Auxiliary equipment for quickly replacing and positioning train bogie wheel set

Abstract

The invention relates to the technical field of train bogie wheel sets, and discloses train bogie wheel set rapid replacing and positioning auxiliary equipment which comprises a framework, a train wheel set is arranged on the framework, a replacing supporting mechanism is arranged on the framework, and a positioning mechanism is arranged on the framework. According to the rapid replacing and positioning auxiliary equipment for the train bogie wheel pair, by arranging a hydraulic rod, when the train wheel pair needs to be replaced for maintenance, a servo motor operates to enable an output shaft of the servo motor to drive a first gear to rotate, a rotating rod is driven to rotate through transmission of the first gear and a second gear, and a positioning clamping block supports and positions the wheel pair; the hydraulic rod extends after running, the supporting plate moves downwards to make contact with and eject the train wheel pair, connection between the train wheel pair and the framework is loosened, disassembly, replacement or overhaul of the wheel pair is facilitated, and after disassembly, replacement or overhaul of the wheel pair is completed, the hydraulic rod shrinks, the supporting returns, the train wheel pair falls again, and connection between the train wheel pair and the framework is recovered.

Description

Technical Field

[0001] The present invention relates to the technical field of train bogie wheelsets, in particular to a train bogie wheelset quick replacement and positioning auxiliary device. Background Art

[0002] The bogie wheelset is the part of the EMU vehicle that contacts the rails. It consists of two left and right wheels firmly pressed onto the same axle. The function of the wheelset is to ensure the operation and steering of the EMU vehicle on the rails. The positioning device of the bogie wheelset refers to the device that needs to keep the position of the wheelset relatively fixed after installation when the wheels are unloaded and replaced.

[0003] At present, existing bogies mostly use a double-torsion fixing method to fix the wheelset. Although it can effectively fix the wheelset, its connection structure is too complicated, resulting in high usage costs. When the staff replaces the wheelset, due to the weight of the wheelset, multiple staff may be required to operate it, which is time-consuming and labor-intensive. In addition, the positioning equipment of the bogie wheelset has low accuracy, resulting in low reliability of the overall structure of the bogie. Summary of the Invention

[0004] (1) Technical problems solved

[0005] In response to the shortcomings of the existing technology, the present invention provides a rapid replacement and positioning auxiliary equipment for train bogie wheelsets, which has the advantages of easy replacement and positioning, and solves the problem that the existing bogies mostly use a double-twist fixing method when fixing the wheelsets. Although it can effectively fix the wheelsets, its connection structure is too complicated, resulting in high usage costs. When the staff replaces the wheelset, due to the weight of the wheelset, multiple staff members may be required to operate it, which is time-consuming and labor-intensive. In addition, the positioning equipment of the bogie wheelset has low accuracy, resulting in low reliability of the overall structure of the bogie.

[0006] (2) Technical solution

[0007] In order to achieve the above-mentioned purpose of facilitating replacement and positioning, the present invention provides the following technical solution: a train bogie wheelset rapid replacement and positioning auxiliary device, comprising a frame, a train wheelset disposed on the frame, a replacement support mechanism disposed on the frame, and a positioning mechanism disposed on the frame;

[0008] The structure includes a load-bearing frame, a middle plate is fixedly mounted on the bottom of the load-bearing frame, and a spring shock-absorbing device is provided on the load-bearing frame;

[0009] The replacement support mechanism includes a hydraulic rod, two groups of hydraulic rods are fixedly installed on the middle plate, two groups of telescopic frames are fixedly installed on the bottom of the middle plate, and a support plate is fixedly installed on the bottom of the hydraulic rods and the telescopic frames; a mechanical locking mechanism is fixedly installed on the front top of the support plate, and a pressure sensor is fixedly installed on the rear top of the support plate.

