Concave cavity head type navigation body time-delay air cushion buffering and load reducing device combined with active ventilation

Abstract

The invention provides a cavity head type navigation body time-delay air cushion buffer load reduction device combined with active ventilation, and belongs to the field of moving object high-speed water entry impact load reduction. The technical problems of a load reduction mechanism and a load reduction effect of the air cushion effect of the navigation body are solved. Through the combined effect of the porous air leakage structure and the active ventilation device, adjustment and control over the load reduction air cushion of the head when the concave cavity head type projectile sails in water are achieved, the load reduction function is achieved, and meanwhile the negative influence of the air cushion effect on the sailing process of the projectile is avoided. A novel porous air leakage method is adopted, the pressure intensity of the air cushion in the concave cavity is kept at a low value through time-delay air leakage, buffering load reduction is achieved in combination with active ventilation, and technical support is provided for high-speed water entry flow control, load reduction design, low-load stable configuration theory development and the like.

Description

Technical Field

[0001] The invention belongs to the field of impact load reduction of a moving object entering water at high speed, and in particular relates to a time-delay air cushion buffering and load reduction device for a concave cavity head-shaped navigation body combined with active ventilation. Background Art

[0002] The high-speed entry of a navigation body into water has a clear application background in the fields of marine engineering and aerospace, among which many important applications are concentrated in the field of national defense, such as cross-medium weapons such as air-dropped torpedoes and supercavitating projectiles. The formation mechanism of high-speed water entry impact loads and the load reduction method are the focus of widespread concern in the field. The high-speed entry of a navigation body into water involves complex mechanical problems such as multiphase flow in the flow field, phase change cavitation, and nonlinear fluid-solid coupling. At present, researchers at home and abroad have conducted systematic and in-depth research and achieved remarkable research results.

[0003] When a spacecraft is recovered on water, the concave shape of the rocket booster tail can capture air to form an air cushion, which can produce a significant buffering and load reduction effect with the help of air cushion compression. This method of buffering and reducing loads based on the concave cavity structure entering the water to form an air cushion is very different from previous load reduction designs. It breaks through the conventional hydrodynamic design concept of using a convex or flat surface for the head of the navigation body, and has important reference significance for the development of new high-speed water entry and load reduction methods.

[0004] Traditional head ventilation and load reduction methods may disrupt the flow field around the head and affect ballistic stability. In the existing research on the load reduction of the concave cavity head shape, there is relatively little research on the air cushion effect inside the head shape, and in the process of air cushion load reduction, the air cushion effect has problems such as transient and uncontrollable. When the internal pressure of the air cushion is too high, the load reduction effect is not ideal. These research aspects need to be explored in depth. The load reduction mechanism and load reduction efficiency of the concave cavity head shape still need to be explored, and the ventilation load reduction efficiency and robustness need to be improved. Summary of the invention

[0005] In view of this, the present invention solves the technical problems of the load reduction mechanism and load reduction effect of the air cushion effect of the navigation body, and proposes a time-delay air cushion buffering and load reduction device for a concave cavity head type navigation body combined with active ventilation. A new porous air release method maintains the air cushion pressure in the concave cavity at a low value through time-delay air release, and combines active ventilation to achieve buffering and load reduction, providing technical support for flow control, load reduction design and theoretical development of low-load stable configuration for high-speed water entry.

[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a time-delay air cushion buffering and load-reducing device for a concave cavity head type navigation body combined with active ventilation, comprising a porous concave cavity warhead, a ventilator, a control member and a replaceable air cabin, wherein the porous concave cavity warhead is connected to the ventilator, and the vacant area formed in the middle is a gas buffer chamber, a plurality of air leakage holes are arranged on the wall of the concave cavity structure of the porous concave cavity warhead, which are used to discharge the air at the bottom of the concave cavity structure, a plurality of active ventilators are arranged at the bottom of the concave cavity structure, an exhaust duct is axially arranged in the middle of the ventilator, and the gas will pass through the area to enter the gas buffer chamber during active ventilation, the rear end of the ventilator is connected to the control member, and the rear end of the control member is connected to the replaceable air cabin;

