US20190071168A1 - Drive system for aircraft landing gear - Google Patents
Drive system for aircraft landing gear Download PDFInfo
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- US20190071168A1 US20190071168A1 US16/175,526 US201816175526A US2019071168A1 US 20190071168 A1 US20190071168 A1 US 20190071168A1 US 201816175526 A US201816175526 A US 201816175526A US 2019071168 A1 US2019071168 A1 US 2019071168A1
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- United States
- Prior art keywords
- drive
- drive system
- liquid
- rotary damper
- flow circuit
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C25/00—Alighting gear
- B64C25/32—Alighting gear characterised by elements which contact the ground or similar surface
- B64C25/405—Powered wheels, e.g. for taxing
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F16F15/00—Suppression of vibrations in systems; Means or arrangements for avoiding or reducing out-of-balance forces, e.g. due to motion
- F16F15/02—Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems
- F16F15/04—Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems using elastic means
- F16F15/06—Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems using elastic means with metal springs
- F16F15/073—Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems using elastic means with metal springs using only leaf springs
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F16F15/00—Suppression of vibrations in systems; Means or arrangements for avoiding or reducing out-of-balance forces, e.g. due to motion
- F16F15/10—Suppression of vibrations in rotating systems by making use of members moving with the system
- F16F15/16—Suppression of vibrations in rotating systems by making use of members moving with the system using a fluid or pasty material
- F16F15/161—Suppression of vibrations in rotating systems by making use of members moving with the system using a fluid or pasty material characterised by the fluid damping devices, e.g. passages, orifices
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F16F15/00—Suppression of vibrations in systems; Means or arrangements for avoiding or reducing out-of-balance forces, e.g. due to motion
- F16F15/10—Suppression of vibrations in rotating systems by making use of members moving with the system
- F16F15/16—Suppression of vibrations in rotating systems by making use of members moving with the system using a fluid or pasty material
- F16F15/162—Suppression of vibrations in rotating systems by making use of members moving with the system using a fluid or pasty material with forced fluid circulation
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F16F15/00—Suppression of vibrations in systems; Means or arrangements for avoiding or reducing out-of-balance forces, e.g. due to motion
- F16F15/10—Suppression of vibrations in rotating systems by making use of members moving with the system
- F16F15/16—Suppression of vibrations in rotating systems by making use of members moving with the system using a fluid or pasty material
- F16F15/163—Suppression of vibrations in rotating systems by making use of members moving with the system using a fluid or pasty material fluid acting as a lubricant
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H1/00—Toothed gearings for conveying rotary motion
- F16H1/02—Toothed gearings for conveying rotary motion without gears having orbital motion
- F16H1/24—Toothed gearings for conveying rotary motion without gears having orbital motion involving gears essentially having intermeshing elements other than involute or cycloidal teeth
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H57/00—General details of gearing
- F16H57/0006—Vibration-damping or noise reducing means specially adapted for gearings
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H57/00—General details of gearing
- F16H57/04—Features relating to lubrication or cooling or heating
- F16H57/0402—Cleaning of lubricants, e.g. filters or magnets
- F16H57/0404—Lubricant filters
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H57/00—General details of gearing
- F16H57/04—Features relating to lubrication or cooling or heating
- F16H57/0412—Cooling or heating; Control of temperature
- F16H57/0415—Air cooling or ventilation; Heat exchangers; Thermal insulations
- F16H57/0417—Heat exchangers adapted or integrated in the gearing
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H57/00—General details of gearing
- F16H57/04—Features relating to lubrication or cooling or heating
- F16H57/042—Guidance of lubricant
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H57/00—General details of gearing
- F16H57/04—Features relating to lubrication or cooling or heating
- F16H57/0434—Features relating to lubrication or cooling or heating relating to lubrication supply, e.g. pumps ; Pressure control
- F16H57/0436—Pumps
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H57/00—General details of gearing
- F16H57/02—Gearboxes; Mounting gearing therein
- F16H2057/02034—Gearboxes combined or connected with electric machines
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H57/00—General details of gearing
- F16H57/02—Gearboxes; Mounting gearing therein
- F16H2057/02039—Gearboxes for particular applications
- F16H2057/02043—Gearboxes for particular applications for vehicle transmissions
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
- F16H55/02—Toothed members; Worms
- F16H55/10—Constructively simple tooth shapes, e.g. shaped as pins, as balls
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T50/00—Aeronautics or air transport
- Y02T50/80—Energy efficient operational measures, e.g. ground operations or mission management
Definitions
- the present invention relates to a drive system for rotating a wheel of an aircraft landing gear.
- a drive system for rotating a wheel of an aircraft landing gear is shown in WO-A-2014/023939 and WO-A-2014/023941.
- the drive system comprises a drive pinion; a motor operable to rotate the drive pinion via a drive path; and a driven gear adapted to be attached to the wheel so as to be capable of rotating the wheel, wherein the drive system has a drive configuration in which the drive pinion is capable of meshing with the driven gear to permit the motor to drive the driven gear via the drive path.
