JPH01257695A - Wheel position adjusting leg - Google Patents

Abstract

PURPOSE:To obtain a sufficient horizontal empennage load for facilitating the nosing up of an aircraft at takeoff by providing a leg which is allowed to adjust a wheel contact point in relation to the center of gravity of an airframe according to the horizontal movement of the center of gravity due to loading. CONSTITUTION:A load is detected by each load sensor mounted on the front and main legs of an aircraft, so that the overall weight and center of gravity of the aircraft are calculated. And the distance between the center of gravity corresponding to nosing up moment and a ground point is calculated. According to the calculation results, the length of a drag cylinder 1 is controlled, so that the longitudinal position of a wheel 2, that's a ground point P is controlled in the longitudinal direction of an airframe. The length of the drag cylinder 1 or a leg lifting cylinder 3 is controlled by detecting the moving quantity of a position detector 7 fixed at the end of a piston 6 by a position detector 8 which is fired to the drag cylinder 1 or the leg lifting cylinder 3, thereby detecting the predetermined length of the drag cylinder 1 or the leg lifting cylinder 3, and controlling the length by a hydraulic servo valve 8a.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to aircraft legs.

[Conventional technology]

The conventional aircraft landing gear is 1 as shown in the side view in Figure 9.
The elements that make up the legs are wheels 25, leg raising cylinder 3. G3
It consists of structural members such as lug links 4 and buffer struts 17 having dimensions determined by the model of the aircraft, and when the legs are extended, the wheels 2 are at a fixed position with respect to the aircraft body.

Depending on the model, as shown in Figure 10, due to the structure of the shock absorber in the legs, the wheels 2 may move slightly back and forth with each contraction, but this is not to optimize the relationship with the center of gravity. This was due to the structure of the shock absorber.

[Problem to be solved by the invention]

The above-mentioned conventional aircraft legs had the following problems to be solved.

In other words, in conventional aircraft, the weight and center of gravity of the entire aircraft vary depending on the loaded state, but the relative position of the wheels on the landing gear remains constant with respect to the aircraft, which causes the following problems during takeoff and maintenance. There is.

(1) Problems during takeoff When an aircraft takes off, it accelerates on the runway, and when it reaches a speed that allows it to fly through the air, it lifts its nose and takes off.

At this time, as shown in Figure 11, in order to raise the nose of the aircraft, K is directed downward with the horizontal stabilizer to overcome the head-down moment, which is the product of the aircraft weight W and the distance between the grounding point of the main wheels and the center of gravity of the aircraft. A load P must be generated. The downward load that can be generated by the horizontal stabilizer is a function of speed, but in some cases, even though the aircraft has reached the speed at which it can fly, the horizontal stabilizer load is not sufficient, causing it to continue taxiing and increasing. In some cases, it may be necessary to increase the speed of the aircraft by 1″l: the ground run distance may become unnecessarily long.

(2) Problems during maintenance On the ground, equipment mounted on an aircraft may be removed for maintenance.1 For example, if a large amount of equipment from the front is removed at some point, the center of gravity will shift to the rear. In some cases, it can become unstable and cause you to fall on your butt.

[Means to solve the problem]

The present invention, as a means of solving the above-mentioned problem, is intended to solve the above-mentioned problems in that the aircraft legs are equipped with wheels that support the weight of the aircraft below the aircraft and rotate as a result of movement of the aircraft on the ground. It is an object of the present invention to provide a variable wheel position leg, which is characterized by being equipped with a leg that can adjust the position of the wheel grounding point relative to the center of gravity according to movement.

[For production]

Since the present invention is configured as described above, it has the following effects. That is, since the ground contact points of the wheels can be adjusted appropriately according to changes in the position of the center of gravity of the aircraft, the distance between the center of gravity and the wheel contact points can be adjusted to an appropriate distance for takeoff, for example.

〔Example〕

The first to third embodiments of the present invention will be explained with reference to FIGS. 1 to 3. FIG. 1 is a side view of a first embodiment in which the drag cylinder 1 is controlled to control the longitudinal position @5 of the wheel 2, that is, the grounding point P in the longitudinal direction of the aircraft body.

FIG. 2 is a side view of a second embodiment in which the longitudinal position of the wheel 2 is controlled by controlling the length of the leg raising cylinder 3 for raising and lowering the leg via the drag link 4.

