Assembly method and assembly tool for metal shell with lifting lugs

Abstract

According to the assembling method and the assembling tool for the metal shell with the lifting lug, a coaxiality control tool is utilized, the original technological process of scribing, assembling and positioned welding is simplified into assembling and positioned welding, and the assembling of the metal shell with an external characteristic structure is achieved through the coaxiality control tool, a welding auxiliary tool and positioned welding. And the positioned welding procedure is completed under the condition that a tool exists. By means of the coaxiality control tool, the multiple lifting lugs and the barrel are assembled and positioned at a time. The coaxiality control tool has the characteristic of flexibility, and by designing and replacing the sizes of the inner molded surface sliding block and the outer molded surface sliding block and adjusting the positions of the inner molded surface sliding block and the outer molded surface sliding block on the stand column, assembling and positioning of lifting lugs of various sizes are achieved. Product verification shows that the coaxiality of the lifting lugs is smaller than 0.3 mm, the out-of-tolerance situation caused by manual alignment assembly is avoided, and the assembly precision is effectively guaranteed. And moreover, the assembling complexity is reduced, the production efficiency is improved, and the whole assembling and positioning process saves 8-10 minutes compared with the prior art.

Description

Technical Field

[0001] The invention relates to the field of pressure vessel shell manufacturing, in particular to a method capable of ensuring the assembly accuracy of a shell with multiple lifting ears. Background Art

[0002] A pressure vessel product is welded from multiple lifting lugs and a cylinder. The characteristic structure of this product requires that the coaxiality of the lifting lugs after welding should not exceed 0.5mm, and sufficient machining margin should be left for the next machining process. The early assembly method uses pre-marking and manual assembly. This assembly method is highly dependent on manual labor and the assembly coaxiality cannot be effectively guaranteed. There is a problem of multiple repairs and reassemblies due to coaxiality deviation, which affects production efficiency.

[0003] A utility model patent with the announcement number CN216263971U discloses a tool for argon arc welding that can ensure coaxiality. The tool proposes to use a lower support and a top pressure cover mechanism to locate and constrain the coaxiality of the parts to be welded through the coaxiality of the positioning pin. Although the tool has a simple structure, it cannot meet the requirements of simultaneous positioning welding of more than two rotating parts.

[0004] The invention patent with the announcement number CN113977486B discloses a positioning mechanism and assembly method for maintaining the coaxiality of the refiner discs of a double-disc refiner. The method proposes to limit the movement of the machine body and the machine cover by bolt connection, and then to coordinate the position of the pin holes on the positioning plate, so as to effectively ensure the coaxiality of the machine body and the machine cover. However, the tooling does not consider the adjustment of the misalignment after the parts are assembled. Summary of the invention

[0005] In order to overcome the deficiency in the prior art that both assembly efficiency and precision cannot be taken into consideration at the same time, the present invention proposes an assembly method and assembly tool for a metal shell with a lifting ear.

[0006] The present invention is an assembly method of a metal shell with a lifting ear. The metal shell with the lifting ear is a multi-section structure, each section is welded by a lifting ear and a cylindrical part; the lifting ear is annular, and a radially protruding lifting block is provided on the outer circumference of the annular ring; the lifting block cooperates with a slider on an assembly tool to realize the assembly of the metal shell with the lifting ear. The lifting ear is divided into an outer profile lifting ear and an inner profile lifting ear according to the profile of the matching lifting block and the slider.

[0007] The specific process is:

[0008] Step 1, initial assembly:

[0009] According to the design, the cylindrical part in the metal shell assembled with the lifting ear is vertically placed on the upper surface of the bottom plate of the coaxiality control tooling. The lifting ear is placed on the upper end surface of the cylindrical part and the two are coaxial. The lifting ear is an outer profile lifting ear or an inner profile lifting ear.

[0010] When the external surface lifting ear is used, the external surface slider of the coaxiality control tooling is embedded in the slider groove on the column according to the axial size of the lifting ear, so that the external surface slider is fully constrained to ensure that no movement and circumferential rotation occur during the assembly process, and the inner surface of the external surface slider groove on the external surface slider is fit with the two side surfaces of the lifting ear.

[0011] When an inner profile lifting ear is used, the inner profile slider of the coaxiality control tooling is embedded in the slider groove on the column according to the axial size of the lifting ear, so that the inner profile slider is fully constrained to ensure that no movement or circumferential rotation occurs during the assembly process, and the surfaces on both sides of the inner profile slider are fitted with the inner surface of the lifting ear.