- a first aspect of the invention provides a drive system for rotating a wheel of an aircraft landing gear, the drive system comprising: a drive pinion; a motor operable to rotate the drive pinion via a drive path; a rotary damper in the drive path between the motor and the drive pinion; and a driven gear adapted to be attached to the wheel so as to be capable of rotating the wheel, wherein the drive system has a drive configuration in which the drive pinion is capable of meshing with the driven gear to permit the motor to drive the driven gear via the drive path.
- one of the drive pinion and the driven gear comprises a roller gear having a series of rollers arranged to form a ring, each roller being rotatable about a roller axis (typically at a fixed distance from an axis of rotation of the drive pinion or driven gear, respectively), and the other of the drive pinion and the driven gear comprises a sprocket.
- a rotary damper is particularly beneficial when used in combination with a roller gear in this way, since the roller gear can create particularly high transmission errors.
- the rotary damper may comprise an elastomeric damper such as a “cush drive”, or a sprung damper as described in GB-A-2398619.
- the rotary damper is a hydraulic rotary damper, typically comprising an input part and an output part, and a damping liquid for hydraulic damping of rotational oscillations between the parts.
- a hydraulic damper is preferred since it has improved efficiency and stable properties over a wide temperature range.
- the rotary damper may only provide a damping function, but more preferably it comprises one or more springs arranged to bias the input part or output part towards a centred position relative to the other part.
- the motor may be naturally cooled, or cooled by forced air.
- the drive system further comprises a flow circuit arranged to supply liquid (such as oil or any other viscous liquid) to the motor; and a pump arranged to pump the liquid around the flow circuit so the liquid cools the motor.
- liquid such as oil or any other viscous liquid
- the flow circuit is also arranged to supply the liquid to the hydraulic rotary damper, and the pump is arranged to pump the liquid around the flow circuit so the liquid also provides damping liquid for the hydraulic rotary damper.
- the drive path further comprises a set of meshed gears provide a desired gearing ratio between the motor and the drive pinion.
- the drive system further comprises a flow circuit arranged to supply liquid (such as oil or any other viscous liquid) to the set of meshed gears, and a pump arranged to pump the liquid around the flow circuit so the liquid lubricates the set of meshed gears.
- the flow circuit is also arranged to supply the liquid to the hydraulic rotary damper and/or the motor, and the pump is arranged to pump the liquid around the flow circuit so the liquid also provides damping liquid for the hydraulic rotary damper and/or cools the motor.
- the drive path further comprises one or more hydrostatic bearings
- the drive system further comprises a flow circuit arranged to supply liquid (such as oil or any other viscous liquid) to the hydrostatic bearing(s), and a pump arranged to pump the liquid around the flow circuit so the liquid lubricates the hydrostatic bearing(s).
- the flow circuit is also arranged to supply the liquid to the hydraulic rotary damper and/or the set of meshed gears and/or the motor, and the pump is arranged to pump the liquid around the flow circuit so the liquid provides damping liquid for the hydraulic rotary damper and/or lubricates the meshed gears and/or cools the motor.
- the flow circuit may omit one or more of the motor, the set of meshed gears, the hydrostatic bearing(s) and the hydraulic rotary damper.
- the flow circuit is arranged to supply liquid to the motor, the set of meshed gears, the hydrostatic bearing(s) and the hydraulic rotary damper, and the pump is arranged to pump the liquid around the flow circuit so the liquid cools the motor, lubricates the bearing(s) and the set of meshed gears, and also provides damping liquid for the hydraulic rotary damper.
- the flow circuit comprises a filter arranged to filter the liquid.
- the rotary damper comprises an input part and an output part, one of the parts having a cantilevered resilient finger, a free end of which frictionally engages a cam surface on the other part via a frictional interface thereby to provide resilient resistance to relative rotation of the part in either direction from a minimum energy position, with damping of rotational oscillations between the parts.
- one of the parts has one or more channels for feeding damping liquid into the frictional interface, the channel(s) forming part of the flow circuit.
- FIG. 1 shows an aircraft landing gear incorporating a drive system according to an embodiment to the present invention
- FIG. 2 shows part of the drive system
- FIG. 5 is an enlarged view of part of the rotary damper in a centred position
- FIG. 7 is an enlarged view of part of a hydraulic rotary damper in a centred position
- FIG. 8 is an enlarged view of part of the hydraulic rotary damper in an off-centre position.
- FIG. 9 is a schematic diagram of a pressurised lubrication flow circuit.
- FIG. 1 shows an aircraft landing gear 10 comprising a wheel 11 .
- a drive system for rotating the wheel 11 comprises a drive pinion 13 ; a motor 15 operable to rotate the drive pinion 13 via a drive path 14 ; and a driven gear 12 attached to the wheel so as to be capable of rotating the wheel.
- the drive system has a drive configuration shown in FIG. 1 in which the drive pinion meshes with the driven gear to permit the motor to drive the driven gear via the drive path.
- the drive pinion 13 is switchable between the drive configuration of FIG. 1 and a neutral configuration in which the drive pinion is not capable of meshing with the driven gear.
