RU2539433C2 - Aircraft retractable undercarriage strut - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: invention relates to aircraft (AC) alighting gears and concerns retractable undercarriage designs. Ac retractable undercarriage strut contains lever with wheel gimbal-mounted on fuselage, gear centring hydraulic cylinder with locks of extended and retracted position, where cylinder chambers are connected with AC hydraulic system, and gas-hydraulic shock-absorber one end of which is pivotally connected with the lever and the other - with fuselage. Hydraulic cylinder and shock-absorber are made articulated. Rods of hydraulic cylinder and shock-absorber are installed coaxially being capable to reciprocate relative to each other and to from cavities in one of which gas chamber is located and in the other liquid chamber is located. Hydraulic cylinder is provided with accumulating cavity with dividing piston and mechanical lock the elements of which are made capable to fix dividing piston in extended position and to contact with lock of retracted position.

EFFECT: reduced quantity of assembly units for attachment to AC due to execution of combined aggregate - shock-absorber - hoist, reduced structural dimensions and weight.

4 cl, 5 dwg

Description

The invention relates to takeoff and landing devices of aircraft, in particular to the design features of retractable landing gear.

Known from the prior art is a retractable landing gear support of the aircraft (hereinafter referred to as LA), comprising a lever with a wheel pivotally mounted on the fuselage, a cleaning-release hydraulic cylinder with collet locks of the released and retracted positions, the cavities of which are connected to the aircraft hydraulic system by means of hydraulic locks, and a remote gas-hydraulic shock absorber, the housing of which is pivotally connected to the lever. In the body of the shock absorber, one end of the rod is movably mounted. The other end of the piston rod is mounted in the cylinder body. The stem cavity is filled with gas and acts as a gas chamber of the shock absorber. The hydraulic cylinder is equipped with a plunger, one end of which is rigidly fixed in the housing, and the other, the free end, is sealed in the stem cavity with the ability to move and change the volume of the gas chamber of the shock absorber (RF patent No. 2183179, IPC B64C 25/10, B64C 25/58, published on June 10, 2002).

In the known design, for cleaning the landing gear, a double-sided hydraulic cylinder is used, including a housing, a rod with a piston forming two hydraulic chambers connected to the aircraft hydraulic system through hydraulic locks and a plunger. In addition, the rod of the hydraulic cylinder is the rod of the shock absorber, therefore, it is subject to significant loads during the operation of the shock absorber, which necessitates the installation of collet locks in the hydraulic cylinder to prevent the rod from moving relative to the cylinder body during landing and run along the aircraft runway. This leads to an increase in the weight and dimensions of the landing gear.

Also known is a retractable landing gear support of the aircraft, containing a lever with a wheel pivotally mounted on the fuselage, a remote gas-hydraulic shock absorber with a harvesting-release cylinder, the rod of which is stepped, and the hydraulic cylinder has a hydraulic lock (RF patent No. 22585823, IPC B64C 25/22 of 04/07/2003 published on 02/10/2005). In the known design there is no rod stop at maximum compression of the shock absorber, which makes it possible to compress the shock absorber during rough landing more than the calculated course of depreciation. To compress the shock absorber during the cleaning process by means of the aircraft hydraulic system, significant efforts will be required, caused by the nonlinear increase in the force on the shock absorber from its stroke, and as a result, the dividing piston and lift will have significant dimensions and weight.

This technical solution was adopted as a prototype for the claimed invention.

The basis of the present invention is the task of creating a combined unit that provides cleaning-release support from the hydraulic system of the aircraft, the amortization of landing loads in the released position, regardless of the hydraulic system of the aircraft.

The task underlying the present invention is solved by the fact that in the retractable landing gear of the aircraft, containing a lever with a wheel, pivotally mounted on the fuselage, a cleaning-release hydraulic cylinder with locks of the released and retracted positions, the cavities of which are connected with the hydraulic system of the aircraft, and gas-hydraulic a shock absorber, one end of which is pivotally connected to the lever, and the other to the fuselage, the hydraulic cylinder and shock absorber are made articulated, the rods of the hydraulic cylinder and shock absorber are installed coaxially with the possibility of reciprocating movement relative to each other and the formation of cavities, in one of which there is a gas chamber, and in the other a liquid chamber, while the hydraulic cylinder is equipped with a storage cavity with a separation piston and a mechanical lock, the elements of which are made with the possibility of fixing the separation piston in the released position and contact with the lock of the retracted position.

In addition, the separation piston is configured to form two hydraulic chambers, one of which is connected with the hydraulic system of the aircraft, and the other is the hydraulic chamber of the shock absorber.

In addition, the lock of the retracted position is made in the form of crackers.

In addition, the mechanical lock consists of a ring and a piston, on the outer surface of which spring-loaded tongue and stop are connected by a threaded connection.

The technical result achieved by the implementation of the present invention is to expand the functionality of the landing gear of the aircraft, namely, this landing gear requires the smallest possible number of nodes connecting to the aircraft due to the fact that the depreciation and cleaning-release are performed by a combined unit - shock absorber-lift, while the internal layout of the latter allows you to place the landing gear in the smallest possible size while reducing the weight of the latter.

