Buffer for aircraft tail skid
阅读说明:本技术 一种用于飞机尾橇的缓冲器 (Buffer for aircraft tail skid ) 是由 吴晓宇 晁灿 张璞 张恒康 沈强 谭临池 于 2020-07-20 设计创作,主要内容包括:本发明涉及一种用于飞机尾橇的缓冲器,其包括外筒、第一内套筒、第二内套筒、弹性膜以及活塞。第一内套筒、第二内套筒沿径向由内至外地设置在外筒的空腔中。第一内套筒、第二内套筒的壁面上分别形成有多个第一通孔、第二通孔。弹性膜设置于第二内套筒和外筒之间,并且在弹性膜和外筒的内壁之间形成填充有高压气体的气室。活塞在外界压力的作用下对液压流体加压,从而促使液压流体通过各内套筒上的通孔进入位于弹性膜和第二内套筒之间的第二液压腔。根据本发明的缓冲器能够使减轻飞机机体受到的撞击载荷。(The invention relates to a buffer for an aircraft tail skid, which comprises an outer cylinder, a first inner sleeve, a second inner sleeve, an elastic membrane and a piston. The first inner sleeve and the second inner sleeve are arranged in the cavity of the outer barrel from inside to outside along the radial direction. The wall surfaces of the first inner sleeve and the second inner sleeve are respectively provided with a plurality of first through holes and second through holes. The elastic membrane is disposed between the second inner sleeve and the outer sleeve, and an air chamber filled with high-pressure gas is formed between the elastic membrane and the inner wall of the outer sleeve. The piston pressurizes the hydraulic fluid under the influence of ambient pressure, thereby forcing the hydraulic fluid through the through-holes in each inner sleeve into a second hydraulic chamber located between the flexible membrane and the second inner sleeve. The buffer according to the invention enables the impact load to which the aircraft body is subjected to be reduced.)
1. a bumper for an aircraft tail skid, the bumper comprising:
an outer barrel, the interior of the outer barrel defining a cavity;
a first inner sleeve disposed in the cavity and including a first hydraulic chamber filled with hydraulic fluid, a wall surface of the first inner sleeve being formed with a plurality of first through holes;
the second inner sleeve is arranged in the cavity and positioned between the first inner sleeve and the outer cylinder, and a plurality of second through holes are formed in the wall surface of the second inner sleeve;
an elastic membrane disposed between the second inner sleeve and the outer sleeve and forming a gas chamber filled with gas between the elastic membrane and an inner wall of the outer sleeve; and
and one end of the piston can extend into the first hydraulic cavity of the first inner sleeve under the action of external pressure so as to pressurize the hydraulic fluid, so that the hydraulic fluid is enabled to enter the second hydraulic cavity between the elastic membrane and the second inner sleeve through the first through hole and the second through hole in sequence.
2. The damper of claim 1, wherein the second through-hole and the first through-hole are offset from each other in a radial direction of the damper.
3. The damper according to claim 2, further comprising a third inner sleeve disposed between the second inner sleeve and the first inner sleeve, and a plurality of third through holes having a cross section not smaller than that of the first through holes are formed in a wall surface of the third inner sleeve.
4. A buffer according to claim 3 wherein the first, third through holes are arranged to enable the hydraulic fluid to flow in a radial direction of the first inner sleeve.
5. The damper of claim 4, wherein the first through holes and the third through holes correspond one-to-one.
6. A damper according to claim 4 in which the axis of each third through-hole is coaxial with the axis of the corresponding first through-hole.
7. A damper as claimed in any one of claims 3 to 6 wherein the third aperture comprises a straight tube section and a tapered tube section.
8. A damper as claimed in claim 7 wherein the first end of the tapered tube section has the same cross-sectional dimensions as the straight tube section and the second end of the tapered tube section has cross-sectional dimensions greater than the straight tube section.
9. The damper of claim 8, wherein the straight tube section opposes the first through-hole and the tapered tube section opposes the second through-hole.
10. The damper of claim 5, wherein the hydraulic fluid discharged from the third through-hole includes a second plurality of through-holes in a lash region formed by the second inner sleeve.
11. A damper as claimed in claim 10 wherein, viewed radially of the first inner sleeve, an edge of at least a portion of the plurality of second through holes is tangential to an edge of the third through hole.
12. A buffer according to claim 4 wherein the first and third inner sleeves are conformable to one another and wherein circumferentially spaced sets of first through holes of different apertures are provided, wherein the first through holes in a same set have the same aperture.
