Linear actuator with testable cone no-back and torque limiter
A cone brake no-back includes an input no-back disk, an output no-back disk; and a no-back ball ramp mechanism operably connected to the input no-back disk and the output no back disk. An input no-back cone is operably connected to and supportive of the input no-back disk. The input no-back cone is axially loaded by an input no-back spring. An output no-back cone is operably connected to and supportive of the output no-back disk. The output no-back cone is axially loaded by an output no-back spring. A no-back input shaft is operably connected to the input no-back disk and the output no back disk, and a no-back output shaft is operably connected to the output no back disk.
1. A no back system, comprising:
a cone brake no-back;
a no-back input shaft operably connected to the cone brake no-back;
a no-back output shaft operably connected to the cone brake no-back; and
a cone torque limiter operably connected to the no-back output shaft, the cone torque limiter including:
a cone torque limiter reaction ball ramp rotatably driven by the no-back output shaft;
a torque limiter cone brake;
a cone torque limiter ball ramp mechanism disposed between the cone torque limiter reaction ball ramp and the torque limiter cone brake and engaged therewith; and
a torque limiter reaction cone disposed such that when a surface jam or an overtorque load is applied via a drive gear the torque limiter cone brake engages the torque limiter reaction cone for transmission of the load to structural ground;
wherein the cone torque limiter reaction ball ramp is supported by a thrust bearing set.
2. The no-back system of claim 1 , wherein the torque limiter cone brake is axially preloaded by a torque limiter preload spring.
3. The no-back system of claim 1 , wherein the cone brake no-back includes:
an input no-back disk;
an output no-back disk;
a no-back ball ramp mechanism operably connected to the input no-back disk and the output no back disk;
an input no-back cone operably connected to and supportive of the input no-back disk, the input no-back cone axially loaded by an input no-back spring; and
an output no-back cone operably connected to and supportive of the output no-back disk, the output no-back cone axially loaded by an output no-back spring;
wherein the no-back input shaft is operably connected to the input no-back disk and the output no back disk; and
wherein the no-back output shaft is operably connected to the output no back disk.
4. The no-back system of claim 3 , further comprising an input no-back disk lining applied to the input no-back disk and the input no-back cone.
5. The no-back system of claim 4 , wherein the input no-back disk lining is formed from an aramid or composite material containing aramid.
6. The no-back system of claim 3 , wherein the no-back output shaft is a hollow torque shaft.
7. The no-back system of claim 6 , wherein the no-back input shaft is coaxial with and disposed radially inside of the no-back output shaft.
8. The no-back system of claim 3 , wherein an axial travel of the input no-back cone due to the input no-back spring is limited by a mechanical stop.
9. The no-back system of claim 1 , further comprising a no-back test mechanism coupled to an output drive gear of the no-back system, the no-back test mechanism including:
a test pinion gear selectably engagable with the output drive gear; and
a test power source operably connected to the test pinion gear and configured to apply a back drive load to the cone brake no-back via the output drive gear when the test pinion gear is engaged with the output drive gear.
10. The no-back system of claim 9 , further comprising a test spring to bias the test pinion gear out of engagement with the output drive gear.
11. A no-back system comprising:
a cone brake no-back driven by a no-back input shaft;
a cone torque limiter operably connected to the cone brake no-back via a no-back output shaft;
an output drive gear operably connected to the cone torque limiter;
a linear power screw operably connected to and driven by the output drive gear; and
a no-back test mechanism selectably engagable with the output drive gear to test the cone brake no-back.
12. The no-back system of claim 11 , wherein the cone brake no-back includes:
an input no-back disk;
an output no-back disk;
a no-back ball ramp mechanism operably connected to the input no-back disk and the output no back disk;
an input no-back cone operably connected to and supportive of the input no-back disk, the input no-back cone axially loaded by an input no-back spring; and
an output no-back cone operably connected to and supportive of the output no-back disk, the output no-back cone axially loaded by an output no-back spring;
wherein the no-back input shaft is operably connected to the input no-back disk and the output no back disk; and
wherein the no-back output shaft is operably connected to the output no back disk.
13. The no-back system of claim 11 , wherein the cone torque limiter includes:
a cone torque limiter reaction ball ramp rotatably driven by the no-back output shaft;
a torque limiter cone brake;
a cone torque limiter ball ramp mechanism disposed between the cone torque limiter reaction ball ramp and the torque limiter cone brake and engaged therewith; and
a torque limiter reaction cone disposed such that when a surface jam or an overtorque load is applied via the drive gear the torque limiter cone brake engages the torque limiter reaction cone for transmission of the load to structural ground.