Electrically actuated aircraft brakes

Claim 2

An improved recirculating-ball screw drive comprising in combination: a relatively stationary annular-shaped member having a bore and a ball bearing race groove formed within the bore; an annular-shaped ram member mounted within the bore of the stationary member and adapted for axial linear motion through the bore, said ram member having a plurality of helical ball race grooves of a particular pitch within an outwardly facing annular surface thereof; and a relatively rotatable annular-shaped member mounted coaxially between the relatively stationary and ram members and having a ball bearing race groove in an outwardly facing annular surface in relative alignment with the ball race groove in the stationary member, said two races and a plurality of ball bearings carried between them forming a thrust bearing to maintain the relative positions of the two members, said rotatable member further comprising a plurality of gear teeth about a peripheral edge surface adapted for driving the member into rotation and at least one helical ball groove turn formed within its bore of the same pitch as the ball race grooves formed in the outer facing surface of the ram member, said ball grooves and a plurality of ball bearings carried therebetween forming a ball-screw drive of the ram member upon rotation of the rotatable member, said balls being recirculated back through a ball transfer passageway formed within the bore of the rotatable member to effect continued ball-screw drive motion of the linearly moving ram member.

Claim 3

The improved recirculating-ball screw drive as set forth in claim 1 wherein the ball transfer passageway is machined within the bore of the rotatable member and is not more than one ball diameter in depth.

Claim 4

The improved recirculating-ball screw drive as set forth in claim 1 wherein the ball transfer passageway is defined by inlet and outlet centerline arcs which are drawn tangent to a centerline established for the helical ball grooves.

Claim 5

The improved recirculating-ball screw drive as set forth in claim 3 wherein the inlet and outlet centerline arcs are defined by radii having centers located at opposite ends respectively of a line drawn through a midpoint of the ball transfer passageway.

Claim 6

The improved recirculating-ball screw drive as set forth in claim 4 wherein the radius of arc of the centerline at the input is equal to the radius of arc of the centerline at the output and the arcs are tangent at the midpoint of the ball transfer passageway.

Claim 7

The improved recirculating-ball screw drive as set forth in claim 1 wherein the ball transfer passageway crosses over from one ball groove to another at an angle of not more than 15 degrees.

Claim 8

The improved recirculating-ball screw drive as set forth in claim 1 wherein the ball transfer passageway is within an arc length of not more than 45 degrees within the bore of the rotatable member.

Claim 9

The improved recirculating-ball screw drive as set forth in claim 7 wherein the ball transfer passageway is within an arc length which is within the range of 20-40 degrees.

Claim 10

The improved recirculating-ball screw drive as set forth in claim 8 wherein the ball transfer passageway is within an arc length of 30 degrees.

Claim 11

The recirculating-ball screw drive as set forth in claim 1 wherein the ball transfer passageway is magnetic such as to attract balls traversing the passageway to the bottom surface thereof.

Claim 12

In a brake assembly comprising a brake disk stack and a pressure plate in communication with the stack, the improvement comprising: a recirculating-ball screw drive operatively positioned with respect to the pressure plate comprising (a) a relatively stationary annular-shaped member having a bore and a ball bearing race formed within its bore; (b) an annular-shaped ram member mounted within the bore of the stationary member and adapted for axial linear motion therethrough for effecting contacting engagement with the pressure plate, said ram having a plurality of helical ball grooves of a particular pitch about an outwardly facing surface thereof; and (c) a relatively rotatable annular-shaped member mounted coaxially between the relatively stationary and ram members and having a ball bearing race formed in an outwardly facing surface and in relative position to the ball race within the bore of the stationary member, the two races and a plurality of ball bearings carried between them forming a thrust bearing as between the two members, said rotatable member further comprising a plurality of ring gear teeth about a peripheral edge surface thereof and at least one helical ball groove turn formed within its bore of the same pitch as the ball grooves in the ram member, said ball grooves carrying a plurality of balls therebetween to drive the ram member upon rotation of the rotatable member, said balls being recirculated through a ball transfer passageway formed within the bore of the rotatable member to effect continued ball-screw drive motion of the linearly moving ram member; and a plurality of torque motors mounted within the relatively stationary member, each said motor carrying a pinion gear operatively engageable with the ring gear of the relatively rotatable member, said torque motors regulated by an operator for selectively moving the ram into and out of forceful contacting engagement with the pressure plate.

Claim 13

In a brake assembly comprising a brake disk stack and a pressure plate in communication with the stack, the improvement comprising: a recirculating-ball screw drive operatively positioned with respect to the pressure plate comprising (a) a relatively stationary annular-shaped member having a bore and a ball bearing race formed within its bore; (b) an annular-shaped ram member mounted within the bore of the stationary member and adapted for axial linear motion therethrough for effecting contacting engagement with the pressure plate, said ram having a plurality of helical ball grooves of a particular pitch about an outwardly facing surface thereof; and (c) a relatively rotatable annular-shaped member mounted coaxially between the relatively stationary and ram members and having a ball bearing race formed in an outwardly facing surface and in relative position to the ball race within the bore of the stationary member, the two races and a plurality of ball bearings carried between them forming a thrust bearing as between the two members, said rotatable member further comprising a plurality of ring gear teeth about a peripheral edge surface thereof and at least one helical ball groove turn formed within its bore of the same pitch as the ball grooves in the ram member, said ball grooves carrying a plurality of balls therebetween to drive the ram member upon rotation of the rotatable member, said balls being recirculated through a ball transfer passageway formed within the bore of the rotatable member to effect continued ball-screw drive motion of the linearly moving ram member; and a plurality of torque motors mounted within the relatively stationary member, each said motor carrying a pinion gear operatively engageable with the ring gear of the relatively rotatable member, said torque motors regulated by an operator for selectively moving the ram into and out of forceful contacting engagement with the pressure plate.

Claim 14

The improvement as set forth in claim 11 wherein the ball transfer passageway is machined within the bore of the rotatable member and is not more than one ball diameter in depth.

Claim 15

The improvement as set forth in claim 11 wherein the ball transfer passageway is defined by inlet and outlet centerline arcs which are drawn tangent to a centerline established for the helical ball grooves.

Claim 16

The improvement as set forth in claim 13 wherein the inlet and outlet centerline arcs are defined by radii having centers located at opposite ends respectively of a line drawn through a midpoint of the ball transfer passageway

Claim 17

The improvement as set forth in claim 14 wherein the radius of arc of the centerline at the input is equal to the radius of the arc of the centerline at the output and the arcs are tangent at the midpoint of the ball transfer passageway.

Claim 18

The improvement as set forth in claim 11 wherein the angle of the ball transfer passageway between the two adjacent ball grooves is not more than 15 degrees.

Claim 19

The improvement as set forth in claim 11 wherein the ball transfer passageway covers no more than 45 degrees of arc length within the bore of the member.

Claim 20

The improvement as set forth in claim 17 wherein the ball transfer passageway is within the range of 20-40 degrees of arc length.

Claim 21

The improvement as set forth in claim 18 wherein the ball transfer passageway is within an arc length of 30 degrees.

Claim 22

The improvement as set forth in claim 11 wherein the ball transfer passageway is magnetic such as to attract balls traversing the passageway to the bottom surface thereof.