13. The damper according to claim 1, wherein the first through hole and the second through hole are arranged from sparse to dense in a moving direction in which the piston pressurizes the hydraulic fluid.
14. The damper according to claim 1, comprising an upper cover closing an upper end surface of the damper, a lower cover closing a lower end surface of the damper, and a guide rod fixed to the upper cover, wherein the piston has a through hole adapted to the guide rod.
15. The damper of claim 14, wherein the upper and/or lower covers are formed with a hydraulic adjustment bore, the damper further comprising a hydraulic adjustment circuit in communication with the hydraulic adjustment bore, the hydraulic adjustment circuit configured to be capable of adjusting hydraulic pressure within the first hydraulic chamber.
16. The damper of claim 1, wherein the outer cylinder is formed with a gas adjustment aperture, the damper further comprising a gas pressure adjustment circuit in communication with the gas pressure adjustment aperture, the gas pressure adjustment circuit configured to adjust a gas pressure within the gas chamber to return the piston.
17. The damper of claim 3, wherein the upper end surfaces of the second and third inner sleeves are each formed with a groove, the damper further comprising a fixing pin capable of being seated in the groove and preventing the second and third inner sleeves from rotating relative to the outer sleeve.
18. An aircraft tail skid, wherein the aircraft tail skid has a buffer as defined in any one of claims 1 to 17.
Technical Field
The invention relates to the technical field of aircraft construction and design, in particular to a buffer for an aircraft tail skid.
Background
The tail is at risk of touchdown when the aircraft is performing a minimum ground clearance test. For this purpose, the tail of the aircraft is usually provided with a tail skid. When the airplane is lifted off the ground, the tail sledge at the tail part of the airplane touches the ground, so that the impact energy generated by collision between the tail part of the airplane and the ground due to an overlarge head-up angle of the airplane is absorbed and dissipated.
Fig. 1 shows a conventional aircraft tail skid device, which includes components such as bumpers, rocker arms, friction blocks, etc. The buffer comprises an outer cylinder, a piston rod and the like. The lower end of the outer barrel is hinged with the rocker arm, and the inner base is provided with a variable cross-section oil needle. The piston rod is of a hollow structure, and an oil hole matched with the variable-section oil needle is formed in the end face, facing the outer cylinder, of the piston rod. And a single lug joint is arranged at one end of the piston rod, which is back to the outer cylinder. Two ends of the tail sledge device are respectively hinged on the machine body structure through a rocker arm and a single-lug joint.
Referring to fig. 2, the buffer device of the tail skid is a single-cavity variable-section oil-gas type buffer, and energy generated by collision and friction generated by collision between the tail of the aircraft and the ground is mainly absorbed by the buffer device. After the airplane leaves the ground, a friction block facing the ground is arranged at one end of the rocker arm connected with the buffer, and the friction block collides with the ground to enable the outer cylinder to drive the variable-section oil needle to move upwards. Along with the compression of the buffer, the variable cross-section oil needle on the outer cylinder base penetrates through the oil fixing hole on the piston rod to extrude oil into the piston rod from the outer cylinder. The cooperation of the variable cross-section oil needle and the oil fixing hole enables the oil fixing hole of the buffer to form the function of the oil changing hole, so that proper oil liquid damping is provided for the tail skid, and energy is dissipated. During the oil entering the piston rod, the gas in the piston rod is compressed at the same time, which may also absorb a part of the energy.
According to the above, the variable cross-section oil-gas type buffer has the air cavity, so that the piston rod can automatically rebound, however, the stroke of the buffer is uncontrollable, and the requirement on the internal space is high due to the built-in variable cross-section oil needle.
Disclosure of Invention
In view of the above-mentioned situation of the tail skid bumper, an object of the present invention is to provide a bumper for an aircraft tail skid, which can efficiently absorb and dissipate impact energy generated by collision between an aircraft tail and the ground due to an excessive aircraft nose-up angle.
This object is achieved by the following form of the apparatus of the invention. The buffer comprises an outer cylinder, a first inner sleeve, a second inner sleeve, an elastic membrane and a piston. Wherein the interior of the outer barrel defines a cavity. The first inner sleeve is arranged in the cavity and comprises a first hydraulic cavity filled with hydraulic fluid, and a plurality of first through holes are formed in the wall surface of the first inner sleeve. The second inner sleeve is arranged in the cavity and located between the first inner sleeve and the outer barrel, and a plurality of second through holes are formed in the wall surface of the second inner sleeve. The elastic membrane is disposed between the second inner sleeve and the outer sleeve, and a gas chamber filled with high-pressure gas is formed between the elastic membrane and an inner wall of the outer sleeve. One end of the piston can extend into the first hydraulic cavity of the first inner sleeve under the action of external pressure so as to pressurize the hydraulic fluid, so that the hydraulic fluid is enabled to sequentially pass through the first through hole and the second through hole to enter the second hydraulic cavity between the elastic membrane and the second inner sleeve.
