A helicopter strut type landing gear

Abstract

The application provides a helicopter strut type landing gear, which comprises an outer cylinder and a rotating cylinder, the rotating cylinder is connected with one end of the outer cylinder and can extend into the outer cylinder, an inner cylinder is connected with the other end of the rotating cylinder, the inner cylinder can extend into the rotating cylinder, and an anti-twist arm assembly is arranged between the inner cylinder and the rotating cylinder; the outer cylinder is connected with the body structure in a flange form, a hole with the same diameter as the outer cylinder is formed on the joint of the body structure, the hole can cooperate with the outer cylinder to transmit the heading and lateral load, the landing gear is connected with the lower joint through the flange at the bottom of the outer cylinder, the flange is fixed on the lower joint through a plurality of bolts, and the heading, lateral and vertical load can be transmitted.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of helicopter landing gear, and particularly relates to a helicopter strut type landing gear. BACKGROUND

[0002] The strut type landing gear is generally installed on the machine body structure in a hinged manner. In order to ensure the structural stability and the transmission of load, at least two upper and lower hinge points are required. When the landing gear is installed, the staff needs to enter the inside of the machine body to operate. Due to special reasons, the landing gear of some helicopters needs to be arranged at a position with relatively small space. These positions not only limit the length of the landing gear inserted into the inside of the machine body, but also cannot allow the staff to enter the inside of the machine body to install the landing gear. Therefore, the landing gear cannot be installed in a hinged manner.

[0003] Generally speaking, the strut type landing gear used for helicopters needs to have the functions of absorbing landing energy, steering, and automatically returning to the neutral position.

[0004] The landing gear absorbing landing energy structure adopts a series structure of a gas cavity and an oil cavity. In the initial state, the gas cavity is filled with a certain pressure gas. When landing, the volume of the gas is compressed, the pressure is increased, and the spring effect is provided, so that appropriate stiffness can be provided. The throttle valve is arranged in the oil cavity. The throttle valve is provided with an oil hole with a small diameter. When landing, the throttle valve moves in the oil cavity, can generate resistance, and provide appropriate damping. The stiffness and damping together make the landing gear able to absorb the landing energy. On the structure, a cavity is formed by a rotating cylinder and an inner cylinder. The cavity is divided into an oil cavity and a gas cavity by a floating piston inside. The throttle valve is fixed on the inner cylinder. When the inner cylinder is compressed, the volume of the gas cavity is compressed, and the throttle valve slides in the oil cavity to generate stiffness and damping.

[0005] The realization mode of the steering function is to make the landing gear able to rotate around a specific shaft. Generally speaking, the strut type is arranged by arranging the energy absorbing structure in the inner cylinder and rotating around the outer cylinder to realize the steering function.

[0006] The helicopter landing gear generally does not set a steering device. In order to ensure that the landing gear symmetry plane is parallel to the helicopter heading before the helicopter lands, the above-mentioned landing gear needs to be able to return to the neutral position after taking off, that is, the landing gear symmetry plane is coincident with the helicopter symmetry plane. Generally, a pair of cylindrical cams is used to realize the automatic returning to the neutral position function. The cylindrical cam is divided into upper and lower parts. The upper cam is fixed on the inner cylinder, and the lower cam is fixed on the outer cylinder through a special structure. After the landing gear takes off, the inner cylinder is elongated outward, so that the upper and lower cams are engaged. At this time, if the landing gear symmetry plane deviates from the machine body symmetry plane, the cam can be pushed by the gas cavity pressure to make the landing gear return to the neutral position. The upper and lower cams and the attached structure are generally called the automatic returning to the neutral position mechanism.

[0007] The landing gear air cavity, oil cavity, automatic centering mechanism, throttle valve and other structures are arranged in series, which is very long in axial direction, and many parts need to be inserted into the inside of the body structure, which is not convenient for arrangement in a small area. SUMMARY

[0008] In view of the above technical problems, the helicopter strut landing gear provided by the application comprises:

[0009] The outer cylinder comprises a flange plate.

[0010] The rotating cylinder is connected to one end of the outer cylinder and can be inserted into the outer cylinder.