[0007] The control unit includes a pressure data collector, a rotation engine, an acceleration sensor, a rotation power supply system and an angular velocity sensor. The pressure data collector, the rotation engine, the acceleration sensor, the rotation power supply system, the pressure sensor and the angular velocity sensor are installed on the panel of the control unit. The rotation power supply system is connected to the rotation engine and the rotation engine. A pressure sensor is installed at the center of the bottom of the cavity of the multi-porous cavity warhead to measure the real-time data of the head pressure when sailing in water and input it into the pressure data collector. After receiving the signal, the rotation power supply system outputs a power signal and transmits it to the rotation engine. The bottom of the rotation engine is fixed to the bottom of the control room;

[0008] The rotating shaft passes through the ventilator and the main body of the control part. The head of the rotating shaft is connected to the rotating engine. When installing, the tail is reinforced with a fixing part so that it does not have axial relative movement with the main body of the projectile. There is a protrusion at the connection position between the middle part of the shaft and the air hole turntable. The air hole turntable passes through the rotating shaft. There is a concave cavity in the middle of the turntable. When installing, the two are closely connected so that the air hole turntable can rotate with the rotating shaft. One end of the torsion spring is sleeved with the rotating shaft to generate a restoring torque as the rotating shaft rotates; the other end is fixed to the front wall of the control part.

[0009] The gas delivery port at the lower end of the replaceable gas cabin is tightly connected to the gas inlet of the control component, and the upper end of the replaceable gas cabin is sequentially equipped with an inflation joint.

[0010] Furthermore, threaded holes are circumferentially distributed at the connection points between the porous cavity bullet and the vent, the vent and the control, and the control and the tail shell. When two adjacent parts are connected, screws are used to tighten them to achieve a tight connection between the two parts.

[0011] Furthermore, during the test, a blocking piece is used to close the air vent holes on the porous cavity warhead. When the projectile is sailing in the water, the air cushion in the cavity structure will reach a certain pressure value, which will break through the blocking piece and exhaust air to the outside, achieving a time-delay air release effect.

[0012] Furthermore, the bottom of the protective cover is fixed on the front wall of the control member to protect the torsion spring and prevent the torsion spring from being worn and impacted by the outside world and causing failure.

[0013] Furthermore, a connection structure with a torsion spring is provided inside the protective cover, and one end of the outermost circle of the torsion spring is fixedly connected to the connection structure inside the protective cover.

[0014] Furthermore, the rotary engine outputs torque after receiving the power signal, driving the rotating shaft to rotate, thereby controlling the discharge flux of active ventilation and realizing adaptive active ventilation for underwater navigation.

[0015] Furthermore, the acceleration sensor and angular velocity sensor are located inside the control room to measure the acceleration and angular velocity of the projectile.

[0016] Furthermore, the inflation connector includes an inflation head, a valve spring and an inflation valve which are connected in sequence, and the plug of the inflation device is connected to the inflation valve.

[0017] Furthermore, when not inflated, the upward rebound force of the valve spring causes the inflation valve to block the airway of the inflation head. When the upper end of the inflation valve is pressed downward, the airway opens to allow high-pressure gas to enter. When the gas is inflated to a certain pressure, the inflation device is released. At this time, the valve spring, which is no longer under pressure, will provide upward rebound force again to cause the inflation valve to block the airway, thereby realizing a complete inflation process and ensuring air tightness.

[0018] Furthermore, a protrusion is provided at the connection position between the rotating shaft and the air hole rotating disk, and a concave cavity is provided in the middle through hole of the air hole rotating disk. When installed, the two are matched and connected so that the air hole rotating disk can rotate with the rotating shaft.

[0019] Furthermore, the air hole turntable is a disc-shaped steel structure, and the shape of its central hole is a circle plus two rectangles on both sides. When the rotating shaft passes through, the raised structure on the rotating shaft fits with the two rectangles of the central hole, so that the two structures do not rotate relative to each other.

[0020] Compared with the prior art, the time-delay air cushion buffering and load-reducing device for a concave cavity head-shaped vehicle combined with active ventilation and the load-reducing method thereof described in the present invention have the following beneficial effects:

[0021] (1) When the projectile is completely in the water, a pressure sensor is installed on the projectile head, and the data is input into the pressure data collector for corresponding data conversion and processing, and the output is transmitted to the rotation engine as a power signal. The rotation engine is powered by the power supply system and gives the corresponding torque through the received signal. When it rotates to a specific position, its torque is equal to the restoring torque provided by the torsion spring. At this time, the ventilation pore position corresponding to the rotation angle can pass the corresponding flux of gas to complete the active ventilation process, thereby realizing the function of controlling the air cushion effect of the projectile head according to the head pressure.