The arrangement of the inner sleeve in multiple layers helps to reduce the flow rate of the high pressure hydraulic fluid. This allows the damper to satisfy the damping action while preventing the oil from being damaged by being sprayed at a high speed against the elastic film.
According to a preferred embodiment of the present invention, the second through hole and the first through hole are offset from each other in a radial direction of the damper. The hydraulic fluid flowing out of the first through hole rushes to the inner wall surface of the second inner sleeve, and the second inner sleeve plays a role in reducing the speed and delaying the hydraulic fluid. Thanks to the first through holes and the second through holes which are arranged in a staggered manner, the second inner sleeve can avoid high-speed hydraulic fluid from directly impacting the elastic membrane.
According to a preferred embodiment of the present invention, the damper further includes a third inner sleeve disposed between the second inner sleeve and the first inner sleeve, and a plurality of third through holes having a cross section not smaller than that of the first through holes are formed in a wall surface of the third inner sleeve, thereby facilitating dispersion of the hydraulic fluid.
According to a preferred embodiment of the invention, the first, third through hole are arranged to enable a flow of the hydraulic fluid in a radial direction of the first inner sleeve. By means of the guiding effect of the third through holes, the hydraulic fluid can flow dispersedly and uniformly to the respective second through holes located downstream of the third through holes.
According to a preferred embodiment of the present invention, the first through holes and the third through holes correspond one to one.
According to a preferred embodiment of the invention, the axis of each third through hole is coaxial with the axis of the corresponding first through hole.
According to a preferred embodiment of the invention, the third through hole comprises a straight pipe section and a conical pipe section.
According to a preferred embodiment of the invention, the first end of the conical section has the same cross-sectional dimensions as the straight section, and the second end of the conical section has cross-sectional dimensions greater than the straight section.
According to a preferred embodiment of the invention, the straight tube section is opposite to the first through hole and the tapered tube section is opposite to the second through hole.
According to a preferred embodiment of the invention, the hydraulic fluid discharged from the third through hole comprises a plurality of second through holes in the alluvial area formed by the second inner sleeve.
According to a preferred embodiment of the invention, an edge of at least a part of the second through holes is tangent to an edge of the third through holes, seen in a radial direction of the first inner sleeve.
According to a preferred embodiment of the present invention, the first inner sleeve and the third inner sleeve are capable of being fitted to each other, and a plurality of sets of first through holes having different apertures are provided alternately in the circumferential direction of the first inner sleeve, wherein the first through holes in the same set have the same aperture.
According to a preferred embodiment of the present invention, the first through hole and the third through hole are arranged from sparse to dense in a moving direction in which the piston pressurizes the hydraulic fluid. The first through holes which are specifically arranged are formed in the first inner sleeve in the outer barrel, when the piston rod moves in the axial direction after being compressed, the oil holes in the first hydraulic cavity gradually become fewer, the effective oil hole area gradually becomes smaller, and the damping coefficient becomes larger along with the effective oil hole area, so that the implementation mode of the arrangement mode can play a role in adjusting the oil holes.
According to a preferred embodiment of the present invention, the damper includes an upper cover closing an upper end surface of the damper, a lower cover closing a lower end surface of the damper, and a guide rod fixed to the upper cover, wherein the piston has a through hole adapted to the guide rod.
According to a preferred embodiment of the present invention, the upper cover and/or the lower cover is formed with a hydraulic pressure adjusting hole, and the shock absorber further includes a hydraulic pressure adjusting circuit communicating with the hydraulic pressure adjusting hole, the hydraulic pressure adjusting circuit being configured to be able to adjust the hydraulic pressure in the first hydraulic pressure chamber.
According to a preferred embodiment of the present invention, the outer cylinder is formed with a gas adjusting hole, and the damper further includes a gas pressure adjusting circuit communicating with the gas pressure adjusting hole, the gas pressure adjusting circuit being configured to be capable of adjusting a gas pressure within the gas chamber so that the piston is returned.
According to a preferred embodiment of the present invention, the upper end surfaces of the third inner sleeve and the second inner sleeve are each formed with a groove, and the damper further includes a fixing pin which can be seated in the groove and prevents the third inner sleeve and the second inner sleeve from rotating relative to the outer sleeve.