A process for controlling the lengths of the drag cylinder 1 and the leg raising cylinder 3 shown in FIGS. 1 and 2 will be explained with reference to FIG. 4. The amount of movement of the position detector n7 fixed to the tip of the piston 6 is detected by the position detector 8 fixed to the drag cylinder 1 or the leg-lifting cylinder 3.t/%Thereby, the final length of the drag cylinder 1 or the leg-raising cylinder 3 is determined. is detected L, and the length is controlled by the hydraulic servo pulp 8a. Here is the position detector 8
and the hydraulic servo pulp 8a are purchased together. Third
The figure is a side view of a third embodiment in which one wheel 2 is controlled back and forth by controlling the length of the drag link 4a.

The process of controlling the length of the drag link 4a shown in FIG. 3 will be explained with reference to FIG. One end has a right-hand thread, and the other end has a left-hand thread; - the distance between the links 9 is determined.

The change is made by rotating the turnbuckle 10, which has a right-hand thread and a left-hand thread on its outer side. The turnbuckle 10 is a servo motor 1 fixed to one side of the link 9.
It is rotated by rotating the worm gear 12 attached to 1.

FIG. 6 is a side view of a fourth embodiment in which the wheels 2 are controlled back and forth by moving the position of the metal fitting 15 that attaches the toe lug sill 1 or the toe lug link 4 to the fuselage side.

FIG. 7 is a detailed view of the metal fitting 15. A female thread is provided inside the metal fitting 15, and a screw 14 having a thread equivalent to a worm gear on the neck is screwed into the female thread. This screw 14 is rotated by a worm gear 12 fixed to a metal fitting 15 and rotated by a servo motor 11 to move it back and forth. Mounting bracket 1 is attached to screw 14.
3 is installed so that it can rotate freely. To this mounting bracket 13,
Install lug cylinder 1 or drag link 4.

Figure 8 is a block diagram showing the entire system for controlling the position of the landing gear.
Detects the load and calculates the overall weight and center of gravity. Calculate the takeoff speed from the obtained total aircraft weight. Calculate the load that the horizontal stabilizer can exert at the obtained takeoff speed. From this, the nose-up moment is determined, and the distance between the center of gravity and the grounding point is calculated accordingly. so that it is the calculated distance.

9 lug cylinder 1. Or drag link 4, 4a or leg raising cylinder 3. Or control the mounting bracket 13.

〔Effect of the invention〕

The present invention is based on the above 5&Cl1l! This has the following effects. That is, by controlling the wheel position of the landing gear relative to the 1L center, it is easier to raise the head during takeoff.

Takeoff run distance can be shortened. This makes it possible to expand the operational range at airports with short runways.

Furthermore, by shortening the runway distance and keeping the takeoff speed low, safety is also increased in terms of emergency situations and stopping.

Furthermore, during maintenance, it is possible to prevent accidents such as the center of gravity going too far to the rear, causing your butt to stick.

[Brief explanation of the drawing]

Fig. 1 is a side view of the first embodiment of the present invention, Fig. 2 is a side view of the second embodiment, Fig. 3 is a side view of the third embodiment, and Fig. 4 is the same as Fig. 1 and Fig. 2. An enlarged vertical cross-sectional view of the lug cylinder 1 and the leg raising cylinder 3 used, FIG.
5th enlarged vertical cross-sectional view of the billab link 4a used in the figure.
Figure fb+ is b1' of Figure 5 fQ, l! 6 is a side view of the fourth embodiment of the present invention, FIG. 7 is a detailed view of the metal fitting 15 used in FIG.
The figure is a block diagram of the entire leg system. Figure 9 is a side view of a conventional example, Figure 10 is a side view of another conventional example, and Figure 11 is based on the distance between the center of gravity of the aircraft and the landing gear at takeoff, its moment, and the downward load 1J[P of the elevator]. It is an explanatory diagram of a moment.

Claims (1)

[Claims] The aircraft landing gear is equipped with wheels that support the weight of the aircraft below the aircraft's fuselage and rotate as a result of the aircraft's movement on the ground.The wheel grounding point position relative to the center of gravity is adjusted in response to horizontal movement of the aircraft's center of gravity due to fluctuations in the aircraft's cargo. A variable wheel position leg comprising adjustable legs.