusion is connected to the rim through surface contact.

[0019] In a more preferred embodiment, the thickness distance between the bottom wall of the inner groove and the outer peripheral wall of the annular wall body is smaller than the thickness of the circular arc transition section.

[0020] Compared with the prior art, the technical solution of the utility model has the following beneficial effects:

[0021] 1. The thickness of the arc transition section is greater than or equal to 12 mm and less than or equal to 16 mm, which can prevent stress tearing caused by linear stress concentration. Even if part of the arc transition section is torn, the wing will not fail directly due to the thick thickness of the arc transition section, and can still maintain the same performance as the existing lining tape. After the thickness of the arc transition section is thickened, only a single lining tape can be used to achieve the technical problem of stress tearing prevention that can only be achieved with two lining tapes, which is more convenient during the installation process.

[0022] 2. The axial spacing between the axial inner ends of the two arc transition sections is less than or equal to 110 mm [covering 128 mm (twice 64 mm) in this example; (twice 64 mm), it should be noted that 128 mm is the actual measured value of the fault position, and the actual fault may shift to the left or right, so the standard allowable error is 130±20]; the axial spacing between the axial outer ends of the two arc transition sections is greater than or equal to 150 mm [covering 137 mm (twice 68.5 mm) in this example. mm (twice 68.5 mm), it should be noted that 137 mm is the actual measured value of the fault position, and the actual fault may shift to the left or right, so the standard allowable error is 130±20]. If set in this way, it can be ensured that the reinforced tire lining can have the corresponding anti-stress tearing effect when used between 8.6" wide rims and 9" wide rims. After stress tearing occurs on one wing (due to its thickness, it will not be completely torn), the wing can be turned around and the wing on the other side that has not been torn can be used to fit the gap. Therefore, the reinforced tire lining in this application can be used twice, saving costs.

[0023] 3. The inner circumferential wall of the annular wall body is recessed to form an inner groove, the inner groove extends along the circumferential direction, and the groove bottom wall of the inner groove is convexly provided with a plurality of pattern protrusions arranged in an array; the axial outer side of the inner groove is arranged close to the axial inner end of the arc transition section. The groove bottom wall of the inner groove is spaced apart from the outer surface of the central shaft column of the rim, so that the heat transfer path is blocked by air, and because the axial sides of the inner groove are supported on the central shaft column, and the axial sides of the inner groove are supported on the central shaft column by the pattern protrusions, a gap is formed between the groove bottom wall of the inner groove and the outer surface of the central shaft column.

[0024] 4. The two axial sides of the inner groove form a full circle of line contact connection with the rim, and the pattern protrusion is connected to the rim through surface contact. Since the pattern protrusion is located between the two axial sides of the inner groove, the annular wall body is supported between the two axial sides of the inner groove and the rim, and the pattern protrusion is supported between the middle part of the central axis column of the rim. After reducing the contact area with the rim, a better support effect can still be achieved. In addition, since the axial outer side of the inner groove is arranged close to the axial inner end of the arc transition section, the thickness of the two axial sides of the inner groove is relatively thick, and the support strength is relatively high. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the connection between the reinforced tire lining and the 8.6" wheel rim in the preferred embodiment of the utility model;

[0026] Figure 2 This is a schematic diagram of the connection between the reinforced tire lining and the 9" wheel rim in the preferred embodiment of the utility model;

[0027] Figure 3 A cross-sectional schematic diagram of a tire in a preferred embodiment of the utility model;

[0028] Figure 4 It is a cross-sectional schematic diagram of a reinforced tire lining in a preferred embodiment of the utility model;

[0029] Figure 5 This is a cross-sectional schematic diagram of a wheel rim in a preferred embodiment of the utility model;

[0030] Figure 6 It is a cross-sectional view of a reinforced tire lining in a preferred embodiment of the utility model;

[0031] Figure 7 It is a schematic plan view of the inner peripheral wall of the reinforced tire lining in the preferred embodiment of the utility model;

[0032] Figure 8 It is a side view of the patterned protrusion in the preferred embodiment of the utility model. DETAILED DESCRIPTION

[0033] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods.

