Variable speed transmission and related methods

Patent metadata

Field	Value
Publication number	US-11459098-B2
Application number	US-201916698742-A
Country	US
Kind code	B2
Filing date	Nov 27, 2019
Priority date	Nov 27, 2019
Publication date	Oct 4, 2022
Grant date	Oct 4, 2022

Abstract

A variable speed transmission is disclosed, with a transmission apparatus which includes a planetary gear set having a ring gear and a sun gear. The variable speed transmission further includes a primary engine for powering the sun gear, a braking device engaging the ring gear, and a controller configured to alter the rotational speed of the ring gear by adjusting the braking device.

First claim

What is claimed is:

1. A variable speed transmission system, comprising:
a first transmission apparatus including a planetary gear set having a ring gear and a sun gear,
a primary engine for powering the sun gear,
a braking device engaging the ring gear, and
a controller configured to alter the rotational speed of the ring gear by adjusting the braking device,
wherein the braking device includes a virtual elliptical drive and a positive engagement brake, the positive engagement brake preventing rotation of the ring gear when engaged.

2. The system of claim 1 , wherein the planetary gear set includes a set of planet gears that orbit the sun gear in a first rotational direction, the braking device having a neutral mode and a drive mode, wherein the ring gear is stationary when the braking device is in the neutral mode, and the braking device driving the ring gear in a second rotational direction, opposite from the first rotational direction, when the braking device is in the drive mode.

3. The system of claim 2 , wherein the virtual elliptical drive includes a pair of wobble plates that nutate when the braking device is in the drive mode.

4. The system of claim 1 , wherein the ring gear has an outer circumferential side, and a first set of teeth on the outer circumferential side, the braking device including an output gear engaging the first set of teeth.

5. The system of claim 4 , wherein the braking device includes a plurality of virtual elliptical drives, each virtual elliptical drive including an output gear engaging the first set of teeth on the ring gear.

6. The system of claim 4 , wherein the ring gear has a second set of teeth on an internal side for engaging a set of planet gears inside the ring gear.

7. The system of claim 1 , wherein the braking device includes an electromagnet.

8. The system of claim 1 , wherein the transmission apparatus is configured for driving a propulsor on a rotorcraft.

9. The system of claim 1 , further including a second transmission apparatus having a second virtual elliptical drive, wherein the second transmission apparatus is configured to rotate the first transmission apparatus.

10. The system of claim 1 , wherein the transmission system has an output speed range between 50% and 110% of a rated output speed of the primary engine and the transmission apparatus.

11. A rotorcraft, comprising:
a main body portion,
an engine contained in the main body portion,
a first transmission assembly connected to the engine, including a planetary gear set having a planetary ring structure engaging a set of planet gears that orbit a sun gear in a first rotational direction, and
a first virtual elliptical drive engaging teeth on an outer circumferential side of the planetary ring structure, and configured to adjust a rotational speed of the planetary ring structure,
wherein the engine and first transmission assembly are configured to drive an aft propulsor.

12. The rotorcraft of claim 11 , wherein the virtual elliptical drive includes a pair of nutating wobble plates.

13. The rotorcraft of claim 11 , wherein the first virtual elliptical drive has a neutral mode and a drive mode, wherein the planetary ring structure is stationary when the first virtual elliptical drive is in the neutral mode, and the first virtual elliptical drive drives the planetary ring structure in a second rotational direction, opposite from the first rotational direction, when the first virtual elliptical drive is in the drive mode.

14. The rotorcraft of claim 11 , wherein the rotorcraft is a helicopter, and the engine and first transmission assembly are configured to drive a shaft-driven main lift rotor of the helicopter.

15. The rotorcraft of claim 11 , further comprising:
a second transmission assembly including a second virtual elliptical drive, the second transmission assembly configured to rotate the first transmission assembly.

16. The rotorcraft of claim 11 , wherein the first virtual elliptical drive is one of a plurality of virtual elliptical drives, each virtual elliptical drive including an output gear engaging the teeth on the outer circumferential side of the planetary ring structure.

17. A method of varying speed of a planetary gear system, comprising:
driving planet gears to orbit a sun gear in a first rotational direction, the planet gears engaging a stationary ring gear, and
varying the orbital speed of the planet gears by driving the ring gear in a second rotational direction, opposite from the first rotational direction,
engaging a brake to mechanically lock the ring gear, wherein the ring gear is driven by one or more virtual elliptical drives.

18. The method of claim 16 , wherein each of the one or more virtual elliptical drives has a pair of wobble plates that nutate during the step of varying the orbital speed of the planet gears.

19. The method of claim 16 , further comprising:
electromagnetically driving the one or more virtual elliptical drives.

20. The method of claim 16 , wherein each of the one or more virtual elliptical drives includes an output gear that engages teeth on an outer circumferential side of the ring gear.

Assignees

• Boeing Co

Inventors

• Heath Gregory Forrest
• Slaughter Stephen C
• Atmur Robert J
• Sargent William Patrick
• Shen Tse-Hua
• Owen Bryant Scott
• Murphy Alice A

Classifications

• F16H2200/2005

  with one sets of orbital gears · CPC title

• F16H3/724

  using externally powered electric machines · CPC title

• B64C27/82 Primary

  characterised by the provision of an auxiliary rotor or fluid-jet device for counter-balancing lifting rotor torque or changing direction of rotorcraft · CPC title

• B64D35/04

  characterised by the transmission driving a plurality of propellers or rotors · CPC title

• B64C2027/125

  including toroidal transmissions, e.g. of the CVT type · CPC title