Rocker arm type undercarriage

Abstract

The invention relates to a rocker arm type undercarriage which solves the problems that a buffer of a conventional rocker arm type undercarriage is designed to be close to the inner side, the additional windward area is increased, the airflow field of the whole machine is damaged, and large air resistance is brought. Comprising an undercarriage supporting column, a rocker arm section and a buffer composed of a buffer inner rod and a buffer outer barrel, the undercarriage supporting column is rigidly connected with an airplane body, the rocker arm section is rigidly connected with airplane wheels, and the lower end of the undercarriage supporting column is rotatably connected with the upper end of the rocker arm section; the upper end of the buffer outer cylinder is rotatably connected with the undercarriage strut, and the buffer inner rod is rotatably connected with the rocker arm section. Except for the main body structure, no redundant windward side exists basically, the overall resistance is small, and particularly the design of the buffer reduces the windward resistance.

Description

Technical Field

[0001] The present invention belongs to the field of aircraft landing gears and relates to a rocker-type landing gear. Background Art

[0002] At present, fixed-wing unmanned aerial vehicles mainly use leaf spring landing gears and air-liquid buffer type metal landing gears for buffering during landing. The leaf spring landing gear absorbs energy through tire deformation and leaf spring deformation, and the air-liquid buffer absorbs energy through gas compression and oil flow. The landing gear described in the present invention belongs to a type of air-liquid buffer landing gear.

[0003] Generally, the main landing gears of small fixed-wing unmanned aerial vehicles do not retract. During flight, the main landing gears are exposed to the oncoming flow, destroying the smooth flow field of the whole machine and bringing relatively large air resistance.

[0004] Traditional buffer-type landing gears are generally designed vertically, with a relatively large length and diameter of the buffer, which additionally increases the frontal area, increases air resistance, and affects flight performance. The buffer of a conventional rocker-type landing gear is designed close to the inner side, which also increases the additional frontal area, has a destructive effect on the airflow field of the whole machine, and brings relatively large air resistance. Summary of the Invention

[0005] The present invention provides a rocker-type landing gear, which solves the problem that the buffer of a conventional rocker-type landing gear is designed close to the inner side, increasing the additional frontal area, having a destructive effect on the airflow field of the whole machine, and bringing relatively large air resistance.

[0006] The purpose of the present invention is to design a rocker-type landing gear, which has basically no redundant frontal area except for the main structure, has relatively small overall resistance, and especially the design of its buffer reduces the frontal resistance.

[0007] The present invention is realized by the following technical solutions:

[0008] A rocker-type landing gear includes a landing gear strut, a rocker arm section, and a buffer composed of a buffer inner rod and a buffer outer cylinder. The landing gear strut is rigidly connected to the airframe, the rocker arm section is rigidly connected to the wheel, the lower end of the landing gear strut is rotatably connected to the upper end of the rocker arm section, the buffer is located on the leeward side of the side of the landing gear strut and the rocker arm section, the upper end of the buffer outer cylinder is rotatably connected to the landing gear strut, and the buffer inner rod is rotatably connected to the rocker arm section.

[0009] The lower end of the landing gear strut and the upper end of the rocker arm section are connected through a revolute pair I.

[0010] The buffer inner rod and the rocker arm section are connected through a revolute pair II.

[0011] The upper end of the outer cylinder of the buffer is connected to the landing gear strut through a cross joint. Both ends of the cross joint are two rotating pairs perpendicular to each other. The lower part is connected to the outer cylinder of the buffer, and the upper part is connected to the landing gear strut.

[0012] The buffer is an independent part and can be detachably installed on the landing gear strut and the rocker arm section.

[0013] The upper part of the inner rod of the buffer forms a buffer with the outer cylinder of the buffer through a linear pair. There is an oil and gas mixture between the inner rod of the buffer and the outer cylinder of the buffer.