[0022] (2) The present invention can realize the adjustment and control of the load-reducing air cushion on the head of a projectile with a concave cavity head when it is sailing in water through the combined effect of a porous air release structure and an active ventilation device, thereby achieving the load-reducing function while avoiding the negative impact of the air cushion effect on the navigation process of the projectile.

[0023] (3) The present invention can adjust and modify the preset signal processing system of the pressure sensor under different environmental conditions and different working conditions, and adapt to different external conditions and meet specific ventilation requirements by adjusting the parameters of the numerical processing.

[0024] (4) The different structures and accessories of the present invention are easy to install, and the head cavity structure and the tail shell structure can be replaced with the required appearance structure, which is flexible in configuration and convenient to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0026] Figure 1 It is a schematic diagram of the appearance of the present invention;

[0027] Figure 2 is a side sectional view of the present invention;

[0028] Figure 3 It is a top view of the AA axial section of the air hole rotating disk;

[0029] Figure 4 This is a schematic diagram of the control room structure;

[0030] Figure 5 It is a schematic diagram of the pore position structure of the cavity bottom structure of the porous cavity bullet of the present invention;

[0031] In the figure: 1-porous concave warhead, 2-ventilation part, 3-control part, 4-tail shell, 5-replaceable air chamber, 6-rotating axis, 7-air hole turntable, 8-torsion spring, 9-protective cover, 10-inflating head, 11-inflating valve, 12-valve spring, 13-control room, 14-pressure data collector, 15-rotating engine, 16-power supply system connecting line, 17-acceleration sensor, 18-data transmission line, 19-rotating power supply system, 20-pressure sensor, 21-blocking part, 22-angular velocity sensor, 23-buffer air chamber, 24-vent valve, 25-center hole. Specific implementation methods

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely explain the technical solutions in the embodiments of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict, and the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0034] See also Figure 1-5 The present implementation method is described as a time-delay air cushion buffering and load-reducing device for a concave cavity head type navigation body combined with active ventilation. The main body of the projectile is mainly composed of four structures, namely, a porous concave cavity warhead 1, a ventilator 2, a control member 3, and a tail shell 4. The porous concave cavity warhead 1 is connected to the ventilator 2, and the vacant area formed in the middle is a gas buffer chamber 23. There are threaded holes distributed circumferentially at the connection between the two components. When the two components are connected, they are tightened with screws to achieve a tight connection between the two components. The same connection method as above is used to connect the ventilator 2 and the control member 3, and the control member 3 and the tail shell 4.

[0035] The wall of the cavity structure of the porous cavity bullet 1 is provided with a plurality of vent holes for discharging the air at the bottom of the cavity structure. The bottom of the cavity structure is provided with a plurality of active vent holes. An exhaust passage is axially provided in the middle of the vent member 2. During active ventilation, the gas will pass through the area and enter the gas buffer chamber. The rear end of the vent member 2 is connected to the control member 3, and the rear end of the control member 3 is connected to the replaceable gas capsule 5.

[0036] The replaceable gas capsule 5 can be installed on the vent valve 24 at the rear end of the control component 13. After installation, the gas enters the control chamber 13 through the vent, and the gas flux is controlled by the vent turntable 7. The tail shell 4 is connected to the control component 3 and wraps the replaceable gas capsule 5. The above components constitute a complete projectile structure.

[0037] The bottom of the cavity structure in the porous cavity bullet 1 is provided with active vents, the number of which is 6. The side walls of the cavity are provided with air release holes, which are used to release the air at the bottom of the cavity. In the initial state, the air release holes are closed by a blocking piece 21 made of acrylic material. When the projectile is sailing in the water, the navigation body and the air and water flow field produce strong impact and strong compression, and the air is captured in the cavity to form an air cushion. When the air cushion in the cavity reaches a certain pressure value, the gas will break through the blocking piece 21 and enter the cavitation flow field from the porous structure, changing the air cushion flow, and also affecting the cavitation evolution, achieving the effect of time-delay air release.

