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BR-102019026575-B1 - ACTUATOR, AND, AIRCRAFT

BR102019026575B1BR 102019026575 B1BR102019026575 B1BR 102019026575B1BR-102019026575-B1

Abstract

ACTUATOR, AND, AIRCRAFT This is an actuator (10) comprising a screw shaft (32) and a nut assembly (25). The nut assembly (25) comprises a primary nut (50) for transmitting load through the actuator (10) along a primary load path and a secondary nut (60) that transmits load through the actuator (10) along a secondary load path. The secondary nut (60) comprises first and second parts (100, 102) that move relative to each other. As the load is transmitted through the actuator (10) along the primary load path, the secondary nut (60) does not transmit load through the actuator (10), wherein, upon failure of the primary load path, the first and second parts (100, 102) move relative to each other, wherein this relative movement causes the first and second parts (100, 102) to engage the screw shaft (32) and allows the transmission of load through the secondary nut (60) of the actuator (10) along the secondary load path.

Inventors

  • Raphael Medina
  • Rui Amaral

Assignees

  • GOODRICH ACTUATION SYSTEMS SAS

Dates

Publication Date
20260317
Application Date
20191213
Priority Date
20190904

Claims (14)

  1. 1. Actuator (10), which comprises a screw shaft (32) and a nut assembly (25), wherein said nut assembly (25) comprises a primary nut (50) for transmitting load through said actuator (10) along a primary load path, and a secondary nut (60) for transmitting load through said actuator (10) along a secondary load path, wherein said secondary nut (60) comprises first and second parts (100, 102) movable relative to each other, wherein when load is transmitted through the actuator (10) along the primary load path, the secondary nut (60) does not transmit load through the actuator (10) and, upon failure of the primary load path, the first and second parts (100, 102) move relative to each other, wherein such relative movement causes the first and second parts (100, 102) to engage the screw shaft (32) and allow load transmission through of the secondary nut (60) of the actuator (10) along that secondary load path, characterized in that the actuator (10) further comprises one or more movable supports (130) configured to engage one or the other, or both of the first and second parts (100, 102) after such relative movement of the first and second parts (100, 102) engages the screw shaft (32), so that, by means of such engagement, the movable supports (130) are configured to prevent further relative movement of the first and second parts (100, 102).
  2. 2. Actuator according to claim 1, characterized in that the first part (100) is configured to move between a first position in which the first part (100) does not engage the screw shaft (32), and a second position in which the first part (100) engages the screw shaft (32) to allow load to be transferred through the secondary nut (60) through the first part (100).
  3. 3. Actuator according to claim 2, characterized in that the second part (102) is configured to move between a first position in which the second part (102) does not engage a screw shaft (16), and a second position in which the second part (102) engages the screw shaft (16) to allow load to be transferred through the secondary nut (60) through the second part (102).
  4. 4. Actuator according to claim 3, characterized in that it further comprises a resilient member (120) propelled between the first part (100) and the second part (102) and configured to cause said relative movement of the first and second parts (100, 102) to engage the screw shaft (32).
  5. 5. Actuator according to any one of claims 1 to 4, characterized in that it further comprises one or more spindle pins (104) configured to prevent said relative movement of the first and second parts (100, 102) to engage the screw shaft (32) while load is transmitted through the actuator (10) along the primary load path.
  6. 6. Actuator according to claim 5, characterized in that said spindle pins (104) extend radially inward through the first and second parts (100, 102).
  7. 7. Actuator according to any one of claims 1 to 6, characterized in that one of the first and second parts (100, 102) fits inside the other of the first and second parts (100, 102) to allow said relative movement between them in an axial direction.
  8. 8. Actuator according to any one of claims 1 to 7, characterized in that at least one of the first and second parts (100, 102) comprises a screw thread (110, 112), and the screw thread is disengaged from the screw shaft (32) when load is transmitted through the actuator (10) along the primary load path, and moved to engagement with the screw shaft (32) to allow load transmission through the actuator (10) along the secondary load path by means of said relative movement of the first and second parts (100, 102).
  9. 9. Actuator according to claim 8, characterized in that both the first and second parts (100, 102) comprise a screw thread (110, 112), and the screw threads are both disengaged from the screw shaft (32) when load is transmitted through the actuator (10) along the primary load path, and both are moved to engagement with the screw shaft (32) to allow load transmission through the actuator (10) along the secondary load path by means of said relative movement of the first and second parts (100, 102).
  10. 10. Actuator according to claim 9, characterized in that the screw thread (110) in the first part (100) is propelled in a first axial direction and against one side of a screw thread (17) of the screw shaft (32), and the screw thread (112) in the second part (102) is propelled in a second opposite axial direction and against the other side of the screw thread (17) of the screw shaft (32).
  11. 11. Actuator according to any one of claims 1 to 10, characterized in that one or more movable supports (130) are restrained against axial movement, and are configured, each, to slide into a respective circumferential cavity (106) located in one or the other of the first and second parts (100, 102) so as to prevent said additional relative movement of the first and second parts (100, 102).
  12. 12. Actuator according to any one of claims 1 to 11, characterized in that it further comprises one or more resilient members (132) configured to propel said one or more movable supports (130) into said engagement with one or the other, or both of the first and second parts (100, 102) to prevent said further relative movement of the first and second parts (100, 102).
  13. 13. Actuator according to any one of claims 1 to 12, characterized in that the actuator (10) is for a flight control surface of an aircraft.
  14. 14. Aircraft, characterized in that it comprises an actuator (10) as defined in claim 13.

