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CN-114466792-B - Shock absorbing strut

CN114466792BCN 114466792 BCN114466792 BCN 114466792BCN-114466792-B

Abstract

A shock strut is provided that includes a first energy absorbing stage or first load limiter and a second energy absorbing stage or second load limiter. The second energy absorbing stage or second load limiter may include one or more belleville springs (205). Shock struts may be used for both fixed and retractable landing gear while providing design adjustability for achieving load-deflection curves that accommodate a range of descent or impact speeds.

Inventors

  • Robert Chappell
  • RANDY LEE
  • Peter Pistes
  • Michael. Sarkozy

Assignees

  • 赛峰起落架系统加拿大公司
  • 赛峰起落架系统加拿大公司

Dates

Publication Date
20260421
Application Date
20200727
Priority Date
20200727

Claims (15)

  1. 1. An energy absorbing device for an aircraft, the device comprising: A first load limiter comprising an oil and gas shock strut configured to absorb shock energy applied to the strut, wherein the oil and gas shock strut comprises a lumen containing a strut fluid composed of a gas and a hydraulic fluid, an orifice support tube located within the lumen and defining at least one damping orifice, and a piston movable within the lumen to force the strut fluid through the at least one damping orifice, and A second load limiter integrally formed within the hydro-pneumatic shock strut, wherein the second load limiter comprises one or more belleville springs configured to absorb impact energy applied to the strut by compressing the one or more belleville springs, wherein the one or more belleville springs are located in the inner cavity.
  2. 2. The apparatus of claim 1, wherein the first load limiter is configured to absorb impact energy associated with normal operating conditions, and wherein the second load limiter is configured to absorb additional impact energy beyond impact energy associated with normal operating conditions of the aircraft.
  3. 3. The apparatus of claim 1, wherein the one or more springs comprise a first set of belleville springs positioned in the interior cavity and a second set of belleville springs positioned in the interior cavity a distance apart from the first set of belleville springs.
  4. 4. The apparatus of claim 1 wherein the hydro-pneumatic shock strut further comprises a metering pin in the piston, and wherein the orifice support tube is arranged to slidably receive the metering pin through a damping hole.
  5. 5. The apparatus of claim 4, wherein the hydro-pneumatic shock strut further comprises a plate positioned around the orifice support tube or the metering pin to retain and contact the one or more belleville springs.
  6. 6. The apparatus of claim 5, wherein the piston impacts the plate when the piston moves a predetermined distance in the inner cavity or the orifice support tube impacts the plate when the piston moves a predetermined distance in the inner cavity.
  7. 7. A retractable landing gear comprising the apparatus of claim 1.
  8. 8. A shock absorbing pillar for a vehicle, comprising: An inner housing portion slidably coupled within the outer housing portion; an inner chamber formed by the inner housing portion and the outer housing portion, the inner chamber defining a sealed fluid volume for containing a strut fluid, the strut fluid comprising a hydraulic fluid and a gas; An orifice support tube positioned within the lumen and defining at least one damping hole; a piston movable a predetermined distance within the inner chamber to force the strut fluid through the at least one orifice, and One or more belleville springs positioned within the interior cavity and about the orifice support tube to absorb additional energy acting on the strut after the piston moves the predetermined distance.
  9. 9. The shock absorbing strut of claim 8, wherein the piston is integrally formed with the inner housing portion.
  10. 10. The shock absorbing strut of claim 8, wherein the one or more belleville springs are located at an end of the housing portion and the piston acts on the one or more belleville springs when the piston moves the predetermined distance.
  11. 11. The shock absorbing strut of claim 8, further comprising: a metering pin in the piston, the orifice support tube being arranged to slidably receive the metering pin through the damping bore; Wherein the piston is integrally formed with the inner housing portion.
  12. 12. The shock absorbing strut of claim 8, wherein the one or more belleville springs comprise a first set of belleville springs located in the inner cavity a distance apart from a second set of belleville springs, and wherein the first set of belleville springs or the second set of belleville springs comprise a plurality of belleville springs arranged in parallel, in series, or a combination thereof.
  13. 13. The shock absorbing strut of claim 8, further comprising a source of pressurized gas selectively connected in fluid communication with the inner chamber.
  14. 14. The shock absorbing strut of claim 13, further comprising a control valve in fluid communication with the source of pressurized gas, wherein control of the control valve selectively supplies pressurized gas from the source of pressurized gas to the inner chamber to cause the strut to rapidly extend.
  15. 15. A retractable landing gear comprising a shock absorbing strut according to claim 8.

