阅读说明：本技术 一种低温薄壁贮箱固定支撑装置 (Low temperature thin wall storage tank fixed support device ) 是由 唐斌运 刘洋 徐鸿鹏 梁永鹏 祝敏 霍涛 张中柱 刘涛 于 2021-07-16 设计创作，主要内容包括：本发明提供一种低温薄壁贮箱固定支撑装置,以解决大容积薄壁低温贮箱可靠支撑困难,以及针对贮箱在实验中快速回温需要支撑方式具有低滞后特性的技术问题。该支撑装置包括底部及顶部固定支撑装置；所述底部固定装置包括底部支撑架和支撑底座；支撑底座包括底板、筒体、顶部环板以及加强筋板；顶部环板包括多层叠放的环形钢板,每层环形钢板之间采用点焊的方式连接；加强筋板为多条。该支撑底座制备方法是将多层环形钢板通过点焊连接成顶部环板,筒体垂直焊接在底板上,顶部环板与筒体焊接后设置加强筋板,然后沿圆周方向均匀开第一通孔,并插入螺栓进行多次拉紧,再对顶部环板进行加热处理,并进行上表面平整加工。(The invention provides a fixing and supporting device for a low-temperature thin-wall storage tank, which aims to solve the technical problems that a large-volume thin-wall low-temperature storage tank is difficult to support reliably and a supporting mode is required to have low hysteresis in an experiment for quick temperature return of the storage tank. The supporting device comprises a bottom fixing and supporting device and a top fixing and supporting device; the bottom fixing device comprises a bottom supporting frame and a supporting base; the supporting base comprises a bottom plate, a cylinder body, a top annular plate and a reinforcing rib plate; the top annular plate comprises a plurality of layers of stacked annular steel plates, and each layer of annular steel plate is connected in a spot welding manner; the reinforcing rib plate is provided with a plurality of ribs. The preparation method of the supporting base comprises the steps of connecting multiple layers of annular steel plates into a top annular plate through spot welding, vertically welding a barrel on a bottom plate, welding the top annular plate and the barrel, arranging reinforcing rib plates, uniformly opening first through holes in the circumferential direction, inserting bolts for tensioning for multiple times, heating the top annular plate, and carrying out upper surface leveling processing.)

1. The utility model provides a low temperature thin wall storage tank fixed stay device which characterized in that: comprises a bottom fixing and supporting device for supporting and fixing the bottom (2) of the storage tank and a top fixing and supporting device for supporting and fixing the top (1) of the storage tank;

the bottom fixing and supporting device comprises a bottom supporting frame (11) and a supporting base (6);

the supporting base (6) comprises a bottom plate (22), a cylinder body (19), a top annular plate (23) and a reinforcing rib plate (20);

the cylinder (19) is vertically arranged on the bottom plate (22); a plurality of second through holes (21) which are used for being butted with the bottom support frame (11) are formed in the bottom plate (22) along the circumferential direction;

the inner wall of the top annular plate (23) is welded with the upper end of the cylinder (19), and the excircle part of the top annular plate (23) is connected with the bottom (2) of the storage tank; the top annular plate (23) comprises a plurality of layers of stacked annular steel plates, and each layer of annular steel plate is connected in a spot welding mode;

the reinforcing rib plates (20) are uniformly distributed outside the cylinder body (19) along the circumferential direction, one ends of the reinforcing rib plates (20) are welded with the top annular plate (23), and the other ends of the reinforcing rib plates are welded with the bottom plate (22).

2. The fixed supporting device of the low-temperature thin-wall tank as claimed in claim 1, wherein the supporting base (6) is manufactured by the following steps:

step 1, assembling a supporting base

1.1, laminating a plurality of annular steel plates, and performing spot welding on the inner circumference and the outer circumference between each layer of annular steel plates after lamination to form a top annular plate (23);

1.2, vertically welding a cylinder body (19) on the bottom plate (22), and welding the inner wall of the top annular plate (23) obtained in the step 1.1 with the upper end of the cylinder body (19);