[0012] Step 2, assemble the first section.

[0013] The misalignment and gap between the first cylindrical part and the first lifting ear are adjusted by welding fixture so that the misalignment is less than 0.2 mm and the gap is less than 0.3 mm.

[0014] The limiting rod is slid along the slide groove (7) in the bottom plate, so that the inner surface of the limiting rod contacts the outer circumferential surface of the cylindrical member and the limiting rod is fixed by a tightening bolt to constrain the cylindrical member. The first cylindrical member and the first lifting ear are assembled in place to complete the assembly of the first section.

[0015] There are multiple welding tools, which are used for assembling each section respectively; the welding tool comprises a circular top cylinder, an adjusting bolt and an adjusting nut. When in use, the circular top cylinder is sleeved on the outer circumference of the cylindrical part, and the circular top cylinder is made coaxial with the cylindrical part, and then the misalignment and gap between the cylindrical part and the lifting ear are adjusted by adjusting the tightness of the adjusting bolt.

[0016] Step 3, assemble the remaining sections.

[0017] Repeat step 2 to continue assembling the cylindrical piece and other lifting ears. Specifically,

[0018] Place the second cylindrical part on the upper end surface of the first hanging ear; and fit the second welding tool onto the second cylindrical part according to the method for assembling the first cylindrical part. Repeat the process of adjusting the misalignment and gap between the cylindrical part and the hanging ear during the first stage of assembly to adjust the misalignment and gap between the second cylindrical part and the first hanging ear.

[0019] Place the second lifting ear on the upper end surface of the second cylindrical member; match and fix the inner profile slider or the outer profile slider with the profile of the lifting ear. Repeat the process of adjusting the misalignment and gap between the second cylindrical member and the first lifting ear to adjust the misalignment and gap between the second lifting ear and the second cylindrical member.

[0020] At this point, the second section of assembly is completed.

[0021] Repeat the assembly process between the second cylindrical member and the second lifting ear to complete the assembly of the remaining sections in sequence.

[0022] Step 4, positioning welding.

[0023] After the assembly of the remaining sections is completed in sequence, argon arc welding is used to spot weld the welds according to the process requirements. During positioning welding, the positioning welding points are required to be evenly distributed, with every two positioning points forming a group, and a group of welding points is symmetrically distributed at 180°.

[0024] After completing the spot welding positioning of each weld position, the metal shell with the lifting lug is welded according to the process requirements.

[0025] At this point, the welding assembly of the metal shell with lifting ears is completed.

[0026] The coaxiality control tooling for the metal shell equipped with the lifting ear proposed by the present invention comprises a base plate, a slider, a column and a limit rod; the slider comprises an inner profile slider and an outer profile slider. The column is vertically welded and fixed on the surface of the base plate, and the geometric center of the column is located on the center line of the width direction of the base plate; the distance between the surface of the side of the column close to the limit rod and the edge of the base plate must be greater than the outer diameter of the cylindrical member.

[0027] A surface of the bottom plate in the length direction is provided with a pair of limit rod sliding grooves for assembling the limit rod and extending along the length of the bottom plate.

[0028] A plurality of slider grooves are evenly distributed on one side surface of the column along the height direction; the sliders are respectively embedded and fixed in the slider grooves on the surface of the column; the number of the sliders increases or decreases according to the number of the lifting ears.

[0029] The limiting rod is located on the upper surface of the bottom plate, and the two ends of the limiting rod are clamped in a pair of limiting rod sliding grooves on the upper surface of the bottom plate; a tightening bolt is arranged on the limiting rod.

[0030] After welding and assembly, the verticality between the column and the base plate is ≤0.2°.

[0031] The geometric center distance between adjacent slider slots is 50 mm.

[0032] The outer profile slider is in a concave shape, and the inner groove surface is the profile that matches the outer profile ear; the two side surfaces of the inner profile slider are the profiles that match the inner profile ear. The structure of the outer profile slider is similar to that of the inner profile slider, except that the top surface of the outer profile slider is processed with a slider groove, and the size of the slider groove profile matches the radial size of the ear to prevent it from rotating around the axis during assembly.

