Propeller and system of counter-rotating propellers comprising improved means for limiting pitch, and a turbine engine comprising them
View Patent ↗A propeller for an aircraft turbine engine, comprising means for adjusting the pitch of the blades comprising a hydraulic actuator borne by the rotor and including a cavity and a piston displaceable in said cavity and dividing said cavity into two chambers, as well as means for limiting the stroke of the piston in order to prevent displacement of said blades in a predetermined direction beyond a predetermined limiting pitch angle, and comprising hydraulic connection means with which both chambers may be put into communication with each other as soon as the pitch angle of the blades becomes equal to said predetermined limiting pitch angle during the displacement of said blades in said predetermined direction, these hydraulic connection means being borne by said rotor of the propeller.
1. A propeller for an aircraft turbine engine, comprising:
a first rotor;
first blades borne by the first rotor and having an adjustable pitch angle;
a first double acting hydraulic actuator borne by the first rotor and including a first cavity and a first piston slidably movable in the first cavity,
wherein the first piston divides the first cavity into a first chamber and a second chamber, and the first piston is mechanically connected to the first blades so that the first piston changes the pitch angle of the first blades into a first pitch change direction when the first piston moves in a first displacement direction oriented from the second chamber towards the first chamber and vice versa,
the propeller further comprising:
a first couple of pressurized fluid inlet channels respectively connected to the first and second chambers of the first cavity whatever the position of the first piston, for moving the first piston,
at least one first hydraulic circuit borne by the first rotor and including:
a first portion which is connected to a first region of the first cavity which belongs to the first chamber whatever the pitch angle of the first blades,
a second portion connected to a second region of the first cavity which is located so that, when the first piston moves in the first piston displacement direction from a position in which the second region is initially part of the first chamber of the first cavity, the second region becomes part of the second chamber of the first cavity as soon as the pitch angle of the first blades becomes equal to a first it pitch angle, and
a first valve commutable between a first operational mode and a second operational mode,
wherein, in the first operational mode, the first valve connects the first and second portions of the first hydraulic circuit to one another so as to form a closed circuit, and
wherein, in the second operational mode, the first valve isolates the first and second portions of the first hydraulic circuit from one another.
2. The propeller according to claim 1 , wherein the first pitch change direction is oriented towards the small pitch angles.
3. A system of counter-rotating propellers for an aircraft turbine engine, comprising:
a first propeller according to claim 1 , wherein the first rotor of the first propeller rotates in a first direction of rotation around a common longitudinal axis of the system relatively to a stator of this system;
a second propeller comprising a second rotor which rotates in a second direction of rotation, opposite to the first direction of rotation, around the longitudinal axis, relatively to the stator of the system, and second blades borne by the second rotor; and
a second double acting hydraulic actuator borne by the first rotor of the first propeller and comprising a second cavity and a second piston slidably movable in the second cavity,
wherein the second piston divides the second cavity into a first chamber and a second chamber, and the second piston is mechanically connected to the second blades so that the second piston changes the pitch angle of the second blades into a second pitch change direction when the second piston moves in a second piston displacement direction oriented from the second chamber of the second cavity towards the first chamber of the second cavity and vice versa,
the second propeller further comprising:
a second couple of pressurized fluid inlet channels respectively connected to the first and second chambers of the second cavity whatever the position of the second piston, for moving the second piston,
a second hydraulic circuit borne by the first rotor of the first propeller and including:
a first portion which is connected to a first region of the second cavity which belongs to the first chamber thereof whatever the pitch angle of the second blades,
a second portion connected to a second region of the second cavity which is located so that, when the second piston moves in the second piston displacement direction from a position in which the second region is initially part of the first chamber of the second cavity, the second region becomes part of the second chamber of the second cavity as soon as the pitch angle of the second blades becomes equal to a second limit pitch angle, and
a second valve commutable between a first operational mode and a second operational mode,
wherein, in the first operational mode, the second valve connects the first and second portions of the second hydraulic circuit to one another so as to form a closed circuit, and
wherein, in the second operational mode, the second valve isolates the first and second portions of the second hydraulic circuit from one another.
4. The system of counter-rotating propellers according to claim 3 , wherein the second pitch change direction is oriented towards the small pitch angles.
5. The system of counter-rotating propellers according to claim 3 , further comprising a transfer bearing for supplying pressurized fluid from the stator of the system to the first and second double acting hydraulic actuators and to the first and second valves, the transfer bearing including two pairs of hydraulic routes respectively connected to the first and second couples of pressurized fluid inlet channels and a fifth hydraulic route jointly connected to the first and second valves.