[0010] Preferably, the positioning mechanism includes a protective plate, and protective plates are fixedly installed on the tops of the two groups of hydraulic rods, and a servo motor is fixedly installed on the tops of the two protective plates, and a first gear is fixedly installed at the output shaft of the servo motor and located inside the protective plate, and bearings are fixedly installed on the front and rear inner walls of the protective plate, and a rotating rod is rotatably connected between the two bearings, and a second gear meshing with the first gear is fixedly installed on the outside of the rotating rod, and a guide rod is fixedly installed inside the protective plate and at the bottom of the rotating rod, and a moving block is movably installed on the outside of the rotating rod and the guide rod, and a connecting block extending to the outside of the protective plate is fixedly installed on one side of the moving block, and an electric push rod extending to the outside of the connecting block is fixedly installed on the inside of the connecting block, and a positioning clamp is fixedly installed on the telescopic end of the electric push rod.

[0011] Preferably, the train wheelset includes a wheel body and an axle, two axles are provided on the load-bearing frame, and two wheel bodies are provided outside the axle.

[0012] Preferably, the outside of the rotating rod is provided with two sets of thread rings, which are bidirectional threads, and the inside of the moving block is provided with a threaded hole threadedly connected to the thread rings.

[0013] Preferably, a guide hole adapted to the guide rod is provided on the upper portion of the moving block and at the bottom of the threaded hole.

[0014] Preferably, the separated surfaces of the two protective plates are each provided with a movable groove adapted to the connecting block, the positioning clamp block is a "U"-shaped block, and a position sensor is provided on the inner side of the positioning clamp block.

[0015] Preferably, the telescopic frame includes a mounting base and an articulated frame, and the telescopic frame is divided into two groups, with three in each group, and is equidistantly distributed between the middle plate and the support plate.

[0016] Preferably, the two groups of hydraulic rods each have two hydraulic rods, and the four hydraulic rods are distributed at the four corners of the middle plate.

[0017] (3) Beneficial effects

[0018] Compared with the prior art, the present invention provides a train bogie wheelset rapid replacement and positioning auxiliary device, which has the following beneficial effects:

[0019] 1. The train bogie wheelset rapid replacement and positioning auxiliary equipment is equipped with a hydraulic rod. When the train wheelset needs to be replaced for maintenance, the servo motor is first operated to make its output shaft drive the first gear to rotate, and the first gear and the second gear drive the rotating rod to rotate, so that the positioning clamping block supports and positions the wheelset. Then, the hydraulic rod is operated and extended, so that the support plate moves down to contact and lift the train wheelset, so that the connection between the train wheelset and the frame is loosened, which is convenient for the removal, replacement or maintenance of the wheelset. After completion, the hydraulic rod is retracted, the support returns to its original position, and the train wheelset is re-positioned and restored to the connection with the frame. The lifting and supporting of the train wheelset and the bottom components can be realized accurately and efficiently, simplifying the tedious process of manual replacement of wheelsets and improving the efficiency of bogie maintenance operations. The combination of hydraulic and mechanical transmission ensures stable support, ensures the safety of the bogie and components during maintenance, and reduces the difficulty and labor intensity of manual operation.

[0020] 2. The train bogie wheelset quick replacement and positioning auxiliary equipment is equipped with a servo motor. When the vehicle is running, the servo motor drives the moving block, the connecting block and the positioning clamp block to move according to the vehicle running status (such as passing through a curve, driving in a straight line, etc.) through the first gear, the second gear and the rotating rod. The guide rod and the guide hole cooperate to adjust the horizontal and vertical positions of the train wheelset relative to the frame, so that the position between the train wheelset and the track and the frame is adapted to ensure operational stability. At the same time, the protective plate can protect the internal transmission components when not in operation, realize dynamic and precise adjustment of the position between the train wheelset and the frame, improve the guidance and stability of the vehicle when passing through a curve, and reduce wheel-rail wear; the positioning clamp block has high positioning accuracy through structural coordination, which enhances the reliability of the overall structure of the bogie; and the drive of the electric push rod and the servo motor has fast response and flexible adjustment, which adapts to the requirements of different operating conditions and helps to improve the stability and safety of the vehicle operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of the present invention;

[0022] Figure 2 This is a schematic diagram of the load-bearing frame of the present invention;

[0023] Figure 3 This is a schematic diagram of a train wheelset according to the present invention;

[0024] Figure 4 It is a schematic diagram of the local structure of the present invention;

[0025] Figure 5 It is a right side cross-sectional schematic diagram of a local structure of the present invention;

[0026] Figure 6 It is a schematic diagram of the local positioning mechanism of the present invention.

