Electric brake actuator module for aircraft
An electro-mechanical brake assembly comprising a brake disk stack having a center axis; and a plurality electro-mechanical actuators for applying braking pressure to the brake disk stack. The actuators are circumferentially arranged around the center axis, and each actuator includes a housing, a linearly movable ram, a screw for linearly moving the ram, a nut mounted for rotation in the housing and operatively engaged with the screw such that rotation of the nut effects linear movement of the screw for urging the ram into forceful engagement with the brake disk stack, an electric motor for rotating the nut, and an anti-rotation device for preventing rotation of the screw relative to the housing when the nut is rotated to effect linear movement of the screw. The foregoing arrangement provides for greater stroke than prior art actuators without sacrificing durability and performance.
1. An electro-mechanical brake assembly, comprising:
a brake head;
a brake disk stack adjacent the brake head and having a center axis; and
an electro-mechanical actuator mounted to the brake head for applying braking pressure to the brake disk stack, the actuator being radially offset from the center axis;
the actuator including:
a housing removably mounted to the brake head such that the housing can be removed from the brake head without removal of the brake disk stack,
a linearly movable ram,
a screw for linearly moving the ram, the screw being retained within the housing such that screw is carried by the housing when the housing is removed from the brake head, and
a nut mounted for rotation in the housing such that the nut is carried by the housing when the housing is removed from the brake head, the nut being operatively engaged with the screw such that rotation of the nut effects linear movement of the screw for urging the ram into forceful engagement with the brake disk stack,
an electric motor for rotating the nut, and
a plurality of the electro-mechanical actuators circumferentially arranged around the center axis,
wherein an anti-rotation device is provided for preventing rotation of the screw relative to the housing when the nut is rotated to effect linear movement of the screw, wherein the screw has a bore opening to an end thereof opposite the ram, wherein the bore opening is coaxial to the screw and wherein the anti-rotation device includes an anti-rotation guide extending into the bore opening in the screw for rotationally interfering between the anti-rotation guide and the bore opening, to restrain rotation of the screw relative to the housing, wherein the anti-rotation guide is coaxial to the screw,
wherein the anti-rotation guide further functions to support the screw against lateral movement, and
wherein the nut has an internally threaded portion, and the anti-rotation guide extends to a point overlapping the internally threaded portion.
2. The electro-mechanical brake assembly as set forth in claim 1 , wherein the anti-rotation guide overlaps at least about half the internally threaded portion.
3. The electro-mechanical brake assembly as set forth in claim 1 , wherein the nut and screw are a ball-screw device.
4. The electro-mechanical brake assembly as set forth in claim 1 , wherein the nut has an integral gear, and the motor is connected by gearing to the integral gear.
5. The electro-mechanical brake assembly as set forth in claim 1 , wherein the electric motor is mounted to and carried by the housing.
6. The electro-mechanical brake assembly as set forth in claim 1 , further comprising a wheel mount to which the brake disk stack is mounted, and the actuator is a self-contained unit mounted to the wheel mount for removal independently of the brake disk stack.
7. The electro-mechanical brake assembly as set forth in claim 1 , comprising a position sensor which supplies a position signal representative of the position of the ram.
8. The electro-mechanical brake assembly as set forth in claim 7 , wherein the position sensor is fully enclosed within the housing.
9. The electro-mechanical brake assembly as set forth in claim 7 , wherein the screw has a bore opening to an end thereof opposite the ram, and the position sensor is disposed within the interior of the screw.
10. The electro-mechanical brake assembly as set forth in claim 7 , wherein the position sensor is connected to the nut.
11. The electro-mechanical brake assembly as set forth in claim 1 , wherein the nut and screw are a ball-screw device.
12. The electro-mechanical brake assembly as set forth in claim 1 , wherein the electric motor is mounted to and carried by the housing.
13. The electro-mechanical brake assembly as set forth in claim 1 , further comprising a wheel mount to which the brake disk stack is mounted, and each actuator is a self-contained unit mounted to the wheel mount for removal independently of one another and the brake disk stack.
14. The electro-mechanical brake assembly as set forth in claim 1 , wherein the ram is formed by an outboard end of the screw.