1.3, uniformly arranging reinforcing rib plates (20) outside the cylinder body (19) along the circumferential direction, wherein one ends of the reinforcing rib plates (20) are welded with a top annular plate (23), and the other ends of the reinforcing rib plates (20) are welded with a bottom plate (22);

step 2, carrying out secondary processing on the assembled supporting base

2.1, uniformly forming a plurality of first through holes (24) in the top annular plate (23) along the circumferential direction, inserting bolts into the first through holes (24) from one side of the top annular plate, mounting nuts on the bolts on the other side, screwing the nuts to fasten the bolts, then integrally heating the top annular plate (23), screwing the nuts to fasten the bolts again, then repeating the processes of integrally heating and fastening the bolts for multiple times until the bolts are not obviously loosened after heating, and taking out the bolts;

2.2, using gas cutting to integrally heat the supporting base, and then repeatedly heating the top annular plate (23) to eliminate the relative gap of the top annular plate (23) and release the internal stress of the material;

and 2.3, integrally processing the upper surface of the top annular plate (23) processed in the step 2.2 to enable the whole upper surface of the top annular plate (23) to be flat.

3. The low-temperature thin-wall tank fixing and supporting device as claimed in claim 2, wherein: the outer diameter of the top annular plate (23) is larger than 3000mm, the difference between the outer diameter and the inner diameter of the top annular plate (23) is 300 mm-400 mm, and the top annular plate (23) is formed by overlapping and welding a plurality of steel plates with the thickness of 2 mm.

4. The fixed support device of the low-temperature thin-wall tank of claim 3, wherein: and (2) when each layer of annular steel plate is subjected to spot welding in the step 1, the distance between two adjacent welding spots in the same circumferential direction is 5 mm.

5. The low-temperature thin-wall tank fixing and supporting device as claimed in claim 1, wherein:

the top fixing and supporting device comprises at least three upright posts (5), an annular hoop beam (4) and a plurality of L-shaped suspension structures (9);

the at least three upright posts (5) are uniformly distributed around the storage box along the circumferential direction; the top of the upright post (5) is fixedly provided with the annular hoop beam (4); the inner wall of the ring-shaped hoop beam (4) or the upright post (5) is connected with the top part (1) of the storage tank through a plurality of L-shaped suspension structures (9).

6. The fixed support device of the low-temperature thin-wall tank of claim 5, wherein: the L-shaped suspension structure (9) comprises a vertical connecting plate (12) and a horizontal connecting plate (17);

the vertical connecting plate (12) is parallel to the upright column and is used for adjusting and controlling the radial displacement of the storage tank;

and the horizontal connecting plate (17) is vertical to the upright column and is used for adjusting and controlling the axial displacement and the radial displacement of the storage tank.

7. The fixed support device of the low-temperature thin-wall tank of claim 6, wherein: the vertical connecting plate (12) is connected with the upright post (5) or the annular hoop beam (4) through a base fixing hole (13), and a plurality of kidney-shaped holes (15) are formed in the vertical connecting plate (12); the plurality of kidney-shaped holes (15) are arranged at intervals in the direction vertical to the upright post (5).

8. The fixed support device of the low-temperature thin-wall tank of claim 6, wherein: horizontal connecting plate (17) one end is passed through storage tank fixed orifices (18) and is connected with storage tank (10), and the other end is connected with vertical connecting plate (12), and the middle part region of horizontal connecting plate (17) is cavity, the center of cavity is equipped with circular deformation ring (14), and circular deformation ring is connected through the outside region of many ribs (16) with horizontal connecting plate (17).

9. The low-temperature thin-wall tank fixing and supporting device according to any one of claims 1 to 8, characterized in that: the bottom support frame (11) comprises a square frame formed by fixedly connecting columnar plates and at least three support columns fixedly connected to the bottom surface of the frame.

10. The fixed support device of the low-temperature thin-wall tank of claim 9, wherein: the bottom support frame (11) is fixedly provided with an upright post fixing plate (8) parallel to the upright post (5), and the upright post fixing plate (8) is fixedly connected with the upright post (5) through an extension bracket (7).

Technical Field

The invention relates to a fixed support of a thin-wall storage tank, in particular to a fixed support device of a low-temperature thin-wall storage tank.

Background

In rocket engine testing, to simulate the supply of propellant under actual flight conditions, a large volume thin-walled cryogenic tank was designed and manufactured, which is thin-walled and less rigid than conventional ground-based vessels. As shown in FIG. 1, the top and bottom of the tank are ellipsoidal, the barrel is cylindrical, the wall of the tank is thin and light, and the total weight of the tank is not more than 1.5 tons.

