VSV actuation arrangement

Abstract

An actuation arrangement for effecting actuation of a variable stator vane pivotally mounted on a tubular casing. The actuation arrangement includes: an actuator connector connected to the variable stator vane via an actuating lever; an anchor fixedly mounted relative to the circumference of the tubular casing; an actuator; and a belt extending from the actuator to the fixed pulley. The actuation arrangement further includes a movable pulley movable relative to the tubular casing and connected to the actuator connector. The belt has a loop portion provided between the proximal and distal ends which loops around the movable pulley, the loop portion for transferring forces generated in the belt by the actuator to the movable pulley to effect movement of the movable pulley and actuator connector towards the anchor to effect actuation of the variable stator vane via the actuating lever.

Claims

1. An actuation arrangement for effecting actuation of a variable stator vane pivotally mounted on a tubular casing, said actuation arrangement comprising: an actuator connector connected to the variable stator vane via an actuating lever; an anchor fixedly mounted relative to the circumference of said tubular casing; an actuator; and a belt having a proximal end affixed to the actuator and a distal end affixed to the anchor, wherein the actuation arrangement further comprises a movable pulley movable relative to said tubular casing and connected to the actuator connector, and wherein the belt has a loop portion provided between the proximal and distal ends which loops around the movable pulley, the loop portion for transferring forces generated in the belt by the actuator to the movable pulley to effect movement of the movable pulley and thereby the actuator connector towards the anchor to effect actuation of the variable stator vane via the actuating lever.

2. The actuation arrangement according to claim 1 wherein the actuator is a winding actuator adapted to wind or spool the belt to reduce the length of the belt extending from the actuator.

3. The actuation arrangement according to claim 1 wherein the movable pulley is movable in a circumferential direction about the tubular casing.

4. The actuation arrangement according to claim 3 further comprising at least one circumferentially-extending guide rail mounted on the tubular casing for supporting and guiding the movable pulley about the circumference of the tubular casing.

5. The actuation arrangement according to claim 1 wherein the movable pulley is movable in an axial direction along the tubular casing.

6. The actuation arrangement according to claim 5 further comprising at least one axially-extending guide rail mounted on the tubular casing for supporting and guiding the movable pulley along the tubular casing.

7. The actuation arrangement according to claim 1 wherein the actuator connector is an actuator ring that at least partially circumscribes the tubular casing.

8. The actuation arrangement according to claim 1 wherein the movable pulley is nearer to the actuator than the anchor and wherein the belt includes a further loop portion positioned between the proximal end and the loop portion which loops around the anchor or a further anchor.

9. The actuation arrangement according to claim 1 further comprising a biasing mechanism for biasing the anchor and movable pulley away from one another.

10. The actuation arrangement according to claim 1 further comprising a restoring mechanism comprising a resilient element connected between the tubular casing and the actuator connector.

11. The actuation arrangement according to claim 1 further comprising a second belt passing around a second movable pulley and connected to a second anchor.

12. The actuation arrangement according to claim 11 further comprising a second actuator connected to the second belt.

13. The actuation arrangement according to claim 11 wherein the anchor is a fixed pulley and/or the second anchor is a second fixed pulley.

14. The actuation arrangement according to claim 1 wherein at least one of the anchor and moveable pulley comprises at least one groove for housing the loop portion of the belt.

15. An axial multi-stage compressor comprising the actuation arrangement according to claim 1.

16. A gas turbine engine comprising the axial multi-stage compressor according to claim 15.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which:

(2) FIG. 1 shows a compressor section of an aircraft gas turbine engine;

(3) FIG. 2 shows an axial cross-section through a first embodiment of the present invention;

(4) FIG. 3 shows an axial cross-section through a second embodiment of the present invention with the VSV vanes in a neutral position;

(5) FIG. 4 shows an axial cross-section through a second embodiment of the present invention with the VSV vanes in an open;

(6) FIG. 5 shows an axial cross-section through a second embodiment of the present invention with the VSV vanes in a closed position;

(7) FIG. 6 shows an aerial view of a portion of an actuation arrangement according to a third embodiment; and

(8) FIG. 7 shows an aerial view of a portion of an actuation arrangement according to a fourth embodiment.