[0038] The wider hollow structure in the middle of the vent 2 is the exhaust duct. During active ventilation, the gas will pass through this area into the gas buffer chamber, and then pass through the active ventilation holes evenly distributed at the bottom of the concave cavity structure of the porous concave cavity bullet 1, thereby realizing the active ventilation load reduction function.

[0039] The rotating shaft 6 passes through the main body of the ventilator 2 and the control part 3, the head of the rotating shaft 6 is connected to the rotating engine 15, and the tail is reinforced with a fixing member during installation so that it does not have axial relative movement with the main body of the projectile, and there is a protrusion at the connection position between the middle of the shaft and the pore turntable 7, and the pore turntable 7 passes through the rotating shaft 6. There is a concave cavity in the middle of the turntable, and the two are closely connected during installation, so that the pore turntable 7 can rotate with the rotating shaft 6. One end of the torsion spring 8 is sleeved with the rotating shaft 6, and generates a restoring torque as the rotating shaft 6 rotates; the other end is fixed on the protective cover 9 to prevent the torsion spring from being worn and impacted by the outside world and causing failure.

[0040] The bottom of the protective cover 9 is fixed to the front wall of the control part 3 and is fastened with screws. There is a connection structure with the torsion spring 8 inside the protective cover 9. One end of the outermost circle of the torsion spring 8 is fixed to the connection structure inside the protective cover 9, and the end of the inner circle is connected to the rotating shaft 6. When the rotating shaft 6 rotates to a certain angle, the torsion spring 8 provides a restoring torque to reset it.

[0041] The pore turntable 7 is a disc-shaped steel structure, and the shape of the central hole 25 is a circle plus two rectangles on both sides. When the rotating shaft 6 passes through, the convex structure on the rotating shaft 6 fits with the two rectangles of the central hole 25, so that the two structures do not rotate relative to each other. Half of the surface of the disk is dug with ventilation holes that gradually increase in area from one end to the other end, and the other half is not provided with a ventilation structure. When the pore turntable 7 is in the initial position, that is, when no ventilation is performed, the half surface of the disk without a ventilation structure covers the gas channel. After receiving the ventilation command, the rotating shaft 6 drives the pore turntable 7 to rotate. When one end of the pore rotates to the top of the gas channel, ventilation begins. When the command requires an increase in ventilation, the pore turntable 7 continues to rotate. At the maximum point, the gas channel is fully opened. If the ventilation volume is reduced, it will rotate back to a specific position under the action of the restoring torque of the torsion spring 8. When ventilation is not required, the pore turntable 7 will reset to the initial state.

[0042] The control unit 3 includes a pressure data collector 14, a rotation engine 15, an acceleration sensor 17, a rotation power supply system 19 and an angular velocity sensor 22, wherein the pressure data collector 14, the acceleration sensor 17, the pressure sensor 20 and the angular velocity sensor 22 belong to the collection system. The pressure data collector 14, the rotation engine 15, the velocity sensor 17, the rotation power supply system 19, the pressure sensor 20 and the angular velocity sensor 22 are installed on the panel of the control unit 13. The rotation power supply system 19 is connected with the rotation engine 15 and the pressure data collector 14. The center of the bottom of the cavity of the multi-porous cavity warhead 1 is installed with a pressure sensor 20 to measure the real-time data of the head pressure when sailing in water. The data transmission line 18 is used to connect the pressure data collector 14 with the rotation power supply system 19. The rotation power supply system 19 outputs a power signal after receiving the signal, and transmits it to the rotation engine 15 through the power supply system connection line 16. The bottom of the rotating engine is fixed to the bottom of the control room 13 with screws. After receiving the power signal, it outputs torque to drive the rotating shaft 6 to rotate, thereby controlling the discharge flux of active ventilation and realizing adaptive active ventilation for underwater navigation. The acceleration sensor 17 and the angular velocity sensor 22 are located inside the control room 13 and are used to measure the acceleration and angular velocity of the projectile.