Because the low-temperature thin-wall storage tank has small wall thickness and large diameter, the low-temperature thin-wall storage tank is different from the traditional container, if the base is uneven, the container can be seriously deformed, the use of the container is influenced, and even damage is caused in serious cases, so that the butt joint plane of the base of the container must be ensured to be flat enough. The outer diameter of the low-temperature thin-wall storage tank generally exceeds 3600, and even if a strict welding deformation resistance measure is adopted, the deformation of the base after welding is large due to the large diameter and the small relative thickness. In order to ensure that the upper end is integrally flat, integral processing is required after welding, the deformation of the integral processing is expected to be larger than 20mm, so that the integral processing can be completed by adopting a steel plate with the thickness not less than 30mm, and the whole process has poor controllability, and parts can be scrapped if the deformation exceeds the standard.

The conventional base is a large-diameter thin-wall adapter ring frame, but the base is large in deformation after welding, high in integrated machining cost and long in period, and meanwhile, the low-temperature thin-wall storage tank for the ground test of the rocket engine cannot be welded after being flatly combined with the base by self pressure like a rigid storage tank due to poor rigidity and small quality of the wall.

Compared with a storage tank in a flying state, the top of the flying state is in a free state, the top of a ground simulation test has test management constraint, and the working environment of a test bench is poor in the test process, so that the top of the storage tank also faces the difficult problem of reliable fixed support. Meanwhile, in the test, the high-low temperature layered interface of the storage tank moves rapidly due to the rapid consumption of the propellant, and in order to adapt to the change, a supporting and fixing mode is required to have a low-hysteresis characteristic aiming at rapid temperature return.

Disclosure of Invention

The invention aims to solve the technical problems that a large-volume thin-wall low-temperature storage tank designed and manufactured by simulating propellant supply of a rocket engine in an actual flight state is difficult to support reliably and a support mode is required to have low hysteresis characteristic for quick temperature return of the storage tank in an experiment, and provides a fixing and supporting device for the low-temperature thin-wall storage tank.

The technical scheme of the invention is as follows:

the invention provides a low-temperature thin-wall storage tank fixing and supporting device, which comprises a bottom fixing and supporting device for supporting and fixing the bottom of a storage tank and a top fixing and supporting device for supporting and fixing the top of the storage tank;

the bottom fixing and supporting device comprises a bottom supporting frame and a supporting base;

the supporting base comprises a bottom plate, a cylinder body, a top annular plate and a reinforcing rib plate;

the cylinder is vertically arranged on the bottom plate; a plurality of second through holes for butting with the bottom support frame are formed in the bottom plate along the circumferential direction;

the inner wall of the top annular plate is welded with the upper end of the cylinder, and the excircle part of the top annular plate is connected with the bottom of the storage tank; the top annular plate comprises a plurality of layers of stacked annular steel plates, and each layer of annular steel plate is connected in a spot welding manner;

the reinforcing rib plates are multiple and are evenly distributed outside the cylinder along the circumferential direction, one end of each reinforcing rib plate is welded with the top annular plate, and the other end of each reinforcing rib plate is welded with the bottom plate.

Further, the manufacturing steps of the supporting base are as follows:

step 1, assembling a supporting base

1.1, laminating a plurality of annular steel plates, and performing spot welding on the inner circumference and the outer circumference between each layer of annular steel plates after lamination to form a top annular plate;

1.2, vertically welding a cylinder body on the bottom plate, and welding the inner wall of the top annular plate obtained in the step 1.1 with the upper end of the cylinder body;

1.3, uniformly arranging reinforcing rib plates outside the cylinder along the circumferential direction, wherein one end of each reinforcing rib plate is welded with the top annular plate, and the other end of each reinforcing rib plate is welded with the bottom plate;

step 2, carrying out secondary processing on the assembled supporting base

2.1, uniformly forming a plurality of first through holes in the circumferential direction on the top ring plate, inserting bolts into the first through holes from one side of the top ring plate, mounting nuts on the bolts on the other side, screwing the nuts to fasten the bolts, then integrally heating the top ring plate, screwing the nuts to fasten the bolts again, then repeating the processes of integrally heating and fastening the bolts for multiple times until the bolts are not obviously loosened after heating, and taking out the bolts;

2.2, using gas cutting to integrally heat the support base, and then repeatedly heating the top ring plate to eliminate the relative gap of the top ring plate and release the internal stress of the material;

2.3, integrally processing the upper surface of the top annular plate subjected to the heating treatment in the step 2.2 to enable the whole upper surface of the top annular plate to be flat.