On the basis of the common general knowledge in the field, the preferred embodiments can be combined randomly to obtain the preferred examples of the invention. Other systems, methods, features and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description and this summary, be within the scope of the invention, and be protected by the accompanying claims.
Drawings
For a better understanding of the above and other objects, features, advantages and functions of the present invention, reference should be made to the preferred embodiments illustrated in the accompanying drawings. Like reference numerals in the drawings refer to like parts. It will be appreciated by persons skilled in the art that the drawings are intended to illustrate preferred embodiments of the invention without any limiting effect on the scope of the invention, and that the various components in the drawings are not drawn to scale.
FIG. 1 is a schematic diagram of a prior art aircraft tail skid.
FIG. 2 is a schematic cross-sectional view of the damper of FIG. 1.
FIG. 3 is a schematic structural view of an aircraft tail skid according to a preferred embodiment of the present invention.
Fig. 4 is a schematic cross-sectional view of a bumper according to a preferred embodiment of the present invention.
Figure 5 is a schematic view of the inner sleeve of figures 2 and 3.
Figure 6 is an exploded view of the inner sleeve of figure 5.
Fig. 7 is an enlarged sectional view of a portion a of fig. 4.
Fig. 8 is a partial enlarged view in the left-hand direction of fig. 7.
Fig. 9 is a partial enlarged view of a lower portion of the damper of fig. 4.
Figure 10 is a top view of the first inner sleeve.
Fig. 11 is a plan view of the lower cover (upper cover).
Detailed Description
The inventive concept of the present invention will be described in detail below with reference to the accompanying drawings. What has been described herein is merely a preferred embodiment in accordance with the present invention and other ways of practicing the invention will occur to those skilled in the art and are within the scope of the invention. In the following detailed description, directional terms, such as "upper", "lower", "inner", "outer", "longitudinal", "lateral", and the like, are used with reference to the orientation depicted in the accompanying drawings. Components of embodiments of the present invention can be positioned in a number of different orientations and the directional terminology is used for purposes of illustration and is in no way limiting.
Referring to FIG. 3, an aircraft tail skid employing the bumpers of the present disclosure is shown. The aircraft tail skid is composed of a rocker arm 200, a
Referring to FIG. 4, a cross-sectional schematic view of the
The interior of the
Referring to fig. 5 and 6 in conjunction with fig. 4, fig. 5 shows the
Similar to the first
The third
An
One end of the piston 140 (i.e., the piston head) is movably inserted into the first hydraulic chamber S1 of the first
In the case where the
When the
It will be appreciated that, as an alternative, the third
According to the present disclosure, the upper and
Referring to fig. 7, 8, wherein fig. 7 shows an enlarged view of the detail a according to fig. 4, fig. 8 shows a left side view of fig. 7. In the preferred embodiment, the first and third through
Preferably, the first through
In the embodiment of fig. 7, 8, the first through-
The diameter D2 of the
Referring to FIG. 8 in conjunction with FIG. 7, the hydraulic fluid discharged from the third through-
More preferably, referring to fig. 8, the edges of the third through
Referring to fig. 4 and 7, after the
A slight radial gap for temporarily containing a small amount of hydraulic fluid is formed between the second
Referring to fig. 9 and 11, fig. 9 is a partially enlarged view of the vicinity of the lower end of the
It should be understood that, according to the above disclosure, those skilled in the art can know the embodiments in which the number of sets of the first through
In order to position the third
The first and third through
Referring further to fig. 4, preferably, the
Referring further to fig. 4, the upper and
Similarly, the
The scope of the invention is limited only by the claims. Persons of ordinary skill in the art, having benefit of the teachings of the present invention, will readily appreciate that alternative structures to the structures disclosed herein are possible alternative embodiments, and that combinations of the disclosed embodiments may be made to create new embodiments, which also fall within the scope of the appended claims.
Description of reference numerals:
a buffer: 100.
rocker arm: 200.
an outer cylinder: 110.
inner sleeve: 120.
a first inner sleeve: 122.
a first through-hole: 123.
a third inner sleeve: 124.
a third through hole: 125.
a straight pipe section: 125A.
A conical pipe section: 125B.
A second inner sleeve: 126.
a second through hole: 127.
groove: 128.
an elastic film: 130.
a piston: 140.
and (4) covering: 141.
and a
A second positioning hole: 142A.
A single-lug joint: 144.
fastening the rod: 146.
positioning pins: 148.
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