[0043] The rotating shaft 6 passes through the ventilation part and the control part. The pressure sensor 20 distributed at the bottom of the cavity of the porous cavity bullet 1 transmits data to the pressure data collector 14, and converts it into power information and transmits it to the rotation engine, which outputs the rotation torque accordingly, so that the rotating shaft 6 rotates to the corresponding position. The air hole turntable 7 is fixed on the rotating shaft 6 and rotates with the rotating shaft 6 to control the ventilation volume.

[0044] The pressure data collector 14, the acceleration sensor 17 and the angular velocity sensor 22 are plugged into their corresponding positions in the storage chamber, and each has a power supply system to maintain operation.

[0045] The sensors, the acquisition system, the rotation power supply system 19 , and the rotation engine 15 are all installed on the rear surface of the control unit 13 .

[0046] The gas delivery port at the lower end of the replaceable gas capsule 5 is tightly connected to the gas inlet of the control component 3, and a rubber ring is used around the gas delivery port for airtight sealing. After installation, the replaceable gas capsule 5 is inflated, and the plug of the inflating device is connected to the inflating head 10 of the gas capsule. When not inflated, the upward rebound force of the valve spring 12 causes the inflating valve 11 to block the airway of the inflating head 10. When the upper end of the inflating valve is pressed downward, the airway is opened to allow high-pressure gas to enter. When the gas is inflated to a certain pressure, the inflating device is released. At this time, the valve spring 12, which is no longer under pressure, will provide upward rebound force again to cause the inflating valve 11 to block the airway, realizing a complete inflation process and ensuring airtightness, which is convenient and safe.

[0047] For the present invention, the porous cavity warhead 1, the tail shell 4 and the replaceable air chamber 5 of different sizes and specifications can be selected as needed to meet different working conditions. The power conversion parameters of the rotating power supply system 19 can also be adjusted to change the power output to meet specific ventilation conditions.

[0048] The load reduction method of the time-delay air cushion buffer load reduction device of the concave cavity head type navigation body combined with active ventilation:

[0049] After the projectile is launched through the launch tube, it enters the water. The air in the concave cavity of the head is not discharged in time after impacting the water, forming an air cushion to reduce the impact of the impact load. During navigation in the water, active ventilation is controlled by the head pressure to maintain the air cushion effect and continue to reduce the load. At the same time, excess gas overflows from the side holes and merges into the shoulder cavitation, enhancing the cavitation effect.

[0050] The embodiments of the present invention disclosed above are only used to help illustrate the present invention. The embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. According to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well.

Claims

1. A time-delay air cushion and load-reducing device for a concave-cavity head-shaped vehicle combined with active ventilation, characterized in that: The invention comprises a porous concave cavity warhead (1), a ventilator (2), a control member (3) and a replaceable gas chamber (5); the porous concave cavity warhead (1) is connected to the ventilator (2); an empty area formed in the middle is a gas buffer chamber; a plurality of air leakage holes are arranged on the wall of the concave cavity structure of the porous concave cavity warhead (1) for leaking the air at the bottom of the concave cavity structure; a plurality of active air leakage holes are arranged at the bottom of the concave cavity structure; an exhaust channel is axially arranged in the middle of the ventilator (2); during active ventilation, the gas will pass through the area and enter the gas buffer chamber; the rear end of the ventilator (2) is connected to the control member (3); and the rear end of the control member (3) is connected to the replaceable gas chamber (5); The control unit (3) comprises a pressure data collector (14), a rotation engine (15), an acceleration sensor (17), a rotation power supply system (19) and an angular velocity sensor (22). The pressure data collector (14), the rotation engine (15), the acceleration sensor (17), the rotation power supply system (19), the pressure sensor (20) and the angular velocity sensor (22) are installed on the panel of the control unit (3). The rotation power supply system (19) is connected to the rotation engine (15) and the pressure data collector (14). A pressure sensor (20) is installed at the center of the cavity bottom of the porous cavity warhead (1) to measure the real-time data of the pressure of the porous cavity warhead (1) when sailing in water and input it into the pressure data collector (14). After receiving the signal, the rotation power supply system (19) outputs a power signal and transmits it to the rotation engine (15). The bottom of the rotation engine (15) is fixed to the bottom of the control room (13); The rotating shaft (6) passes through the ventilation member (2) and the main body of the control member (3), the head of the rotating shaft (6) is connected to the rotating engine (15) on the control member (3), and during installation, the tail of the rotating shaft (6) is reinforced with a fixing member so that it does not have axial relative movement with the main body of the projectile, and the middle of the shaft is penetrated by an air hole rotating disk (7), and the air hole rotating disk (7) rotates with the rotating shaft (6), one end of the torsion spring (8) is sleeved with the rotating shaft (6), and a restoring torque is generated as the rotating shaft (6) rotates, and the other end is fixed to the front wall of the control member (3); The gas delivery port at the lower end of the replaceable gas chamber (5) is tightly connected to the gas inlet of the control component (3), and an inflation joint is installed at the upper end of the replaceable gas chamber (5).

