阅读说明：本技术 配装有用于检测其减震器触底的装置的飞行器起落架 (Aircraft landing gear equipped with a device for detecting bottoming of its shock absorber ) 是由 M·法希 T·法勒 F·雷诺特 于 2020-04-24 设计创作，主要内容包括：本发明涉及一种飞行器起落架,该飞行器起落架包括减震器,该减震器包括第一和第二部分(1、2),第一和第二部分(1、2)安装成相对于彼此可伸缩地滑动并且在减震器被压缩的情况下成为内部邻接,飞行器起落架配装有用于检测减震器成为内部邻接的检测器装置,装置首先包括冲头(10),该冲头(10)固定至减震器的第一部分或固定至起落架相对于减震器的第一部分不滑动的一部分,并且其次包括牺牲件(15),该牺牲件(15)固定至减震器的第二部分或固定至起落架相对于减震器的第二部分不滑动的第二部分,冲头和牺牲件布置成使得在减震器的两个部分成为内部邻接的情况下,冲头撞击牺牲件从而在其中形成凹口。(The invention relates to an aircraft landing gear comprising a shock absorber comprising first and second portions (1, 2), the first and second portions (1, 2) being mounted so as to slide telescopically with respect to one another and to become internally abutting in the event of the shock absorber being compressed, the aircraft landing gear being equipped with detector means for detecting the shock absorber becoming internally abutting, the means comprising firstly a punch (10), the punch (10) being fixed to the first portion of the shock absorber or to a portion of the landing gear which is not sliding with respect to the first portion of the shock absorber, and secondly a sacrificial member (15), the sacrificial member (15) being fixed to the second portion of the shock absorber or to a second portion of the landing gear which is not sliding with respect to the second portion of the shock absorber, the punch and the sacrificial member being arranged such that, in the event of the two portions of the shock absorber becoming internally abutting, the punch impacts the sacrificial member to form a recess therein.)

1. An aircraft landing gear (50; 100; 200) comprising a shock absorber comprising first and second portions (1, 2; 105, 102; 201, 202) mounted to slide telescopically with respect to one another and to become in-abutment if the shock absorber is compressed, the landing gear being fitted with detector means for detecting that the shock absorber becomes in-abutment, the aircraft landing gear being characterised in that the means firstly comprise a punch (10; 110; 210) fixed to the first portion of the shock absorber or to a portion of the landing gear which is not sliding with respect to the first portion of the shock absorber, and secondly comprise a sacrificial member (15; 115; 215) fixed to the second portion of the shock absorber or to a second portion of the landing gear which is not sliding with respect to the second portion of the shock absorber, the punch and the sacrificial member are arranged such that: with the two parts of the damper brought into internal abutment, the punch strikes the sacrificial member to form a recess therein.

2. The aircraft landing gear of claim 1, wherein the punch is a pyramidal tip.

3. The aircraft landing gear according to claim 2, wherein the pyramid tips are fixed to a plate (11) fitted to the landing gear with an interposed peelable shim (14).

4. The aircraft landing gear according to claim 1, wherein the sacrificial member is a pellet (15).

5. The aircraft landing gear according to claim 4, wherein the pellets are carried by a tray (16) formed integrally with the sliding rod (2) of the landing gear.

6. The aircraft landing gear according to claim 1, characterized in that it is of the direct type, wherein a first portion of the shock absorber is formed by a strut (1) of the landing gear and a second portion of the shock absorber is formed by a sliding rod (2) carrying at least one axle (3) and mounted so as to slide telescopically in the strut, and wherein the punch (10) is carried by the strut and the sacrificial member (15) is carried by the sliding rod (2).

7. The aircraft landing gear according to claim 1, characterized in that it is of the type having a rocker lever (106) articulated to a strut (101), the shock absorber being coupled to the rocker lever and to the strut and comprising a cylinder (101) in which a rod (102) is mounted to slide telescopically, the punch (110) and the sacrificial member (105) being fixed, one to the cylinder and the other to the rod.

