A variable air pressure buffer device that can prevent ground resonance

Abstract

A variable-pressure buffer device capable of preventing ground resonance provided by the present application includes: a buffer for absorbing energy; a pressure regulating component connected to the buffer; and a controller respectively connected to the buffer, the pressure regulating component and a wheel load signal switch. Wherein, when the helicopter takes off, the pressure of the buffer is reduced to a rated value, and the controller drives the pressure regulating component based on the wheel load signal and the pressure signal of the buffer to further reduce the pressure of the buffer to a target pressure value; after the helicopter leaves the ground, the controller drives the pressure regulating component based on the wheel load signal to increase the pressure of the buffer to the rated value. The present application reduces the air chamber pressure in a large lift state by means of an external air chamber, so that the buffer can be compressed to provide stiffness damping, and the buffer is restored to the rated pressure in the takeoff state.

Description

Technical Field

[0001] This application belongs to the technical field of helicopter structure design, and particularly relates to a variable-pressure buffer device that can prevent ground resonance. Background Art

[0002] The ground resonance problem is a self-excited vibration problem that endangers the safety of helicopters. The main factors affecting the ground resonance characteristics of helicopters are: the dynamic characteristics of the rotor, the stiffness and damping characteristics of the landing gear, the weight, center of gravity, and moment of inertia of the airframe, and the intersection data among the three. In the ground resonance calculation model, it is required that the landing gear can provide sufficient stiffness and damping to dissipate energy under the condition of 0-80% lift ratio.

[0003] For large and heavy helicopters, in order to ensure the ground clearance of the airframe during parking and be able to absorb sufficient landing energy, a relatively high air pressure is often filled in the air chamber of the buffer. When entering the high-lift state, the buffer is no longer compressed and thus cannot provide stiffness and damping, and there is a risk of triggering ground resonance at this time. Summary of the Invention

[0004] In view of the above technical problems, this application provides a variable-pressure buffer device that can prevent ground resonance. The buffer device includes:

[0005] A buffer for absorbing energy;

[0006] A pressure regulating assembly connected to the buffer; wherein, the pressure regulating assembly is used to regulate the pressure inside the buffer;

[0007] A controller respectively connected to the buffer, the pressure regulating assembly, and the wheel load signal switch;

[0008] Wherein, when the helicopter takes off, the pressure of the buffer is reduced to the rated value, and the controller drives the pressure regulating assembly based on the wheel load signal and the pressure signal of the buffer to further reduce the pressure of the buffer to the target pressure value;

[0009] After the helicopter takes off, the controller drives the pressure regulating assembly based on the wheel load signal to increase the pressure of the buffer to the rated value.

[0010] Preferably, the buffer device further includes:

[0011] A pressure sensor disposed on the buffer, and the pressure sensor is used to monitor the pressure of the buffer.

[0012] Preferably, the pressure regulating assembly includes:

[0013] An external air chamber connected to the buffer;

[0014] The drive rod is connected to the external air chamber;

[0015] The drive motor is connected to the drive rod; wherein, when the drive motor receives an instruction issued by the controller, it drives the drive rod to move right or left based on the instruction.

[0016] Preferably, the pressure regulating assembly includes:

[0017] The external air chamber is connected to the buffer;

[0018] The drive device is connected to the external air chamber;

[0019] The hydraulic source is connected to the drive device; wherein, when the hydraulic source receives an instruction issued by the controller, it drives the drive device to move based on the instruction.

[0020] Preferably, the pressure regulating assembly further includes:

[0021] The flow switch is arranged between the buffer and the external air chamber.

[0022] Preferably, the external air chamber is connected to the buffer through a pipeline.

[0023] Preferably, the controller is connected to the flow switch.

[0024] Preferably, the flow switch includes a normally closed switch.

[0025] Advantageous technical effects of the present application:

[0026] By means of the external air chamber, the present application reduces the air chamber pressure in the large lift state, so that the buffer can be compressed to provide stiffness damping, and restores the buffer to the rated pressure in the takeoff state.