2. The time-delay air cushion and load-reducing device for a concave cavity head-shaped vehicle combined with active ventilation according to claim 1 is characterized in that: The connection points between the porous concave cavity bullet (1) and the vent (2), the vent (2) and the control part (3), and the control part (3) and the bullet tail shell (4) are all circumferentially provided with threaded holes. When two adjacent parts are connected, they are fastened with screws to achieve a tight connection between the two parts.

3. The time-delay air cushion and load-reducing device for a concave cavity head-shaped vehicle combined with active ventilation according to claim 1 is characterized in that: During the test, a blocking piece (21) is used to close the air leakage hole on the porous concave cavity bullet (1). When the bullet body is sailing in the water, the air cushion in the concave cavity structure will break through the blocking piece (21) and exhaust gas to the outside after reaching a certain pressure value, thereby achieving a time-delayed air leakage effect.

4. The time-delay air cushion buffering and load-reducing device for a concave-cavity-head-shaped vehicle according to claim 1 is characterized in that: The bottom of the protective sleeve (9) is fixed on the front wall of the control member (3) and is used to protect the torsion spring (8) and prevent the torsion spring (8) from being damaged by external wear and impact and thus causing failure.

5. The time-delay air cushion and load-reducing device for a concave cavity head-shaped vehicle combined with active ventilation according to claim 4 is characterized in that: A connection structure with the torsion spring (8) is arranged inside the protective sleeve (9), and one end of the outermost circle of the torsion spring (8) is fixedly connected to the connection structure inside the protective sleeve (9).

6. The time-delay air cushion and load-reducing device for a concave cavity head-shaped vehicle combined with active ventilation according to claim 1 is characterized in that: The acceleration sensor (17) and the angular velocity sensor (22) are located inside the control room (13) and are used to measure the acceleration and angular velocity of the projectile.

7. The time-delay air cushion and load-reducing device for a concave cavity head-shaped vehicle combined with active ventilation according to claim 1 is characterized in that: The inflation joint comprises an inflation head (10), a valve spring (12) and an inflation valve (11) which are connected in sequence, and a plug of the inflation device is connected to the inflation valve (11).

8. The time-delay air cushion and load-reducing device for a concave cavity head-shaped vehicle combined with active ventilation according to claim 7 is characterized in that: When not inflated, the upward rebound force of the valve spring (12) causes the inflation valve (11) to block the airway of the inflation head (10). When the upper end of the inflation valve (11) is pressed downward, the airway is opened to allow high-pressure gas to enter. When the gas is inflated to a certain pressure, the inflation device is released. At this time, the valve spring (12) that is no longer under pressure will provide an upward rebound force again to cause the inflation valve (11) to block the airway.

9. The time-delay air cushion and load-reducing device for a concave cavity head-shaped vehicle combined with active ventilation according to claim 1 is characterized in that: A protrusion is provided at the connection position between the rotating shaft (6) and the air hole rotating disk (7), and a concave cavity is provided in the middle through hole of the air hole rotating disk (7). When installed, the two are matched and connected so that the air hole rotating disk (7) can rotate along with the rotating shaft (6).

10. The time-delay air cushion and load-reducing device for a concave cavity head-shaped vehicle combined with active ventilation according to claim 9, characterized in that: The air hole turntable (7) is a disc-shaped steel structure, and the shape of its central hole (25) is a circle plus two rectangular sides. When the rotating shaft (6) passes through, the protruding structure on the rotating shaft (6) fits with the two rectangles of the central hole (25), so that the two structures do not rotate relative to each other.

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