DETAILED DESCRIPTION AND FURTHER OPTIONAL FEATURES OF THE INVENTION

(9) FIG. 2 shows an axial cross section through a first embodiment.

(10) The first embodiment of the actuation arrangement 1 comprises an actuator ring 22 which partially circumscribes a tubular casing 12. The tubular casing 12 carries the radially outer ends of the variable stator vanes (not shown) which are each connected to the actuator ring 22 via a respective actuating lever (not shown).

(11) The actuation arrangement comprises a fixed pulley 2 which comprises a mount 6 which secures the fixed pulley 2 on the tubular casing 12 in a fixed relationship with the circumference of the tubular casing.

(12) The actuation arrangement further comprises a movable pulley 3 which is mounted between circumferentially-extending guide rails (not shown) which are, in turn, mounted on the tubular casing 12. The movable pulley 3 is free to pivot about its central axis and can also move in a between the guide rails in a circumferential direction around the tubular casing 12.

(13) The movable pulley 3 is connected to the actuator ring 22.

(14) An actuator 4 is provided proximal the movable pulley 3. This is connected to a belt 5 which extends from a proximal end at the actuator 4 to a distal end at the fixed pulley. The belt has a loop portion extending around the movable pulley 3 and a further loop portion extending around the fixed pulley 2.

(15) The movable pulley has two circumferential grooves (not shown), one for receiving the loop portion, whilst the fixed pulley has at least one circumferential groove for receiving the further loop portion.

(16) The belt extends over the movable pulley 3 in a first groove and the further loop portion loops around the fixed pulley 2 within the at least one circumferential groove. The belt then extends back to the movable pulley where the loop portion loops around the movable pulley in a second circumferential groove before the belt extends back to the fixed pulley.

(17) When the actuator 4 exerts a pulling force on the belt 5 by winding it within the actuator and thus reducing the length of the belt extending from the actuator, the force (actuation load) is transmitted through the belt 5 to the movable pulley 3 to effect a circumferential movement (in a clockwise direction in FIG. 2) of the movable pulley 3 and hence the actuator ring 22 which results in an angle adjustment for the stator vanes. This arrangement reduces the amount of force needed to move the actuator ring to (since there are 3 lengths of belt extending between the pulleys).

(18) The actuation arrangement also includes a restoring mechanism 7 comprising a spring 8 connected between the actuator connector 22 and the tubular housing 12. This moves the actuator connector 22 in an opposing direction to the actuator to allow the variable stator vanes to return to a rest position after actuation.

(19) FIGS. 3, 4 and 5 show a second embodiment of the present invention in three different positions.

(20) FIG. 3 shows the second embodiment with the stator vanes (not shown) in a neutral position.

(21) In this embodiment, the movable pulley 3 and fixed pulley 2 each have at least one circumferential groove.

(22) In the second embodiment, the actuator 4 is provided proximal the fixed pulley 2. The belt 5 extends from the proximal end at the actuator 4 over the fixed pulley 2 within the least one circumferential groove and the loop portion loops around the movable pulley 3 within the at least one circumferential groove before the belt extends to its distal end at the fixed pulley 2.

(23) When the actuator 4 exerts a pulling force on the belt 5 by winding it within the actuator and thus reducing the length of the belt extending from the actuator, the force (actuation load) is transmitted through the belt 5 to the movable pulley to effect a circumferential movement (in an anti-clockwise direction in FIG. 3) of the movable pulley and hence the actuator ring 22 which results in an angle adjustment to open the stator vanes as shown in FIG. 4. This arrangement reduces the amount of force needed to move the actuator ring by (since there are 2 lengths of belt extending between the pulleys).

(24) In order to move the stator vanes back to the neutral position shown in FIG. 3 or to move the stator vanes from the neutral position to the closed position shown in FIG. 5 (i.e. to move the actuator ring in a clockwise direction in FIG. 3/5), the actuation arrangement further comprises a second actuator 4 which is connected to a second belt 5 which passes over a second fixed pulley 2, with a loop portion looping around a second movable pulley 3 and back to the fixed pulley 2.