[0027] In addition, the present application can also achieve two functions: one is to timely detect and supplement the pressure loss in the buffer air chamber, and the other is to facilitate the lifting and lowering operations of the helicopter. Description of the Drawings

[0028] Figure 1 It is a schematic structural diagram of a variable air pressure buffer device capable of preventing ground resonance provided by an embodiment of the present application;

[0029] Figure 2 It is a control process flow chart provided by an embodiment of the present application;

[0030] Figure 3 It is a lifting / lowering operation flow chart provided by an embodiment of the present application. Detailed Embodiments

[0031] Please refer toFigures 1-3 , in this application, a variable - volume air chamber is externally connected to the low - pressure chamber of the buffer, and a pressure sensor is installed in the air chamber of the buffer. The extension amount of the piston rod is calculated by the air chamber pressure value.

[0032] It should be noted that when the helicopter takes off, as the collective pitch increases, the height of the helicopter from the ground increases, the buffer extends, and the air chamber pressure decreases. When the air chamber pressure reaches the rated value, the buffer reaches the fully extended state. At this time, the buffer cannot be compressed, and the landing gear cannot provide the damping to absorb the energy generated by ground resonance. By adjusting the volume of the externally connected air chamber and opening the channel between the buffer air chamber and the externally connected air chamber, the buffer pressure can be reduced, and the buffer can provide damping again.

[0033] In the embodiment of this application, it mainly consists of a buffer 1, a pressure sensor 2, a flow switch 3, an externally connected air chamber 4, a drive rod 5, a drive motor 6, a controller 7, wheel load signals, etc.

[0034] Working principle: When the helicopter takes off, the collective pitch increases, the height of the helicopter from the ground increases, the buffer extends, and the air chamber pressure decreases. When the air chamber pressure reaches the rated value, the buffer reaches the fully extended state. At this time, the buffer cannot be compressed.

[0035] Furthermore, after the controller 7 receives the wheel load signal that the wheels have not left the ground and the corresponding signal from the pressure sensor 2, it opens the flow switch 3 and issues an instruction to make the drive motor 6 work, so that the drive rod 5 moves to the right, reducing the air chamber pressure of the buffer 1, and shortening the extension amount of the piston rod of the buffer 1, so that it can continue to provide damping to dissipate the energy during ground resonance. After the helicopter leaves the ground, after the controller 7 receives the wheel load signal that the wheels have left the ground, it issues an instruction to make the drive motor 6 work, so that the drive rod 5 moves to the left, making the air chamber pressure of the buffer reach the rated value. At this time, the controller 7 issues an instruction to close the flow switch 3.

[0036] In a feasible implementation, when the helicopter needs to perform a lifting operation, the controller 7 issues a pressurization instruction, the flow switch 3 is opened, the buffer 1 is connected to the externally connected air chamber 4, the drive motor 6 works and drives the drive rod 5 to move to the left, and the air pressure of the buffer 1 increases accordingly, and the height of the helicopter from the ground increases. When the helicopter needs to perform a descending operation, the controller 7 issues a depressurization instruction, the flow switch 3 is opened, the buffer 1 is connected to the externally connected air chamber 4, the drive motor 6 works and drives the drive rod 5 to move to the right, and the air pressure of the buffer 1 decreases accordingly, and the height of the helicopter from the ground decreases.

[0037] It should be noted that: 1) externally connect an air chamber with variable volume; 2) include that the controller changes the volume of the externally connected air chamber as needed.

[0038] According to requirements, the present application can adjust the stiffness and damping characteristics of the buffer during the takeoff state of the helicopter, avoid the occurrence of ground resonance risk, and at the same time can conveniently realize the lifting / lowering function of the landing gear.

[0039] Please refer to Figure 2 , in other embodiments of the present application, the work flow in the takeoff stage is as follows:

[0040] During the takeoff process of the helicopter, the controller 7 always receives and monitors the wheel load signal and the buffer pressure signal. When the wheel load signal shows that the helicopter has not left the ground and the pressure of the buffer 1 is not greater than the rated pressure, at this time, the buffer 1 is fully extended. The controller 7 issues a pressure reduction command, the flow switch 3 is opened, the buffer 1 is connected to the external air chamber 4, the drive motor 6 works and drives the drive rod 5 to move to the right, and the buffer air pressure drops to the target pressure. With the further increase of the total rotor pitch, the wheel load signal and the buffer pressure signal are repeatedly monitored. Through the command issued by the controller 7, the drive motor 6 drives the drive rod 5 to continue moving to the right to maintain the buffer air pressure at the target pressure value.