6. A turbine engine comprising a propeller according to claim 1 .
7. A turbine engine comprising a system of counter-rotating propellers according to claim 3 .
8. A propeller for an aircraft turbine engine, comprising:
a first rotor;
first blades borne by the first rotor and having an adjustable pitch angle;
a first double acting hydraulic actuator borne by the first rotor and including a first cavity and a first piston slidably movable in the first cavity between two opposite extreme positions, namely a first position and a third position of the first piston,
wherein the first piston divides the first cavity into a first chamber having a bottom at a first extremity of the first cavity on the side of the first position of the first piston, and a second chamber having a bottom at a second extremity of the first cavity opposite to the first extremity thereof, on the side of the third position of the first piston,
wherein the first piston is mechanically connected to the first blades so that the first piston changes the pitch angle of the first blades into a first pitch change direction when the first piston moves in a first displacement direction oriented from the second chamber towards the first chamber and vice versa,
the propeller further comprising:
a first couple of pressurized fluid inlet channels, one of which being connected to the first chamber of the first cavity between the bottom of the first chamber and the first position of the first piston, and the other one of which being connected to the second chamber of the first cavity between the bottom of the second chamber and the third position of the first piston, for moving the first piston;
at least one first hydraulic circuit borne by the first rotor and including:
a first portion connected to the first cavity between the bottom of the first chamber thereof and the first position of the first piston so that the first portion remains connected to the first chamber whatever the position of the first piston,
a second portion connected to the first cavity between the first position and the third position of the first piston, and
a first valve commutable between a first operational mode and a second operational mode,
wherein, in the first operational mode, the first valve connects the first and second portions of the first hydraulic circuit to one another so as to form a closed circuit, and
wherein, in the second operational mode, the first valve isolates the first and second portions of the first hydraulic circuit from one another.
9. The propeller according to claim 8 , wherein the first pitch change direction is oriented towards the small pitch angles.
10. A system of counter-rotating propellers for an aircraft turbine engine, comprising:
a first propeller according to claim 8 , wherein the first rotor of the first propeller rotates in a first direction of rotation around a common longitudinal axis of the system relatively to a stator of this system,
a second propeller comprising a second rotor which rotates in a second direction of rotation, opposite to the first direction of rotation, around the longitudinal axis, relatively to the stator of the system, and second blades borne by the second rotor, and
a second double acting hydraulic actuator borne by the first rotor of the first propeller and comprising a second cavity and a second piston slidably movable in the second cavity between two opposite extreme positions, namely a first position and a third position of the second piston,
wherein the second piston divides the second cavity into a first chamber having a bottom at a first extremity of the second cavity on the side of the first position of the second piston, and a second chamber having a bottom at a second extremity of the second cavity opposite to the first extremity thereof, on the side of the third position of the second piston,
wherein the second piston is mechanically connected to the second blades so that the second piston changes the pitch angle of the second blades into a second pitch change direction when the second piston moves in a second piston displacement direction oriented from the second chamber of the second cavity towards the first chamber of the second cavity and vice versa,
the second propeller further comprising:
a second couple of pressurized fluid inlet channels, one of which being connected to the first chamber of the second cavity between the bottom of this first chamber and the first position of the second piston, and the other one of which being connected to the second chamber of the second cavity between the bottom of this second chamber and the third position of the second piston, for moving the second piston;
a second hydraulic circuit borne by the first rotor of the first propeller and including:
a first portion connected to the second cavity between the bottom of the first chamber thereof and the first position of the second piston so that the first portion remains connected to this first chamber whatever the position of the second piston,
a second portion connected to the second cavity between the first position and the third position of the second piston, and
a second valve commutable between a first operational mode and a second operational mode,
wherein, in the first operational mode, the second valve connects the first and second portions of the second hydraulic circuit to one another so as to forma closed circuit, and
wherein, in the second operational mode, the second valve isolates the first and second portions of the second hydraulic circuit from one another.
11. The system of counter-rotating propellers according to claim 10 , wherein the second pitch change direction is oriented towards the small pitch angles.
12. The system of counter-rotating propellers according to claim 10 , further comprising a transfer bearing for supplying pressurized fluid from the stator of the system to the first and second double acting hydraulic actuators and to the first and second valves, the transfer bearing including two pairs of hydraulic routes respectively connected to the first and second couples of pressurized fluid inlet channels and a fifth hydraulic route jointly connected to the first and second valves.
13. A turbine engine comprising a propeller according to claim 8 .
14. A turbine engine comprising a system of counter-rotating propellers according to claim 10 .