Valve body multi-station casting blank forming device

Abstract

According to the valve body multi-station casting blank forming device, circulating movement of a casting blank forming mold among a casting station, a solidification area, a piece taking station and a mold cooling area is achieved through the rotating part, and the standing time of each station is accurately controlled through the rotating speed of the rotating power part; and when the casting blank is solidified and located at the taking station, the casting blank is automatically ejected through the ejection mechanism, so that the problem that the time of each step in the valve body casting blank forming process is difficult to control is solved, it is ensured that appropriate time is provided for alloy cooling solidification, casting blank ejection and mold cooling, and the situation that the manufacturing cycle is prolonged due to too long time is avoided; and the influence of too short time on the process effect is avoided, so that the automatic control on the duration of each step in the valve body casting blank forming process is realized, and the production efficiency and the product quality stability are improved.

Description

Technical Field

[0001] This utility model relates to the field of valve body manufacturing technology, specifically to a multi-station casting billet forming device for valve bodies. Background Technology

[0002] Valve bodies are common industrial products, typically formed by pouring molten alloy material into a mold to create a cast ingot, which is then removed and precision-machined. In traditional casting processes, after the molten alloy material is poured into the mold, it undergoes several critical steps, including alloy cooling and solidification, ingot ejection, and mold cooling. The timing of these steps has a decisive impact on product quality and production efficiency. The mold cooling step is particularly important; sufficient time must be allowed for the mold to cool fully to create the necessary temperature gradient for the next pour. This facilitates rapid solidification of the ingot and ensures smooth demolding. However, existing technologies have significant process control deficiencies, primarily in the inability to precisely control the duration of each step. If the time for each step is too long, it will lead to an extended overall production cycle and reduced production efficiency; if the time is too short, it will be difficult to achieve the expected process effect, which may cause problems such as casting quality defects or mold damage. Especially in multi-station continuous production scenarios, how to achieve precise coordination and control of the process time of each station has become a key technical bottleneck restricting the improvement of valve body billet production efficiency and quality. In addition, there is room for optimization in the design of the billet ejection mechanism, the planning of mold cooling paths, and the arrangement of rotating stations in the existing equipment. These factors together restrict the technological progress of valve body billet production. To address the above problems, the existing technology urgently needs to be improved. Utility Model Content

[0003] The problem to be solved by this utility model is to provide a valve body multi-station casting billet forming device that can control the time of each step after the alloy material is poured into the mold and has a high space utilization rate.

[0004] The technical solution adopted by this utility model to solve the above problems is: a multi-station casting billet forming device for valve bodies, comprising:

[0005] Multiple billet forming molds;

[0006] A supporting mechanism, wherein the supporting mechanism includes a supporting platform, a rotating power unit disposed on the supporting platform, and a rotating part disposed on the rotating power unit; the rotating part has a casting station, a part removal station, a solidification zone disposed on the path from the casting station to the part removal station, and a mold cooling zone disposed on the path from the part removal station to the casting station; a billet forming mold is disposed at the casting station and the part removal station; the time for the billet forming mold to pass through the solidification zone and the mold cooling zone is controlled by the rotational speed of the rotating power unit; and

[0007] An ejection mechanism is provided, wherein the ejection mechanism is disposed below the part-removal station; the ejection mechanism is configured to eject the casting billet from the casting mold of the part-removal station from bottom to top.

[0008] Compared with the prior art, this utility model realizes the cyclic movement of the billet forming mold between the casting station, solidification zone, part removal station and mold cooling zone through the rotating part. The dwell time at each station is precisely controlled by the rotation speed of the rotating power unit. When the billet is solidified and located at the part removal station, it is automatically ejected by the ejection mechanism. This solves the problem of difficult time control in each step of the valve body billet forming process, ensuring that the alloy cooling and solidification, billet ejection and mold cooling all have appropriate time. This avoids both excessive time leading to extended manufacturing cycle and insufficient time affecting process effect. Thus, it realizes the automated control of the time of each step in the valve body billet forming process, improving production efficiency and product quality stability.

[0009] According to one embodiment of the present invention, the support platform includes a platform and a plurality of support legs disposed below the platform; the platform is supported by the plurality of support legs to form an accommodating space; the rotating power unit is fixed to the platform and passes through the accommodating space and is connected to the rotating unit.