[0027] In the figure: 1. Frame; 101. Load-bearing frame; 102. Middle plate; 103. Spring shock-absorbing device; 2. Train wheelset; 201. Wheel body; 202. Wheel axle; 3. Replacement support mechanism; 301. Hydraulic rod; 302. Telescopic frame; 303. Support plate; 304. Mechanical locking mechanism; 305. Pressure sensor; 4. Positioning mechanism; 401. Protective plate; 402. Servo motor; 403. First gear; 404. Bearing; 405. Rotating rod; 406. Second gear; 407. Guide rod; 408. Moving block; 409. Connecting block; 410. Electric push rod; 411. Positioning clamp; 5. Threaded hole; 6. Guide hole; 7. Position sensor. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] See also Figure 1-6 , a train bogie wheelset rapid replacement and positioning auxiliary device, comprising a frame 1, a train wheelset 2 is provided on the frame 1, a replacement support mechanism 3 is provided on the frame 1, and a positioning mechanism 4 is provided on the frame 1;

[0030] The frame 1 includes a load-bearing frame 101 , a middle plate 102 is fixedly mounted on the bottom of the load-bearing frame 101 , and a spring shock-absorbing device 103 is provided on the load-bearing frame 101 ;

[0031] Among them, the load-bearing frame 101 is the "force center" of the entire vehicle. It not only fixes the wheelset and supports the vehicle body, but also transmits traction, braking force, and vertical loads (such as passenger / cargo weight). The middle plate 102 is a "functional expansion platform" that "extends" the load-bearing surface of the frame downward to provide an installation basis for replacing the support mechanism 3 (the hydraulic rod 301 and the telescopic frame 302 require fixed points); the spring shock absorber 103 is a "buffer isolation layer" that cuts off high-frequency vibrations transmitted from the track (such as impact on rail joints), protects the vehicle body equipment and passenger comfort, and at the same time makes the frame more stable in force, avoiding malfunction of the mechanism due to vibration during wheel changing / positioning.

[0032] The replacement support mechanism 3 includes a hydraulic rod 301. Two sets of hydraulic rods 301 are fixedly mounted on the middle plate 102. Two sets of telescopic frames 302 are fixedly mounted on the bottom of the middle plate 102. A support plate 303 is fixedly mounted on the bottom of the hydraulic rods 301 and the telescopic frames 302. A mechanical locking mechanism 304 is fixedly mounted on the top front side of the support plate 303. A pressure sensor 305 is fixedly mounted on the top rear side of the support plate 303.

[0033] Among them, the hydraulic rod 301 is the "active driving force", which realizes "lifting-falling" by hydraulic pressure and provides the vertical force required for wheel changing (lifting the train wheelset 2 from the track / axle box). The telescopic frame 302 is the "passive cooperative arm", which works in "parallel" with the hydraulic rod 301. On the one hand, it makes up for the travel shortcoming of the hydraulic rod 301 (for example, the maximum extension of the hydraulic rod 301 is 100mm, and the telescopic frame 302 can make up for it by 50mm to meet the lifting height of different wheelsets). On the other hand, it disperses the load (prevents the hydraulic rod 301 from bending due to excessive force at a single point). The support plate 303 is the "contact arm". The "executing end" directly supports the axle box / rim of the train wheelset 2, and replaces "point contact" with "surface contact" to avoid damaging the surface of the train wheelset 2, while making the lifting force more uniform. The mechanical locking mechanism 304 adopts a ratchet-pawl lock (or electromagnetic lock). After the jacking is in place, the locking mechanism automatically clamps the support plate 303. Even if the hydraulic system loses pressure, the wheelset will not fall, ensuring the safety of workers and equipment during the wheel changing process. The pressure sensor 305 monitors the lifting force in real time. If the pressure is abnormal (such as a sudden drop, possible oil leakage), it will immediately trigger an alarm and activate the locking mechanism to prevent the accident from escalating.