- WO-A-2014/023939 and WO-A-2014/023941 describe various methods of switching between the drive configuration and the neutral configuration.
- the drive path 14 comprises a set of meshed gears, the penultimate gear in the set being a gear 31 shown in FIG. 3 on a shaft 21 .
- the set of gears provide a desired gearing ratio between an output shaft (not shown) of the motor 15 and the shaft 21 .
- the final element in the drive path 14 is a rotary damper 30 shown in FIGS. 3-6 .
- the damper 30 is mounted in a casing 20 which is shown in FIG. 2 and removed in FIG. 3 .
- the rotary damper 30 comprises an input part 40 and an output part 41 shown in FIG. 4 .
- the input part 40 has four pairs of cantilevered resilient fingers 50 ( FIG. 5 ), a free end of which frictionally engages a cam surface 60 ( FIG. 6 ) on the other part via a frictional interface.
- a stop surface 60 on the input part prevents any further rotation as shown in FIG. 6 .
- the frictional interface provides resilient resistance to relative rotation of the parts in either direction from a centred minimum energy position shown in FIGS. 4 and 5 , with damping of rotational oscillations between the parts.
- the resilient fingers 50 provide not only a damping function, but they also bias the parts towards the centred minimum energy position shown in FIGS. 4 and 5 .
- the input part 40 has external teeth which engage with external teeth on the gear 31 as shown in FIG. 3 .
- the output part 41 has internal teeth 42 which are coupled to a pinion drive shaft 32 (shown in FIG. 3 ) by a spline joint.
- torque is transmitted from the gear 31 to the pinion 13 via the input part 40 , output part 41 and pinion drive shaft 32 .
- the rotary damper 30 has the effect of reducing the transmission of such vibration into the rest of the drive path or the landing gear.
- the rotary damper 30 is the last element in the drive path 14 before the pinion 13 (so all other elements of the drive path are isolated from vibration originating at the pinion) although it may be positioned in other places in the drive path if necessary.
- FIGS. 7 and 8 illustrate an alternative to the frictional rotary damper 30 .
- the rotary damper 30 a shown in FIGS. 7 and 8 is identical to the rotary damper 30 , except the output part is provided with ducts or channels 70 for feeding oil or any other damping liquid into chambers 80 , 81 on either side of the cam surface.
- the left-hand chamber 80 reduces in volume and the damping liquid is forced through the frictional interface between the fingers and the cam surface, and into an outer chamber 82 .
- This provides an enhanced viscous damping effect and a cooling effect.
- Cover plates (not shown) are provided to seal the damping liquid within the chambers 80 - 82 , and non-return valves (not shown) may also be provided at the outlets of the channels 70 .
- a viscous damping effect is provided by the flow of oil through the frictional interface between the fingers 50 and the cam surface 61 .
- Further viscous damping may be provided in a number of ways.
- One option would be to modify the channels 70 so that one channel into each chamber 80 , 81 is an input channel with a non-return valve, and the other channel from each chamber 80 , 82 is an output channel with a narrow orifice through which the oil is forced as one of the parts rotates to give a damping effect.
- Another option would be to provide orifices or other intentional leakage paths in the cover plates, the oil being forced out of the intentional leakage paths as one of the parts rotates to give a damping effect.
- a pressurised lubrication flow circuit 90 shown in FIG. 9 is arranged to supplying lubrication liquid (typically an oil) to the motor 15 and a gearbox 91 containing the various components of the drive path 14 .
- a pump 93 is arranged to pump lubrication liquid around the lubrication flow circuit 90 .
- the pump 93 can be electrically driven, or mechanically driven via the drive path.
- the flow circuit includes a heat exchanger 94 and a filter 95 .
- the heat exchanger 94 may be in the form of cooling fins in the case of the gearbox 91 .
- the filter 95 removes contaminants from the oil such as metal particles or dirt.
- the drive path 14 within the gearbox 91 also comprises bearings, one being indicated schematically at 100 in FIG. 9 , which are lubricated by jets 97 of pressurised oil.
- the bearings 100 may be hydrostatic bearings (a bush and a film of oil) lubricated by the pressurized oil in the flow circuit 90 , rather than bulkier/heavier ball or roller bearings.
- the use of hydrostatic bearings is particularly beneficial because the pinion 13 is cantilevered/overhung, resulting in high bearing loads requiring large bearings.
- the oil not only cools the motor and lubricates the meshing gears and bearing(s) in the drive path (to reduce wear and improve mechanical efficiency), but also provides damping liquid for the hydraulic rotary damper 30 a .
- the oil also cools the bearing(s), the meshing gears and the rotary damper, heat being removed from the circuit by the heat exchanger 94 .
- Sharing the motor oil with the gearbox oil increases the volume of oil into which heat can be dissipated—the oil bath 92 (and optionally a further oil reservoir) further increasing the capacity of the system to dissipate heat.