Furthermore, the outer diameter of the top ring plate is larger than 3000mm, the difference between the outer diameter and the inner diameter of the top ring plate is 300 mm-400 mm, and the top ring plate is formed by stacking and welding a plurality of steel plates with the thickness of 2 mm.

The supporting base provided by the invention is particularly suitable for the storage box which has a large diameter, high requirement on the flatness of the base and thin base thickness design.

Further, when the annular steel plates of each layer are subjected to spot welding in the step 1, the distance between two adjacent welding points in the same circumferential direction is 5 mm.

Further, the top fixing and supporting device comprises at least three upright posts, an annular hoop beam and a plurality of L-shaped suspension structures;

the at least three upright posts are uniformly distributed around the storage box along the circumferential direction; the top of the upright post is fixedly provided with the annular hoop beam; the inner wall of the annular hoop beam or the upright post is connected with the top of the storage tank through a plurality of L-shaped suspension structures.

The L-shaped suspension structure is combined with the upright post rigid structure, and the rigidity of the upright post is adjusted to ensure that the L-shaped suspension structure does not generate overlarge side load on the top of the storage tank. Meanwhile, the top supporting device has good adaptability to the problems that the size of the storage tank is changed quickly and the change forms are various after the temperature is changed.

Further, the L-shaped suspension structure comprises a vertical connecting plate and a horizontal connecting plate;

the vertical connecting plate is parallel to the upright column and is used for adjusting and controlling the radial displacement of the storage tank;

the horizontal connecting plate is perpendicular to the upright column and is used for adjusting and controlling the axial displacement and the radial displacement of the storage tank.

Furthermore, the vertical connecting plate is connected with the upright post or the annular hoop beam through the foundation fixing hole, and a plurality of kidney-shaped holes are formed in the vertical connecting plate; the plurality of kidney-shaped holes are arranged at intervals in the direction vertical to the upright post.

Further, horizontal connecting plate one end is passed through the storage tank fixed orifices and is connected with the storage tank, and the other end is connected with vertical connecting plate, and horizontal connecting plate's middle part is regional for cavity, the center of cavity is equipped with circular deformation ring, and circular deformation ring is connected through many ribs and horizontal connecting plate's outer region.

This L type structure utilizes whole two-way vertical structure, and the last deformation roof beam that sets up of horizontal structure combines circular deformation ring, and compensation storage tank that can be fine warp, and the waist type hole of vertical direction possesses that the axial flexibility is big, and the side direction bearing capacity is strong, and is little to the storage tank advantage, possesses good dynamic response characteristic, can carry out quick adjustment to possible natural frequency coupling.

Furthermore, the bottom support frame comprises a square frame formed by fixedly connecting columnar plates and at least three support columns fixedly connected to the bottom surface of the frame.

Further, the bottom bracing frame is fixedly provided with a stand column fixing plate parallel to the stand column, and the stand column fixing plate is fixedly connected with the stand column through an extension bracket.

The invention has the beneficial effects that:

1. the low-temperature thin-wall storage tank fixing and supporting device provided by the invention adopts the bottom fixing and supporting device and the top fixing and supporting device to support the low-temperature thin-wall storage tank, and the supporting base designed at the bottom is overlapped by multiple layers of plates, so that the problems of large deformation, high processing cost and long period after welding of the traditional integrated base structure are solved, and the technical problems that the base is difficult to process when the thin-wall storage tank is flat and uniform and the high hysteresis of the low-temperature thin-wall storage tank top supporting device for quick temperature return of the storage tank is solved.

2. The bottom supporting base is firstly connected by spot welding through a plurality of layers of annular steel plates to form a top annular plate after welding, the top annular plate is welded at the upper end of a cylinder body, the cylinder body is vertically welded on a bottom plate, reinforcing rib plates are uniformly welded between the bottom plate and the top annular plate along the circumferential direction, holes are formed in the upper surface of the top annular plate along the circumferential direction, bolts are inserted for tensioning, internal stress is eliminated through integral heating through gas cutting after tensioning, and finally the upper surface of the top annular plate is subjected to flattening processing. The manufacturing method of the supporting base solves the technical problems of high manufacturing difficulty and changeability of the bottom flat supporting base of the large-diameter storage box, and is simple to process, low in cost and high in success rate.

