Device to decrease aircraft undercarriage length

FIELD: transport.

SUBSTANCE: invention relates to aircraft engineering. Undercarriage comprises leg to be hinged to aircraft airframe and lower part with wheels mounted thereat. Lower part can move relative to said leg. Additionally, undercarriage comprises device decreasing undercarriage length between extended and retracted positions. Said device comprises interconnected first and second means. Said first means is engaged with undercarriage lower part or with moving element to displace together when lower part displaces relative to leg. Second means is articulated to airframe to allow it go to stop unless undercarriage is in retracted position.

EFFECT: decreased length of undercarriage without special attachments at undercarriage leg.

5 cl, 5 dwg

The technical field to which the invention relates.

The invention relates to a device for reducing the length of the chassis of the aircraft.

The level of technology

When the chassis is in a released position, before his ascent it has a maximum length, as the shock absorber, which is equipped chassis, fully stretched. This length may be greater than the length of the chassis compartment. Therefore, the chassis must be equipped with a device to reduce the length, allowing him to go into the Bay at the end of the rise.

There are various devices. For example, the main landing gear of the AIRBUS A340 is equipped with a shock absorber made with the possibility of moving in the front of the chassis between the extended position when the landing gear is released, and the retracted position when the chassis comes in the position of the end of the rise, which reduces the overall length of the chassis without compression of the shock absorber.

This device is complex and difficult, as it requires the damper to move the slide in the construction. In addition, the system of rods that controls the movement of the shock absorber exposed to all loads when landing, which requires its corresponding dimension.

In other devices, reducing the length of the shock absorber is compressed to reduce the overall length of the chassis. For example, the well-known chassis containing a telescopic rod, h is life, the end of which is rigidly connected to a movable rod of the shock absorber, and the upper end is rigidly connected with the stand, in particular, with the point of attachment, made with the possibility of moving the rack between the landing position and the position of the lift. When the landing gear is released, the bracket is in position landing, in which the telescopic arm is extended fully to the shock absorber, in turn, was fully stretched. When landing telescopic rod is reduced simultaneously with compression of the shock absorber. During lowering of the chassis mount telescopic rod smoothly into position, lifting, acting pulling force on the telescopic rod, which tends to compress the shock absorber and to shorten, so the chassis. Moving the mounting of the telescopic rod of the position of the landing position of the lifting can be done in different ways. You can use the movement of the front knee while lowering the chassis or you can mount a telescopic rod on the lever, pivotally connected to the building and connected with the fixed point structure of the aircraft by means of thrust so that lifting the chassis led to the lever, which causes the telescopic rod to move from the position of the landing position of the lift.

In other devices, reducing the length of the telescopic rod is replaced by a simple rod, displacement is aushima sliding in the thrust bearing, installed movably on the rack for movement between the position of the landing and position of the lifting. The thrust bearing is moved using a relative movement with respect to the rack during the lowering of the chassis.

All these different devices are too complicated to perform, as in reception it is necessary to provide a special point swivel. Kinematics can be very complex to design.

Disclosure of inventions

The objective of the invention is to create a device to reduce the length, does not require special mounting points on the rack chassis.

The problem is solved in the chassis of the aircraft, containing the rack is configured to swivel with the design of the aircraft, and the lower movable portion with the attached wheels, while the chassis further comprises a device for reducing the length of the chassis between the released position and the retracted position, when the specified device contains first and second means, connected to each other, while the first means is connected with the bottom part of the chassis or a movable element connected with this bottom part during its movement relative to the rack, while the second tool pivotally connected to the aircraft t is to, so that during lifting the chassis of the second tool came in the position of rest before the chassis reaches the retracted position.

Thus, during the first part of the climb before the advent of the second means in the position of the focus, this second tool is rotated under the action of the first means due to rotation of the gear in its retracted position. Then the arrival of the second means in position stop locks it and prevents its further rotation following the rotation of the chassis. This block creates a pulling force in the first tool that pulls the lower part of the chassis, which in turn decreases the length of this chassis.

The device is much simpler than the known device because it contains only two elements. In addition, it requires no mounting points on the rack. In addition, it contains no moving slide element which is more difficult to maintain and use than the hinge elements.

Brief description of drawings

The present invention will be more apparent from the following description with reference to the accompanying drawings.

Figure 1 shows a chassis, equipped with a device to reduce the length according to the private variant of the invention, when the chassis is in a released position, side view;

figure 2 shows the chassis of the image is Agen in figure 1, when the aircraft is on the ground, side view;

figure 3 shows the same chassis as shown at the beginning of the ascent, side view

figure 4 shows the same chassis during ascent when the first vehicle arrives at the position of the focus, side view;

figure 5 shows the chassis at the end of the lift when it is in retracted position, side view.