[0034] In the case implementation, the positioning mechanism 4 includes a protective plate 401, and the tops of the two groups of hydraulic rods 301 are fixedly installed with protective plates 401. The tops of the two protective plates 401 are fixedly installed with servo motors 402. The first gear 403 is fixedly installed at the output shaft of the servo motor 402 and located inside the protective plate 401. Bearings 404 are fixedly installed on the inner walls of the front and rear sides of the protective plate 401. A rotating rod 405 is rotatably connected between the two bearings 404. The outside of the rotating rod 405 is fixedly installed with a second gear 406 that meshes with the first gear 403. A guide rod 407 is fixedly installed inside the protective plate 401 and at the bottom of the rotating rod 405. A moving block 408 is movably installed on the outside of the rotating rod 405 and the guide rod 407. A connecting block 409 extending to the outside of the protective plate 401 is fixedly installed on one side of the moving block 408. An electric push rod 410 extending to the outside of the connecting block 409 is fixedly installed inside the connecting block 409, and a positioning clamp 411 is fixedly installed on the telescopic end of the electric push rod 410.

[0035] Among them, the separated surfaces of the two protective plates 401 are both provided with movable grooves adapted to the connecting block 409, the positioning clamp 411 is a "U"-shaped block, and the positioning clamp 411 adopts a modular clamp, and a position sensor 7 is arranged on the inside of the positioning clamp 411. The position sensor 7 can monitor the movement stroke of the positioning mechanism 4 (such as the lateral movement distance of the moving block 408 and the clamping state of the positioning clamp 411) in real time, and feed back to the control system through an electrical signal to realize automatic closed-loop control. For example, after changing the wheel, the position sensor 7 confirms that the positioning clamp 411 completely clamps the train wheelset 2 before allowing the vehicle to start; when passing a curve, the positioning of the train wheelset 2 is dynamically adjusted according to the data of the position sensor 7 to adapt to the line changes. If the position sensor 7 detects that the positioning mechanism 4 moves abnormally (such as excessive travel deviation, insufficient clamping force), it can trigger an alarm to check for equipment hazards in advance and avoid accidents such as derailment caused by positioning failure of the train wheelset 2.

[0036] In the case implementation, the train wheelset 2 includes a wheel body 201 and an axle 202. Two axles 202 are provided on the load-bearing frame 101, and two wheel bodies 201 are provided outside the axle 202.

[0037] Among them, the tread of the wheel body 201 is pre-embedded with a strain gauge sensor, which can measure the tread thickness and wheel rim height in real time. When the wear approaches the limit, it will automatically alarm to remind you to replace the wheel or repair it. The bearing position of the wheel axle 202 is installed with a temperature sensor, which can monitor the abnormal increase of the axle temperature and avoid axle burning accidents caused by overheating of the wheelset.

[0038] In the embodiment of the case, the outside of the rotating rod 405 is provided with two sets of threaded rings, and the threaded rings are bidirectional. The inside of the moving block 408 is provided with a threaded hole 5 that is threadedly connected to the threaded rings.

[0039] Among them, the rotating rod 405 is a "bidirectional drive shaft" with a "bidirectional thread" (left-hand thread) on the surface, just like "two opposite screws". When the rotating rod is rotated, the two sets of moving blocks 408 will move closer / farther away at the same time (because one side is screwed in and the other side is screwed out), realizing "synchronous symmetrical action". The moving block 408 is an "executor slider" that cooperates with the rotating rod 405 through the threaded hole 5 to convert the "rotation" of the rotating rod into "linear movement", driving the clamping block, push rod and other components of the positioning mechanism 4 to complete the positioning and clamping of the train wheelset 2. The threaded connection between the rotating rod 405 and the moving block 408 is installed with a double nut anti-loosening (or spring washer to prevent vibration from causing the thread to loosen. The threaded parts of the rotating rod 405 and the moving block 408 are sleeved with a telescopic dust cover to block sand, dust and iron filings, avoid debris from getting stuck in the thread, and ensure the long-term smooth operation of the positioning mechanism 4.

