Rotor brake for a rotary-wing aircraft

1. A rotor brake for a helicopter, the rotor brake comprising:

a braking-force actuator;

a brake fluid reservoir;

a first hydraulic line connecting the braking-force actuator and the reservoir;

an electromechanical piston control element having a piezoelectric element, a piezoelectric amplifier, and a pump piston, wherein the piezoelectric element is controllable by the piezoelectric amplifier and is configured to move the pump piston, the electromechanical piston control element connected to the first hydraulic line using a second hydraulic line and a third hydraulic line between the braking force actuator and the brake fluid reservoir, the second hydraulic line having an inlet valve and the third hydraulic line having an outlet valve; and

a release valve positioned in the first hydraulic line and interposed between the second and third hydraulic lines;

wherein the electromechanical piston control element electrohydraulically actuates the braking-force actuator via the first hydraulic line by the piezoelectric element moving the pump piston in accordance with control from the piezoelectric amplifier; and

wherein the hydraulic line is configured for bidirectional flow of a brake fluid, where the first hydraulic line is configured such that the brake fluid flows in a first direction through the hydraulic line when actuating the braking-force actuator, and the brake fluid flows in a second direction through the first hydraulic line when releasing the braking-force actuator.

2. The rotor brake as recited in claim 1 , wherein the piston control element further includes a pump drive having a pump housing and the pump piston.

3. The rotor brake as recited in claim 1 , further comprising a relay configured to actuate the valve.

4. The rotor brake as recited in claim 1 , wherein the piezoelectric element includes piezoceramic.

5. A rotor brake for a rotary-wing aircraft, comprising:

a braking-force pick-up element linked to a rotor shaft; said braking-force pick-up element being operationally connected with a braking-force actuator, said braking-force actuator being configured to be hydraulically actuated;

an electromechanical piston control element connected by means of a first hydraulic line to the braking-force actuator, so that the braking-force actuator can be actuated electro-hydraulically by the control element, the control element is connected to a second hydraulic line and a third hydraulic line, an inlet valve provided in the second hydraulic line and an outlet valve provided in the third hydraulic line, wherein the second and third hydraulic lines are connected to the first hydraulic line of the braking-force actuator, wherein one segment of the first hydraulic line leading towards the braking-force actuator has a valve positioned between the second hydraulic line and the third hydraulic line of the control element for release of the braking-force actuator; and

a brake fluid reservoir connected to the first hydraulic line;

wherein the first hydraulic line is configured such that a brake fluid flows through the first hydraulic line in a first direction when the braking-force actuator is actuated, and the brake fluid flows through the first hydraulic line in a second direction when the braking-force actuator is released.

6. The rotor brake as recited in claim 5 , wherein the piston control element further includes a pump drive having a pump housing and the pump piston.

7. The rotor brake as recited in claim 5 , further comprising a relay configured to actuate the valve.

8. The rotor brake as recited in claim 5 , further comprising a brake fluid reservoir connected to the first hydraulic line.

9. The rotor brake as recited in claim 5 , wherein the braking-force pick-up element includes a brake disk.

10. A method of braking a rotor of a rotary-wing aircraft having a rotor shaft, the method comprising:

providing a braking-force actuator connected to a braking fluid reservoir using a first hydraulic line;

connecting a braking-force pick-up element to the rotor shaft and the braking-force actuator;

connecting an electromechanical piston control element to the first hydraulic line using a second and a third hydraulic line, an inlet valve provided in the second hydraulic line and an outlet valve provided in the third hydraulic line, and providing a release valve in one segment of the first hydraulic line between the second hydraulic line and the third hydraulic line for release of the braking-force actuator;

actuating the braking force actuator electrohydraulically using the electromechanical piston control element, thereby causing a braking fluid to flow through the first hydraulic line in a first direction; and

releasing the braking force actuator using the release valve, thereby causing the braking fluid to flow through the first hydraulic line in a second direction.

11. The method as recited in claim 10 , wherein the rotary-wing aircraft is a helicopter.