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Aviation & Aerospace Engineering (AREA)
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- General Details Of Gearings (AREA)
- Gear Transmission (AREA)
- Retarders (AREA)
Abstract
A drive system for rotating a wheel of an aircraft landing gear. The drive system has a drive pinion and a motor operable to rotate the drive pinion via a drive path. A rotary damper is provided in the drive path between the motor and the drive pinion. A driven gear is adapted to be attached to the wheel so as to be capable of rotating the wheel. The drive system has a drive configuration in which the drive pinion is capable of meshing with the driven gear to permit the motor to drive the driven gear via the drive path. One of the drive pinion and the driven gear comprises a roller gear having a series of rollers arranged to form a ring, each roller being rotatable about a roller axis, and the other of the drive pinion and the driven gear comprises a sprocket.
Description
- This application is a Continuation of U.S. patent application Ser. No. 15/126,806, filed Sep. 16, 2016, now allowed; which is the U.S. National Phase of International Application No. PCT/GB2015/050753, filed Mar. 16, 2015; which claims priority benefit to United Kingdom (GB) patent Application No. 1404704.7, filed Mar. 17, 2014; the entire contents of which are hereby incorporated by reference.
- The present invention relates to a drive system for rotating a wheel of an aircraft landing gear.
- A drive system for rotating a wheel of an aircraft landing gear is shown in WO-A-2014/023939 and WO-A-2014/023941. The drive system comprises a drive pinion; a motor operable to rotate the drive pinion via a drive path; and a driven gear adapted to be attached to the wheel so as to be capable of rotating the wheel, wherein the drive system has a drive configuration in which the drive pinion is capable of meshing with the driven gear to permit the motor to drive the driven gear via the drive path.
- A first aspect of the invention provides a drive system for rotating a wheel of an aircraft landing gear, the drive system comprising: a drive pinion; a motor operable to rotate the drive pinion via a drive path; a rotary damper in the drive path between the motor and the drive pinion; and a driven gear adapted to be attached to the wheel so as to be capable of rotating the wheel, wherein the drive system has a drive configuration in which the drive pinion is capable of meshing with the driven gear to permit the motor to drive the driven gear via the drive path.
- The use of a rotary damper protects the rest of the drive path from vibrations caused by transmission errors between the drive pinion and the driven gear.
- Preferably one of the drive pinion and the driven gear comprises a roller gear having a series of rollers arranged to form a ring, each roller being rotatable about a roller axis (typically at a fixed distance from an axis of rotation of the drive pinion or driven gear, respectively), and the other of the drive pinion and the driven gear comprises a sprocket. The use of a rotary damper is particularly beneficial when used in combination with a roller gear in this way, since the roller gear can create particularly high transmission errors.
- The rotary damper may comprise an elastomeric damper such as a “cush drive”, or a sprung damper as described in GB-A-2398619. However more preferably the rotary damper is a hydraulic rotary damper, typically comprising an input part and an output part, and a damping liquid for hydraulic damping of rotational oscillations between the parts. A hydraulic damper is preferred since it has improved efficiency and stable properties over a wide temperature range.
- The rotary damper may only provide a damping function, but more preferably it comprises one or more springs arranged to bias the input part or output part towards a centred position relative to the other part.
- The motor may be naturally cooled, or cooled by forced air. However more preferably the drive system further comprises a flow circuit arranged to supply liquid (such as oil or any other viscous liquid) to the motor; and a pump arranged to pump the liquid around the flow circuit so the liquid cools the motor. Preferably the flow circuit is also arranged to supply the liquid to the hydraulic rotary damper, and the pump is arranged to pump the liquid around the flow circuit so the liquid also provides damping liquid for the hydraulic rotary damper.
- Typically the drive path further comprises a set of meshed gears provide a desired gearing ratio between the motor and the drive pinion. Optionally the drive system further comprises a flow circuit arranged to supply liquid (such as oil or any other viscous liquid) to the set of meshed gears, and a pump arranged to pump the liquid around the flow circuit so the liquid lubricates the set of meshed gears. Preferably the flow circuit is also arranged to supply the liquid to the hydraulic rotary damper and/or the motor, and the pump is arranged to pump the liquid around the flow circuit so the liquid also provides damping liquid for the hydraulic rotary damper and/or cools the motor.
- Typically the drive path further comprises one or more hydrostatic bearings, and the drive system further comprises a flow circuit arranged to supply liquid (such as oil or any other viscous liquid) to the hydrostatic bearing(s), and a pump arranged to pump the liquid around the flow circuit so the liquid lubricates the hydrostatic bearing(s). Preferably the flow circuit is also arranged to supply the liquid to the hydraulic rotary damper and/or the set of meshed gears and/or the motor, and the pump is arranged to pump the liquid around the flow circuit so the liquid provides damping liquid for the hydraulic rotary damper and/or lubricates the meshed gears and/or cools the motor.
- As described above, the flow circuit may omit one or more of the motor, the set of meshed gears, the hydrostatic bearing(s) and the hydraulic rotary damper. However in a preferred embodiment the flow circuit is arranged to supply liquid to the motor, the set of meshed gears, the hydrostatic bearing(s) and the hydraulic rotary damper, and the pump is arranged to pump the liquid around the flow circuit so the liquid cools the motor, lubricates the bearing(s) and the set of meshed gears, and also provides damping liquid for the hydraulic rotary damper.
