WO1994015831A1

WO1994015831A1 - Device for controlling the revolution speed of an aircraft undercarriage wheel

Info

Publication number: WO1994015831A1
Application number: PCT/EP1994/000021
Authority: WO
Inventors: Nikola Reinke
Original assignee: Nikola Reinke
Priority date: 1993-01-12
Filing date: 1994-01-05
Publication date: 1994-07-21
Also published as: AU5859994A; DE4339884A1

Abstract

To provide a device (100) for controlling the revolution speed of an aircraft undercarriage wheel (10) driven or drivable by a drive system (11) which is of simple construction, operates reliably and provides a permanently and constantly secure revolution speed control without complex technical systems, there is a centrifugal clutch (15a, 16a; 15b, 16b) which, when a predeterminable revolution speed is exceeded, declutches from said drive (11) the undercarriage wheel (10) connected to the drive (11) at speeds below said predeterminable speed. The centrifugal clutch (15a, 16a; 15b, 16b) has at least one spring loaded cylindrical member or plate (15a, 15b) as the pressure member which is pressed by friction against a driven rotating body (11) below a predeterminable speed, each pressure member is movably fitted on a bearing frame (21) and the frame (21) is releasably secured to the undercarriage wheel (10).

Description

Device for regulating the speed of an aircraft wheel

field of use

The device for controlling the speed of an aircraft landing gear wheel can be used in all aircraft.

The invention relates to a device for speed regulation of a driven or drivable aircraft landing gear wheel.

State of the art

Already in DE 21 09 563 C3 it is proposed to prevent the tire wear of the aircraft landing gear tires when the aircraft is landed in that the landing gear wheels are to be accelerated to a speed appropriate to the touchdown speed. Electric motors, which are switched on when landing and are intended to give the wheel the necessary drive torque, are discarded due to their great weight, as are buckets or tires with a turbine-like side profile which are attached to the wheel rim and can be opened in the direction of the wind, and which set the bicycles in rotation should. In order to achieve the required impeller speeds of approximately 180 km / h when touching down, a fully loaded pusher centrifugal turbine is to be used, which acts directly on the impeller blading on the rim of the aircraft landing gear wheel. DE 23 49 343 AI, DE 24 54 226 AI and DE-Ul 82 35 997.0 show the impeller or paddle wheels connected to the wheel and rotating during flight movements.

According to DE 34 20 507 AI, the relevant turbine wheel blades are pneumatically driven, the compressed air being taken either from a compressed air bottle or from the compressed air area of a jet engine. The speed of the wheels should be controlled by the compressed air, which is, however, very complex.

According to the documents of DE-Ul 83 00 709.1, the respective wing fins or air deflector blades are also to be operated with a compressed air blowing device, but the drive device can be an electric or a hydraulic fluid-operated motor.

However, the previously proposed solutions for the chassis wheel drive are still unsatisfactory, so that only recently have passive elements been proposed again, for example in DE-Ul 89 09 176. and DE 37 39 170 C2 turbine wheels or blades which can be mounted in the rim, on the other hand such blade elements which offer great air resistance on one side and which have a low air resistance value on the opposite side after 180 ° rotation of the wheel.

DE 35 12 324 A1 discloses a device for reducing tire wear on the undercarriages of aircraft, in which it is provided that the wheels of the undercarriages rotate about the wheel before landing. axis that is so large that the circumferential speed on the tread of the tire corresponds to the horizontal component of the landing speed at the first contact with the ground. The construction is such that the energy for the rotational acceleration of the inertial masses of the wheels is taken from the ambient air flowing past. For this purpose, next to each wheel there is an air nozzle which is firmly connected to the chassis and which directs an air jet onto a shovel mounted on the wheel rim in such a way that a torque is exerted around the wheel axis. The air nozzle cross sections are dimensioned such that this drive torque is then in equilibrium with the frictional torque of the wheel caused by air resistance, bearing friction, etc., if the angular velocity of the wheel is so great that the peripheral speed on the tread of the tire is equal to the horizontal component of the tire Landing speed at the moment of touchdown on the runway.

Task, solution, advantages

It is an object of the present invention to provide a device for regulating the speed of a driven or drivable aircraft landing gear wheel, which is of simple construction, works reliably and delivers a consistently reliable speed control without any expenditure on control technology. In particular, a device is to be created which can be attached to the chassis wheel and functions without modifications.

