GB2449281A - Screw and nut actuator - Google Patents

Screw and nut actuator Download PDF

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Publication number
GB2449281A
GB2449281A GB0709454A GB0709454A GB2449281A GB 2449281 A GB2449281 A GB 2449281A GB 0709454 A GB0709454 A GB 0709454A GB 0709454 A GB0709454 A GB 0709454A GB 2449281 A GB2449281 A GB 2449281A
Authority
GB
United Kingdom
Prior art keywords
screw shaft
actuator
nut
screw
cowl
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB0709454A
Other versions
GB0709454D0 (en
Inventor
David John Langford
Peter Bacon
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Goodrich Actuation Systems Ltd
Original Assignee
Goodrich Actuation Systems Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Goodrich Actuation Systems Ltd filed Critical Goodrich Actuation Systems Ltd
Priority to GB0709454A priority Critical patent/GB2449281A/en
Publication of GB0709454D0 publication Critical patent/GB0709454D0/en
Publication of GB2449281A publication Critical patent/GB2449281A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02K—JET-PROPULSION PLANTS
    • F02K1/00—Plants characterised by the form or arrangement of the jet pipe or nozzle; Jet pipes or nozzles peculiar thereto
    • F02K1/06—Varying effective area of jet pipe or nozzle
    • F02K1/15—Control or regulation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02K—JET-PROPULSION PLANTS
    • F02K1/00—Plants characterised by the form or arrangement of the jet pipe or nozzle; Jet pipes or nozzles peculiar thereto
    • F02K1/54—Nozzles having means for reversing jet thrust
    • F02K1/76—Control or regulation of thrust reversers
    • F02K1/763—Control or regulation of thrust reversers with actuating systems or actuating devices; Arrangement of actuators for thrust reversers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
    • B64D33/00—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for
    • B64D33/04—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for of exhaust outlets or jet pipes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02K—JET-PROPULSION PLANTS
    • F02K1/00—Plants characterised by the form or arrangement of the jet pipe or nozzle; Jet pipes or nozzles peculiar thereto
    • F02K1/06—Varying effective area of jet pipe or nozzle
    • F02K1/12—Varying effective area of jet pipe or nozzle by means of pivoted flaps
    • 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
    • F16H25/00—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms
    • F16H25/18—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for conveying or interconverting oscillating or reciprocating motions
    • F16H25/20—Screw mechanisms
    • 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
    • F16H25/00—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms
    • F16H25/18—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for conveying or interconverting oscillating or reciprocating motions
    • F16H25/20—Screw mechanisms
    • F16H2025/2053—Screws in parallel arrangement driven simultaneously with an output member moved by the screws
    • 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
    • F16H25/00—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms
    • F16H25/18—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for conveying or interconverting oscillating or reciprocating motions
    • F16H25/20—Screw mechanisms
    • F16H2025/2062—Arrangements for driving the actuator
    • F16H2025/2093—Arrangements for driving the actuator using conical gears
    • 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
    • F16H25/00—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms
    • F16H25/18—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for conveying or interconverting oscillating or reciprocating motions
    • F16H25/20—Screw mechanisms
    • F16H25/22—Screw mechanisms with balls, rollers, or similar members between the co-operating parts; Elements essential to the use of such members
    • F16H25/2204—Screw mechanisms with balls, rollers, or similar members between the co-operating parts; Elements essential to the use of such members with balls

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Transmission Devices (AREA)

Abstract

An actuator 20 comprises a hollow rotatable screw shaft 36, a nut 44 cooperating with the screw shaft 36 such that rotation of the screw shaft 36 whilst the nut 44 is held against rotation results in the nut 44 translating along the screw shaft 36, and a drive member 28 extending into the hollow screw shaft 36 and splined thereto such that rotation of the drive member 28 is transmitted to the screw shall 36. The screw shaft 36 may he supported by housing 40 including a gimbal arrangement 42. The screw shaft 36 and nut 44 may be connected by a ball-screw coupling or a roller-screw coupling and the drive member 28 and screw shaft 36 may be connected by a ball-spline coupling. The actuator may be used to drive a variable air flow fan or VAFN cowl (12 fig 1) relative to a thrust reverser cowl or transcowl (14 fig 1).