(25) The movable pulleys 3, 3 are connected at circumferentially opposing ends of the actuator connector. The fixed pulleys 2, 2 are circumferentially spaced around the tubular casing 12 from one another.

(26) When the second actuator 4 exerts a pulling force on the second belt 5 by winding it within the second actuator 4 and thus reducing the length of the second belt 5 extending from the second actuator 4, the force (actuation load) is transmitted through the second belt 5 to the second movable pulley 3 to effect a circumferential movement (in a clockwise direction in FIG. 3/5) of the second movable pulley 3 and hence the actuator ring 22 in the opposite direction to the movement effected by the first actuator 4. As the second actuator 4 is actuated, the first actuator is deactivated (e.g. by a power divert mechanism) so that there are no competing pulling forces. The belt 5 previously wound into the first actuator will be free to unwind during actuation of the second actuator 4.

(27) FIG. 6 shows an aerial view of a portion of an actuation arrangement according to a third embodiment. In this embodiment, the arrangement further comprises a further fixed pulley 9 which is axially spaced from the fixed pulley 2, with the further fixed pulley 9 and fixed pulley 2 being on opposing axial sides of the actuator ring 22.

(28) The belt 5 extends from the proximal end at the actuator 4 with the further loop portion looping around the further fixed pulley 9 within a circumferential groove and the loop portion looping around the movable pulley 3 within the circumferential groove before the belt extends to its distal end at the fixed pulley 2.

(29) When the actuator 4 exerts a pulling force on the belt 5 by winding it within the actuator and thus reducing the length of the belt extending from the actuator, the force (actuation load) is transmitted through the belt 5 to the movable pulley to effect a circumferential movement of the movable pulley and hence the actuator ring 22 which results in an angle adjustment to open the stator vanes as shown in FIG. 4. This arrangement reduces the amount of force needed to move the actuator ring to (since there are 3 lengths of belt extending between the pulleys).

(30) In the fourth embodiment, shown in FIG. 7, the belt 5 extends from the proximal end at the actuator 4 to the fixed pulley 2 with the loop portion looping around the movable pulley 3 within the circumferential groove. A second belt 5 extends from the proximal end at the second actuator 4 to the second fixed pulley 2 with the second loop portion looping around the second movable pulley 3 within the circumferential groove.

(31) The movable pulley 3 and second movable pulley 3 are both connected to an L-shaped lever 15 which is pivotally connected to the actuator connector 22. The movable pulley 3 is connected to one angled portion of the lever 15 whilst the second movable pulley 3 is connected to the second angled portion of the lever.

(32) In the fourth embodiment, the movable pulleys 3, 3 are movable in an axial direction (between axial guide railsnot shown).

(33) When the actuator 4 exerts a pulling force on the belt 5 by winding it within the actuator and thus reducing the length of the belt extending from the actuator, the force (actuation load) is transmitted through the belt 5 to the movable pulley 3 to effect a axial movement of the movable pulley 3 which pivots the lever 15 on the actuator ring and effects circumferential movement of the actuator ring 22.

(34) In order to move the actuator ring 22 in the opposite direction, the second actuator 4 exerts a pulling force on the belt 5 by winding it within the actuator 4 and thus reducing the length of the belt extending from the actuator 4. The force (actuation load) is transmitted through the belt 5 to the movable pulley 3 to effect a axial movement of the movable pulley 3 which pivots the lever 15 on the actuator ring 22 and effects circumferential movement of the actuator ring 22.

(35) The actuators 4, 4 in the fourth embodiment could be replaced by a single actuator. The fixed pulleys 2, 2 in the fourth embodiment could be replaced by a single fixed pulley.

(36) It will be understood that the invention is not limited to the embodiments above-described and various modifications and improvements can be made without departing from the concepts described herein. Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the disclosure extends to and includes all combinations and sub-combinations of one or more features described herein.

(37) All references referred to above are hereby incorporated by reference.