Description

FIELD OF TECHNIQUE [001] The present invention relates to an actuator, for example, a horizontal adjustable stabilization actuator (“THSA”) for an aircraft, wherein the actuator includes a primary load path and a secondary load path that are configured to carry the actuator load in the event of failure of the primary load path. FUNDAMENTALS [002] Actuators typically provide a structural link between the stationary parts of the actuator (and the object to which the actuator is attached), which provide a driving force for the actuator, and the moving parts of the actuator that actuate a component. Various loads are transmitted from the component to the stationary parts of the actuator via the moving parts of the actuator. Most actuators provide this structural link in the form of a load path, along which various clearances are provided between the components to accommodate excessive loading in use. [003] An example of such an actuator is a horizontally adjustable stabilizing actuator (“THSA”) for an aircraft, which must transmit various aerodynamic loads in use (e.g., vibration caused by turbulence). In some cases, these actuators comprise a primary load path configured to transmit aerodynamic loads under normal conditions and a secondary load path configured to transmit aerodynamic loads in the event of failure of the primary load path. During normal use, the secondary load path must remain in an unloaded condition. [004] It is desirable to provide a mechanism to prevent unwanted loading of the secondary load path during normal operation. SUMMARY [005] According to one aspect, an actuator is presented comprising a screw shaft and a nut assembly. The nut assembly comprises a primary nut for transmitting load through the actuator along a primary load path and a secondary nut for transmitting load through the actuator along a secondary load path. The secondary nut comprises first and second parts that can move relative to each other. Insofar as the load is transmitted through the actuator along the primary load path, the secondary nut does not transmit load through the actuator, whereby upon failure of the primary load path, the first and second parts move relative to each other, such relative movement causes the first and second parts to engage the screw shaft and enables the transmission of load through the secondary nut of the actuator along the secondary load path. [006] The use of a secondary nut with first and second parts moving axially, as described above, leads to an improved mechanism that avoids unwanted loading of the secondary load path during normal operation, as well as an improved mechanism for transitioning between the primary load path and the secondary load path in case of failure of the primary load path. [007] The first part can be configured to move between a first position in which the first part does not engage (and/or contact) the screw shaft, and a second position in which the first part engages (and/or contacts) the screw shaft to allow the load to be transferred through the secondary nut through the first part. [008] The second part can be configured to move between a first position in which the second part does not engage (and/or contact) the screw shaft and a second position in which the second part engages (and/or contacts) the screw shaft to allow the load to be transferred through the secondary nut through the second part. [009] The actuator may further comprise a resilient member (for example, a spring, such as a helical spring located concentrically within the first and second parts) propelled between the first and second parts and configured to cause said relative movement of the first and second parts for engagement/contact with the screw shaft. This helps to ensure that the first and second parts are efficiently separated and in full engagement/contact with the screw shaft. [0010] The actuator may additionally comprise one or more spindle pins configured to prevent said relative movement of the first and second parts from engaging the screw shaft while the load is transmitted through the actuator along the primary load path. These pins may help prevent inadvertent movement of the first and second parts before a predetermined shear force on the pins. The spindle pins may extend radially inward through the first and second parts, which optimizes the reliability of the spindle pins to shear at the predetermined shear force. [0011] One of the first and second parts may fit inside the other between the first and second parts (for example, concentrically) to allow said relative movement between them in an axial direction. This can provide a compact assembly, especially when combined with the helical spring located concentrically within the first and second parts and/or spindle pins that extend radially inward. [0012] At least one of the first and second parts may comprise a screw thread, wherein the screw thread may be disengaged from the screw shaft when the load is transmitted