Description

ACTUATOR
This invention relates to an actuator and in particular to an actuator suitable for use in aerospace applications, for example for use in driving the variable air flow fan (VAFN) cowls of an aircraft for movement relative to associated thrust reverser cowls.
It is known to provide an aircraft engine with a thrust reverser system in which a series of moveable thrust reverser cowls are provided, the cowls each being moveable between a stowed position and a deployed, operative position. It is also known to provide a series of moveable VAFN cowls, the positions of which can be adjusted to vaiy the nozzle dimensions of the engine to suit the operating conditions of the engine. The nozzle dimension is the size of the exit throat defmed between the exit end of the fan cowl and the core engine housing It has been found to be advantageous for the nozzle dimension to be relatively large during the take-off and climb operating phases of the engine, and of reduced size during cruise conditions. During descent, the nozzle dimension is often increased in case it is necessary to abort landing and so enter another climb phase.
Typically, separate sets of actuators are used to drive the thrust reverser cowls and the VAFN cowls. Commonly, the actuators used to drive the VAFN cowls are mounted upon the thrust reverser cowls or the actuators associated therewith. Such mounting of the actuators is convenient in that the deployment of the thrust reverser cowls will automatically result in the VAFN cowls moving therewith, and avoids the use of excessively long actuators for the VAFN cowls to accommodate the thrust reverser cowl range of movement, but difficulties are faced in controlling and driving the actuators associated with the VAFN cowls as the fixed' parts of the actuators move, in use.
It is envisaged that one way of transmitting drive to an actuator so mounted may be by way of a telescopic drive coupling located in the drive train between a motor and the actuator itself An object of the invention is to provide an actuator and associated drive arrangement suitable for use in such an application.
According to the present invention there is provided an actuator comprising a hollow rotatable screw shaft, a nut cooperating with the screw shaft such that rotation of the screw shaft whilst the nut is held against rotation results in the nut translating along the screw shaft, and a drive member extending into the hollow screw shaft and splined thereto such that rotation of the drive member is transmitted to the screw shaft The screw shall is conveniently supported, through appropriate bearings, by a mounting.
In use, with the mounting connected to a thrust reverser cowl or associated actuator, the nut coupled to a VAFN cowl, and the drive member arranged to be driven by a motor, operation of the motor can be used to drive the VAFN cowl for movement relative to the thrust reverser cowl. Deployment of the thrust reverser cowl is accommodated by the splined connection of the shaft to the drive member allowing sliding movement to occur therebetween whilst maintaining the drive connection therebetween.
The mounting conveniently incorporates a gimbal arrangement. The presence of a gimbal arrangement accommodates angular movement of the thrust reverser cowl relative to the drive member and shaft.
The splined connection between the drive member and the shaft is conveniently a ball-spline coupling.
Preferably, the cooperation between the hollow screw shaft and the nut comprises a ball-screw or roller-screw type coupling.
The invention also relates to an actuator arrangement comprising a VAFN cowl, a thrust reverser cowl and a plurality of actuators of the type defined hereinbefore and operable to drive the VAFN cowl for movement relative to the thrust reverser cowl.
The invention will further be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a diagram illustrating an actuator in accordance with one embodiment of the invention, in use; Figures 2 to 4 are views of the actuator of Figure 1 in various operating conditions; and Figure 5 is a sectional view illustrating part of the actuator of Figure 1.
Referring firstly to Figure 1 there is illustrated an actuator arrangement 10 arranged to drive a VAFN cowl 12 for movement relative to a thrust reverser cowl known as a transcowl 14. The transcowl 14 will, in use, be driven for movement by separate actuators (not shown), for example in the form of hydraulic actuators or ball-screw type actuators. The actuator arrangement 10 comprises a motor 16 and gear box 18 arranged to drive a pair of actuators 20. The arrangement is such that, in use, the actuators 20 are driven simultaneously at the same speed as one another.
As illustrated most clearly in Figure 5, each actuator 20 comprises a head 22 containing gears 24, 26 operable to transmit the motor drive to a drive member 28 in the form of an elongate rod or shaft supported for rotation relative to the head 22 by bearings 30. The bearings 30 are arranged to hold the drive member 28 against significant axial movement. The gear 26 is splined to the drive member 28 and secured thereto by a nut 32 which cooperates with a screw thread formed on an end part of the drive member 28.