This object is achieved by the features characterized in claim 1. According to the invention, a centrifugal clutch which separates the drive wheel from the drive and which is connected to the drive below this speed is provided when a predeterminable speed is exceeded and is arranged on a support frame which is detachably fastened to the drive wheel.

Centrifugal clutches are known in principle and automatically establish a force connection depending on the speed. Basically, they consist of flyweights on a drive shaft which, with increasing speed as a result of the centrifugal force acting on them, hit radially outwards against a body part arranged at a certain radial distance and rotate it with frictional engagement. In the sense of the present invention, centrifugal clutches are also to be understood as centrifugal force regulators which ensure frictional engagement of the rotating parts to be coupled until a certain speed is reached, but separate the rotating parts when this speed is exceeded. If the critical speed is undershot again, the clutch is frictionally engaged again.

In a preferred embodiment of the invention, the centrifugal clutch has at least one spring-loaded cylinder piece or a spring-loaded plate, which is pressed below a predeterminable speed onto a driven rotating body with frictional engagement. The rotary body can preferably be part of a turbine wheel or be driven by a turbine wheel, with a planetary gear with a reduction gear between the turbine and the rotary body. tion ratio of about 2: 1 can be provided, which adapts the drive with its component speeds to be achieved to the air flow. According to this embodiment, the landing gear wheel and the drive are arranged on a common axis. To drive the turbine wheel, the air that accumulates during the flight movement or the air flow can be used or supported, or the wheel can be driven from a jet engine by branching the air flow. Since the coupling of the turbine wheel or part of the turbine wheel is mechanically regulated with the undercarriage wheel, further electrical pneumatic or hydraulic regulators or controls can be dispensed with.

According to a further embodiment of the invention, in order to make it more generally applicable to existing aircraft landing gear designs, the rotating body and the turbine wheel are mounted on a supporting shaft attached to the supporting frame.

According to a further embodiment of the invention, the rotary body is rotatable on a support shaft connected to the support frame, but is mounted so that it cannot be displaced relative to the support frame.

The turbine wheel here consists of a cylinder and a plurality of air guide blades arranged at the outer end of the cylinder and protruding from the rotating body through slot-shaped longitudinal cutouts. The turbine wheel can be displaced in the longitudinal direction of the support shaft by means of longitudinal teeth on the inside of the rotating body and on the outside of the turbine wheel cylinder. there being a non-rotatable connection for transmitting the rotary movement of the turbine wheel to the rotating body. The device is covered on the outside by a wheel cap-like cover arranged on the rotating body and having corresponding penetration openings for the air guide vanes. When the turbine wheel is displaced in the rotating body, the air guide vanes are led out through the openings on the outside of the cover or drawn in so far that they are either fully in the air flow on the outside of the cover and thus perform the wheel drive can or that they have been drawn in so far that no drive takes place and no air resistance is formed on the outside of the cover. Some aircraft types have outer main landing gear wheels that are not fully retractable in the fuselage. When the landing gear is pivoted in and out, each aircraft landing gear wheel reaches two end positions, namely a horizontal position and a vertical position. To take advantage of this swiveling operation with the two end positions defined in relation to the normal flight and approach position, it is proposed according to a further embodiment of the invention that on the support shaft a freely rotatable and longitudinally displaceable ring body, which is opposite the outer end of the support shaft at least one spring is supported.

The ring body has a toothing that runs circumferentially on the surface of the support shaft. The same type of transverse toothing is located on the inside of the turbine wheel cylinder. Both transverse toothings are in meshing engagement with at least one gear wheel attached to the rotating body. It is provided that the ring body is supported in a freely sliding manner and has a mass which requires a higher weight than the force which is composed of the weight of the turbine wheel and the spring force. In the vertical direction, the spring force presses the ring body in the direction of the wheel rim, and thus the turbine wheel path from the wheel rim and thus the air guide vanes through the slots in the wheel cap into the air flow via the gear wheels fixed against the rotating body.

If the undercarriage wheel is pivoted horizontally, the ring body revises this process, since it is shifted due to gravity and the turbine wheel is drawn in via the gearbox.

Advantageous refinements and developments of the invention are characterized in the subclaims.