[0010] According to one embodiment of the present invention, the rotating part includes a support plate disposed on the upper end of the rotating power part and mold mounting parts disposed at both ends of the support plate;

[0011] The casting station is located in one of the mold mounting parts, and the part removal station is located in the other mold mounting part;

[0012] The two billet forming molds are disposed in the two mold mounting parts.

[0013] According to one embodiment of the present invention, the ejection mechanism includes a pneumatic part and a push rod that is controlled to extend and retract by the pneumatic part; the pneumatic part is disposed in the receiving space.

[0014] According to one embodiment of the present invention, the table surface has a first clearance position, and the mold mounting part has a second clearance position; when the billet forming mold is located at the part taking station, the push rod passes through the first clearance position and the second clearance position and pushes out the billet in the billet forming mold.

[0015] According to one embodiment of the present invention, the billet forming mold includes a side forming block and a bottom forming block movably disposed on the side forming block; the side forming block has a side forming surface for forming side features of the billet; the bottom forming block has a bottom forming surface for forming bottom features of the billet; the bottom forming block can be moved under the drive of the ejector rod to eject the billet.

[0016] According to one embodiment of the present invention, the side forming block has a tapered mounting hole, and the diameter of the tapered mounting hole decreases from top to bottom; the bottom forming block is disposed in the tapered mounting hole.

[0017] According to one embodiment of the present invention, the tapered mounting hole includes a first tapered step and a second tapered step disposed from top to bottom on the side wall, and a plurality of guide grooves disposed circumferentially distributed along the second tapered step; the bottom forming block includes a first tapered block and a second tapered block disposed from top to bottom, and a plurality of guide portions disposed circumferentially distributed along the second tapered block;

[0018] The first conical block is configured to mate with the first conical step; the second conical block is configured to mate with the second conical step; and the guide portion is configured to mate with the guide groove. Attached Figure Description

[0019] Figure 1 This is a perspective view of a valve body multi-station casting billet forming device according to a preferred embodiment of the present utility model;

[0020] Figure 2 This is a front view schematic diagram of a valve body multi-station casting billet forming device according to a preferred embodiment of the present utility model;

[0021] Figure 3 This is a top view schematic diagram of a valve body multi-station casting billet forming device according to a preferred embodiment of the present utility model;

[0022] Figure 4 This is a cross-sectional schematic diagram of a valve body multi-station casting billet forming device according to a preferred embodiment of the present utility model;

[0023] Figure 5 This is a partial exploded view of a valve body multi-station casting billet forming device according to a preferred embodiment of the present invention;

[0024] Figure 6 This is a top view schematic diagram of a valve body multi-station casting billet forming device according to another embodiment of the present utility model. Detailed Implementation

[0025] Before describing any embodiment of this invention in detail, it should be understood that the invention is not limited in its application to the details of the construction and arrangement of the components set forth in the following description or illustrated in the following figures. The invention is capable of other embodiments and can be practiced or carried out in various ways. Furthermore, it should be understood that the wording and terminology used herein are for descriptive purposes and should not be considered limiting. The use of “comprising” or “having” and variations thereof herein is intended to cover the items set forth below and their equivalents, as well as any additional items. Unless otherwise specified or limited, the terms “installation,” “connection,” “support,” and “linkage,” and variations thereof are used broadly and cover both direct and indirect installation, connection, support, and linking. Moreover, “connection” and “linkage” are not limited to physical or mechanical connections or links.

[0026] Furthermore, firstly, in the disclosure of this utility model, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as a limitation on this utility model. Secondly, the term "a" should be understood as "at least one" or "one or more," that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple. The term "a" should not be construed as a limitation on the quantity.

[0027] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are merely examples and do not limit the present invention. The purpose of the present invention has been fully and effectively achieved. The functions and structural principles of the present invention have been shown and explained in the embodiments. Without departing from the stated principles, the implementation of the present invention may have any variations or modifications.

[0028] The embodiments of this utility model will be further described below with reference to the accompanying drawings.