[0014] Advantages of the present invention:

[0015] The landing gear absorbs the landing impact through the rotation of the rocker arm and the compression of the buffer. The buffer of this structure has a longer telescopic stroke, which can extend the energy absorption time and increase the dissipation speed and efficiency.

[0016] During the impact energy absorption process, the buffer is located at the rear of the main landing gear body and the rocker arm section both statically and dynamically, without increasing the windward area. In this way, the entire landing gear system will not increase the windward area due to the buffer. In the front view, the entire buffer is on the back of the landing gear strut and the rocker arm section, without bringing additional resistance.

[0017] The size and stroke of the buffer can be adjusted according to the characteristics requirements of the landing. Since there is no additional resistance, there is no need to limit the outer dimension and the telescopic stroke, that is, the design space of the buffer is relatively large. Just adjust the position of the cross joint on the landing gear strut to adjust the buffer parameters.

[0018] The buffer is an independent part, which can be quickly disassembled and assembled, facilitating replacement and maintenance. Description of the drawings

[0019] Figure 1 is a schematic structural diagram (front view) of the present invention;

[0020] Figure 2 is Figure 1 the right view of;

[0021] Figure 3 、 4 is a schematic three-dimensional structure diagram of the present invention;

[0022] In the figure, landing gear strut - 1, rotating pair I - 2, rocker arm section - 3, rotating pair II - 4, buffer inner rod - 5, buffer outer cylinder - 6, cross joint - 7. Detailed implementation manners

[0023] Such as Figure 4As shown in the figure, the present invention is a rocker-type landing gear. 1 is the landing gear strut, the upper end of the strut is connected to the airframe, and the lower end is a rotary pair. The landing gear strut mainly transmits the ground load to the airframe; 2 is the rotary pair I between the landing gear strut and the rocker arm section 3, which enables the rocker arm section 3 to rotate around the rotation axis; 3 is the rocker arm section, the upper part of the rocker arm section is the rotary pair I2, the middle part is the rotary pair II4, and it is connected to the buffer composed of the inner rod 5 and the outer cylinder 6 of the buffer through the rotary pair II4. The lower part is a rigidly connected wheel assembly, that is, the wheel can rotate synchronously with the rocker arm section around the rotary pair I2; 4 is the rotary pair II, connecting the rocker arm section 3 and the inner rod 5 of the buffer, enabling the rocker arm section 3 and the piston rod to rotate around the axis; 5 is the inner rod of the buffer, the lower part is connected to the rocker arm section 3 through the rotary pair II4, and the upper part forms a buffer with the outer cylinder 6 of the buffer through a linear pair. And between the inner rod 5 of the buffer and the outer cylinder 6 of the buffer, there is an oil and gas mixture, which can buffer and absorb energy, and absorb the impact energy brought by the ground load; 6 is the outer cylinder of the buffer, the lower part is connected to the inner rod 5 of the buffer through a linear pair, and the upper part is connected to the cross joint 7 through a rotary pair; 7 is the cross joint, the two ends of which are composed of two mutually perpendicular rotary pairs, the lower part is connected to the outer cylinder 6 of the buffer, and the upper part is connected to the landing gear strut 1, enabling the buffer to rotate through the upper rotary pair, and adding a rotary pair in the vertical direction of the rotary pair to eliminate the movement jamming problem caused by assembly errors.

[0024] The landing gear strut 1 is rigidly connected to the airframe; when the wheel is subjected to a ground load, the rocker arm section 3 rigidly connected to the wheel rotates around the landing gear strut 1 with the rotary pair I2 as the axis, and causes the rotary pair II4 to move and push the inner rod 5 of the buffer. At the same time, the rotary pair II4 rotates relatively. Since the outer cylinder 6 of the buffer is pushed and rotated by the inner rod 5 of the buffer, the outer cylinder 6 of the buffer rotates around the cross joint 7, and absorbs the impact energy through the oil and gas substances between the inner rod 5 of the buffer and the outer cylinder 6 of the buffer. At the same time, the cross joint 7 eliminates the jamming caused by assembly errors through the rotary pair in the vertical direction.

