Speed changing gearbox with dual path input

Abstract

Contemplated gearboxes provide first and second power-balanced paths in which a speed changer is configured to operate with only one path. Most preferably, the gearbox includes a friction clutch and a sprag clutch arranged such that, together with a layshaft and spur-gear differential, gear shifting can be done while transmitting power.

Description

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a top view of a rotorcraft having left and right rotors, engines, and gearboxes, all potentially coupled together.

FIG. 2 is a schematic arrangement of a divided input, load-sharing arrangement of gears with a friction clutch and an over-running clutch.

FIG. 3 is an isometric drawing of the intermeshing planet gears of a dual-input, planet-carrier output differential.

Claims

1. A speed changing gearbox having first and second independently and concurrently operational drive paths for transmission of torque.

2. The gearbox of claim 1, further comprising a gearset and associated clutches that are configured to cooperate in a manner to provide a high output speed and alternatively a low output speed.

3. The gearbox of claim 1, further comprising a friction clutch operatively positioned to allow sustained drive torque during a speed changing event.

4. The gearbox of claim 1, further comprising a clutch operatively positioned along the second drive path.

5. The gearbox of claim 4, further comprising a differential that exposes the clutch to a proportion of the torque when the first drive path is carrying a balance of the torque.

6. The gearbox of claim 1, further comprising an input drive connector having a first axis of rotation and an output drive connector having a second axis of rotation, and the first and second axes of rotation are not coaxial.

7. An aircraft having first and second engines powering first and second rotors through first and second gearboxes according to claim 1, respectively.

8. The aircraft of claim 7, further comprising a mechanical link between the gearboxes such that both rotors continue to receive power upon failure of the first engine.

9. The aircraft of claim 7, wherein each of the gearboxes includes an over-running clutch.