[0034] The following limits the orientation: Figure 1 The X-axis shown is the axial direction of the tire, the Y-axis is the radial direction of the tire, the side close to the Y-axis is defined as the inner side, the side away from the Y-axis is defined as the outer side, and the direction perpendicular to the paper is the circumferential direction.

[0035] See also Figure 1-Figure 8The utility model provides a reinforced tire lining 1 including an annular wall body 11 and two winglets 12 connected at two axial ends of the annular wall body 11, the two winglets 12 extend axially outward and radially outward, the two winglets 12 and the outer peripheral wall 113 of the annular wall body 11 form a receiving space 13, the receiving space 13 is used to receive the inner tube 2, the inner peripheral wall 112 of the annular wall body 11 is used to abut the rim 4, the two winglets 12 are clamped between the inner tube 2 and the outer tube 3; the connection between the two ends of the annular wall body 11 and the two winglets 12 also includes a circular arc transition section 123, and the thickness of the circular arc transition section 123 is greater than or equal to 12 mm.

[0036] See also Figure 1-Figure 8 The utility model provides a tire, the tire comprises an inner tube 2, an outer tube 3, a rim 4 and the aforementioned reinforced tire lining strip 1. The rim 4 comprises a rim body 41 and a rim snap ring 42, the rim body 41 comprises an intermediate shaft column 411 and a first side wing 412 fixedly connected to the first end of the intermediate shaft column 411, the rim snap ring 42 is fitted and sleeved on the second end of the intermediate shaft column 411, a second side wing 413 is arranged on the axial outer side of the rim snap ring 42, the second end of the intermediate shaft column 411 is a shrinking structure 4111, the rim snap ring 42 is sleeved outside the shrinking structure 4111, and a fitting gap 43 is formed between the end of the rim snap ring 42 and the shrinking structure 4111.

[0037] The inner tube 2 is a conventional pneumatic inner tube 2 , and the outer tube 3 is a conventional rubber outer tube 3 . The outer tube 3 includes an inner annular opening 31 , and the inner tube 2 is loaded into the outer tube 3 through the inner annular opening 31 .

[0038] During installation, the inner tube 2 is first placed in the outer tube 3, and then the two winglets 12 of the reinforced tire lining strip 1 are respectively installed from the axial sides 1111 of the inner annular opening 31, and the two winglets 12 are respectively clamped between the inner tube 2 and the outer tube 3. Subsequently, the second end of the intermediate shaft column 411 is passed through the reinforced tire lining strip 1, and then the rim clamp ring 42 is sleeved on the shrinking structure 4111 to complete the installation. The installation process also involves the arrangement of the valve nozzle, which is irrelevant to the main purpose of the utility model and will not be repeated here.

[0039] After the installation is completed, the inner tube 2 can be inflated and pressurized. At this time, the inner tube 2 will squeeze the outer wall 113 of the annular wall body 11 and the radial outer sides of the two winglets 12. The inner wall 112 of the annular wall body 11 will be attached to the middle shaft column 411 of the rim 4, and the radial inner sides of the two winglets 12 will be attached to the outer tube 3.

[0040] The connection between the two ends of the annular wall body 11 and the two fins 12 also includes an arc transition section 123, and the thickness of the arc transition section 123 is greater than or equal to 12 mm. One end of the arc transition section 123 is formed at the end of the annular wall body 11. After the inner tube 2 is inflated and pressurized, the two fins 12 will deflect with the arc transition section 123 as the center. At this time, the arc transition section 123 will correspond to the fitting gap 43. When the tire pressure of the inner tube 2 is high, the arc transition section 123 will be partially inserted into the fitting gap 43. The thickness of the arc transition section 123 is greater than or equal to 12 mm, which can prevent the phenomenon of stress tearing caused by linear stress concentration. Even if part of the arc transition section 123 is torn, due to the thick thickness of the arc transition section 123, the fin 12 will not fail directly, and can still maintain the same performance as the existing lining belt. After the thickness of the arc transition section 123 is increased, the technical problem of stress tear prevention that could only be achieved with two lining strips can be achieved with only a single lining strip, which is more convenient during the installation process.