[0033] The present invention aims to address the shortcoming of existing assembly methods that both assembly efficiency and precision cannot be taken into account at the same time. By designing a coaxiality control tool, in combination with conventional welding tool and a reasonable positioning welding method, the present invention can efficiently realize the assembly of a metal shell with multiple lifting ears.

[0034] The present invention utilizes coaxiality control tooling to simplify the original process flow: marking → assembly → tack welding to assembly → tack welding, thereby eliminating the marking process. The specific method is as follows:

[0035] First, place the port of the cylindrical part to be assembled with the lifting ear on the upper surface of the base plate. Then, align and install the outer profile slider in the appropriate slot in the column according to the axial size of the lifting ear, and use M10 bolts to tighten and fix the outer profile slider to make it fully constrained to ensure that no movement or rotation occurs during the assembly process. The outer profile of the lifting ear structure is fitted with the inner surface of the groove of the outer profile slider 3 to prevent it from rotating around the axis. At the same time, the port of the cylindrical part is preliminarily aligned with the port with the lifting ear. The cylindrical part can support the lifting ear and prevent the lifting ear from falling directly. Conventional welding tooling is used to adjust the misalignment and gap between the cylindrical part and the lifting ear to meet the welding process requirements. The misalignment is not greater than 0.2mm and the gap is less than 0.5mm. Then adjust the position of the limit rod along the direction of the slide groove in the base plate 1 to constrain the movement of the cylindrical part. After adjusting the position, use two M6 bolts to clamp and fix the limit rod 5. In this way, the assembly of a cylindrical part and a lifting ear is completed. After the assembly is completed, under the condition of tooling, manual argon arc welding is used to complete the positioning welding process by symmetrical positioning spot welding.

[0036] The key technology in the present invention is:

[0037] 1. Through the coaxiality control tooling, welding auxiliary tooling and positioning welding, the metal shell assembly with external characteristic structure is realized.

[0038] 2. Coaxiality controls the overall structure of the tooling.

[0039] The present invention utilizes a coaxiality control tool to realize one-time assembly and positioning of multiple lifting ears and cylinders. The coaxiality control tool has the characteristics of flexibility, and the assembly and positioning of lifting ears of various sizes can be realized by designing and replacing the sizes of the inner surface slider and the outer surface slider and adjusting the positions of the inner surface slider and the outer surface slider on the column. According to product verification, the present invention can control the coaxiality of the lifting ear within 0.3mm, avoiding the out-of-tolerance situation that occurs in the existing manual alignment assembly, and effectively ensuring the assembly accuracy. At the same time, the assembly method of the present invention reduces the complexity of assembly compared to the existing assembly method, improves production efficiency, and the entire assembly and positioning process saves 8 to 10 minutes compared to the existing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1It is the overall assembly drawing of the coaxiality control tooling.

[0041] Figure 2 is a schematic diagram of the structure of the inner surface slider; Figure 2 a is the main view, Figure 2 b is the right view.

[0042] Figure 3 It is a schematic diagram of the structure of the outer surface slider; Figure 3 a is the main view, Figure 3 b is the right view.

[0043] Figure 4 is a schematic diagram of the structure of the column; Figure 4 a is the main view, Figure 4 b is Figure 4 a in the AA direction view, Figure 4 c is Figure 4 Partial enlarged view of position I in b

[0044] Figure 5 It is a structural diagram of the lifting lug.

[0045] In the figure: 1. bottom plate; 2. inner surface slider; 3. outer surface slider; 4. column; 5. limit rod; 6. lifting ear; 7. slide groove. DETAILED DESCRIPTION

[0046] This embodiment is a method for assembling a metal shell with lifting ears.

[0047] The metal shell with the lifting lug is a multi-section structure, each section is welded together by a lifting lug and a cylindrical part; the structure of the lifting lug is shown in FIG. Figure 4 The assembly requirements of the metal shell must ensure that the coaxiality of the lifting lug is ≤0.5mm; the misalignment is <0.2mm, the gap is <0.5mm, and the welding process requirements are met.

[0048] The lifting lug is in the shape of a ring, and a radially protruding lifting block is provided on the outer circumference of the ring; the lifting block cooperates with a slider on an assembly tool to realize the assembly of the metal shell with the lifting lug. The lifting lug is divided into an outer profile lifting lug and an inner profile lifting lug according to the profile of the matching between the lifting block and the slider.