8. An aircraft landing gear according to claim 1, wherein the landing gear is of the steerable type, comprising a steering tube mounted to rotate relative to a strut of the landing gear and connected to a rod (202) carrying an axle (203) by means of a scissor link and slidably mounted in the strut, the rod forming the cylinder of the shock absorber of the landing gear, the punch and the sacrificial member being fixed, one being fixed to the rod and the other being fixed to the steering tube.

Technical Field

The invention relates to an aircraft landing gear equipped with a device for detecting the bottoming of its shock absorber.

Background

Typically, aircraft landing gears comprise a shock absorber comprising two elements associated to slide telescopically with respect to each other. In a direct landing gear, one element of the shock absorber forms a strut fixed to the landing gear of the aircraft structure, while the other element is a sliding rod carrying the wheels of the landing gear. In a levered landing gear, the shock absorber is coupled firstly to a strut of the landing gear fixed to the aircraft structure and secondly to a lever which is hinged to the strut and carries the wheels of the landing gear.

In special cases, the aircraft may undergo a hard landing, during which the shock absorber of the landing gear is compressed to such an extent that the two elements of the shock absorber are brought into internal abutment (known as "bottoming"), with the risk of deformation of the parts of the shock absorber. This event can also occur during normal landing when the shock absorber is mishandled, or there is insufficient inflation pressure or insufficient internal hydraulic fluid volume. It is appropriate to detect any bottoming and thereby perform an inspection of the shock absorber to verify the status of its components.

Various devices for detecting bottoming are known. Such a device comprises an external indicator arranged to move from a position in which it does not indicate bottoming to a position in which it indicates bottoming if landing gear bottoming occurs. One such indicator is described, for example, in document US 2011/0214601. The indicator moves from one position to another because the pin is shear damaged when the shock absorber bottoms out. Replacing the pin requires the entire indicator apparatus to be disassembled.

Other detector devices are known which comprise a sensor adapted to detect the presence of an object which is in direct proximity to the sensor when the shock absorber bottoms out. However, such devices create reliability problems. It requires regular testing and is likely to fail or, conversely, to trigger a false alarm.

Disclosure of Invention

The object of the present invention is to provide a landing gear equipped with a device for detecting the bottoming of the shock absorber of the landing gear, which is very reliable and does not require the destruction of any part.

In order to achieve this object, there is provided an aircraft landing gear comprising a shock absorber comprising a first portion and a second portion mounted to slide telescopically with respect to one another and to be in internal abutment in the event of the shock absorber being compressed, the landing gear being fitted with a detector device for detecting the internal abutment of the shock absorber, which detector device, according to the invention, firstly comprises a punch fixed to the first portion of the shock absorber or to a portion of the landing gear which does not slide with respect to the first portion of the shock absorber, and secondly comprises a sacrificial member fixed to the second portion of the shock absorber or to a second portion of the landing gear which does not slide with respect to the second portion of the shock absorber, the punch and the sacrificial member being arranged such that, in the event of the internal abutment of the two portions of the shock absorber, the punch impacts the sacrificial member to form a recess therein.

The notch thus formed is easily noticeable by maintenance personnel during inspection and cannot be removed or eliminated. The device of the invention is very reliable, since there is no risk of its failure (break down).

In a particular aspect of the invention, the punch is a pyramidal tip. Then, it is preferable for the pyramid tips to be fixed to the plate that fits the landing gear with the interposition of shims.

In another particular aspect of the invention, the sacrificial member is a pellet (pellet). It is then preferable for the pellets to be carried by a tray formed integrally with the sliding rod of the landing gear.

The invention applies to a landing gear of the direct type in which a first portion of the shock absorber is formed by a strut of the landing gear and a second portion of the shock absorber is formed by a sliding rod carrying at least one axle and mounted to slide telescopically in the strut, and in which the punch is carried by the strut and the sacrificial element is carried by the sliding rod.

The invention is also applicable to landing gear of the type having a rocker lever hinged to a strut, a shock absorber being coupled to the rocker lever and to the strut and comprising a cylinder in which a rod is mounted to slide telescopically, the punch and the sacrificial member being fixed, one to the cylinder and the other to the rod.