[0041] More specifically, the thickness of the circular arc transition section 123 is greater than or equal to 12 mm and less than or equal to 16 mm, and the thickness of the circular arc transition section 123 is uniformly thickened to 14.4 mm from the axial inner end 1231 to the axial outer end 1232 .

[0042] In this embodiment, the extension length L between the axial inner end 1231 and the axial outer end 1232 of the circular arc transition section 123 is less than or equal to 50 mm. The extension length L between the axial inner end 1231 and the axial outer end 1232 of the circular arc transition section 123 is greater than or equal to 9 mm (the 9 mm is the difference between 137 mm and 128 mm mentioned below). The circular arc transition section 123 with a certain length can ensure a certain installation margin during installation and use.

[0043] In addition, during the research and development process, the applicant also found that the rims are non-standard parts, and the widths of the rims produced by various manufacturers are different. For high-load tires, the width of the rims is between 8.6" and 9". When rims of different widths are used, the position of the fitting gap will also change, and the changed position will be offset from the specific thickened part of the first wing or the second wing, which is prone to stress tearing.

[0044] During the actual research and development process, the applicant found that when the reinforced tire lining 1 is used on a 8.6" wide rim 4, the stress tearing position occurs at 64 mm from the Y axis; when the reinforced tire lining 1 is used on a 9" wide rim 4, the stress tearing position occurs at 68.5 mm from the Y axis. Therefore, the applicant sets the extension length L of the arc transition section 123 so that: the axial arc length interval H between the axial inner ends 1231 of the two arc transition sections 123 is less than or equal to 110 mm [covering 128 mm (twice 64 mm), it should be noted that 128 mm is the actual measured value of the fault position, and the actual fault may shift to the left or right, so the standard tolerance is 130±20]; the axial interval H between the axial outer ends 1232 of the two arc transition sections 123 is greater than or equal to 150 mm [covering 137 mm (twice 68.5 mm), it should be noted that 137 mm is the actual measured value of the fault position, and the actual fault may shift to the left or right, so the standard tolerance is 130±20]. If set in this way, it can be ensured that the reinforced tire lining 1 can have the corresponding anti-stress tearing effect when used between the 8.6" wide rim 4 and the 9" wide rim 4. After stress tearing occurs on the wing 12 on one side (due to its thickness, it will not be completely torn), the wing 12 can be turned around and the wing 12 on the other side without tearing can be used to match the gap 43. Therefore, the reinforced tire lining 1 in the present application can be used twice, saving costs.

[0045] During the actual research and development process, the applicant found that due to the high load-bearing capacity of the high-load tire, the inner circumferential wall of the annular wall will be close to the middle shaft column 411 of the rim 4. Since the brake pad of the vehicle rubs against the rim 4 to brake the vehicle, the temperature of the rim 4 rises. Since the reinforced tire lining 1 is close to the rim 4 and the reinforced tire lining 1 is made of rubber material, the heat is completely transferred to the annular wall body 11 of the reinforced tire lining 1, so that the overall temperature of the wheel lining increases, and the strength of the tire decreases, making the arc transition section 123 more susceptible to stress tearing. At the same time, the heat will be transferred to the outer tire and inner tube matched therewith, so that the performance of the outer tire and inner tube decreases.

[0046] The inner circumferential wall 112 of the annular wall body 11 is recessed to form an inner groove 111, and the inner groove 111 extends for one circle along the circumferential direction. The groove bottom wall of the inner groove 111 is convexly provided with a plurality of pattern protrusions 114 arranged in an array; the axial outer side of the inner groove 111 is arranged close to the axial inner end 1231 of the arc transition section 123. The groove bottom wall of the inner groove 111 is spaced apart from the outer surface of the central shaft column of the rim 4, so that the heat transfer path is blocked by air, and since the axial sides 1111 of the inner groove 111 are supported on the central shaft column, and the axial sides 1111 of the inner groove 111 are supported on the central shaft column by the pattern protrusions 114, a gap is formed between the groove bottom wall of the inner groove 111 and the outer surface of the central shaft column.