Brief description of the drawings

Several exemplary embodiments are explained in more detail below with the aid of schematic drawings. Show it

F i g. 1 is a partial view of an aircraft chassis wheel driven in a speed-controlled manner by a turbine wheel,

F i g. 2 is a partial view of a further embodiment of an aircraft landing gear wheel driven in a rotationally speed-controlled manner by a turbine wheel, in the pivoted-out position, Fig. 3 is a partial view of a further embodiment of an aircraft landing gear wheel driven by a turbine wheel in a vertical position, and

F i g. 4 the aircraft landing gear wheel according to FIG. 3 in a pivoted position into a horizontal position.

Detailed description of the invention and best way to carry out the invention

1 shows the aircraft landing gear wheel 10, the rim of which is indicated in the drawing, with the device 100 for speed control, and a drivable rotary body 11 are rotatably arranged on a common axis 12. Possibly. by means of a planetary gear 13, the rotary body 11 is driven by a turbine wheel 14 which is equipped with air guide vanes 17 in a manner known in the prior art. The rotary body 11 can also be part of the turbine wheel 14. The rotationally smaller cylindrical body 11, which is smaller in radius, lies in the coupled state with frictional engagement on plates 15a and 15b, which can also be formed like a cylinder segment and which are acted upon by a compression spring 16a or 16b. The compression spring is possibly mounted in a housing, so that the wheel 10 is connected to the rotary body 11 by frictional engagement in the coupled state. If the speed of the wheel 10 now increases, centrifugal forces experience centrifugal forces due to centrifugal force, which drive them outward against the compressive force of springs 16a and 16b. As a result, however, the frictional engagement of the wheel 10 to the rotating body 11 so that no further acceleration or no further drive of the wheel 10 by the rotating body 11 can take place. If the speed falls below the critical speed again, the centrifugal force decreases accordingly, so that the compression springs 16a and 16b press the plates 15a and 15b again onto the rotating body 11.

The present invention is based on the basic consideration that for every type of aircraft there is a usual touchdown speed which corresponds to a special wheel turning speed. As a rule, this touchdown speed will only fluctuate by 10%, so that a constant speed control for undercarriage wheels can be achieved by selecting the springs 16a and 16b in conjunction with the masses of the plates 15a and 15b. Compared to the complex speed controls, which take into account influencing variables such as approach times, approach wind, head wind and flight speed, the present invention has the advantage that no complex controls and calculations have to be carried out in order to achieve the desired speed control of the aircraft wheels reach. The system is largely maintenance-free and low-wear.

The basic design principles for embodiments of the centrifugal clutch are shown in FIGS. The structure is designed in such a way that the movement, ie the pressing and releasing of the plates 15a by or against the spring 116, 216, 316 occurs without thermal influences by changing the geometry being able to impair the effect of the centrifugal clutch. When executing La is acted on plate 15a radially via the compression spring 116, which is supported on the vehicle wheel 10, while in the embodiment according to Fig. 1b there is a linear action. In the embodiment according to Fig. 1c, the plate is 15a arranged on a leaf spring 216 which is clamped on one end on the vehicle wheel 10. In the embodiment according to FIG. 1d, the plate 15a is held and supported by a torsion spring 316 attached to the vehicle wheel 10. In all embodiments of the centrifugal clutch, the centrifugal clutch components are no longer supported, but only attached, thermal expansion remaining without negative influences. In addition, these embodiments have the advantage that few components are required, that the centrifugal clutch is more resilient and that it can be designed with a low weight.

2 shows a further embodiment of the device 100, the basic principle of which corresponds to the embodiment described above, so that the same reference numerals are used for the same parts. The difference is that in this embodiment the rotating body 11 and the turbine wheel 14 are rotatably arranged on an independent support shaft 20 which is independent of the shaft 12 of the landing gear wheel 10, and the plates 15a, 15b, which are designed in the manner of a cylinder segment, are connected to one another via the compression springs 16a, 16b Support frame 21 suspended and guided on the support frame via sliding bearings 22a, 22b so as to be displaceable in the working direction. The support frame 21, on which the shaft 20 is also mounted, has openings 23a, 23b through which screws 24a, 24 can be screwed into the rim 10. The normal fastening screws or somewhat extended fastening screws can be used here.

In the embodiment shown in FIGS. 3 and 4, compared to the embodiment according to FIG. 2, it is also provided that the rotating body 11 is not fixedly connected to the turbine wheel 14, but that the rotating body 11 is rotatable on the supporting shaft 20 is mounted and that the rotary body 11 is rotatably connected to the turbine wheel 14. However, the turbine wheel 14 is displaceable in the longitudinal direction of the support shaft 20. Furthermore, a freely rotatable and longitudinally displaceable ring body 30 is arranged on the support shaft 20 and is supported against the outer end 31 of the support shaft 20 by a spring 32. The ring body 30 has a mass which, under the influence of gravity G, has a higher weight than the sum of the turbine wheel weight and the force of the spring 32.

