Rotary wing aircraft ball bearing
In a rotary wing aircraft tail rotor head assembly having a ball bearing on a spindle at the head of a rotor wing, the ball bearing contains slug ball separators between the balls in the bearing. The separator may be made from PEEK, PTFE, or polyimide. The ball-to-ball separation between two balls of like diameter provided by the separator may about 3.2 to about 64% of the diameter of one of the balls. A separator may have an annular configuration that defines a passage therethrough, the passage having two ends and the interior of the separator being tapered to define a maximum diameter at each end and a minimum diameter therebetween. The taper of the chamfered surface of the slug ball separator may define a conical angle of about 75° to about 120°. A ball bearing as described herein may also be used in a rotary wing aircraft swashplate having a stationary plate, a rotating plate; and a thrust bearing between the stationary plate and the rotating plate.
1. A swashplate comprising:
a rotating member;
a stationary member; and
a thrust bearing comprising:
an inner race;
an outer race;
a first ball and a second ball, the first ball and the second ball being disposed between the inner race and the outer race and the first ball having a diameter substantially equal to a diameter defined by the second ball;
a slug ball separator disposed between the first ball and the second ball, the slug ball separator comprising a first cylindrical portion, a second cylindrical portion disposed within the first cylindrical portion, and a frustoconical surface between the first cylindrical portion and the second cylindrical portion, and wherein
the inner race is coupled to the stationary member and the outer race is coupled to the rotating member, the slug ball separator provides a separation distance between the first ball and the second ball, the separation distance being equal to about 3.2% to about 64% of the diameter defined by the first ball.
2. The swashplate according to claim 1 , wherein the slug ball separator is comprised of a synthetic polymeric material.
3. The swashplate according to claim 2 , wherein the synthetic polymeric material is comprised of PEEK.
4. The swashplate according to claim 2 , wherein the synthetic polymeric material is comprised of PTFE or polyimide.
5. The swashplate according to claim 1 , wherein the slug ball separator comprises an annular configuration that defines a passage therethrough and that has two ends, the annular configuration includes an interior surface, the interior surface being tapered to a minimum internal diameter between the two ends.
6. The swashplate according to claim 1 , wherein the separation distance between the first ball and the second ball is equal to about 3.2% to about 9.6% of the diameter of the first ball.
7. The swashplate according to claim 6 , wherein the separation distance between the first ball and the second ball is equal to about 6% of the diameter of the first ball.
8. The swashplate according to claim 1 , wherein the diameter of the first ball and the second ball is about 12.7 mm.
9. The swashplate according to claim 1 , wherein the diameter of the first ball is larger than an outer diameter of the slug ball separator.
10. The swashplate according to claim 9 , wherein a ratio of the outer diameter of the slug ball separator to the diameter of the first ball is about 0.85:1.