[0047] The applicant found that if the inner groove 111 is not provided, due to the high temperature of the rim 4 and the high positive pressure of the inner tube 2 on the reinforced tire lining 1, the pattern protrusion 114 is simply used to abut against the rim 4. After a period of use, the pattern protrusion 114 will be continuously melted away until the height of the pattern protrusion 114 is reduced to 0, and the heat dissipation effect between the reinforced tire lining 1 and the rim 4 will be sharply reduced to 0. Moreover, after use under high pressure and high temperature, when the reinforced tire lining 1 needs to be removed from the rim 4, the reinforced tire lining 1 will directly melt and stick to the rim 4, which is very troublesome to remove.

[0048] The axial sides 1111 of the inner groove 111 form a full circle of line-surface contact connection with the rim 4, and the pattern protrusion 114 is connected to the rim 4 through surface-surface contact. Since the pattern protrusion 114 is located between the axial sides 1111 of the inner groove 111, the annular wall body 11 is supported between the axial sides 1111 of the inner groove 111 and the rim 4, and the pattern protrusion 114 is supported between the middle part of the central axis column of the rim 4, and after reducing the contact area with the rim 4, a better support effect can still be achieved. In addition, since the axial outer side of the inner groove 111 is arranged close to the axial inner end 1231 of the arc transition section 123, the thickness of the axial sides 1111 of the inner groove 111 is relatively thick, and the support strength is relatively high.

[0049] In this embodiment, the cross-sectional area of ​​the pattern protrusion 114 gradually decreases in the direction away from the bottom wall of the groove. The bottom of the pattern protrusion 114 can be made larger to enhance the supporting force. The pattern protrusions 114 evenly distributed on the inner circumference are larger and stronger (step-type), and they are sunk. The upper surface of the pattern protrusion 114 does not protrude or only slightly protrude from the inner circumferential plane of the lining belt, so that the pattern protrusion 114 has less wear and tear, and maintains its support and heat dissipation functions for a longer time. The running test was conducted in the laboratory under more stringent use conditions than the market, and the pattern was almost wear-free (1.6mm before use → 1.45mm after use).

[0050] In this embodiment, the thickness of the annular wall body 11 is greater than or equal to 10 mm and less than or equal to 14 mm. The thickness of the annular wall body 11 can be thickened to adapt to the thickened arc transition section 123, which is more convenient for production. The thickness of the annular wall body 11 here refers to the thickness distance between the top of the pattern protrusion 114 and the outer peripheral wall 113 of the annular wall body 11.

[0051] The patterned protrusions 114 arranged on the inner groove 111 of the inner peripheral wall 112 of the annular wall body 11 further enhance the grade of the appearance; it can make a gap between the inner peripheral wall 112 of the annular wall body 11 and the rim 4, which makes it easier to dissipate heat and less likely to stick to the rim 4, which can significantly improve its disassembly workability. The area where the patterned protrusions 114 are set sinks, and the patterned blocks become stepped (large base and small top), which not only ensures the support strength, but also enhances the heat dissipation. In addition, this design change reduces the wear of the patterned protrusions 114 and increases the service life of the reinforced tire lining 1.

[0052] The thickness of the annular wall body 11 is thicker than that of the conventional reinforced tire lining 1, which improves the strength and is not easy to be damaged. More specifically, the thickness of the annular wall body 11 is 11.6 mm.

[0053] In this embodiment, the thickness of the pattern block 114 is greater than or equal to 1.2 mm and less than or equal to 2.0 mm. More specifically, the thickness of the pattern block 114 is 1.6 mm.

[0054] In this embodiment, the top of the pattern protrusion 114 is higher than the inner groove 111. The top of the pattern protrusion 11412 directly abuts against the rim 4 to improve the heat dissipation effect.

[0055] In this embodiment, the thickness spacing T1 between the bottom wall of the inner groove 111 and the outer peripheral wall 113 of the annular wall body 11 is smaller than the thickness of the arc transition section 123. The beneficial effect achieved is that the annular wall body 11 of the reinforced tire lining 1 is thinner than the arc transition section 123, which can make the annular wall body 11 easier to bend and convenient for installation and removal.