[0025] As Figure 3 shown, the landing gear strut is a hollow cylinder with a certain thickness. When the aircraft is parked, the landing gear forms a certain outer V-shaped angle with the ground. Its end is connected to a rotatable rocker arm section. The wheel, brake, etc. are rigidly connected to the end of the rocker arm section. A buffer with appropriate parameters is designed and placed between the middle of the rocker arm section and the main body of the landing gear. The buffer is connected to the main body of the landing gear through a cross joint and connected to the middle of the rocker arm section through a rotary pair.

[0026] As Figure 2As shown in the figure, during landing impact, the landing gear wheel collides with the ground, causing the rocker arm segment to rotate. When rotating, it drives the buffer to compress and rotate, forming a moving triangle with side A unchanged, side B only rotating in angle, and both the length and angle of side C changing, transferring the impact force from the ground to the buffer for energy absorption.

[0027] As Figure 1 shown in the figure, on the windward side of the landing gear, except for the main structure, there is no other redundant structure to increase resistance.

[0028] The present invention has the following characteristics:

[0029] 1. The movement plane of the buffer mechanism is located behind the main structure of the landing gear, and in the front view, the buffer does not bring additional windward area, resulting in relatively small overall resistance.

[0030] 2. The cross joint design at the upper end of the buffer is used to eliminate manufacturing and assembly errors.

[0031] 3. Two revolute pairs in the landing gear can not only meet the rotation requirements but also transfer relatively large load forces.

[0032] 4. The buffer adopts an independent part design, which can achieve quick replacement and is convenient for maintenance.

[0033] Terminology and noun explanations of the present invention:

[0034] Rocker-type landing gear: There is a rotational movement between the landing gear wheel and the strut, and the buffer is compressed during rotation to absorb the landing impact energy.

[0035] Buffer: Composed of an inner rod and an outer cylinder, the inside of the outer cylinder consists of hydraulic oil and nitrogen. The inner rod forces the hydraulic oil to move and the gas to compress, achieving the purpose of buffering and energy absorption.

[0036] Revolute pair: A form of connecting two components, and the two parts can rotate relative to each other around a certain axis.

Claims

1. A rocker-type landing gear, characterized in that: It includes a landing gear strut, a rocker arm section, and a shock absorber composed of an inner shock absorber rod and an outer shock absorber cylinder. The landing gear strut is rigidly connected to the airframe, the rocker arm section is rigidly connected to the wheel, the lower end of the landing gear strut is rotatably connected to the upper end of the rocker arm section, the shock absorber is located on the leeward side of the side of the landing gear strut and the rocker arm section, the upper end of the outer shock absorber cylinder is rotatably connected to the landing gear strut, and the inner shock absorber rod is rotatably connected to the rocker arm section.

2. The swing arm type landing gear according to claim 1, characterized in that: The lower end of the landing gear strut is connected to the upper end of the rocker arm section through a revolute pair I.

3. The swing arm type landing gear according to claim 1, characterized in that: The inner shock absorber rod is connected to the rocker arm section through a revolute pair II.

4. The swing arm type landing gear according to claim 1, characterized in that: The upper end of the outer shock absorber cylinder is connected to the landing gear strut through a cross joint. The two ends of the cross joint are two mutually perpendicular revolute pairs, the lower part is connected to the outer shock absorber cylinder, and the upper part is connected to the landing gear strut.

5. The swing arm type landing gear according to claim 1, characterized in that: The shock absorber is an independent part and can be detachably installed on the landing gear strut and the rocker arm section.

6. The swing arm type landing gear according to claim 1, characterized in that: The upper part of the inner rod of the shock absorber forms a shock absorber with the outer shock absorber cylinder through a prismatic pair. There is an oil and gas mixture between the inner shock absorber rod and the outer shock absorber cylinder.

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