[0049] The specific process of the present invention is:

[0050] Step 1, initial assembly:

[0051] According to the design, the cylindrical part in the metal shell assembled with the lifting ear is vertically placed on the upper surface of the coaxiality control tooling bottom plate 1. The coaxiality control tooling is a tooling designed by the present invention to achieve the technical goal. When assembled and used, the tooling is placed on a horizontal workbench. The lifting ear is placed on the upper end surface of the cylindrical part, and the two are made coaxial. The lifting ear is supported by the cylindrical part to prevent the lifting ear from falling directly.

[0052] According to the design requirements of the metal shell, the ear is an external profile ear or an internal profile ear. When the external profile ear is used, the external profile slider 3 of the coaxiality control tool is embedded in the slider groove on the column 4 according to the axial size of the ear, so that the external profile slider reaches a fully constrained state, ensuring that no movement and circumferential rotation occur during the assembly process, and the inner surface of the external profile slider groove on the external profile slider is in contact with the two side surfaces of the ear.

[0053] When an inner profile ear is used, the inner profile slider 2 of the coaxiality control tooling is embedded in the slider groove on the column 4 according to the axial size of the ear, so that the inner profile slider is fully constrained to ensure that no movement or circumferential rotation occurs during the assembly process, and the surfaces on both sides of the inner profile slider are fitted with the inner surface of the ear.

[0054] The second step is to assemble the first section.

[0055] Conventional welding tooling is used to adjust the misalignment and gap between the first cylindrical part and the first lifting ear so that the misalignment is less than 0.2 mm and the gap is less than 0.3 mm.

[0056] The welding tool is a conventional outer top tool, which includes a circular top cylinder, an adjusting bolt and an adjusting nut. When in use, the circular top cylinder is sleeved on the outer circumference of the cylindrical member, and the circular top cylinder is made coaxial with the cylindrical member, and then the misalignment and gap between the cylindrical member and the lifting ear are adjusted by adjusting the tightness of the adjusting bolt.

[0057] The limiting rod 5 is slid along the slide groove 7 in the bottom plate 1, so that the inner surface of the limiting rod contacts the outer circumferential surface of the cylindrical member and the limiting rod is fixed by the jacking bolt. The cylindrical member is constrained, and the first cylindrical member and the first lifting ear are assembled in place, completing the assembly of the first section.

[0058] The third step is to assemble the remaining sections.

[0059] Repeat the first step to continue assembling the cylindrical piece and other lifting ears. Specifically,

[0060] Place the second cylindrical part on the upper end surface of the first hanging ear; and fit the second welding tool onto the second cylindrical part according to the method for assembling the first cylindrical part. Repeat the process of adjusting the misalignment and gap between the cylindrical part and the hanging ear during the first stage of assembly to adjust the misalignment and gap between the second cylindrical part and the first hanging ear.

[0061] Place the second lifting ear on the upper end surface of the second cylindrical member; match and fix the inner profile slider 2 or the outer profile slider 3 with the profile of the lifting ear. Repeat the process of adjusting the misalignment and gap between the second cylindrical member and the first lifting ear to adjust the misalignment and gap between the second lifting ear and the second cylindrical member.

[0062] At this point, the second section of assembly is completed.

[0063] Repeat the assembly process between the second cylindrical member and the second lifting ear to complete the assembly of the remaining sections in sequence.

[0064] The fourth step is positioning welding.

[0065] After the assembly of the remaining sections is completed in sequence, argon arc welding is used to spot weld the welds according to the process requirements. During positioning welding, the positioning welding points are required to be evenly distributed, with every two positioning points forming a group, and a group of welding points is symmetrically distributed at 180°.

[0066] After completing the spot welding positioning of each weld position, the metal shell with the lifting lug is welded according to the process requirements.

[0067] At this point, the welding assembly of the metal shell with lifting ears is completed.

[0068] The coaxiality control tooling proposed in this embodiment is made of 20 steel, including a base plate 1, a slider, a column 4 and a limit rod 5; the slider includes an inner profile slider 2 and an outer profile slider 3. The column is vertically welded and fixed on the surface of the base plate, and the geometric center of the column is located on the center line of the base plate in the width direction; the distance between the surface of the column close to the limit rod 5 and the edge of the base plate must be greater than the outer diameter of the cylindrical member.