In use, the head 20 is secured to a part of the associated engine's torque box or support structure and so is fixed against movement relative to the engine.
The periphery of the drive member 28 is formed with a series of elongate grooves 28 which extend parallel to the axis of the drive member 28 and which receive drive coupling elements 34 in the form of balls or rollers.
The actuator 20 further comprises a hollow screw shaft 36, the inner periphery of which is provided with formations which also accommodate the drive coupling elements 34.
The drive member 28 extends into the hollow screw shaft 36, and the cooperation of the drive coupling elements 34 with the drive member 28 and the screw shaft 36 is such that the screw shaft 36 can move or slide axially relative to the drive member 28 in a telescopic like fashion, relative angular movement between the drive member 28 and the screw shaft 36 being substantially prevented. The screw shaft 36 and the drive member 28 are thus splined to one another.
The screw shaft 36 is supported through bearings 38 by a housing 40, the bearings 38 permitting the screw shaft 36 to rotate relative to the housing 40 but substantially preventing axial movement of the screw shaft 36 relative thereto. A gimbal mounting structure 42 is provided to secure the housing 40 to the transcowl 14 or an actuator associated therewith.
The screw shaft 36 is provided, externally, with a helical screw thread-like groove formation. A nut 44 encircles part of the screw shaft 36 and is provided with groove formations, ball or roller components being provided in the groove formations of the screw shaft 36 and the nut 44 such that rotation of the screw shaft 36 whilst the nut 44 is held against rotation results in the nut 44 translating axially along the screw shaft 36.
The nut 44 is connected to a tail tube 46 which, in turn, is secured by a mounting 48 to the VAFN cowl 12. The mounting 48 serves to hold the nut 44 against rotation.
In use, starting from a position in which the transcowl 14 and the VAFN cowl 12 both occupy their retracted or stowed positions, the actuator 20 occupying the condition shown in Figure 2, if it is desired to extend the VAFN cowl 12, the motor 16 is driven.
The rotation of the motor 16 is transmitted through the gear box 18 and gears 24, 26 to cause rotation of the drive member 28, the speed and direction of rotation being dependent upon the operating speed and direction of the motor 16 and upon the nature of the gear box 18 and gears 24, 26. The splined connection of the screw shaft 36 to the drive member 28 results in rotation of the drive member 28 being transmitted to the screw shaft 36. As outlined hereinbefore, rotation of the screw shaft 36 causes the nut 44 to translate thereon, the translating movement of the nut 44 being transmitted to the VAFN cowl 12 to move the VAFN cowl 12 towards its extended position. This position of the actuator 20 is illustrated in Figure 3. During this movement, the transcowl 14 is held against movement by its associated actuators (not shown) and so it will be appreciated that the housing 40 will remain in a fixed position relative to the engine housing.
Return movement of the VAFN cowl 12 towards its retracted position is achieved by driving the motor 16 in the reverse direction.
11 from the stowed or retracted position shown in Figure 2 it is desired to deploy the transcowl 14, the actuators (not shown) associated with the transcowl 14 are extended.
The movement of the transcowl 14 results in the gimbal arrangement 42 mounted on the transcowl 14 or associated actuator moving relative to the torque box, and this movement is transmitted to the housing 40 and to the screw shaft 36. The telescopic splined coupling between the screw shaft 36 and the drive member 28 accommodates such movement of the housing 40 and screw shaft 36 whilst maintaining the drive couphng between the motor 16 and the screw shaft 36. This position of the actuator is illustrated in Figure 4.
It will be appreciated that as the drive connection to the screw shaft 36 is maintained throughout the range of movement of the transcowl 14, the VAFN cowl 12 can continue to be driven to and maintained in a desired position relative to the transcowl 14 irrespective of the position of the transcowl 14, thus no loss of drive or control thereof is experienced.
Return movement of the transcowl 14 is achieved by reversing the operation of its actuators, returning the actuator 20 towards the position illustrated in Figure 2.
The provision of the gimbal arrangement 42 in the connection of the housing 40 to the transcowl 14 ensures that angular movement of the transcowl 14 relative to the drive member 28 and screw shaft 36 can be accommodated, avoiding jamming of the actuator or the placing of unnecessary loadings thereon.
It will be appreciated that a number of modifications and alterations may be made to the arrangement described hereinbefore without departing from the scope of the invention.
Further, although one specific application of the actuator is illustrated in Figure 1, it will be appreciated that the actuator may be used in a number of other applications without departing from the scope of the inventioa

