GB2103023A - Damping device - Google Patents

Damping device Download PDF

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Publication number
GB2103023A
GB2103023A GB08219743A GB8219743A GB2103023A GB 2103023 A GB2103023 A GB 2103023A GB 08219743 A GB08219743 A GB 08219743A GB 8219743 A GB8219743 A GB 8219743A GB 2103023 A GB2103023 A GB 2103023A
Authority
GB
United Kingdom
Prior art keywords
damping
movement
damping device
input
stator
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.)
Granted
Application number
GB08219743A
Other versions
GB2103023B (en
Inventor
Geoffrey John Sturtivant
Karl Gallagher
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.)
BAE Systems PLC
Original Assignee
British Aerospace PLC
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 British Aerospace PLC filed Critical British Aerospace PLC
Priority to GB08219743A priority Critical patent/GB2103023B/en
Publication of GB2103023A publication Critical patent/GB2103023A/en
Application granted granted Critical
Publication of GB2103023B publication Critical patent/GB2103023B/en
Expired legal-status Critical Current

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Classifications

    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02KDYNAMO-ELECTRIC MACHINES
    • H02K49/00Dynamo-electric clutches; Dynamo-electric brakes
    • H02K49/02Dynamo-electric clutches; Dynamo-electric brakes of the asynchronous induction type
    • H02K49/04Dynamo-electric clutches; Dynamo-electric brakes of the asynchronous induction type of the eddy-current hysteresis type
    • H02K49/046Dynamo-electric clutches; Dynamo-electric brakes of the asynchronous induction type of the eddy-current hysteresis type with an axial airgap
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16FSPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F15/00Suppression of vibrations in systems; Means or arrangements for avoiding or reducing out-of-balance forces, e.g. due to motion
    • F16F15/10Suppression of vibrations in rotating systems by making use of members moving with the system
    • F16F15/18Suppression of vibrations in rotating systems by making use of members moving with the system using electric, magnetic or electromagnetic means

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Electromagnetism (AREA)
  • Acoustics & Sound (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Dynamo-Electric Clutches, Dynamo-Electric Brakes (AREA)

Abstract

A damping device includes an input member 2, an output member 5, a damping member 6 associated therewith and a pair of plates 7 positioned one to either side of the member 6 and each carrying a plurality of permanent magnets 8 to generate a magnetic field between the plates 7. A gearbox arrangement 4 operatively associates the input member 2 and output member 5 so that movement of the input member at a given velocity effects movement of the output member, and thus the damping member, at an increased velocity, thereby inducing eddy currents in the damping member which effect damping of that member. <IMAGE>