The implementation of the hydraulic cylinder and the shock absorber articulated and the installation of the cylinder rods and the shock absorber coaxially with the possibility of reciprocating movement relative to each other, as well as the provision of the hydraulic cylinder with a storage cavity with a dividing piston and an additional lock, allow these movements both during depreciation and during cleaning-release of the support, thanks to why the longitudinal dimension of the proposed design is much smaller.

These signs are significant and interconnected with the formation of a stable set of essential features sufficient to obtain the specified technical result.

A comparative analysis of the proposed technical solution with the identified analogues of the prior art, from which the invention does not explicitly follow for a specialist in the field of aircraft landing devices, showed that it is not known, and taking into account the possibility of industrial serial production of a retractable landing gear of the aircraft, we can conclude on its compliance with the criteria of patentability.

The present invention is illustrated by a specific example of the proposed retractable landing gear of the aircraft, which clearly demonstrates the possibility of obtaining the specified technical result. Various modifications and improvements are permitted without departing from the scope of the invention as defined by the appended claims.

The presented embodiment of the invention is described further on the basis of the drawings, where:

- figure 1 shows a diagram of a retractable landing gear aircraft;

- figure 2 shows a General view of the shock absorber-lift in an uncompressed state;

- figure 3 shows a General view of the shock absorber-lift, compressed to the full course of depreciation;

- figure 4 shows a General view of the shock absorber-lift in the retracted position;

- figure 5 shows the opening of the lock retracted position.

In graphic materials, the corresponding structural elements of the retractable landing gear of the aircraft chassis are indicated by the following positions:

1 - wheel;

2 - lever;

3 - shock absorber-lift;

4 - stock;

5 - cylinder;

6 - motionless axle box;

7 - movable (floating) axle box;

8 - crackers;

9 - a separating piston;

10 - the piston of the lock;

11 - language;

12 - a spring ring;

13 - emphasis;

14 - a piston;

15 - spring;

16 - stock;

17 - storage camera;

18 - gas (nitrogen) chamber;

19 - liquid chamber;

20 - liquid chamber;

21 - liquid chamber;

22 - charging connector;

23 - filler plug;

24 - outlet fitting;

25 - fitting;

26 - lock fitting.

The retractable landing gear support of the aircraft contains a lever 2 with a wheel 1 pivotally mounted on the fuselage, a cleaning-release hydraulic cylinder with locks of the released and retracted position, cavities of which are connected to the aircraft hydraulic system, and a gas-hydraulic shock absorber (shock absorber-lift) 3, one end of which is articulated connected to the lever 2, and the other with the fuselage. The proposed design of the unit is combined and performs the functions of both a shock absorber and a lift due to the articulation of the hydraulic cylinder and the shock absorber and the installation of rods coaxially with the possibility of reciprocating movement relative to each other and the formation of cavities, in one of which there is a gas chamber 18, and in the other a liquid chamber, while the hydraulic cylinder is equipped with a storage cavity — a chamber 17 with a dividing piston 9 and a mechanical lock, the elements of which are made with the possibility of fixation ii separating piston in the extended position and contact the retracted position with a lock (8 breadcrumbs). The gas (nitrogen) chamber 18 is formed by the inner surfaces of the abutment 13 and piston 14, the chamber 18 is charged through the charging nozzle 22. The liquid chamber 19 is formed by the inner surfaces of the cylinder 5, the separation piston 9 and the floating axle box 7, the chamber 19 is filled through the filler plug 23. The chamber 20 is connected to the hydraulic system of the aircraft through the cleaning nozzle 25, is formed by the inner surfaces of the cylinder 5, the floating axle box 7 and the axle box 6. The chamber 21 is connected to the hydraulic system of the aircraft through the nozzle of the lock 26, formed by the inner surfaces cylinder and piston 10 of the mechanical lock.

In this regard, its operation is possible in two modes: a shock absorber and a lift, while in each operating mode the elements of the rod 4, cylinder 5, axle box 6, piston 14, rod 16 or elements such as axle box 7, crackers 8, language 11 are involved , spring 15, emphasis 13, ring 12, separation piston 9, piston 10 of a mechanical lock.

The shock absorber-lift 3 consists of a rod 4 installed in the cylinder 5 by means of a fixed axle box 6 and an axle box located on the rod, and a rod 16, inside of which a piston 14 separates the gas chamber 18 from the liquid chamber 19. The rod is held in the retracted position due to crackers 8 and parts of a mechanical lock: tongue 11, spring 15, stop 13, spring ring 12 and piston 10, the tongue 11 and stop 13 are connected by a threaded connection and spring loaded by spring 15. Change in the internal volume of the shock absorber-lift 3 when cleaning the supportoccurs due to the movement of the separation piston 9. When the shock absorber-lift 3 is in shock absorber mode, the separation piston 9 is locked, the basis of which is the ring 12.