[0029] Please see Figure 1-6The valve body multi-station casting billet forming device shown includes multiple casting billet forming molds 1, a supporting mechanism 2, and an ejection mechanism 3; wherein the supporting mechanism 2 includes a supporting platform 21, a rotating power unit 22 disposed on the supporting platform 21, and a rotating part 23 disposed on the rotating power unit 22; the rotating part 23 has a casting station 231, a part removal station 232, and a solidification area 233 disposed on the path from the casting station 231 to the part removal station 232, and a solidification area 233 disposed on the path from the casting station 231 to the part removal station 232. A mold cooling area 234 is located on the path from the part removal station 232 to the casting station 231; the billet forming mold 1 is set at the casting station 231 and the part removal station 232; the time for the billet forming mold 1 to pass through the solidification area 233 and the mold cooling area 234 is controlled by the rotation speed of the rotation power unit 22; wherein the ejection mechanism 3 is set below the part removal station 232; the ejection mechanism 3 is configured to eject the billet in the billet forming mold 1 at the part removal station 232 from bottom to top.

[0030] Specifically, the billet forming mold 1 is used to contain molten alloy material so as to form a billet according to the required shape; the rotating power unit 22 can adopt a servo motor or a stepper motor to achieve precise speed control; the support platform 21 can adopt a metal frame structure with sufficient strength and stability; the ejection mechanism 3 can be driven by a hydraulic cylinder or a pneumatic cylinder to provide sufficient ejection force; the solidification zone 233 can be equipped with a temperature sensor to monitor the solidification state of the billet; the mold cooling zone 234 can be equipped with an air cooling or water cooling device to accelerate mold cooling.

[0031] In actual use, the rotating part 23 enables the casting mold 1 to circulate between the casting station 231, the solidification zone 233, the part removal station 232, and the mold cooling zone 234. The dwell time at each station is precisely controlled by the rotation speed of the rotating power unit 22. When the casting is solidified and located at the part removal station 232, it is automatically ejected by the ejection mechanism 3. This solves the problem of difficult time control in each step of the valve body casting process, ensuring that the alloy cooling and solidification, casting ejection, and mold cooling all have appropriate time. This avoids both excessive time leading to a longer manufacturing cycle and insufficient time affecting the process effect, thereby achieving automated control of the valve body casting process and improving production efficiency and product quality stability.

[0032] Please continue reading. Figure 1 , Figure 2 The support platform 21 includes a platform 211 and a plurality of support legs 212 disposed below the platform 211; the platform 211 is supported by the plurality of support legs 212 to form an accommodating space 213; the rotation power unit 22 is fixed to the platform 211 and passes through the accommodating space 213 and is connected to the rotation unit 23 via the platform 211.

[0033] Specifically, the platform 211 serves as the basic component of the load-bearing mechanism 2, and a receiving space 213 is formed beneath it via support legs 212. This space can be used to arrange components such as the rotating power unit 22. The rotating power unit 22 passes through the platform 211 and connects to the rotating part 23, thereby realizing power transmission. As a preferred embodiment, the support legs 212 can adopt an adjustable height structure so that the level of the platform 211 can be adjusted according to actual installation requirements. Furthermore, a heat dissipation structure, such as heat sink fins or a fan, can be installed in the receiving space 213 to reduce the operating temperature of the rotating power unit 22. The platform 211 can be made of high-strength cast iron material to ensure load-bearing stability.

[0034] In use, by optimizing the structure of the support platform 21, the rotating power unit 22 is arranged in the receiving space 213 below the platform 211, which saves equipment space and facilitates the installation and maintenance of the rotating power unit 22. The design of the support feet 212 creates a regular receiving space 213 below the platform 211, which is conducive to the rational arrangement of other functional components, thereby achieving a compact equipment structure and improving space utilization. At the same time, it ensures a stable connection between the rotating power unit 22 and the rotating part 23, providing a structural foundation for the precise control of subsequent workstations. Through the cooperative design of the platform 211 and the support feet 212, the problems of excessive equipment size and inconvenient maintenance caused by the external placement of the rotating power unit 22 in traditional devices are effectively solved.

[0035] Please continue reading. Figure 1 , Figure 2 , Figure 3 The rotating part 23 includes a bearing plate 235 disposed on the upper end of the rotating power part 22 and mold mounting parts 236 disposed at both ends of the bearing plate 235; the casting station 231 is disposed in one of the mold mounting parts 236, and the part removal station 232 is disposed in the other mold mounting part 236; the two billet forming molds 1 are disposed in the two mold mounting parts 236.