- Optionally the flow circuit comprises a heat exchanger arranged to remove heat from the liquid.
- Optionally the flow circuit comprises a filter arranged to filter the liquid.
- Optionally the rotary damper comprises an input part and an output part, one of the parts having a cantilevered resilient finger, a free end of which frictionally engages a cam surface on the other part via a frictional interface thereby to provide resilient resistance to relative rotation of the part in either direction from a minimum energy position, with damping of rotational oscillations between the parts. Optionally one of the parts has one or more channels for feeding damping liquid into the frictional interface, the channel(s) forming part of the flow circuit.
- The drive pinion may be permanently meshed with the driven gear, but more typically the drive system is switchable between the drive configuration and a neutral configuration in which the drive pinion is not capable of meshing with the driven gear.
- Embodiments of the invention will now be described with reference to the accompanying drawings, in which:
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FIG. 1 shows an aircraft landing gear incorporating a drive system according to an embodiment to the present invention; -
FIG. 2 shows part of the drive system; -
FIG. 3 shows the part ofFIG. 2 with part of the gearbox casing removed to show the rotary damper; -
FIG. 4 shows the rotary damper; -
FIG. 5 is an enlarged view of part of the rotary damper in a centred position; -
FIG. 6 is an enlarged view of part of the rotary damper in an off-centre position; -
FIG. 7 is an enlarged view of part of a hydraulic rotary damper in a centred position; -
FIG. 8 is an enlarged view of part of the hydraulic rotary damper in an off-centre position; and -
FIG. 9 is a schematic diagram of a pressurised lubrication flow circuit. -
FIG. 1 shows anaircraft landing gear 10 comprising awheel 11. A drive system for rotating thewheel 11 comprises adrive pinion 13; amotor 15 operable to rotate thedrive pinion 13 via adrive path 14; and a drivengear 12 attached to the wheel so as to be capable of rotating the wheel. The drive system has a drive configuration shown inFIG. 1 in which the drive pinion meshes with the driven gear to permit the motor to drive the driven gear via the drive path. - The
drive pinion 13 comprises a roller gear having a series ofrollers 22 arranged to form a ring, each roller being rotatable about a roller axis at a fixed distance from an axis of rotation. The drivengear 12 comprises a sprocket. In another embodiment, the rollers may be provided on the driven gear, and the pinion gear comprises a sprocket. A variety of suitable rollers gears are described in WO-A-2014/023939 and WO-A-2014/023941, the contents of which are incorporated herein by reference. - The
drive pinion 13 is switchable between the drive configuration ofFIG. 1 and a neutral configuration in which the drive pinion is not capable of meshing with the driven gear. WO-A-2014/023939 and WO-A-2014/023941 describe various methods of switching between the drive configuration and the neutral configuration. - The
drive path 14 comprises a set of meshed gears, the penultimate gear in the set being agear 31 shown inFIG. 3 on ashaft 21. The set of gears provide a desired gearing ratio between an output shaft (not shown) of themotor 15 and theshaft 21. - The final element in the
drive path 14 is arotary damper 30 shown inFIGS. 3-6 . Thedamper 30 is mounted in acasing 20 which is shown inFIG. 2 and removed inFIG. 3 . - The
rotary damper 30 comprises aninput part 40 and an output part 41 shown inFIG. 4 . Theinput part 40 has four pairs of cantilevered resilient fingers 50 (FIG. 5 ), a free end of which frictionally engages a cam surface 60 (FIG. 6 ) on the other part via a frictional interface. When theinput part 40 rotates relative to the output part 41 (or vice versa), astop surface 60 on the input part prevents any further rotation as shown inFIG. 6 . - The frictional interface provides resilient resistance to relative rotation of the parts in either direction from a centred minimum energy position shown in
FIGS. 4 and 5 , with damping of rotational oscillations between the parts. Theresilient fingers 50 provide not only a damping function, but they also bias the parts towards the centred minimum energy position shown inFIGS. 4 and 5 . - Further details of the sprung
damper 30 are described in GB-A-2398619, the contents of which are incorporated herein by reference. - The
input part 40 has external teeth which engage with external teeth on thegear 31 as shown inFIG. 3 . Thus theinput part 40 and thegear 31 provide the final pair of meshing gears in the drive path. The output part 41 hasinternal teeth 42 which are coupled to a pinion drive shaft 32 (shown inFIG. 3 ) by a spline joint. Thus torque is transmitted from thegear 31 to thepinion 13 via theinput part 40, output part 41 andpinion drive shaft 32. - When the
pinion 13 is rotated, the rollers at its circumference are brought into contact with the teeth in the drivengear 12. The transmission from the pinion rollers to the driven gear is not smooth, but is instead subject to undesirable cyclical variations in both torque and speed which are one or two orders of magnitude higher than the equivalent variations for a spur gear. This transmission error, if fed back into thedrive path 14 and landing gear, may lead to undesirable vibration in thedrive path 14 and landing gear. Therotary damper 30 has the effect of reducing the transmission of such vibration into the rest of the drive path or the landing gear. Preferably therotary damper 30 is the last element in thedrive path 14 before the pinion 13 (so all other elements of the drive path are isolated from vibration originating at the pinion) although it may be positioned in other places in the drive path if necessary. -