[0069] After welding and assembly, the verticality between the column 4 and the base plate 1 is ≤0.2°.

[0070] The bottom plate 1 is rectangular, and one surface in the length direction thereof is provided with a pair of limit rod sliding grooves for mounting the limit rod 5 and extending along the length of the bottom plate.

[0071] The sliders are respectively embedded in the slider grooves on the surface of the column; the number of sliders increases or decreases according to the number of lugs. Each slider is fixedly connected to the column by screws.

[0072] A plurality of slider grooves are evenly distributed on one side surface of the column along the height direction; the geometric center distance between adjacent slider grooves is 50 mm.

[0073] The limiting rod is located on the upper surface of the bottom plate, and the two ends of the limiting rod are clamped in a pair of limiting rod sliding grooves on the upper surface of the bottom plate; a tightening bolt is arranged on the limiting rod.

[0074] In this embodiment, the length of the bottom plate 1 is ld=990mm, the width is wd=900mm, and the height is hd=20mm; the length of the limit rod slide slot is 600mm, the width is 10mm, and the depth is 10mm. The column 4 is in the shape of a long strip, and the length of the column 4 is lz=80mm, the width is wz=50mm, and the height is hz=2000mm. 39 slider grooves with a length of 30mm, a width of 20mm, and a depth of 32mm are evenly distributed on the surface of the column. The geometric center spacing between two adjacent slider grooves is 50mm, and a through hole of φ12 is processed at the geometric center of the bottom surface of each groove. The position of the inner profile slider 2 and the outer profile slider 3 on the column can be arbitrarily adjusted through the slider groove, so as to cover the metal shell with a hanging ear whose total assembly length is not greater than the height of the column 4.

[0075] The outer profile slider is in a concave shape, and the inner groove surface is the profile that matches the outer profile ear; the two side surfaces of the inner profile slider are the profiles that match the inner profile ear. The outer profile slider 3 is similar in structure to the inner profile slider 2, except that the top surface of the outer profile slider is processed with a slider groove, and the size of the slider groove profile matches the radial size of the ear to prevent it from rotating around the axis during assembly. The limit rod 5 is symmetrically processed with two M6 threaded holes, which are clamped and fixed to the base plate 1 by bolts.

[0076] In this embodiment, the inner surface slider 2 is processed with a boss of 30 mm in length, 20 mm in width and 32 mm in depth, and a threaded hole of 40 mm in depth is provided thereon for connection with the column 4. The top surface structural dimensions of the inner surface slider 2 match the inner surface dimensions of the inner surface lifting ear.

Claims

1. A method for assembling a metal shell with a lifting ear, characterized in that: The metal shell with the lifting ear is a multi-section structure, each section is welded by a lifting ear and a cylindrical part; the lifting ear is annular, and a radially protruding lifting block is provided on the outer circumference of the annular ring; the lifting block cooperates with the slider on the assembly tool to realize the assembly of the metal shell with the lifting ear; the lifting ear is divided into an outer profile lifting ear and an inner profile lifting ear according to the profile of the matching between the lifting block and the slider; The specific process is: Step 1, initial assembly: According to the design, the cylindrical part in the metal shell assembled with the lifting ear is vertically placed on the upper surface of the bottom plate of the coaxiality control tooling; the lifting ear is placed on the upper end surface of the cylindrical part and the two are made coaxial; the lifting ear is an outer profile lifting ear or an inner profile lifting ear; Step 2, assemble the first section; Adjust the misalignment and gap between the first cylindrical part and the first lifting ear by welding fixture, so that the misalignment is less than 0.2mm and the gap is less than 0.3mm; Slide the limiting rod (5) along the slide groove (7) in the bottom plate (1) so that the inner surface of the limiting rod contacts the outer circumferential surface of the cylindrical member and fix the limiting rod via a tightening bolt to constrain the cylindrical member; assemble the first cylindrical member and the first lifting ear in place to complete the assembly of the first section; Step 3, assemble the remaining sections; Repeat step 2 to continue assembling the cylindrical piece and other lifting ears; specifically, Placing the second cylindrical member on the upper end surface of the first lifting ear; fitting the second welding tool on the second cylindrical member according to the method for assembling the first cylindrical member; repeating the process of adjusting the misalignment and gap between the cylindrical member and the lifting ear during the first stage of assembly to adjust the misalignment and gap between the second cylindrical member and the first lifting ear; Placing the second lifting ear on the upper end surface of the second cylindrical member; fitting the inner profile slider (2) or the outer profile slider (3) with the profile of the lifting ear and fixing them; repeating the process of adjusting the misalignment and gap between the second cylindrical member and the first lifting ear to adjust the misalignment and gap between the second lifting ear and the second cylindrical member; At this point, the assembly of the second section is completed; Repeat the assembly process between the second cylindrical member and the second lifting ear to complete the assembly of the remaining sections in sequence; Step 4, positioning welding; After completing the assembly of the remaining sections in sequence, argon arc welding is used to spot weld the positions of each weld according to the process requirements; during positioning welding, the positioning welding points are required to be evenly distributed, with every two positioning points forming a group, and a group of welding points is symmetrically distributed at 180°; After completing the spot welding positioning of each weld position, the metal shell with the lifting lug is welded according to the process requirements; At this point, the welding assembly of the metal shell with lifting ears is completed.