[0011] The inner cylinder is connected to the other end of the rotating cylinder, and the inner cylinder can be inserted into the rotating cylinder.

[0012] The anti-twist arm assembly is arranged between the inner cylinder and the rotating cylinder.

[0013] Preferably, the helicopter strut landing gear further comprises:

[0014] The central rod is arranged in the rotating cylinder.

[0015] The valve seat comprises an oil hole, is sleeved on the central rod, can slide along the central rod, and is connected to the inner cylinder.

[0016] The valve cover is arranged on the valve seat.

[0017] The upper cam is arranged in the inner cylinder.

[0018] The lower cam is matched with the upper cam, and the upper cam and the lower cam are sleeved on the central rod.

[0019] Preferably, the helicopter strut landing gear further comprises:

[0020] The spring is in contact with one end of the upper cam and the other end of the valve cover.

[0021] The upper cam is connected to the inner cylinder, and the lower cam is connected to the central rod.

[0022] Preferably, the helicopter strut landing gear further comprises:

[0023] The cap comprises a boss, can be sleeved on the central rod, and the boss can be embedded in the groove on the outer cylinder.

[0024] The screw cover is threadedly connected to the central rod.

[0025] The screw is used for fixedly mounting the cap on the outer cylinder.

[0026] Preferably, the inner cylinder comprises:

[0027] Floating piston

[0028] Bottom plug, forming a gas cavity with the floating piston

[0029] Preferably, the inner cylinder further comprises:

[0030] Inflating nozzle, for supplying gas to the gas cavity

[0031] End cap, for fixing the bottom plug

[0032] Preferably, further comprising:

[0033] Supporting sleeve, arranged between the rotating cylinder and the inner cylinder

[0034] Preferably, the anti-twist arm assembly comprises:

[0035] Upper anti-twist arm, one end of which is connected with the rotating cylinder

[0036] Lower anti-twist arm, one end of which is connected with the other end of the upper anti-twist arm, and the other end of which is connected with the inner cylinder

[0037] The beneficial technical effects of the present application are:

[0038] The present application adopts a flange form to butt joint with the body structure through the outer cylinder. A hole with the same diameter as the outer cylinder is opened on the upper joint of the body structure, and the cooperation with the outer cylinder can transmit the heading and lateral load. The landing gear is connected with the lower joint through the flange at the bottom of the outer cylinder, and the flange is fixed on the lower joint through a plurality of bolts, which can transmit the heading, lateral and vertical load. The landing gear of the present application can be installed on the body structure outside the fuselage, and the operator does not need to enter the inside of the fuselage, which is convenient to operate. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 The landing gear installation schematic diagram provided by the embodiment of the present application;

[0040] Figure 2 The landing gear flange wheel structure schematic diagram provided by the embodiment of the present application;

[0041] Figure 3 The landing gear structure schematic diagram provided by the embodiment of the present application;

[0042] Figure 4 The landing gear internal structure schematic diagram provided by the embodiment of the present application;

[0043] Figure 5 The landing gear provided by the embodiment of the present application Figure 4 The enlarged view of A in FIG. 8;

[0044] Figure 6 is a schematic diagram of a coaxial degree compensation structure provided by the embodiment of the application;

[0045] Wherein, 1 - screw cover; 2 - screw; 3 - cap; 4 - outer cylinder; 5 - rotating cylinder; 6 - shaft one; 7 - upper anti-twist arm; 8 - inner cylinder; 9 - bolt one; 10 - lower anti-twist arm; 11 - shaft two; 12 - axle; 13 - bolt two; 14 - plug; 15 - center rod; 16 - valve seat; 17 - valve cover; 18 - spring; 19 - pin one; 20 - upper cam; 21 - lower cam; 22 - pin two; 23 - floating piston; 24 - support sleeve; 25 - inflation nozzle; 26 - bottom plug; 27 - end cover. DETAILED DESCRIPTION

[0046] The application adopts flange form for the outer cylinder to be connected with the body structure. A hole with the same diameter as the outer cylinder is formed on the joint of the body structure, and the hole can transmit the heading and lateral load in cooperation with the outer cylinder. The landing gear is connected with the lower joint through the flange at the bottom of the outer cylinder, and the flange is fixed on the lower joint through a plurality of bolts, which can transmit the heading, lateral and vertical load. The landing gear of the application can be installed on the body structure outside the fuselage, and the operator does not need to enter the inside of the fuselage, so the operation is convenient. Figure 1 、 Figure 2 .