3. The multi-point suspension support structure with the waist-shaped hole combined with the L-shaped suspension structure is adopted at the top of the invention, and the structure has the advantages of large axial flexibility, strong lateral bearing capacity and small influence on the storage tank, can quickly adapt to the axial and radial size changes of a container due to precooling or low-temperature medium use, and realizes reliable support of the top of the thin-wall low-temperature storage tank in the test process.

4. The invention adopts a simple multi-flexible upright post structure to ensure the top of the low-temperature thin-wall storage tank to be fixedly supported, and the structure ensures that the upright posts do not generate overlarge side load on the top of the storage tank through the rigid upright post structure.

Drawings

FIG. 1 is a schematic view of a low temperature thin-walled tank configuration;

FIG. 2 is a schematic view of a thin-walled tank support apparatus of the present invention;

FIG. 3 is a side view of the support base of FIG. 2;

FIG. 4 is an enlarged view of A in FIG. 3;

FIG. 5 is a top view of the support base of FIG. 2;

FIG. 6 is a schematic view of the top stationary support assembly of FIG. 2;

FIG. 7 is a perspective view of the L-shaped suspension structure of FIG. 3;

FIG. 8 is a front view of FIG. 7;

FIG. 9 is a left side view of FIG. 8;

fig. 10 is a bottom view of fig. 8.

The reference numbers are as follows:

1-top of storage tank, 2-bottom of storage tank, 3-barrel section of storage tank, 4-ring beam, 5-column, 6-support base, 7-extension support, 8-column fixing plate, 9-L type suspension structure, 10-storage tank, 11-bottom support frame, 12-vertical connecting plate, 13-basic fixing hole, 14-circular deformation ring, 15-waist-shaped hole, 16-rib, 17-horizontal connecting plate, 18-storage tank fixing hole, 19-barrel, 20-reinforcing rib plate, 21-second through hole, 22-bottom plate, 23-top ring plate, and 24-first through hole.

Detailed Description

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in fig. 2 to fig. 10, the low-temperature thin-walled tank fixing and supporting device provided by the present embodiment includes a bottom fixing and supporting device for supporting and fixing the tank bottom 2, and a top fixing and supporting device for supporting and fixing the tank top 1.

The bottom fixing and supporting device comprises a bottom supporting frame 11 and a supporting base 6; the bottom support frame 11 comprises a square frame formed by fixedly connecting columnar plates and three support columns fixedly connected to the bottom surface of the frame. It will be appreciated that in other embodiments a plurality of support posts may be provided to make the device more stable.

The supporting base 6 comprises a bottom plate 22, a cylinder 19, a top annular plate 23 and a reinforcing rib plate 20; the cylinder 19 is vertically arranged on the bottom plate 22; the bottom plate 22 is provided with a plurality of second through holes 21 along the circumferential direction for butting with the bottom support frame 11.

The inner wall of the top annular plate 23 is welded with the upper end of the cylinder 19, and the excircle part of the top annular plate 23 is connected with the bottom 2 of the storage tank; the top annular plate 23 comprises a plurality of layers of stacked annular steel plates, and each layer of annular steel plates are connected in a spot welding manner; the outer diameter of the top ring plate 23 is larger than 3000mm, the difference between the outer diameter and the inner diameter of the top ring plate 23 is 300mm to 400mm, and the top ring plate 23 is formed by stacking and spot-welding a plurality of steel plates with the thickness of 2 mm.

The reinforcing rib plates 20 are multiple and evenly distributed outside the cylinder 19 along the circumferential direction, one end of each reinforcing rib plate 20 is welded with the top annular plate 23, and the other end of each reinforcing rib plate 20 is welded with the bottom plate 22.