All figures compartment of the chassis shown schematically.

The implementation of the invention

In this example, the device in accordance with the present invention is applied to the auxiliary chassis of the aircraft. As shown in figure 1 and as is well known, the chassis includes a stand 1, pivotally connected to the aircraft around the X axis, in this case perpendicular to the plane of the figure.

Inside the rack moves the sliding rod 2, the lower end of which is mounted an axle and wheels 3. The sliding rod 2 forms one element internal shock-absorber. In this case, the sliding rod 2 is shown in its extended position, which it occupies when the aircraft is in flight with the gear extended.

To ensure the orientation of the wheels of the landing gear when the aircraft is on the ground, the rack 1 is equipped with the rotary sleeve 4. The sliding rod 2 moves freely by turning the sleeve 4, but is locked in rotation Rel is relative to this sleeve. This chassis is equipped with dvuhtomnika 5 with the upper part 5A and the lower link 5, pivotally interconnected at their tops by means of an axis, referred to as the Central axis. Upper part 5A pivotally connected with the rotary sleeve 4, and the lower part 5B pivotally connected with a sliding rod 2. In the position shown, all of the hinge axis of dvuhtomnika 5 parallel to the hinge axis X of the rack. The rotation of the rotary sleeve 4 controls drive 6 orientation, in this case a hydraulic drive with a toothed rack. The stability of the chassis shown in the extended position is provided by a folding strut 7, for simplification of the figure shows only its longitudinal axis. All this is well known and is listed only as information.

According to the invention, the chassis is provided with a device 10 reduce the length, containing:

first means 11 in the form of an elongated thrust, United with the Central axis of dvuhtomnika 5 through a universal joint 13. For this purpose the Central axis of dvuhtomnika is to be installed on its shaft 13;

second means 12, pivotally connected to the aircraft and established for the first means, when viewed in the direction of lift, and United with the first means 11 at point a through ball joint. In this case, the second tool 12 has curved the Orme.

The device in accordance with the present invention operates as follows. In the position shown in figure 1, the sliding rod 2 is in its extended position until it stops, so dvukhzonnykh 5 hour and form a rigid unit. Chassis smoothly rises under the action of a not shown lifting actuator, which causes the chassis to rotate around the hinge axis X. For this purpose, as shown in figure 3, the drive unlock (not shown) pre violates the linearity of the strut 7.

When this node chassis - device for reducing the length of the kinematically behaves as a system of three pivotally interconnected elements, two of which (1 hour, and the second tool 12) pivotally connected with a fixed design (the aircraft), and the third element (formed by the first medium 11 and shaft 13) hinged to the other two elements. The site freely and in a certain way) is deformed under the action of the lifting actuator, which causes the gear to rotate the first means 11 is rotated forward together with the chassis.

Lifting the chassis continues until the situation shown in figure 4, in which the second means 12 comes to a position of emphasis in the rack 1. Since then, the rotation of the second means 12 is locked. At this point a swivel of the second means 12, and per the CSO means 11 is fixed. The continued recovery contributes to the creation of the first means 11 of the pulling effort, which acts on dvukhzonnykh 5 voltage, seeking to remove the sliding rod 2 in the rack. 1, resulting in reduced length of the chassis.

The climb continues to the retracted positions shown in figure 5, the length of the chassis is reduced gradually. During this latter part of the second lifting means 12 remains in the position of the focusing rack. It is noted that in the retracted position, the length L2 of the chassis is less than the length L1 of the chassis in the released position (shown here by the dashed line).

The plot of the rack, which rests against the second tool 12, forms a curved track, performing the role of the Cam. Preferably, the Cam has a circular profile centered on the hinge axis X, so at the end of the second lifting means 12 stores the position in which it was during his arrival in the position of emphasis in the rack 1. In the embodiment, the specified Cam may have a variable profile. For example, you can complete the reduction of the length of the front of the chassis until the going down of the landing gear compartment of the aircraft. In this case, the rack should be run round the profile of the Cam, except for the last part of the ascent, which will have a profile in which the first means 11 will no longer be acting pulling force on the two the owner 5 and which will stop the decrease in the length of the chassis. Thus, for this last part of the stroke the Cam profile provides an additional rotation of the second means 12.