[0047] The application reduces the axial length by integrating the throttle valve, the automatic centering mechanism and the inner cylinder support structure. As shown in Figure 5 , the valve seat 16, the valve cover 17, the spring 18, the pin one 19 and the upper cam 20 constitute the structure of the throttle valve, which is used for supporting between the inner cylinder 8 and the rotating cylinder 5. The pin one 19, the upper cam 20, the lower cam 21 and the pin two 22 constitute the automatic centering mechanism. The valve seat 16 integrates the inner cylinder support structure, and the throttle valve and the automatic centering mechanism are integrated together through the pin one 19 and the upper cam 20, which greatly reduces the axial length of the landing gear.

[0048] To realize the integrated design, the outer cylinder 4, the rotating cylinder 5, the inner cylinder 8, the center rod 15 and the valve seat 16 need to be guaranteed to meet the coaxial degree at the position shown in Figure 5 . If the coaxial degree cannot be guaranteed, the landing gear will appear compression jam, slow centering and other faults. To realize the centering function, the relative rotation between the outer cylinder 4 and the center rod 15 needs to be limited, and the conventional method will cause the center rod 15 and the rotating cylinder 5 and the inner cylinder 8 to exceed the specified range, which will cause the occurrence of the faults.

[0049] To solve the above problems, the application provides a compensation structure. As shown in Figure 6As shown, the boss along the X direction and the groove along the Y direction are designed on the cap 3, the groove along the X direction is designed on the outer cylinder 4, and the boss along the Y direction is designed on the center rod 15. The boss on the cap 3 cooperates with the groove on the outer cylinder 4, so that the cap 3 can slide along the X direction relative to the outer cylinder 4. The groove on the cap 3 cooperates with the boss on the center rod 15, so that the cap 3 can slide along the Y direction relative to the center rod 15. The cap 3 is fixed with the center rod 15 through the screw cap 1, and the cap 3 is fixed with the outer cylinder 4 through the screw 2, thereby limiting the relative rotation between the outer cylinder 4 and the center rod 15. The X and Y directions are not parallel, but at a certain angle (such as 90 degrees), and the cap 3 can slide along the X and Y directions during assembly to realize the function of compensating for manufacturing tolerances. Through the structure, the coaxiality at the position can be guaranteed Figure 5 .

[0050] In a feasible implementation manner, the application is composed of the following basic mechanisms:

[0051] The screw cap 1, the screw 2, the cap 3, the outer cylinder 4, the rotating cylinder 5, the shaft one 6, the upper anti-twist arm 7, the inner cylinder 8, the bolt one 9, the lower anti-twist arm 10, the shaft two 11, the wheel shaft 12, the bolt two 13, the plug 14, the center rod 15, the valve seat 16, the valve cover 17, the spring 18, the pin one 19, the upper cam 20, the lower cam 21, the pin two 22, the floating piston 23, the support sleeve 24, the inflation nozzle 25, the bottom plug 26, and the end cover 27.

[0052] The application forms a sealed cavity by the rotating cylinder 5, the inner cylinder 8, the plug 14, the center rod 15, the support sleeve 24, the bottom plug 26, and the end cover 27. The inside of the sealed cavity is divided into two parts, an oil cavity and an air cavity, by the floating piston 23. Figure 6 As shown, the upper part of the floating piston 23 is the oil cavity, and the lower part is the air cavity. The air cavity can be inflated through the inflation nozzle 25, and the oil cavity can be filled with oil after the plug 14 is unscrewed.