The ring body 30 and the turbine wheel 14 are connected via a gear 33, the internal transverse toothing of the turbine wheel 34 and the external transverse toothing of the ring body 35 having at least one gear wheel 36a which is rotatably attached to the center of the rotating body 11 , 36b is in meshing engagement.

The mode of operation of this arrangement now consists in the fact that when the undercarriage wheel 10 is pivoted at Y, the ring body 30 is moved by the force of gravity G into 4 is moved and the turbine wheel retracts via the gear 33 so that the air guide vanes 17, which in their working position are moved out through openings 37a, 37b in the wheel cap 38 into the air flow, are withdrawn as shown in Fig.4.

The reverse process occurs when the chassis wheel 10 is pivoted back into FIG. 3.

Claims

Expectations:

1. A device (100) for speed control of an aircraft landing gear wheel (10) driven or drivable by means of a drive (11), characterized in that when a predeterminable speed is exceeded, the undercarriage wheel (10) connected to the drive (11) below this speed. A centrifugal clutch (15a, 16a; 15b, 16b) separating the drive (11) is provided such that the centrifugal clutch (15a, 16a; 15b, 16b) has at least one spring-loaded cylinder piece or a spring-loaded plate (15a, 15b) as a pressing body, the or the below a predeterminable speed is pressed onto a driven rotary body (11) with frictional closure, and that each pressing body is slidably arranged on a support frame (21) via a slide bearing (22a, 22b) and the support frame (21) the undercarriage wheel (10) is detachably fastened.

2. Apparatus according to claim 1, characterized in that the support frame (21) is fixed to the rim of a chassis wheel (10) consisting of a known rim and a tire.

3. Apparatus according to claim 2, characterized in that the support frame (21) has the openings for the known rim fastening screws (24a, 24b) corresponding openings (23a, 23b) and can be fastened via the rim fastening screws or via extended fastening screws.

4. Device according to one of claims 1 to 3, characterized in that the rotary body (11) part of a turbine wheel (14) or by a turbine wheel (14) is driven.

5. The device according to claim 4, characterized in that the turbine wheel (14) has air guide vanes (17) which can be driven by the air pressure present during flight.

6. The device according to claim 4 or 5, characterized in that the rotary body (11) via a planetary gear (13) with the turbine wheel (14) is connected.

7. Device according to one of claims 1 to 6, characterized in that the reduction ratio between the speed of the turbine wheel (14) and the rotary body (11) is approximately 2: 1.

8. Device according to one of claims 1 to 7, characterized in that the landing gear wheel (10) and the rotating body (11) are arranged on a common axis (12).

9. The device according to claim 4 or 5, characterized in that the rotary body (11) and the turbine wheel (14) on a support shaft (21) connected to the support shaft (20) are rotatably mounted that the rotary body (11) with the turbine wheel (14) rotatably, but this (14) is connected to this (11) in the longitudinal direction of the support shaft (20).

10. The device according to claim 9, characterized in that on the support shaft (20) a freely rotatable and longitudinally displaceable ring body (30) which is supported against the outer end (31) of the support shaft (20) via at least one spring (32), is arranged, which is connected to the turbine wheel (14) via a gear (33).

11. The device according to claim 10, characterized in that the turbine wheel (14) has an internal toothing (34) extending transversely to the supporting shaft (20) and the ring body (30) has an external toothing (35) also extending transversely to the supporting shaft (20) , both of which are in meshing engagement with at least one rotatable gear wheel (36a, 36b) fastened to the rotary body (11), and in their entirety represent the gear (33).

12. The apparatus according to claim 10 or 11, characterized in that the ring body (30) has a mass which, under the influence of gravity, causes a higher weight than the sum of the turbine wheel weight and the force of the spring supporting the ring body (30) ( 32).

13. Device according to one of claims 9 to 12, characterized in that the device (100) is almost completely covered by an opening (37a, 37b) for the implementation of the air guide vanes (17) having wheel cap (38).

14. Device according to one of claims 1 to 13, characterized in that each pressure body of the centrifugal clutch via a compression spring (16a, 16b; 116), a leaf spring (216) or a torsion spring (316) can be pressed onto the rotary body (11) is.