FIGS. 7 and 8 illustrate an alternative to the frictionalrotary damper 30. Therotary damper 30 a shown inFIGS. 7 and 8 is identical to therotary damper 30, except the output part is provided with ducts orchannels 70 for feeding oil or any other damping liquid intochambers FIG. 8 , the left-hand chamber 80 reduces in volume and the damping liquid is forced through the frictional interface between the fingers and the cam surface, and into anouter chamber 82. This provides an enhanced viscous damping effect and a cooling effect. Cover plates (not shown) are provided to seal the damping liquid within the chambers 80-82, and non-return valves (not shown) may also be provided at the outlets of thechannels 70. - As mentioned above, a viscous damping effect is provided by the flow of oil through the frictional interface between the
fingers 50 and thecam surface 61. Further viscous damping may be provided in a number of ways. One option would be to modify thechannels 70 so that one channel into eachchamber chamber - A pressurised
lubrication flow circuit 90 shown inFIG. 9 is arranged to supplying lubrication liquid (typically an oil) to themotor 15 and agearbox 91 containing the various components of thedrive path 14. Apump 93 is arranged to pump lubrication liquid around thelubrication flow circuit 90. Thepump 93 can be electrically driven, or mechanically driven via the drive path. The flow circuit includes aheat exchanger 94 and afilter 95. Theheat exchanger 94 may be in the form of cooling fins in the case of thegearbox 91. Thefilter 95 removes contaminants from the oil such as metal particles or dirt. - The
drive path 14 within thegearbox 91 comprises a set of gears including meshing gears 98, 99 shown inFIG. 9 andgear 31 shown inFIG. 3 . The pressurised oil in theflow circuit 90 providesjets 96 which lubricate the meshing teeth of thegears drive path 14 is the hydraulicrotary damper 30 a, and oil in theflow circuit 90 is also fed into the hydraulicrotary damper 30 a via thechannels 70 shown inFIG. 7 . - The
drive path 14 within thegearbox 91 also comprises bearings, one being indicated schematically at 100 inFIG. 9 , which are lubricated byjets 97 of pressurised oil. Optionally thebearings 100 may be hydrostatic bearings (a bush and a film of oil) lubricated by the pressurized oil in theflow circuit 90, rather than bulkier/heavier ball or roller bearings. The use of hydrostatic bearings is particularly beneficial because thepinion 13 is cantilevered/overhung, resulting in high bearing loads requiring large bearings. - The use of a pressurised or forced
lubrication circuit 90 with apump 93 ensures that all of the meshing gears in the drive path are well lubricated, not just those which are bathed in theoil bath 92. - The oil not only cools the motor and lubricates the meshing gears and bearing(s) in the drive path (to reduce wear and improve mechanical efficiency), but also provides damping liquid for the hydraulic
rotary damper 30 a. The oil also cools the bearing(s), the meshing gears and the rotary damper, heat being removed from the circuit by theheat exchanger 94. - The
motor 15 may be a radial flux electric motor or an axial flux electric motor. The temperature of themotor 15 must be carefully managed to avoid irreversible damage—this is particularly important where permanent rotor magnets are used since excessive temperature may permanently de-magnetize the rotor magnets. In uncooled motors this is achieved by increasing the mass of the motor to provide a heat sink. Thus the cooling effect of the forced oil enables the size of themotor 15 to be reduced, which is particularly important in the context of a landing gear drive system in which all parts must be small and light. - Sharing the motor oil with the gearbox oil increases the volume of oil into which heat can be dissipated—the oil bath 92 (and optionally a further oil reservoir) further increasing the capacity of the system to dissipate heat.
- In another embodiment of the invention, the
rotary damper FIG. 9 . - Although the invention has been described above with reference to one or more preferred embodiments, it will be appreciated that various changes or modifications may be made without departing from the scope of the invention as defined in the appended claims.
Claims (16)
1. A drive system for rotating a wheel of an aircraft landing gear, the drive system comprising: a drive pinion; a motor operable to rotate the drive pinion via a drive path; a rotary damper in the drive path between the motor and the drive pinion; and a driven gear adapted to be attached to the wheel so as to be capable of rotating the wheel, wherein the drive system has a drive configuration in which the drive pinion is capable of meshing with the driven gear to permit the motor to drive the driven gear via the drive path.
2. A drive system according to claim 1 , wherein one of the drive pinion and the driven gear comprises a roller gear having a series of rollers arranged to form a ring, each roller being rotatable about a roller axis, and the other of the drive pinion and the driven gear comprises a sprocket.
3. A drive system according to claim 1 , wherein the rotary damper is a hydraulic rotary damper.
4. A drive system according to claim 3 , wherein the hydraulic rotary damper comprises an input part and an output part, and a damping liquid for hydraulic damping of rotational oscillations between the parts.