[0056] In this embodiment, the outer peripheral wall 122 of the winglet 12 is provided with a first arc segment 1221 and a first straight segment 1222 in sequence along the direction away from the annular wall body 11, and the inner peripheral wall 121 of the winglet 12 is provided with a second arc segment 1211 and a second straight segment 1212 in sequence along the direction away from the annular wall body 11, the first arc segment 1221 and the second arc segment 1211 form the arc transition segment 123 correspondingly, and the first straight segment 1222 and the second straight segment 1212 are connected at their ends. The first straight segment 1222 is used to abut against the inner tube 2, and the second straight segment 1212 is used to abut against the outer tube 3. Both the first straight segment 1222 and the second straight segment 1212 are straight lines, and the first straight segment 1222 and the second straight segment 1212 have a better fit with the inner tube 2 and the outer end.

[0057] The above is only a preferred specific implementation method of the utility model, but the design concept of the utility model is not limited to this. Any technician familiar with the technical field who uses this concept to make non-substantial changes to the utility model within the technical scope disclosed by the utility model shall be deemed to infringe the protection scope of the utility model.

Claims

1. A reinforced tire lining, characterized in that: It comprises an annular wall body and two fins connected to the two axial ends of the annular wall body, the two fins extend axially outward and radially outward, the two fins and the outer peripheral wall of the annular wall body form a receiving space, the receiving space is used to receive the inner tube of the tire, and the inner peripheral wall of the annular wall body is used to abut against the rim; The connection between the two ends of the annular wall body and the two fins also includes an arc transition section respectively, and the thickness of the arc transition section is greater than or equal to 12 mm and less than or equal to 16 mm.

2. A reinforced tire lining according to claim 1, characterized in that: The extending length between the axial inner end and the axial outer end of the arc transition section is less than or equal to 50 mm.

3. A reinforced tire lining as claimed in claim 2, characterized in that: The axial arc length interval between the axial inner ends of the two circular arc transition sections is less than or equal to 128 mm; The axial arc length interval between the axial outer ends of the two arc transition sections is greater than or equal to 137 mm; The extending length between the axial inner end and the axial outer end of the arc transition section is greater than or equal to 9 mm.

4. A reinforced tire lining as claimed in claim 1, characterized in that: The axial arc length interval between the axial inner ends of the two arc transition sections is less than or equal to 110 mm; The axial arc length interval between the axial outer ends of the two circular arc transition sections is greater than or equal to 150 mm.

5. A reinforced tire lining as claimed in claim 1, characterized in that: The thickness of the arc transition section increases uniformly from the axial inner end to the axial outer end to 14.4 mm.

6. A reinforced tire lining as claimed in claim 1, characterized in that: The outer circumferential wall of the wing is provided with a first arc segment and a first straight line segment in sequence along the direction away from the annular wall body, and the inner circumferential wall of the wing is provided with a second arc segment and a second straight line segment in sequence along the direction away from the annular wall body, the first arc segment and the second arc segment correspondingly form the arc transition segment, and the ends of the first straight line segment and the second straight line segment are connected.

7. A reinforced tire lining according to any one of claims 1 to 6, characterized in that: The inner circumferential wall of the annular wall body is recessed to form an inner groove, the inner groove extends along the circumferential direction, and a plurality of patterned protrusions arranged in an array are convexly provided on the bottom wall of the inner groove; The axial outer side of the inner groove is arranged close to the axial inner end of the circular arc transition section.

8. A reinforced tire lining as claimed in claim 7, characterized in that: The cross-sectional area of ​​the pattern lug gradually decreases along the direction away from the groove bottom wall.

9. A reinforced tire lining as claimed in claim 7, characterized in that: A full circle of line-surface contact connection is formed between the axial two sides of the inner groove and the rim, and the pattern protrusion is connected to the rim through surface contact.

10. A reinforced tire lining as claimed in claim 7, characterized in that: The thickness spacing between the bottom wall of the inner groove and the outer peripheral wall of the annular wall body is smaller than the thickness of the circular arc transition section.

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