The invention also applies to a steerable type of landing gear comprising a steering tube mounted to rotate with respect to a strut of the landing gear and connected to a rod carrying the axle by means of a scissor link and slidably mounted in the strut, the rod forming the cylinder of the shock absorber of the landing gear, the punch and the sacrificial element being fixed, one being fixed to the rod and the other being fixed to the steering tube.

Drawings

The invention will be better understood from the following description given with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a bottom portion of an aircraft landing gear having a direct shock absorber provided with a detector device of the present invention, the shock absorber being shown fully extended;

FIG. 2 is an enlarged view of area A of FIG. 1 showing the punch of the detector apparatus of the present invention;

FIG. 3 is an enlarged view of region B of FIG. 1 showing the sacrificial member of the detector device of the present invention;

FIG. 4 is a view similar to FIG. 1, with the shock absorber illustrated fully compressed and bottoming out;

FIG. 5 is an enlarged view of area C of FIG. 4 showing the sacrificial member impacted by the punch;

FIG. 6 is a perspective view of an aircraft landing gear having a rocker lever fitted with a detector device of the present invention; and

Figure 7 is a perspective view of an aircraft landing gear having steerable wheels fitted with a detector device of the present invention.

Detailed Description

With reference to fig. 1, in this example, the invention is applied to an aircraft landing gear 50 of the direct type, this aircraft landing gear 50 comprising a strut 1 fixed to the structure of the aircraft and a sliding rod 2, the sliding rod 2 being mounted to slide telescopically in the strut 1 and carrying at its end an axle 3 for receiving two wheels (not shown for clarity). The strut 1 and the rod 2 form the telescopic part of the shock absorber, the strut 1 forming the cylinder of the shock absorber and the sliding rod 2 forming the rod. The scissor link 4 comprises two branches 4a and 4b, the two branches 4a and 4b being articulated to each other and to the pillar 1 and the sliding bar 2, respectively, about parallel articulation axes, the scissor link 4 serving to prevent any rotation of the sliding bar 2 with respect to the pillar 1, while allowing them to slide with respect to each other.

The internal structure of the shock absorber is well known and therefore not described in detail herein. As long as it is recalled, the sliding rod 2 is continuously pushed towards its extended position as shown, and during landing the shock absorber becomes compressed against an internal damping force comprising both an elastic component, generated by compressing the internal gas volume, and an inelastic component, generated by throttling the hydraulic fluid.

During normal landing, the shock absorber is never compressed to such an extent that the sliding rod 2 is in internal abutment (i.e. "bottoming") against the strut 1 when in the compressed position. However, this may occur in certain exceptional cases, such as during hard landings in particular, or when landing at a specified speed and weight but at which time the shock absorber suffers a disposal defect (hydraulic fluid leakage, insufficient inflation pressure … …). It is well established that any such event is detected, as this may result in damage to the internal parts of the shock absorber. A check must then be made to ensure that there is no such damage.

To this end, and in accordance with the invention, the landing gear 50 is fitted with means for detecting such events. As can be seen more particularly in fig. 2 and 3, the detector device first comprises a punch, in this example in the form of a pyramidal point 10, formed on the bottom face of a plate 11 fastened to the bottom portion of the column 1 by means of two bolts 12, the bolts 12 fixing the plate 11 to a lug 13 of the column 1 with an interposed gasket 14 of adjustable thickness (for example a peelable gasket). Secondly, the detector device comprises a sacrificial member, in this example in the form of a pellet 15, which pellet 15 is carried on a tray 16 made integral with the slide bar 2. Naturally, the pyramid tips 10 are made of a material that is much harder than the material of the granules 15, whereas the granules 15 are made of a material that is much softer and suitable for easy marking. As can be seen in fig. 4 and 5, the pyramid tips 10 and the granules 15 are arranged relative to each other such that: when the shock absorber is fully compressed to bottom out, the pyramidal tips 10 strike the pellets 15 and leave permanent pyramidal indentations therein. As a result, the telescopic portion of the shock absorber which becomes adjacent in this way is not overlooked and is left over during visual inspection, and is easily detected.