5. A drive system according to claim 4 , wherein the rotary damper comprises one or more springs arranged to bias the input part or output part towards a centred position relative to the other part.
6. A drive system according to claim 3 , further comprising a flow circuit arranged to supply liquid to the motor and the hydraulic rotary damper; and a pump arranged to pump the liquid around the flow circuit so the liquid cools the motor and provides damping liquid for the hydraulic rotary damper.
7. A drive system according to claim 6 wherein the drive path further comprises a set of meshed gears provide a desired gearing ratio between the motor and the drive pinion, the flow circuit is arranged to supply the liquid to the set of meshed gears, and the pump is arranged to pump the liquid around the flow circuit so the liquid lubricates the set of meshed gears.
8. A drive system according to claim 3 , wherein the drive path further comprises a set of meshed gears provide a desired gearing ratio between the motor and the drive pinion; and the drive system further comprises a flow circuit arranged to supply liquid to the set of meshed gears and the hydraulic rotary damper, and a pump arranged to pump the liquid around the flow circuit so the liquid lubricates the set of meshed gears and provides damping liquid for the hydraulic rotary damper.
9. A drive system according to claim 3 , wherein the drive path further comprises one or more hydrostatic bearings, and the drive system further comprises a flow circuit arranged to supply liquid to the hydrostatic bearing(s) and the hydraulic rotary damper, and a pump arranged to pump the liquid around the flow circuit so the liquid lubricates the hydrostatic bearing(s) and provides damping liquid for the hydraulic rotary damper.
10. A drive system according to claim 6 , wherein the flow circuit comprises a heat exchanger arranged to remove heat from the liquid.
11. A drive system according to claim 6 , wherein the flow circuit comprises a filter arranged to filter the liquid.
12. A drive system according to claim 11 , wherein the rotary damper comprises an input part and an output part, one of the parts having a cantilevered resilient finger, a free end of which frictionally engages a cam surface on the other part via a frictional interface thereby to provide resilient resistance to relative rotation of the part in either direction from a minimum energy position, with damping of rotational oscillations between the parts.
13. A drive system according to claim 12 , wherein one of the parts has one or more channels for feeding damping liquid into the frictional interface.
14. A drive system according to claim 13 , wherein the one or more channels form part of the flow circuit.
15. A drive system according to claim 1 , wherein the drive system is switchable between the drive configuration and a neutral configuration in which the drive pinion is not capable of meshing with the driven gear.
16. An aircraft landing gear comprising a wheel and a drive system according to claim 1 , wherein the driven gear of the drive system is attached to the wheel so as to be capable of rotating the wheel.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US16/175,526 US20190071168A1 (en) | 2014-03-17 | 2018-10-30 | Drive system for aircraft landing gear |
Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1404704.7 | 2014-03-17 | ||
GB1404704.7A GB2524242A (en) | 2014-03-17 | 2014-03-17 | Drive system for aircraft landing gear |
PCT/GB2015/050753 WO2015140520A1 (en) | 2014-03-17 | 2015-03-16 | Drive system for aircraft landing gear |
US201615126806A | 2016-09-16 | 2016-09-16 | |
US16/175,526 US20190071168A1 (en) | 2014-03-17 | 2018-10-30 | Drive system for aircraft landing gear |
Related Parent Applications (2)
Application Number | Title | Priority Date | Filing Date |
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US15/126,806 Continuation US10144506B2 (en) | 2014-03-17 | 2015-03-16 | Drive system for aircraft landing gear |
PCT/GB2015/050753 Continuation WO2015140520A1 (en) | 2014-03-17 | 2015-03-16 | Drive system for aircraft landing gear |
Publications (1)
Publication Number | Publication Date |
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US20190071168A1 true US20190071168A1 (en) | 2019-03-07 |
Family
ID=50634876
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
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US15/126,806 Active 2035-11-28 US10144506B2 (en) | 2014-03-17 | 2015-03-16 | Drive system for aircraft landing gear |
US16/175,526 Abandoned US20190071168A1 (en) | 2014-03-17 | 2018-10-30 | Drive system for aircraft landing gear |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