[0040] In the embodiment of the case, a guide hole 6 adapted to the guide rod 407 is provided on the upper portion of the moving block 408 and at the bottom of the threaded hole 5;

[0041] Among them, the guide hole 6 adopts a spring floating sleeve (or a linear bearing). When the frame 1 is slightly deformed, the floating sleeve can "adaptively offset" to maintain the matching accuracy of the guide rod 407 and the moving block 408, avoid jamming, and ensure that the positioning mechanism 4 continues to work reliably.

[0042] In the case implementation, the telescopic frame 302 includes a mounting base and an articulated frame. The telescopic frame 302 is divided into two groups, three in each group, and is equidistantly distributed between the middle plate 102 and the support plate 303;

[0043] Among them, the extension and retraction of the hydraulic rod 301 is "actively driven", but the stroke of the hydraulic rod 301 alone may be limited. The telescopic frame 302 can be synchronously extended and retracted when the hydraulic rod 301 moves, to make up for the lifting or falling stroke range, to ensure that the support plate 303 can firmly support the train wheelset 2, or completely return to its position without interfering with the operation of the bogie. At the same time, it cooperates with the hydraulic rod 301 to disperse the vertical load, avoid deformation of the hydraulic rod 301 due to excessive force at a single point, and improve the stability and durability of the overall support, which is especially critical during heavy-load wheel changing.

[0044] During implementation, follow these steps:

[0045] 1) First, the servo motor 402 is operated so that its output shaft drives the first gear 403 to rotate. The first gear 403 and the second gear 406 drive the rotating rod 405 to rotate, so that the positioning clamping block 411 supports and positions the wheelset 2;

[0046] 2) The hydraulic rod 301 is then extended after operation, causing the support plate 303 to move downward to contact and lift the train wheelset 2, thereby loosening the connection between the train wheelset 2 and the frame 1, making it easier to disassemble, replace or repair the wheelset;

[0047] 3) After the final completion, the hydraulic rod 301 is retracted, the support 303 returns to its original position, and the train wheelset 2 is repositioned and restored to its connection with the frame.

[0048] When the train wheelset 2 needs to be replaced for maintenance, the servo motor 402 is first operated to make its output shaft drive the first gear 403 to rotate, and the first gear 403 and the second gear 406 are used to drive the rotating rod 405 to rotate, so that the positioning clamping block 411 supports and positions the wheelset 2, and then the hydraulic rod 301 is extended after operation to make the support plate 303 move down to contact and lift the train wheelset 2, so that the connection between the train wheelset 2 and the frame 1 is loosened, which is convenient for the wheelset to be disassembled, replaced or repaired. After completion, the hydraulic rod 301 is retracted, the support 303 returns to its original position, and the train wheelset 2 is repositioned and restored to its connection with the frame, which can accurately and efficiently realize the lifting and supporting of the train wheelset 2 and the bottom components, simplify the tedious process of manual replacement of wheelsets, and improve the efficiency of bogie maintenance operations; the combination of hydraulic and mechanical transmission ensures stable support, ensures the safety of the bogie and components during maintenance, and reduces the difficulty and labor intensity of manual operation.

[0049] In addition, by setting up a servo motor 402, when the vehicle is running, the servo motor 402 is driven according to the vehicle running state (such as passing through a curve, driving in a straight line, etc.) through the first gear 403, the second gear 406 and the rotating rod 405, driving the moving block 408, the connecting block 409 and the positioning clamp 411 to move, and through the cooperation of the guide rod 407 and the guide hole 6, the lateral and longitudinal positions of the train wheelset 2 relative to the frame 1 are adjusted, so that the position between the train wheelset 2 and the track and the frame 1 is adapted to ensure the operation stability. At the same time, the protective plate 401 can protect the internal transmission components when not in operation, realize dynamic and precise adjustment of the position between the train wheelset 2 and the frame 1, improve the guidance and stability of the vehicle when passing through a curve, and reduce wheel-rail wear; the positioning clamp 411 has high positioning accuracy through structural cooperation, which enhances the reliability of the overall structure of the bogie; and the drive of the electric push rod 410 and the servo motor 402 has fast response and flexible adjustment, adapts to the requirements of different operating conditions, and helps to improve the stability and safety of the vehicle operation.