2. The method for assembling a metal shell with a lifting ear as claimed in claim 1, characterized in that: When the external profile lifting ear is used, the external profile slider (3) of the coaxiality control tooling is embedded in the slider groove on the column (4) according to the axial size of the lifting ear, so that the external profile slider reaches a fully constrained state, ensuring that no movement or circumferential rotation occurs during the assembly process, and the inner surface of the external profile slider groove on the external profile slider is in contact with the two side surfaces of the lifting ear.

3. The method for assembling a metal shell with lifting ears as claimed in claim 1, characterized in that: When an inner profile lifting ear is used, the inner profile slider (2) of the coaxiality control tooling is embedded in the slider groove on the column (4) according to the axial size of the lifting ear, so that the inner profile slider is in a fully constrained state, ensuring that no movement or circumferential rotation occurs during the assembly process, and the profiles on both sides of the inner profile slider are in contact with the inner surface of the lifting ear.

4. The method for assembling a metal shell with lifting ears as claimed in claim 1, characterized in that: There are multiple welding tools, which are used for assembling each section respectively; the welding tool comprises a circular top cylinder, an adjusting bolt and an adjusting nut; when in use, the circular top cylinder is mounted on the outer circumference of the cylindrical part, and the circular top cylinder is made coaxial with the cylindrical part, and then the misalignment and gap between the cylindrical part and the lifting ear are adjusted by adjusting the tightness of the adjusting bolt.

5. A coaxiality control tool for the metal shell equipped with lifting ears as claimed in claim 1, characterized in that: It comprises a base plate (1), a slider, a column (4) and a limit rod (5); the slider comprises an inner profile slider (2) and an outer profile slider (3); the column is vertically welded and fixed on the surface of the base plate, and the geometric center of the column is located on the center line of the base plate in the width direction; the distance between the surface of the column close to the limit rod and the edge of the base plate must be greater than the outer diameter of the cylindrical member; A surface of the bottom plate (1) in the length direction is provided with a pair of limit rod sliding grooves for mounting the limit rod (5) and extending along the length of the bottom plate; A plurality of slider grooves are evenly distributed on one side surface of the column in the height direction; the sliders are respectively embedded and fixed in the slider grooves on the surface of the column; the number of sliders increases or decreases according to the number of lifting ears; The limiting rod is located on the upper surface of the bottom plate, and the two ends of the limiting rod are clamped in a pair of limiting rod sliding grooves on the upper surface of the bottom plate; a tightening bolt is arranged on the limiting rod.

6. A coaxiality control tool for the metal shell equipped with lifting ears as claimed in claim 5, characterized in that: After welding and assembly, the verticality between the column (4) and the base plate (1) is ≤0.2°.

7. A coaxiality control tool for the metal shell equipped with lifting ears as claimed in claim 5, characterized in that: The geometric center distance between adjacent slider slots is 50 mm.

8. A coaxiality control tool for the metal shell equipped with lifting ears as claimed in claim 5, characterized in that: The outer surface slider is concave in shape, and the inner groove surface is the surface that matches the outer surface ear; the two side surfaces of the inner surface slider are the surfaces that match the inner surface ear; the structure of the outer surface slider (3) is similar to that of the inner surface slider (2), the difference being that a slider groove is processed on the top surface of the outer surface slider, and the size of the slider groove surface matches the radial size of the ear to prevent it from rotating around the axis during assembly.

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