Pitch change mechanism
AssigneeGeneral Electric Company
InventorsPetr Hora, Edwin K. Miller
Life of this patent
Estimating the term…
Abstract
The invention concerns a pitch change mechanism for an aircraft propeller in which a common ring gear (51) changes pitch of all propeller blades on a given rotor simultaneously. Motion of the ring gear (51) is induced by a planet (40)-and-carrier (101) system driven by a pinion (110). Acceleration of the pinion causes a change toward flat pitch. Deceleration of the pinion causes change toward feathered pitch. If the motor driving the pinion fails, a large deceleration occurs, driving the blades to a safe, feathered position.
Claims3
A pitch-change mechanism for aircraft propulsor blades, comprising:
- a) an axis of rotation of the propulsor blades;
- b) a motor rotating a gear wherein:
- i) said motor includes a rotating shaft directly engaging said gear;
- ii) said motor constantly rotates said gear even when blade pitch remains constant;
- iii) said motor is mounted to a stationary support in such a manner that said motor rotating shaft is offset relative to said propulsor blade axis of rotation;
- iv) said motor operates at maximum speed during aircraft landing when the propulsor blades are driven into a reverse pitch position;
- and
- c) gear train means for
- i) linking the gear with propulsor blades;
- ii) maintaining a constant blade pitch when gear speed is constant;
- iii) increasing blade pitch when gear speed decreases;
- and
- iv) decreasing blade pitch when gear speed increases.
The pitch-change mechanism of claim 13 wherein said gear train means comprises:
- a) a first ring gear which is fixed with respect to propulsor blades;
- b) a second ring gear which is movable with respect to the propulsor blades;
- c) a linkage which induces pitch-change of the propulsor blades in response to motion of the second ring gear with respect to the first ring gear;
- and
- d) means for inducing relative rotation between said first and second ring gears, wherein said inducing means comprises a plurality of compound planet gears supported by a rotatable carrier with each of said compound planet gears including a pair of gears of different tooth number.
Dependencies are inferred from the claim text.