[0050] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0051] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A train bogie wheelset quick replacement and positioning auxiliary device, comprising a frame (1), characterized in that: The frame (1) is provided with a train wheel set (2), the frame (1) is provided with a replacement support mechanism (3), and the frame (1) is provided with a positioning mechanism (4); The frame (1) comprises a load-bearing frame (101), a middle plate (102) is fixedly mounted on the bottom of the load-bearing frame (101), and a spring shock-absorbing device (103) is provided on the load-bearing frame (101); The replacement support mechanism (3) comprises a hydraulic rod (301), two groups of hydraulic rods (301) are fixedly mounted on the middle plate (102), two groups of telescopic frames (302) are fixedly mounted on the bottom of the middle plate (102), and a support plate (303) is fixedly mounted on the bottom of the hydraulic rods (301) and the telescopic frames (302); a mechanical locking mechanism (304) is fixedly mounted on the top of the front side of the support plate (303), and a pressure sensor (305) is fixedly mounted on the top of the rear side of the support plate (303).

2. The train bogie wheelset rapid replacement and positioning auxiliary equipment according to claim 1, characterized in that: The positioning mechanism (4) comprises a protective plate (401), the tops of the two groups of hydraulic rods (301) are fixedly mounted with protective plates (401), the tops of the two protective plates (401) are fixedly mounted with servo motors (402), a first gear (403) is fixedly mounted at the output shaft of the servo motor (402) and inside the protective plate (401), bearings (404) are fixedly mounted on the inner walls of the front and rear sides of the protective plate (401), a rotating rod (405) is rotatably connected between the two bearings (404), and a first gear (403) is fixedly mounted on the outside of the rotating rod (405) and connected to the first gear (403). A second gear (406) is meshed with a gear (403), a guide rod (407) is fixedly installed inside the protective plate (401) and at the bottom of the rotating rod (405), a moving block (408) is movably installed outside the rotating rod (405) and the guide rod (407), a connecting block (409) extending to the outside of the protective plate (401) is fixedly installed on one side of the moving block (408), an electric push rod (410) extending to the outside of the connecting block (409) is fixedly installed inside the connecting block (409), and a positioning clamp (411) is fixedly installed at the telescopic end of the electric push rod (410).

3. The train bogie wheelset rapid replacement and positioning auxiliary equipment according to claim 1, characterized in that: The train wheel set (2) comprises a wheel body (201) and a wheel axle (202); two wheel axles (202) are arranged on the load-bearing frame (101); and two wheel bodies (201) are arranged outside the wheel axle (202).

4. The train bogie wheelset rapid replacement and positioning auxiliary equipment according to claim 1, characterized in that: The rotating rod (405) is provided with two sets of threaded rings on the outside, and the threaded rings are bidirectional. The moving block (408) is provided with a threaded hole (5) on the inside, which is threadedly connected to the threaded rings.

5. The train bogie wheelset rapid replacement and positioning auxiliary equipment according to claim 4, characterized in that: A guide hole (6) adapted to the guide rod (407) is provided on the upper portion of the moving block (408) and at the bottom of the threaded hole (5).

6. The train bogie wheelset rapid replacement and positioning auxiliary equipment according to claim 2, characterized in that: The separated surfaces of the two protective plates (401) are each provided with a movable groove adapted to the connecting block (409); the positioning clamp block (411) is a "U"-shaped block; and a position sensor (7) is provided inside the positioning clamp block (411).

7. The train bogie wheelset rapid replacement and positioning auxiliary equipment according to claim 1, characterized in that: The telescopic frames (302) include a mounting seat and an articulated frame. The telescopic frames (302) are divided into two groups, with three in each group, and are equidistantly distributed between the middle plate (102) and the support plate (303).

8. The train bogie wheelset rapid replacement and positioning auxiliary equipment according to claim 1, characterized in that: There are two hydraulic rods (301) in each of the two groups, and the four hydraulic rods (301) are distributed at the four corners of the middle plate (102).

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