Description

SPECIFICATION Damping device This invention relates to damping devices in which a damping force is generated by movement of an electrically conducting member through a magnetic field which movement causes eddy currents to be induced in the member which, in turn, generate a force resisting movement of the member dependent upon its velocity. In particular, but not exclusively, this invention relates to eddy current dampers for use on spacecraft.
The energy required for the deployment of structures (e.g. antennae) from spacecraft may be supplied by a spring or pneumatic arrangement without intrinsic speed control. However, an uncontrolled deployment of a space structure could cause de-stabilisation of the spacecraft and wouid normally be unacceptable. It is known to provide viscous damping to control such deployments. The performance of viscous damping is generally acceptable but methods using fluids cause many problems for the spacecraft designer.
Containment of fluids in space is particularly difficult with outgassing and susceptibility to temperature changes as disadvantages.
An object of the present invention is to provide a device which provides a damping effect but which does not use fluids.
According to this invention, there is provided a damping device which includes an input member, a damping member, velocity increasing means operatively associating the input member and the damping member so that movement of the input member at a given velocity effects movement of the damping member at an increased velocity and a stator member, one of the stator member and the damping member having associated therewith magnetic field generating means, the other being of an electrically conducting material the two being magnetically associated so that movement of the input member causes the dampin member to move relative to the stator member, thereby inducing eddy currents in the other of the stator member and the damping member to generate a damping force which resists movement of the input member.
Preferably, said input member is a rotatable shaft and the velocity increasing means include meshing gear means.
Preferably, the magnetic field generating means includes a plurality of permanent magnets.
In one arrangement, the damping member may be in the form of a rotatable disc, the stator element including two plate elements positioned one to each side of the damping member each of said plate elements carrying at least one permanent magnet. A plurality of magnets may be provided on each plate element, radially located around a central axis thereof, each magnet being positioned in reverse polarity to its neighbours, the poles of each magnet on one plate element being axially aligned with respective reverse poles of the magnets on the other plate element.
By way of example only, one embodiment of the invention will now be described with reference to the accompanying drawings, in which Figure 1 shows a damping device of this invention, and Figure 2 shows a magnetic array employed in the device of Figure 1.
In the Figures there is shown a damping device for damping rotational movement on deployment of a structure from a spacecraft.
The structure 1 to be deployed is attached to one end of a rotatable input shaft 2. A spring 3 acts on the shaft 2 to urge it from a stowed angular position to a deployed angular position.
The other end of the shaft 2 is coupled to the slow end of a high ratio gearbox 4, the fast end of the gearbox being coupled to a rotatable output shaft 5. Towards its end remote from the gearbox 4, the output shaft 5 includes an integrally-formed aluminium disc 6.
Two magnetic arrays are positioned one to each side of the disc 6, and concentric with output shaft 5. Referring to Figure 2, each array includes an annular aluminium backing plate 7 to which are secured twelve magnets 8 of ferrite or rare earth metal material, each having two soft iron pole pieces 9. Each magnet 8, together with its pole pieces 9, is aligned radially with respect to the backing plate 7 and is positioned in reverse polarity to its neighbours.
The two arrays are positioned, as shown in Figure 1 , with each pole of each array axially aligned with an opposite pole of the other array, so that a magnetic field is set up between the arrays through which the disc 6 passes on deployment of the structure 1.
In use, when the structure 1 is released for deployment, the spring 3 exerts a torque on the shaft 2 to urge the input shaft 2 to rotate towards its deployed position. This rotation will be geared up by the gearbox 4 to impart to the output shaft 5 a higher rotational speed and a lower torque.
As the aluminium disc 6 spins in the magnetic field between the arrays, its interaction with the magnetic field induces eddy currents in the disc, dissipating energy as heat within the disc and generating a counter torque acting on the output shaft 5. This counter torque is transmitted through the gearbox 4, where it is amplified, to the input shaft 2, thereby to create a damping or braking effect.
In practice, when the space structure 1 is released to initiate deployment the spring 3 will tend to rotate input shaft 2, deploying the space structure and causing the disc 6 to spin faster and faster as the torque causes the rotational speed of the system to accelerate. The faster the disc 6 spins, the greater is the counter torque generated, and an equilibrium is reached where the speed of the input shaft 2 is such that the torque from the damping device equals the torque from the spring 2, at which point the rotational speed of the input shaft 2 will stop increasing, and become stable.
It will be noted that the above described embodiment is relatively simple in construction, and that the mass and volume of the device may be relatively small, these features being of particular importance for space applications.
The structure 2 may be deployed by means other than spring 3, for example, a deployment torque may be generated by an electric motor, or pneumatically.
In addition, whilst the above embodiment employs a flat plate array of magnets and a rotary gearbox, the invention is not so limited.