Description

Shock absorbing strut Background Most aircraft are equipped with landing gear that enables the aircraft to safely land on the ground. In some types of landing gear, shock absorbing struts are used to cushion landing shocks, dampen repetitive oscillations, and reduce the tendency of the aircraft to bounce or "rebound. A shock absorbing strut suitable for use in landing gear that achieves these advantages is known as an oil and gas shock absorbing strut ("oil pressure" strut) which converts kinetic energy into potential energy through the use of pressurized gas to provide resilient spring characteristics. The damping of this energy conversion and the reduction of the "rebound" is achieved by oil or the like, usually forced through damping holes. In some constructions of shock absorbing struts, in addition to compression and expansion of the gas, the damping force of the oil passing through the orifice also contributes to the reaction force of the oil strut. An oil hydraulic prop known in the art is disclosed in U.S. patent 9,914,532 and shown in fig. 1A. Referring to FIG. 1A, a conventional single stage hydrocarbon shock absorber strut is indicated generally at 10. The post 10 includes an inner housing portion (inner housing portion) 12 slidably coupled within an outer housing portion 14. The inner shell portion 12 and the outer shell portion (outer housing portion) 14 together define an interior cavity 16 containing a fluid 18, the fluid 18 being composed of oil 20 contained in a lower portion thereof and gas 22 contained in an upper portion thereof. The strut 10 further includes an orifice support tube 28 defining a conventional damping orifice 30 at an axial end. To increase the efficiency of the strut 10, an optional metering pin 32 may be provided for interaction with the damping orifice 30. Fig. 1B shows another oil hydraulic prop known in the prior art. Referring now to FIG. 1B, a conventional two-stage hydrocarbon shock absorber strut is indicated generally at 10'. The two-stage strut 10' includes an inner housing portion 12' slidably coupled in an outer housing portion 14 '. The floating piston 40' is slidably disposed within the inner housing portion 12' defining a chamber 42' between the floating piston 40' and the closed lower end of the inner housing portion 12'. A seal, ring or other suitable sealing means, generally designated 44', is provided to form a sealed chamber for containing gas 46' at high pressure. To increase the efficiency of the strut 10', an optional metering pin (similar to FIG. 1A but not shown) for interaction with the orifice 30' may also be provided. Opposite the high pressure gas chamber 42' (e.g., above the floating piston), the inner housing portion 12' and the outer housing portion 14' together define an inner cavity 16' containing a fluid 18' comprised of oil 20' contained in a lower portion thereof and gas 22' at low pressure contained in an upper portion thereof. An orifice support tube 28 'is provided in the housing portion 14', the orifice support tube 28 'defining a conventional damping orifice 30' at an axial end. The two-stage strut 10 'further includes an orifice plate 48' fixedly mounted within the lower portion of the inner housing portion 12 'and above the floating piston 40'. In some landing gears, such as nose landing gears, one type of hydrocarbon shock strut, known as a "jump strut," may be used to increase nose rotation during take-off in addition to reducing its impact capability. The trip strut typically comprises an oil hydraulic strut and a pneumatic system controlled by an electrical control system. The pneumatic system provides high pressure gas to the gas chamber of the oil hydraulic strut based on control signals received from the electronic control system. The application of high pressure gas to the upper gas chamber causes the struts to extend rapidly and then the reaction force from the ground causes the nose of the aircraft to rise. Disclosure of Invention This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. According to one aspect of the present disclosure, an energy absorbing device for an aircraft is provided. The apparatus in one embodiment includes a first load limiter including a hydro-pneumatic shock strut configured to absorb impact energy and a second load limiter integrally formed within the hydro-pneumatic shock strut. In one embodiment, the second load limiter comprises one or more belleville springs. In one embodiment, the first load limiter is configured to absorb impact energy associated with normal operating conditions, and the second load limiter is configured to absorb additional impact energy beyond impact energy associated with normal operating conditions