Retractable landing gear aircraft operates as follows.

Unit operation in shock absorber mode

In this mode, the separation piston 9 is in the extreme position and is fixed by a spring ring 12, which is locked with tongue 11 (which is structurally made in the form of a sleeve with a chamfer and is designed to lock the lock in the absence of pressure in the hydraulic system) under the action of the spring 15. The spring ring 12 is made with cut and in the absence of external loads it is compressed to a position when its outer diameter is less than the reciprocal internal diameter of the separation piston 9. The tongue 11, under the action of the spring 15, always tends to press the spring ring 12, however, this is prevented by the separation piston 9. As soon as the groove made on the inner surface of the separation piston 9 coincides with the spring ring 12, the latter is opened by the action of the spring 15 and fixed by the tongue 11. When the rod moves, the movable axle 7 will be pressed against fixed axle box 6 pressure in the shock absorber. When work is absorbed by the shock absorber, the rod 4 moves inside the cylinder 5 and the piston 14 inside the rod 16, which is structurally made in the form of a pipe, on the inner surface of which the piston 14 moves, causing the gas chamber 18 to be compressed. When the shock absorber is fully compressed, the rod 4 becomes abutted , which is structurally a skirt of the separation piston 9.

Unit operation in lift mode

When cleaning the landing gear into the aircraft nacelle, the hydraulic pressure is supplied to the chamber 21 through the lock fitting 26, the piston 10 of the mechanical lock is moved (the piston 10 is structurally made in the form of a body of revolution containing a skirt with seals on the one hand and a thread on the other) and tongue 11 (structurally, the piston 10 and the tongue 11 are connected by means of a thread and, when pressure is applied to the lock piston 10, both elements move as a unit), the spring 15 is crimped, the spring ring 12 is unlocked and compressed. By means of excess internal pressure in the shock absorber, the separation piston 9 begins to move towards the increase in the shock absorber cavity, displacing fluid from the chamber 17 into the aircraft hydraulic system, which, after the piston lock is opened using the electro-hydraulic distributor, the chamber 17 is connected to the hydraulic discharge line via the outlet 24. Pressure from the hydraulic system is supplied to the chamber 20 through the cleaning nozzle, the floating axle box 7 under the pressure in the chamber 20 will begin to move towards the compression of the shock absorber together with the rod 4 to the position until the crackers 8 fall into the groove of the lock of the retracted position and the lock of the retracted position closes in the following sequence: crackers 8 located on the stem 4, which is mixed under the action of pressure in the chamber 20, at the end of the stroke of the stem will abut the tongue 11, compressing the spring 15 to the position until the crackers 8 fall into the groove of the lock a, made on the cylinder 5, after which the tongue 11 under the action of the spring 15 will move under the crackers 8 and the lock will close.

The proposed layout of the retractable support and the shock absorber-lift chassis allows you to reduce the size and weight of the support due to the fact that the internal elements of the shock absorber-lift, such as the rod 4 and the cylinder of the shock absorber 5, are involved both in the depreciation and cleaning / release of the support. The change in the course of cleaning and during depreciation (the stroke during cleaning of the support exceeds the stroke of the shock absorber-lift during depreciation) in the shock absorber-lift occurs by moving the separation piston 9 and changing the internal volumes of the shock absorber chambers, as a result of which the longitudinal dimension of the shock absorber is significantly reduced lift.

A sample of the proposed retractable landing gear of the aircraft was developed on the basis of detailed experimental studies of the design parameters and the process of its operation.

The manufacture of the proposed retractable landing gear for the aircraft does not require the development of new equipment and the re-equipment of existing facilities, and the tools used are widely used in the aviation industry, which confirms the possibility of practical implementation and achievement of the technical result.

Claims (4)

1. A retractable landing gear support of the aircraft, comprising a lever with a wheel pivotally mounted on the fuselage, a cleaning-release hydraulic cylinder with locks of the released and retracted position, cavities of which are connected to the aircraft hydraulic system, and a gas-hydraulic shock absorber, one end of which is pivotally connected to the lever, and the other has a fuselage, characterized in that the hydraulic cylinder and shock absorber are articulated, the rods of the hydraulic cylinder and shock absorber are mounted coaxially with the possibility of a reciprocating movement relative to each other and the formation of cavities, in one of which there is a gas chamber, and in the other a liquid chamber, while the hydraulic cylinder is equipped with a storage cavity with a separation piston and a mechanical lock, the elements of which are made with the possibility of fixing the separation piston in the released position and contact with the lock of the cleaned position. 2. The support according to claim 1, characterized in that the dividing piston is configured to form two hydraulic chambers, one of which is connected with the hydraulic system of the aircraft, and the other is the hydraulic chamber of the shock absorber. 3. The support according to claim 1, characterized in that the lock of the retracted position is made in the form of crackers. 4. The support according to claim 1, characterized in that the mechanical lock consists of a ring and a piston, on the outer surface of which there are spring-loaded tongue and stop connected by a threaded connection.

Images