[0053] The throttle valve is composed of the valve seat 16, the valve cover 17, the spring 18, the pin one 19, and the upper cam 20, and is fixed on the inner cylinder 8 through the pin one 19. The valve seat 16 is provided with an oil hole. When landing, the inner cylinder 8 moves upward, the volume of the air cavity is compressed to provide rigidity, the throttle valve slides in the oil cavity, and the oil flowing through the oil hole on the valve seat 16 will generate damping. The upper cam 20 is connected with the inner cylinder 8 through the pin one 19, and the lower cam 21 is connected with the center rod 15 through the pin two 22. The rotating cylinder 5 is connected with the upper anti-twist arm 7 through the shaft one 6, the upper anti-twist arm 7 is connected with the lower anti-twist arm 10 through the bolt one 9, and the lower anti-twist arm 10 is connected with the inner cylinder 8 through the shaft two 11. The relative rotation between the rotating cylinder 5 and the inner cylinder 8 can be limited through the upper anti-twist arm 7, the lower anti-twist arm 10, and the connecting member, so that the rotating cylinder 5 rotates together with the inner cylinder 8 and the internal structure thereof around the axis of the outer cylinder 4, and the steering function is realized.

[0054] The central rod 15 is fixed on the outer cylinder 4 by the screw cap 1, the screw 2 and the cap 3. When the rotating cylinder 5 and the inner cylinder 8 deflect to form the structure, the upper cam 20 and the lower cam 21 produce a rotation angle in the axial direction. After the landing gear leaves the ground, it will return to the neutral position under the action of the air cavity pressure, thereby realizing the automatic centering function.

[0055] The wheel shaft 12 is installed on the inner cylinder 8 by the bolt 13, and is used for installing a wheel.

[0056] The present application has the advantages that:

[0057] 1) The landing gear is installed on the body structure in the form of a flange plate, can be operated outside the body, and can be installed in a narrow space.

[0058] 2) The throttle valve, the automatic centering mechanism and the inner cylinder support structure are designed in an integrated manner, so that the axial length of the landing gear can be reduced, and the landing gear can be arranged in a narrow space.

[0059] 3) The present application provides a compensation structure, which can solve the coaxiality problem caused by the structure.

Claims

1. A helicopter strut type landing gear, characterized by, The landing gear can be mounted to the airframe structure outside the fuselage, comprising: an outer cylinder including a flange plate; a rotating cylinder, one end of which is connected to the outer cylinder, and the rotating cylinder can extend into the outer cylinder; an inner cylinder connected to the other end of the rotating cylinder; wherein the inner cylinder can extend into the rotating cylinder; a twist prevention arm assembly arranged between the inner cylinder and the rotating cylinder; Further comprising: a center rod arranged in the rotating cylinder; a valve seat including an oil hole, the valve seat being sleeved on the center rod and being able to slide along the center rod, the valve seat being connected to the inner cylinder; a valve cover arranged on the valve seat; an upper cam arranged in the inner cylinder; a lower cam matched with the upper cam; wherein the upper cam and the lower cam are sleeved on the center rod; a cap designed with a boss in the X direction and a groove in the Y direction; wherein a groove in the X direction is designed on the outer cylinder, and a boss in the Y direction is designed on the center rod.

2. The helicopter strut type landing gear according to claim 1, characterized in that, Further comprising: a spring, one end of the spring being in contact with the upper cam, and the other end of the spring being in contact with the valve cover; wherein the upper cam is connected to the inner cylinder, and the lower cam is connected to the center rod.

3. The helicopter strut type landing gear according to claim 2, characterized in that, Further comprising: a screw cap threadedly connected to the center rod; a screw for fixedly mounting the cap on the outer cylinder.

4. The helicopter strut type landing gear according to claim 3, characterized in that, The inner cylinder comprises: a floating piston; a bottom plug forming a gas cavity with the floating piston.

5. The helicopter strut type landing gear according to claim 4, characterized in that, The inner cylinder further comprises: an inflation nozzle for supplying gas to the gas cavity; an end cover for fixing the bottom plug.

6. The helicopter strut type landing gear according to claim 5, characterized in that, Further comprising: a support sleeve arranged between the rotating cylinder and the inner cylinder.

7. The helicopter strut type landing gear according to claim 6, characterized in that, The twist prevention arm assembly comprises: an upper twist prevention arm, one end of which is connected to the rotating cylinder; a lower twist prevention arm, one end of which is connected to the other end of the upper twist prevention arm, and the other end of which is connected to the inner cylinder.

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