If a notch is seen in the pellet 15 after landing, this means that the two telescopic parts of the shock absorber have bottomed out and the shock absorber needs to be disassembled to inspect its internal components. Once the inspection has been performed, the pellet that has been marked should be replaced with a new pellet without any notches.

It should be observed that the degree to which the component of the shock absorber undergoes internal deformation can be estimated by examining the notches in the granules 15 left by the pyramidal tips 10. In particular, the length of the sides of the recess, which in this example is square, depends on the depth to which the pyramid tips 10 have penetrated and, therefore, on the internal deformation of the part of the shock absorber. For example, in a particular embodiment, a square notch having sides of 0.94 millimeters (mm) represents a 0.1mm deformation of the inner member. Thus, the size of the square forming the notch gives an indication as to the severity of bottoming. Preferably, the maintenance operator has a computer program or chart correlating the size of the squares with the expected internal deformations and/or with the maintenance operations that need to be performed.

The peelable shim 14 enables the position of the pyramid tip 10 to be accurately adjusted so that the notch left in the sacrificial member is large enough to be detected at a glance.

The invention applies to other types of landing gear. In fig. 6, for example, a landing gear 100 can be seen, in which a strut 101 is hinged to a rocker lever 106 carrying an axle 103. The separate shock absorber 104 is coupled firstly to the strut 101 and secondly to the rocker lever 106. Shock absorber 104 includes a cylinder 105, cylinder 105 having telescopically slidable rod 102 therein. According to the invention, barrel 105 is fitted with a punch 110, punch 110 being carried by a support 111 fixed to barrel 105, and rod 102 is fitted with a sacrificial member 115, sacrificial member 115 being carried by a support 116 fixed to rod 102. The punch 110 and the sacrifice member 115 are arranged to collide with each other if the shock absorber 104 bottoms out during landing.

Naturally, the simplest arrangement comprises fixing the punch and the sacrificial member to a respective one of several telescopic elements of the shock absorber of the landing gear, as indicated above. However, this is not always possible. In figure 7, the nose landing gear can be seen, in which the lever is steerable in order to steer the wheels and thus allow the aircraft to turn on the ground. More precisely, the landing gear 200 comprises a strut 201, the strut 201 being fitted at its bottom end with a steering tube 205, so as to be turned by a steering actuator 206. A rod 202 carrying an axle 203 is mounted to slide inside a steer tube 205 and is constrained to rotate with the steer tube 205 by means of a scissor link 204. In this example, the slidable rod 202 forms the first telescopic element of the shock absorber (in particular the cylinder thereof), while the second telescopic element of the shock absorber is a rod that is not visible in the figures but is elongated inside the strut 201, being fastened to the top end thereof. The rod is not accessible from the outside. To solve this difficulty, as mentioned above, the sliding rod 202 is fitted with a sacrificial element in the form of a pellet 215, but the punch, in particular the pyramid tip 210, is now carried by the steering tube 205, i.e. by the element of the landing gear that does not slide with respect to the second telescopic element of the shock absorber. Thus, in the case of a bumper bottoming, the pyramid tips 210 strike the pellet 215 as described above, leaving a notch therein.

The invention is not limited to the above description but covers any variant within the scope defined by the claims. In particular, although the punch has been indicated in the form of a pyramidal point, any other shape (conical point, ball, … …) may be used, provided it is suitable to leave a notch in the sacrificial member. Although the punch has been described as being associated with a position adjustment element in the form of a peelable shim, other adjustment means may be used, such as a cursor, or indeed the adjustment means may be associated not with the punch but with the sacrificial member.

Although it is preferable to fix the punch to one of the telescopic sliding portions of the shock absorber and the sacrificial member to the other of said portions whenever possible, it is also possible to associate the punch and/or the sacrificial member more generally with a portion of the landing gear that does not slide with respect to the corresponding portion of the shock absorber (for example the steering tube in figure 7), or indeed with a support fixed to the rocker lever of figure 6, as long as, when the shock absorber bottoms out, the punch strikes the sacrificial member leaving a recess therein.

The punch and sacrificial member may be made of any material so long as the punch can penetrate into the sacrificial member when bottoming occurs.