It should be noted that in the situation shown in figure 1, the second means 12 and the node formed by the first medium 11 and the shaft 13, form together with the stand 1 and the upper part 5A of dvuhtomnika 5 articulated parallelogram. During the landing the aircraft and the respective hours of the sliding rod in the rack 1, the node is freely deformed and does not offer resistance to the going down of the moving rod, while the second tool 12 is rotated backward, as shown in figure 2. Thus, even without the use of a sliding or telescopic element of the device reduce the length in accordance with the present invention is compatible with the movement of the landing gear upon landing.

It should also be noted that the device reduce the length is also compatible with the orientation of the wheels of the chassis. Indeed, the ball pivot joint between the first medium 11 and the second medium 12 and the connection shaft 13 between the first medium 11 and the Central axis of dvuhtomnika 5 allow the device to follow dvuhtomnika 5 during rotation of the rotary sleeve 4 and stay connected with dvuhtomnika.

The device reduce the length in accordance with the present invention is a Ki is a completely passive device, contains a minimum of parts which are all very simple. It can be easily adapted to an existing chassis, changing only the Central axis of dvuhtomnika and installing the design of the aircraft pivotally mounting the second means. If necessary, the rack is equipped opposite of the first funds from the special track on which rests the second means during the lifting of the chassis.

The invention is not limited by the present description and, on the contrary covers any variant that is not beyond the scope defined by the claims.

In particular, although the device reduce the length was submitted in connection with the chassis, equipped with a device orientation of the wheels, it can also be applied to the chassis without the installation orientation of the wheels, such as the main chassis. The device can also be applied to the chassis, in which the hinge axis of dvuhtomnika not parallel to the hinge axis of the column.

Similarly, although the device reduce the length was presented for direct chassis, shock absorber which is located inside the rack and wheels mounted on the sliding rod, the device can also be used with beam absorber, in which the wheels are mounted on a Cam, pivotally mounted on the rack, with the absorber, on the one hand, hinged to the rocker, and on the other the part, with a rack chassis or aircraft. In this case, preferably, the first means is connected to the balancer.

The first tool can generally be combined with the bottom chassis, which is equipped with wheels (for example, in this case, the sliding rod or rocker), or any other movable element moving along with this bottom part when it moves relative to the rack (for example, with one of the links of dvuhtomnika, with the Central axis of dvuhtomnika...). In all cases, the device reduce the length should be positioned relative to the chassis so that the pulling force generated by the first means, led to the movement of the lower part relative to the rack, seeking to reduce the length of the chassis. However, as it turned out, the first connection means with dvuhtomnika (the most practical is, of course, the connection with the Central axis of dvuhtomnika) allows you to use the effect of lowering the gear ratio, in a natural way created by dvuhtomnika, and provides, therefore, an even more significant decrease in length.

In addition, the connection between the means of the device reduce the length, on the one hand, and between the means and the design of the aircraft and the chassis, on the other hand, can have any shape (swivel pin, ball on the ora, universal joint...)due to circumstances or special kinematics of the chassis.

In addition, although the above it was indicated that the decrease in the length of the chassis begins when the second tool comes in the position of emphasis, it is possible to start earlier due to the run so that both tools are located on the same line until the arrival of the second means in a position of emphasis.

Finally, the second tool can come in a position of emphasis in the rack, as indicated, but also in the position of the stop element fixedly connected to the reception for example, in the Cam track mounted on a rack or emphasis, still connected to the aircraft. In this case, after the second contact means with this focus he remains motionless during further ascent.

1. The chassis of the aircraft, containing the rack (1), is configured to swivel with the design of the aircraft, and the lower part (2) with the attached wheels, movable relative to the rack, while the chassis further comprises a device for reducing the length of the chassis between the released position and the retracted position, wherein said device includes first and second means (11, 12)connected to each other with the first means (11) connected with the bottom part (2) of the chassis or the movable element (5), moving along with this lower part (2) during its movement relative to the rack, and a second tool (12) pivotally connected to the aircraft so that during lifting the chassis of the second tool came in the position of rest before the chassis reaches the retracted position.

2. The chassis of claim 1, wherein the lower part includes a rod mounted for movement with the slide in the rack between the rack and the sliding rod is dvukhzonnykh, and first means (11) connected to dvuhtomnika.

3. Chassis according to claim 2, in which the first means (11) connected to the Central axis of dvuhtomnika.

4. Chassis according to claim 3, in which the first means (11) connected to the Central axis of dvuhtomnika by means of a universal joint (13).

5. The chassis of claim 1, wherein the second means (12) comes to the position of the focusing rack (1) or element fixedly connected to this counter.