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US15/126,806 Active 2035-11-28 US10144506B2 (en) | 2014-03-17 | 2015-03-16 | Drive system for aircraft landing gear |
Country Status (5)
Country | Link |
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US (2) | US10144506B2 (en) |
EP (2) | EP3495264A1 (en) |
CN (2) | CN110406665A (en) |
GB (1) | GB2524242A (en) |
WO (1) | WO2015140520A1 (en) |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB201519755D0 (en) | 2015-11-09 | 2015-12-23 | Airbus Operations Ltd And Airbus Operations Gmbh | Cooling of a motor for driving an aircraft wheel |
CN108054873B (en) * | 2017-12-05 | 2020-04-21 | 海信(山东)空调有限公司 | Flexible connection gear and vertical air conditioner |
GB2571348A (en) | 2018-02-27 | 2019-08-28 | Airbus Operations Ltd | A drive system for rotating a wheel of a landing gear |
FR3079570B1 (en) * | 2018-03-28 | 2020-04-17 | Safran Landing Systems | METHOD OF ENGAGING TWO GEAR ELEMENTS AND DRIVE DEVICE IMPLEMENTING SUCH A METHOD |
CN108910020B (en) * | 2018-07-14 | 2019-11-22 | 神木特种飞行器工程研究院有限公司 | A kind of wheel system braked and raised speed for fixed-wing unmanned plane |
FR3087513B1 (en) * | 2018-10-17 | 2022-08-26 | Safran Trans Systems | COMPACT REDUCER FOR AN AIRCRAFT TAXATION DEVICE |
EP3998204A1 (en) * | 2021-02-19 | 2022-05-18 | Lilium eAircraft GmbH | Aircraft landing gear |
US11984794B2 (en) * | 2021-10-08 | 2024-05-14 | Dana Heavy Vehicle Systems Group, Llc | Cooling and lubrication system for an electric motor and gearbox assembly |
Family Cites Families (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2812648A (en) * | 1955-06-28 | 1957-11-12 | Louis P Croset | Couplings for rotary members |
US2841000A (en) * | 1955-09-06 | 1958-07-01 | Caterpillar Tractor Co | Resilient gear |
US4411341A (en) * | 1981-03-17 | 1983-10-25 | Houdaille Industries, Inc. | Rotary hydraulic damper |
CN2044665U (en) * | 1987-07-30 | 1989-09-20 | 陈椿年 | Internal-ring coupled synchronous roller wheel apparatus |
DE3735335A1 (en) | 1987-10-19 | 1989-04-27 | Porsche Ag | DEVICE FOR TURNING THE VIBRATION IN A GEAR GEAR |
CN2378576Y (en) * | 1999-01-29 | 2000-05-17 | 中国人民解放军55254部队 | External engagement roller chain wheel driving device |
RO117639B1 (en) | 1999-12-20 | 2002-05-30 | St. Constantin Ion | Toothed gear and process for manufacturing a gear toothing |
GB2398619B (en) * | 2003-02-21 | 2005-10-19 | Christopher Paulet Mel Walters | Rotary devices |
GB0915009D0 (en) | 2009-08-28 | 2009-09-30 | Airbus Operations Ltd | Aircraft landing gear |
WO2011134503A1 (en) * | 2010-04-28 | 2011-11-03 | L-3 Communications Magnet-Motor Gmbh | Drive unit for aircraft running gear |
FR2975340B1 (en) * | 2011-05-20 | 2014-01-31 | Messier Bugatti Dowty | DEVICE FOR COUPLING ROTATION FROM A CROWN TO A WHEEL AND AN AIRCRAFT ENGINEER WITH SUCH A DEVICE. |
WO2012171589A1 (en) * | 2011-06-17 | 2012-12-20 | L-3 Communications Magnet-Motor Gmbh | Drive unit for aircraft running gear wheels |
GB201214198D0 (en) | 2012-08-08 | 2012-09-19 | Airbus Uk Ltd | Landing gear drive system |
EP3241745A1 (en) * | 2012-08-08 | 2017-11-08 | Airbus Operations Limited | Landing gear drive systems |
US20140187370A1 (en) * | 2012-12-31 | 2014-07-03 | Goodrich Corporation | Landing gear wheel drive system |
US9139291B2 (en) * | 2013-05-28 | 2015-09-22 | Hamilton Sundstrand Corporation | Integrated hydrostatic transmission for electronic taxiing operations |
US20150210384A1 (en) * | 2014-01-24 | 2015-07-30 | Honeywell International Inc. | Aircraft wheel driving system |
-
2014
- 2014-03-17 GB GB1404704.7A patent/GB2524242A/en not_active Withdrawn
-
2015
- 2015-03-16 WO PCT/GB2015/050753 patent/WO2015140520A1/en active Application Filing
- 2015-03-16 EP EP19153892.5A patent/EP3495264A1/en not_active Withdrawn
- 2015-03-16 US US15/126,806 patent/US10144506B2/en active Active
- 2015-03-16 CN CN201910609815.2A patent/CN110406665A/en active Pending
- 2015-03-16 EP EP15714894.1A patent/EP3119672B1/en active Active
- 2015-03-16 CN CN201580012335.8A patent/CN106103271B/en not_active Expired - Fee Related
-
2018
- 2018-10-30 US US16/175,526 patent/US20190071168A1/en not_active Abandoned
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US20170137119A1 (en) | 2017-05-18 |
CN106103271B (en) | 2019-08-06 |
EP3119672B1 (en) | 2019-05-08 |
CN106103271A (en) | 2016-11-09 |
EP3495264A1 (en) | 2019-06-12 |
US10144506B2 (en) | 2018-12-04 |
CN110406665A (en) | 2019-11-05 |
GB2524242A (en) | 2015-09-23 |
WO2015140520A1 (en) | 2015-09-24 |
GB201404704D0 (en) | 2014-04-30 |
EP3119672A1 (en) | 2017-01-25 |
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