[0041] When the wheel load signal shows that the helicopter has left the ground, at this time, the buffer 1 is in the fully extended state. It is necessary to restore the filling state of the buffer before landing. The controller 7 issues a pressure increase command, the flow switch 3 is opened, the buffer 1 is connected to the external air chamber 4, the drive motor 6 works and drives the drive rod 5 to move to the left, and the buffer air pressure increases to the rated pressure. At this time, the flow switch 3 is closed and the drive motor 6 stops working, and the operation of the variable air pressure buffer in the takeoff stage ends.

[0042] In a feasible implementation manner, for the lifting / lowering operation of the landing gear, please refer to Figure 3 , and the lifting / lowering work flow is as follows:

[0043] When the landing gear is lifted, first set the target pressure of the buffer to a value greater than the parking pressure, and select the current operation as the lifting operation. At this time, the controller 7 issues a pressure increase command, the flow switch 3 is opened, the buffer 1 is connected to the external air chamber 4, the drive motor 6 works and drives the drive rod 5 to move to the left, and the buffer air pressure gradually increases to the target pressure. At this time, the flow switch 3 is closed and the drive motor 6 stops working, and the lifting operation is completed.

[0044] When the landing gear is lowered, first set the target pressure of the buffer to a value less than the parking pressure, and select the current operation as the lowering operation. At this time, the controller 7 issues a pressure reduction command, the flow switch 3 is opened, the buffer 1 is connected to the external air chamber 4, the drive motor 6 works and drives the drive rod 5 to move to the right, and the buffer air pressure gradually decreases to the target pressure. At this time, the flow switch 3 is closed and the drive motor 6 stops working, and the lowering operation is completed.

Claims

1. A variable air pressure buffer device capable of preventing ground resonance, characterized in that The buffer device includes: A buffer for absorbing energy; A pressure regulating component connected to the buffer; wherein, the pressure regulating component is used to regulate the pressure inside the buffer; A controller respectively connected to the buffer, the pressure regulating component and the wheel load signal switch; Wherein, when the helicopter takes off, the pressure of the buffer is reduced to the rated value, the piston rod of the buffer fully extends, and the controller drives the pressure regulating component based on the wheel load signal and the pressure signal of the buffer, so that the pressure of the buffer is further reduced to the target pressure value, and the piston rod of the buffer contracts to continue to provide damping to dissipate the energy during ground resonance; After the helicopter leaves the ground, the controller drives the pressure regulating component based on the wheel load signal to increase the pressure of the buffer to the rated value.

2. The variable air pressure buffer device capable of preventing ground resonance according to claim 1, wherein The buffer device further includes: A pressure sensor arranged on the buffer, and the pressure sensor is used to monitor the pressure of the buffer.

3. The variable air pressure buffer device capable of preventing ground resonance according to claim 2, wherein The pressure regulating component includes: An external air chamber connected to the buffer; A drive rod connected to the external air chamber; A drive motor connected to the drive rod; wherein, when the drive motor receives an instruction issued by the controller, it drives the drive rod to move right or left based on the instruction.

4. The variable air pressure buffer device capable of preventing ground resonance according to claim 2, wherein The pressure regulating component includes: An external air chamber connected to the buffer; A drive device connected to the external air chamber; A hydraulic source connected to the drive device; wherein, when the hydraulic source receives an instruction issued by the controller, it drives the drive device to move based on the instruction.

5. The variable air pressure buffer device capable of preventing ground resonance according to claim 3, wherein The pressure regulating component further includes: A flow switch arranged between the buffer and the external air chamber.

6. The variable air pressure buffer device capable of preventing ground resonance according to claim 5, characterized in that, The external air chamber is connected to the buffer through a pipeline.

7. The variable air pressure buffer device capable of preventing ground resonance according to claim 6, characterized in that, The controller is connected to the flow switch.

8. The variable air pressure buffer device capable of preventing ground resonance according to claim 7, wherein The flow switch includes a normally closed switch.

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