Claims (7)

1. A damping device which includes an input member, a damping member, velocity increasing means operatively associating the input member and the damping member so that movement of the input member at a given velocity effects movement of the damping member at an increased velocity and a stator member, one of the stator member and damping member having associated therewith magnetic field generating means, the other being of an electrically conducting material the two in use being of an electrically conducting material, the two being magnetically associated so that movement of the input member causes the damping member to move relative to the stator member, thereby inducing eddy currents in the other of the stator member and the damping member to generate a damping force which resists movement of the input member.
2. A damping device as claimed in Claim 1, wherein the input member is a rotatable shaft and the velocity increasing means include meshing gear means.
3. A damping device as claimed in any of the preceding Claims, wherein the magnetic field generating means includes a plurality of permanent magnets.
4. A damping device as claimed in Claim 3, wherein the damping member is in the form of a rotatable disc, the stator member including two plate elements positioned one to each side of the damping member, each of said plate elements carrying at least one permenant magnet.
5. A damping device as claimed in Claim 4, wherein each plate element carries a plurality of permanent magnets arranged radially with respect to a central axis thereof, each magnet being positioned in reverse polarity to its neighbours on the plate element, the poles of each magnet on one plate element being axially aligned with respective reverse poles of the magnets on the other plate element.'
6. A dampint device according to any of the preceding Claims, wherein the damping member is formed of aluminium material.
7. A damping device substantially as hereinbefore described with reference to the accompanying drawing.
GB08219743A 1981-07-09 1982-07-08 Damping device Expired GB2103023B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08219743A GB2103023B (en) 1981-07-09 1982-07-08 Damping device

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8121269 1981-07-09
GB08219743A GB2103023B (en) 1981-07-09 1982-07-08 Damping device

Publications (2)

Publication Number Publication Date
GB2103023A true GB2103023A (en) 1983-02-09
GB2103023B GB2103023B (en) 1985-07-03

Family

ID=26280082

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08219743A Expired GB2103023B (en) 1981-07-09 1982-07-08 Damping device

Country Status (1)

Country Link
GB (1) GB2103023B (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2140978A (en) * 1983-05-26 1984-12-05 Myano Seisakusho Kk Eddy current retarder for emergency escape device
GB2216601A (en) * 1988-03-23 1989-10-11 Lucas Ind Plc Throttle valve assembly
EP1068665A1 (en) * 1998-04-01 2001-01-17 Bell Helicopter Textron Inc. Support assembly for a rotating shaft
BE1018032A3 (en) * 2008-03-04 2010-04-06 Cloet Arthur Fall protection system for rock or wall climber, uses rotating permanent magnets and eddy current recordable plate for providing controlled braking in cable drum
US20130326969A1 (en) * 2011-03-04 2013-12-12 Moog Inc. Structural damping system and method
EP2561262A4 (en) * 2010-04-23 2017-11-15 Salte Tekniske AS Device for damping of pendular movements and method of using same
ES2685287A1 (en) * 2017-03-31 2018-10-08 Heron Davits As Brake of permanent magnets for launch of life saving equipment (Machine-translation by Google Translate, not legally binding)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2140978A (en) * 1983-05-26 1984-12-05 Myano Seisakusho Kk Eddy current retarder for emergency escape device
GB2216601A (en) * 1988-03-23 1989-10-11 Lucas Ind Plc Throttle valve assembly
EP1068665A1 (en) * 1998-04-01 2001-01-17 Bell Helicopter Textron Inc. Support assembly for a rotating shaft
EP1068665A4 (en) * 1998-04-01 2003-04-23 Bell Helicopter Textron Inc Support assembly for a rotating shaft
BE1018032A3 (en) * 2008-03-04 2010-04-06 Cloet Arthur Fall protection system for rock or wall climber, uses rotating permanent magnets and eddy current recordable plate for providing controlled braking in cable drum
EP2561262A4 (en) * 2010-04-23 2017-11-15 Salte Tekniske AS Device for damping of pendular movements and method of using same
US20130326969A1 (en) * 2011-03-04 2013-12-12 Moog Inc. Structural damping system and method
US9175467B2 (en) * 2011-03-04 2015-11-03 Moog Inc. Structural damping system and method
ES2685287A1 (en) * 2017-03-31 2018-10-08 Heron Davits As Brake of permanent magnets for launch of life saving equipment (Machine-translation by Google Translate, not legally binding)

Also Published As

Publication number Publication date
GB2103023B (en) 1985-07-03

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PCNP Patent ceased through non-payment of renewal fee