Claims (9)

1. An actuator comprising a hollow rotatable screw shaft, a nut cooperating with the screw shaft such that rotation of the screw shaft whilst the nut is held against rotation results in the nut translating along the screw shaft, and a dnve member extending into the hollow screw shaft and splined thereto such that rotation of the drive member is transmitted to the screw shaft
2. An actuator according to Claim 1, wherein the screw shaft is rotatably supported by a mounting.
3. An actuator according to Claim 2, wherein the mounting incorporates a gimbal arrangement.
4. An actuator according to any of the preceding claims, wherein the splined connection between the drive member and the screw shaft is a ball-spline coupling.
5. An actuator according to any of the preceding claims, wherein the cooperation between the hollow screw shaft and the nut comprises a ball-screw type coupling.
6. An actuator according to any of Claims I to 4, wherein the cooperation between the hollow screw shaft and the nut comprises a roller-screw type coupling
7. An actuator substantially as hereinbefore described with reference to the accompanying drawings.
8. An actuator arrangement comprising a moveable thrust reverser cowl, a VAFN cowl, and a plurality of actuators as claimed in any of the preceding claims, the screw shafts of the actuators being rotatably mounted to the thrust reverser cowl and the nuts of the actuators being mounted to the VAFN cowl, the actuators being operable to drive the VAFN cowl for movemit relative to the thrust reverser cowl.
9. An actuator arrangement substantially as hereinbefore described with reference to the accompanying drawings.
GB0709454A 2007-05-17 2007-05-17 Screw and nut actuator Withdrawn GB2449281A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB0709454A GB2449281A (en) 2007-05-17 2007-05-17 Screw and nut actuator

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB0709454A GB2449281A (en) 2007-05-17 2007-05-17 Screw and nut actuator

Publications (2)

Publication Number Publication Date
GB0709454D0 GB0709454D0 (en) 2007-06-27
GB2449281A true GB2449281A (en) 2008-11-19

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ID=38234583

Family Applications (1)

Application Number Title Priority Date Filing Date
GB0709454A Withdrawn GB2449281A (en) 2007-05-17 2007-05-17 Screw and nut actuator

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9488130B2 (en) 2013-10-17 2016-11-08 Honeywell International Inc. Variable area fan nozzle systems with improved drive couplings
WO2017103464A1 (en) * 2015-12-17 2017-06-22 Safran Nacelles Nacelle for aircraft turbojet engine provided with a hydraulic roto-linear actuator of a thrust reverser and a variable-area nozzle
US20190271282A1 (en) * 2018-03-01 2019-09-05 Goodrich Actuation Systems Limited Coupling

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4519561A (en) * 1983-05-23 1985-05-28 Rohr Industries, Inc. Aircraft thrust reverser mechanism
US20050056146A1 (en) * 2003-09-12 2005-03-17 Messier-Bugatti Actuator having both a hydraulic mode and a mechanical mode of operation

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4519561A (en) * 1983-05-23 1985-05-28 Rohr Industries, Inc. Aircraft thrust reverser mechanism
US20050056146A1 (en) * 2003-09-12 2005-03-17 Messier-Bugatti Actuator having both a hydraulic mode and a mechanical mode of operation

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9488130B2 (en) 2013-10-17 2016-11-08 Honeywell International Inc. Variable area fan nozzle systems with improved drive couplings
WO2017103464A1 (en) * 2015-12-17 2017-06-22 Safran Nacelles Nacelle for aircraft turbojet engine provided with a hydraulic roto-linear actuator of a thrust reverser and a variable-area nozzle
US10190605B2 (en) 2015-12-17 2019-01-29 Safran Nacelles Nacelle for an aircraft turbojet engine provided with a hydraulic roto-linear actuator of a thrust reverser and of a variable-section nozzle
US20190271282A1 (en) * 2018-03-01 2019-09-05 Goodrich Actuation Systems Limited Coupling
US11280294B2 (en) * 2018-03-01 2022-03-22 Goodrich Actuation Systems Limited Coupling with eccentric bearing arrangement

Also Published As

Publication number Publication date
GB0709454D0 (en) 2007-06-27

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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)