In this embodiment, the specific manufacturing process of the supporting base 6 is as follows:

s1 assembling of supporting base

S11, 6-7 annular steel plates are stacked, the thickness of each annular steel plate is 2mm, and spot welding is carried out on the inner circumference and the outer circumference between every two layers of annular steel plates after stacking; when spot welding is carried out between each layer of annular steel plates, the distance between two adjacent welding spots in the same circumferential direction is 5mm, and a top annular plate 23 is formed after spot welding;

s12, vertically welding the cylinder 19 on the bottom plate 22, and welding the inner wall of the top annular plate 23 with the upper end of the cylinder 19;

s13, uniformly arranging reinforcing rib plates 20 outside the cylinder 19 along the circumferential direction, wherein one ends of the reinforcing rib plates 20 are welded with the top annular plate 23, and the other ends of the reinforcing rib plates 20 are welded with the bottom plate 22;

s2, secondary processing of the assembled supporting base

S21, uniformly forming 100 first through holes 24 of phi 14 in the welded top annular plate 23 along the circumferential direction, wherein the first through holes 24 are multiple and uniformly distributed along the circumferential direction, inserting bolts into the first through holes 24 from the upper surface of the top annular plate 23, installing nuts on the bolts below the top annular plate 23, integrally tensioning the top annular plate 23 for multiple times, and taking out the bolts after tensioning;

the multiple integral tightening means that the nuts are tightened to fasten the bolts, then the top ring plate 23 is heated integrally, after heating, due to the fact that stress is redistributed, part of the fastening bolts are loosened, the nuts are tightened again, and then the process of integral heating and bolt tightening is repeated for multiple times until the bolts are not loosened obviously after heating.

S22, using gas cutting to heat the supporting base integrally, and then heating the top annular plate 23 repeatedly to eliminate the relative gap of the top annular plate 23 and release the internal stress of the material;

s23, the flattening process is performed on the top surface of the top ring plate 23 after the heat treatment at S22, so that the entire top surface of the top ring plate 23 is flattened. The flatness after processing is not less than 0.1mm, preferably 0.05-0.1 mm.

According to the embodiment, the annular steel plates with 6-7 layers and 2mm thickness are used for multi-layer building and machining, the machining deformation is small compared with that of a whole annular steel plate, and when the surface is machined flatly, the flatness of the whole upper surface can meet the requirement only by machining 2-4 mm.

The base formed by multilayer building and welding is particularly suitable for a large-diameter thin-wall storage box which has higher requirement on the flatness of the base and has more self connecting bolts, the processing difficulty of the base can be effectively reduced, the support flatness is improved, and the working reliability of a thin-wall container is ensured.

The prepared supporting base 6 is fixedly connected with the bottom supporting frame 11 through a second through hole 21 reserved on the bottom plate 22 along the circumferential direction, and the manufacturing and assembling of the low-temperature thin-wall storage tank bottom supporting device are completed.

The low-temperature thin-wall storage tank 10 is placed on a supporting base 6 of a bottom supporting device, and the contact surface of the bottom 2 of the storage tank and the supporting base 6 is fixed through bolts.

The top fixing and supporting device comprises three upright posts 5, an annular hoop beam 4 and an L-shaped suspension structure 9; the bottom support frame 11 is fixedly provided with a column fixing plate 8 parallel to the column 5, the column fixing plate 8 is fixedly connected with the column 5 through an extension bracket 7, and the number of columns in other embodiments can be larger than three, so as to support the top support device.

The three upright posts 5 are uniformly distributed around the storage box 10 along the circumferential direction; the top of the upright post 5 is fixedly provided with the annular hoop beam 4; the inner wall of the upright post 5 is connected with the top 1 of the storage tank through three L-shaped suspension structures 9.

The L-shaped suspension structure 9 comprises a vertical connection plate 12 and a horizontal connection plate 17; the vertical connecting plate 12 is connected with the upright post 5 through a base fixing hole 13 by using a screw, and a plurality of kidney-shaped holes 15 are formed in the vertical connecting plate 12; a plurality of kidney-shaped holes 15 are provided at intervals in the direction perpendicular to the column 5.

In other embodiments, a plurality of L-shaped suspension structures may be provided, and may also be connected to the hoop beam through the vertical connecting plate 12.

One end of the horizontal connecting plate 17 is connected with the storage tank 10 through a storage tank fixing hole 18, the other end of the horizontal connecting plate is connected with the vertical connecting plate 12, the middle area of the horizontal connecting plate 17 is hollow, a circular deformation ring 14 is arranged at the center of the hollow part, and the circular deformation ring is connected with the outer area of the horizontal connecting plate 17 through four ribs 16.