[0036] Specifically, the mold mounting part 236 can be mechanically connected to the support plate 235 by bolt connection, snap-fit ​​fixing or welding. As a preferred embodiment, the mold mounting part 236 is provided with positioning pin holes, which cooperate with the positioning holes of the casting mold 1 to achieve precise positioning. Furthermore, the mold mounting part 236 can be equipped with a quick clamping mechanism, such as a pneumatic clamp or hydraulic gripper, to facilitate mold replacement. The material of the support plate 235 is preferably cast iron or alloy steel, and the thickness is determined according to the load calculation, preferably in the range of 50-200mm. The support plate 235 can be designed as a circular, rectangular or polygonal structure, and the center distance of the mold mounting parts 236 symmetrically arranged at both ends is concentric with the output shaft of the rotating power unit 22.

[0037] In use, the dual-station rotary design allows for simultaneous casting and unloading processes. When one mold is in the casting station 231, the other mold can simultaneously eject the cast billet, thus achieving continuous production. The rotary power unit 22 drives the bearing plate 235 to rotate intermittently, rotating 180° per work cycle, allowing the mold to alternate between the casting station 231 and the unloading station 232. The symmetrical arrangement of the mold mounting unit 236 ensures dynamic balance during rotation, reducing equipment vibration. Compared with single-station equipment, this structure integrates mold cooling time into the production cycle. By rationally controlling the rotation speed, solidification and cooling time can be precisely adjusted, significantly improving production efficiency while ensuring process requirements. In specific implementation, the rotation speed can be adjusted according to the solidification characteristics of different alloy materials. For example, aluminum alloy castings are typically set to 2-5 rpm, and cast iron castings are set to 0.5-2 rpm.

[0038] Please continue reading. Figure 6 It is understood that in some other embodiments, the rotating part 23 may also include a plurality of circumferentially distributed mold mounting parts 236, which rotate gradually according to the rhythm of the rotating power part 22; under this arrangement, a device can have more billet forming molds 1, thereby improving production efficiency and equipment utilization.

[0039] Please continue reading. Figure 2 The ejection mechanism 3 includes a pneumatic part 31 and a push rod 32 that is controlled to extend and retract by the pneumatic part 31; the pneumatic part 31 is disposed in the receiving space 213.

[0040] Specifically, the pneumatic unit 31 can use a cylinder, hydraulic cylinder, or electric push rod as a power source, with cylinders being the preferred choice due to their simple structure and ease of control. The push rod 32 and the pneumatic unit 31 can transmit power through threaded connection, snap-fit ​​connection, or flange connection. The push rod 32 is preferably made of high-temperature resistant alloy steel, and its diameter can be adjusted between 20-50mm according to the weight of the billet. The installation position of the pneumatic unit 31 must meet the following requirements: firstly, it must be perpendicularly aligned with the part-picking station 232 of the rotating part 23; secondly, it must coincide with the central axis of the first clearance position 2111 of the table 211. The pneumatic unit 31 can be controlled by using a solenoid valve in conjunction with a PLC to achieve precise stroke control, and the adjustable range of the ejection speed is preferably 5-20mm / s.

[0041] In use, by integrating the pneumatic unit 31 into the space below the support platform 21, a compact layout of the ejection mechanism 3 and the rotation mechanism is achieved. Compared with traditional mechanical ejection, the pneumatic drive method has the advantages of fast response speed and adjustable ejection force, which can adapt to the demolding requirements of different sized billets. The linear motion trajectory of the ejector rod 32 is strictly aligned with the movement direction of the mold bottom forming block 12, ensuring that no lateral stress is generated during the ejection of the billet. The setting of the accommodating space 213 isolates the pneumatic unit 31 from the high-temperature mold area, extending the service life of the pneumatic components. When the mold rotates to the part removal station 232, the ejector rod 32 can accurately pass through the table 211 and the clearance hole of the mold, pushing the bottom forming block 12 to complete the ejection action of the billet. The entire process is completed in a short time. Furthermore, after the billet is ejected, it can be removed by a robotic arm or manually and transferred to subsequent finishing equipment.

