GB2210833A

GB2210833A - Variable speed aircraft landing wheels

Info

Publication number: GB2210833A
Application number: GB8821527A
Authority: GB
Inventors: James Balloch
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-10-14
Filing date: 1988-09-14
Publication date: 1989-06-21
Also published as: GB8821527D0; GB8724123D0

Abstract

The invention relates to a landing wheel device for airborne vehicles such as aircraft. Power is provided from the aircraft power plant or from a motor (2), which may be an electric motor, to cause the wheels (24) of the vehicle to rotate at a speed such that the surface of the tyres (22) is moving at a speed at or about the relative speed between the aircraft and the ground. When contact is then made with the ground as the aircraft lands, excess friction between the tyres and the ground is substantially reduced along with the risk of tyre blow-out. <IMAGE>

Description

VARIABLE SPEED AIRCRAFT LANDING WHEELS The present invention relates to a variable speed synchro drive system particularly, but not exclusively, for use with aircraft landing wheels.

Landing wheels on aircraft are substantially stationary even when landing gear has been deployed. On touchdown the wheels are subjected to a considerable frictional force causing wear on the rubber based tyres. This wear results in frequent tyre changes which are costly and, if the wear remains unnoticed, a considerable danger during and after aircraft have landed.

An object of the present invention is to provide apparatus which obviates or mitigates at least one of the aforesaid problems.

Accordingly in one aspect of the present invention there is provided an aircraft landing wheel device for an aircraft comprising a variable speed motor associated with at least one wheel or pair of wheels on a transverse axle member for engagement and subsequent disengagement prior to contact with a landing surface by said wheels, said driving means being provided with a speed control means formed and arranged for bringing the speed of rotation of said at least one wheel up to a value generally similar to the ground speed of the aircraft in use of the device, said motor having a transverse drive transmission for transmitting drive to said wheels on said transverse axle member.

Preferably said transverse axle member is supported by axle support means.

Advantageously said speed control means are provided with sensing means for sensing altitude and the speed of aircraft relative to the ground.

Preferably said transverse drive transmission includes a differential means allowing rotation of two or more wheels mounted on said support member at different speeds, e.g. during taxiing.

These and other aspects of the invention will become apparent from the following description when taken in combination with the accompanying drawings in which: Fig. 1 is a general view of a variable speed synchro drive device of the invention mounted in the under carriage of an aircraft; Fig. 2 shows a front view of the synchro drive device of Fig. 1; Fig. 3 shows a top view of the synchro drive device.

The variable speed synchro drive device 1 can be disposed on the landing gear 5 of an aircraft 3 as shown in Fig. 1.

The gear 5 may be a single nose wheel or the main undercarriage of the aircraft.

Reference is now made to Fig. 2 and Fig. 3 which show the variable speed synchro drive device in detail.

The variable speed synchro drive device 1 comprises a drive means, being a variable speed drive means in the form of an electric motor 2 provided with speed control means 9 arranged to determine the ground speed of the aircraft and operate the drive means 2 to turn the aircraft wheels 24 until the surface speed of the tyres 22 is brought up to that of the aircraft. The drive means 2 is activated and deactivated by control means 9.

At a predetermined aircraft altitude, the coupling control means 9 will activate the drive means 2 which is coupled into a transverse drive transmission 10, the action of the drive means 2 causing the drive transmission 10 to rotate a shaft 12. The shaft 12 has disposed along its length a gear wheel 14 which is in contact with a second gear wheel 16 mounted on the wheel member 24. On rotation of the first gear wheel 14, the second gear wheel 16 will rotate and cause the wheel 24 to rotate on axle member 18.

A number of parameters such as aircraft speed, wetness of the landing surface, and wind direction and velocity can readily be determined. These and other factors may be used to determine at what altitudes the drive means 2 should be activated and deactivated and at what speed the drive means 2 should rotate the wheels 24 relative to the aircraft's ground speed to cause minimal wear on the tyres 22 during touchdown.

The device 1 may be raised and lowered by hydraulic means. When in an inoperative position, the gear wheels 14 and 16 are then out of meshing contact.

A number of modifications to the above described embodiment can be made without departing from the scope of the present invention as defined in the following claims. The drive shaft can be powered directly from the aircraft engines rather than the electric motor.

More than one pair of wheels can be rotated using this device.

Claims

1. A landing wheel device for airborne vehicles comprising, a variable speed power device associated with at least one wheel or pair of wheels on a transverse axle member for engagement and subsequent disengagement prior to contact with a landing surface by said wheels, said driving means being provided with a speed control means formed and arranged for bringing the speed of rotation of said at least one wheel up to a value generally similar to the ground speed of the aircraft in use of the device, said motor having a transverse drive transmission for transmitting drive to said wheels on said transverse axle member.

2. A device as claimed in claim 1, including sensing means for sensing speed and altitude of the aircraft relative to the ground.

3. A device as claimed in claim 1, wherein the transverse drive transmission includes a differential means allowing rotation of a wheel or wheels at a different speed to an associated wheel when in contact with the ground.

4. A device as claimed in claim 1 wherein the power device comprises a power transfer device operable from the aircraft power plant.

5. A device as claimed in claim 1 wherein the power device is a separate motor mounted in association with the aircraft landing gear.

6. A device as claimed in claim 5, wherein the motor is an electric motor.

7. A device as claimed in either one of claims 5 or 6, wherein the power device is adapted to be raised and lowered by hydraulic means.

8. A device as claimed in any one of the preceding claims wherein said variable speed power device operates to rotate shaft means having rotatable gear members secured to outer ends thereof, said rotatable gear members being engageable with further gear members mounted in association with said wheel(s).

9. Landing wheel device for aircraft, constructed, arranged and adapted to operate substantially as hereinbefore described with reference to and as shown in the drawings.