[0042] Please continue reading. Figure 4 The table 211 has a first clearance position 2111, and the mold mounting part 236 has a second clearance position 2361. When the billet forming mold 1 is located at the part removal station 232, the push rod 32 passes through the first clearance position 2111 and the second clearance position 2361 and pushes out the billet in the billet forming mold 1.

[0043] Specifically, the first clearance position 2111 is configured as a groove-shaped structure that penetrates the table 211, and its size is slightly larger than the diameter of the ejector pin 32 to ensure that the ejector pin 32 can pass smoothly; the second clearance position 2361 is configured as an opening structure at the bottom of the mold mounting part 236, and the opening is coaxially aligned with the cavity of the casting mold 1.

[0044] In use, by setting up mutually cooperating clearance structures, the ejection mechanism 3 can accurately act on the casting mold 1; when the rotating part 23 drives the mold to rotate to the part removal station 232, the first clearance 2111 and the second clearance 2361 automatically align, the ejector rod 32 rises along the clearance channel and pushes the casting in the mold to complete demolding, thereby ensuring the stability and reliability of the casting ejection process.

[0045] Please continue reading. Figure 4 , Figure 5 The billet forming mold 1 includes a side forming block 11 and a bottom forming block 12 movably disposed on the side forming block 11; the side forming block 11 has a side forming surface 111 for forming side features of the billet; the bottom forming block 12 has a bottom forming surface 121 for forming bottom features of the billet; the bottom forming block 12 can be moved under the drive of the ejector rod 32 so as to eject the billet.

[0046] Specifically, the use of a conical structure ensures the stability of the bottom forming block 12 during movement, preventing it from shifting or jamming.

[0047] In use, after the billet solidifies in the mold, the ejector rod 32 moves upward, pushing the bottom forming block 12 to move upward along the conical mounting hole 112, thereby ejecting the billet from the side forming block 11. Since the bottom forming block 12 and the side forming block 11 adopt a conical fit structure, it can ensure that the force is transmitted more evenly during the ejection process, avoiding deformation or damage to the billet.

[0048] Please continue reading. Figure 4 , Figure 5 The side forming block 11 has a conical mounting hole 112, and the diameter of the conical mounting hole 112 decreases from top to bottom. The bottom forming block 12 is disposed in the conical mounting hole 112. The conical mounting hole 112 includes a first conical step 1121 and a second conical step 1122 disposed from top to bottom on the side wall, and a plurality of guide grooves 1123 disposed circumferentially along the second conical step 1122. The bottom forming block 12 includes a first conical block 122 and a second conical block 123 disposed from top to bottom, and a plurality of guide portions 124 disposed circumferentially along the second conical block 123. The first conical block 122 is configured to cooperate with the first conical step 1121. The second conical block 123 is configured to cooperate with the second conical step 1122. The guide portions 124 are configured to cooperate with the guide grooves 1123.

[0049] Specifically, the structural design of the conical mounting hole 112 enables the bottom forming block 12 to achieve precise positioning through the conical surface engagement. The first conical step 1121 and the second conical step form a dual positioning structure, which can effectively prevent the bottom forming block 12 from shifting during the ejection process. The engagement of the guide groove 1123 and the guide part 124 further restricts the circumferential rotation of the bottom forming block 12, ensuring its linear movement in the vertical direction. As a preferred embodiment, the guide groove 1123 can also adopt a dovetail groove structure, and the guide part 124 is correspondingly set as a dovetail protrusion to enhance guiding stability. In addition, the inclination angle of the conical step is preferably 5-15 degrees, which can ensure positioning accuracy and facilitate processing and manufacturing.

[0050] Furthermore, the taper of the first conical step 1121 and the second conical step 1122 can be the same or different; the number of guide grooves 1123 can be set to 3-6, evenly distributed on the circumference of the second conical step 1122; the cross-sectional shape of the guide portion 124 can be rectangular, trapezoidal or semi-circular, matching the shape of the guide groove 1123; as a preferred embodiment, the depth of the guide groove 1123 is 5-15mm and the width is 3-10mm; the first conical block 122 and the second conical block 123 can be manufactured by integral casting or separate assembly, and the material is preferably heat-resistant alloy steel.

[0051] In use, the technical problem of the bottom forming block 12 easily deflecting or getting stuck during the ejection process of the billet is solved by the synergistic effect of the conical surface and the guide structure. Specifically, the double conical steps provide an axial positioning reference, while the circumferentially distributed guide structure eliminates the rotational degree of freedom, thereby ensuring that the bottom forming block 12 always maintains a vertical movement trajectory under the action of the ejection mechanism 3.

[0052] The above description only illustrates the preferred embodiment of this utility model and should not be construed as limiting the scope of the claims. This utility model is not limited to the above embodiments, and variations in its specific structure are permitted. All changes made within the scope of the independent claims of this utility model are also within the scope of protection of this utility model.

Claims

1. A multi-station casting billet forming device for valve bodies, characterized in that, include: Multiple billet forming molds (1); A support mechanism (2), wherein the support mechanism (2) includes a support platform (21), a rotary power unit (22) disposed on the support platform (21), and a rotating part (23) disposed on the rotary power unit (22); the rotating part (23) has a casting station (231), a part removal station (232), and a solidification zone (233) disposed on the path from the casting station (231) to the part removal station (232), and a mold cooling zone (234) disposed on the path from the part removal station (232) to the casting station (231); the billet forming mold (1) is disposed on the casting station (231) and the part removal station (232); the time for the billet forming mold (1) to pass through the solidification zone (233) and the mold cooling zone (234) is controlled by the rotation speed of the rotary power unit (22); and An ejection mechanism (3) is provided below the part-taking station (232); the ejection mechanism (3) is configured to eject the casting billet from the casting mold (1) of the part-taking station (232) from bottom to top.

2. The valve body multi-station casting billet forming device according to claim 1, characterized in that: The support platform (21) includes a platform (211) and a plurality of support legs (212) disposed below the platform (211); the platform (211) is supported by the plurality of support legs (212) to form an accommodating space (213); the rotating power unit (22) is configured to be fixed to the platform (211) and to be connected to the rotating unit (23) through the platform (211) from the accommodating space (213).

3. The valve body multi-station casting billet forming device according to claim 2, characterized in that: The rotating part (23) includes a support plate (235) disposed on the upper end of the rotating power part (22) and mold mounting parts (236) disposed at both ends of the support plate (235). The casting station (231) is located in one of the mold mounting parts (236), and the part removal station (232) is located in the other mold mounting part (236). The two billet forming molds (1) are disposed in the two mold mounting parts (236).

4. The valve body multi-station casting billet forming device according to claim 3, characterized in that: The ejection mechanism (3) includes a pneumatic part (31) and a push rod (32) that is controlled to extend and retract by the pneumatic part (31); the pneumatic part (31) is disposed in the receiving space (213).

5. The valve body multi-station casting billet forming device according to claim 4, characterized in that: The table (211) has a first clearance position (2111), and the mold mounting part (236) has a second clearance position (2361). When the billet forming mold (1) is located at the part taking station (232), the push rod (32) passes through the first clearance position (2111) and the second clearance position (2361) and pushes out the billet in the billet forming mold (1).

6. The valve body multi-station casting billet forming device according to claim 4, characterized in that: The billet forming mold (1) includes a side forming block (11) and a bottom forming block (12) movably disposed on the side forming block (11); the side forming block (11) has a side forming surface (111) for forming side features of the billet; the bottom forming block (12) has a bottom forming surface (121) for forming bottom features of the billet; the bottom forming block (12) can be moved under the drive of the push rod (32) so as to eject the billet.

7. The valve body multi-station casting billet forming device according to claim 6, characterized in that: The side forming block (11) has a tapered mounting hole (112), and the diameter of the tapered mounting hole (112) decreases from top to bottom; the bottom forming block (12) is disposed in the tapered mounting hole (112).

8. The valve body multi-station casting billet forming device according to claim 7, characterized in that: The tapered mounting hole (112) includes a first tapered step (1121) and a second tapered step (1122) disposed from top to bottom on the side wall, and a plurality of guide grooves (1123) disposed circumferentially distributed along the second tapered step (1122); the bottom forming block (12) includes a first tapered block (122) and a second tapered block (123) disposed from top to bottom, and a plurality of guide portions (124) disposed circumferentially distributed along the second tapered block (123); The first conical block (122) is configured to cooperate with the first conical step (1121); the second conical block (123) is configured to cooperate with the second conical step (1122); and the guide portion (124) is configured to cooperate with the guide groove (1123).

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