Planetary gear system and air turbine starter
An apparatus for an air turbine starter for an engine. The air turbine starter includes a housing defining an inlet, an outlet, and a flow path extending between the inlet and the outlet for communicating a flow of gas there through. A turbine member is journaled within the housing and disposed within the flow path for rotatably extracting mechanical power from the flow of gas and having a turbine output shaft. The air turbine starter further includes a planetary gear system drivingly coupled with the turbine output shaft and including a sun gear, a ring gear mounted to the housing, and a set of planetary gears operably coupling the sun gear and the ring gear with the sun gear is coupled to the turbine output shaft.
1. An air turbine starter for an engine, comprising:
a housing defining an inlet, an outlet, and a flow path extending between the inlet and the outlet for communicating a flow of gas there through;
a turbine member journaled within the housing and disposed within the flow path for rotatably extracting mechanical power from the flow of gas and having an output;
a planetary gear system drivingly coupled with the output, the planetary gear system comprising:
a sun gear,
the ring gear comprising a flexible ring gear with a radially inner portion defining a gear face and a radially outer portion mounted to the housing and having a set of slots located therebetween, the flexible ring gear including a set of bridges located between the set of slots and coupling the radially inner portion and the radially outer portion, and at least one bumper separate from the set of bridges extending from one of the radially inner portion or the radially outer portion into a slot of the set of slots where the bumper engages the other of the of the radially inner portion or the radially outer portion during abnormal loading, and
a set of planetary gears configured to mesh with the gear face and operably coupling the sun gear and the ring gear where the sun gear is coupled to an input; and
a drive shaft configured to be operably coupled to and rotate with the engine;
wherein the planetary gear system transfers torque from the output to the drive shaft and where the flexible ring gear is configured to distribute loading among interfaces between the ring gear and the set of planetary gears.
2. The air turbine starter of claim 1 wherein at least one bridge of the set of bridges is configured to deflect under loading.
3. The air turbine starter of claim 2 wherein the at least one bridge is configured to deflect without closing a slot of the set of slots during normal loading of the planetary gear system.
4. The air turbine starter of claim 3 wherein the at least one bridge is configured to deflect to close at least a portion of the slot during abnormal loading of the planetary gear system.
5. The air turbine starter of claim 4 , wherein when the bumper engages the other of the of the radially inner portion or the radially outer portion the at least a portion of the slot becomes closed.
6. The air turbine starter of claim 1 wherein the at least one bumper is adjacent the at least one bridge.
7. The air turbine starter of claim 6 wherein the at least one bumper comprises at least two bumpers adjacent the at least one bridge.
8. The air turbine starter of claim 7 wherein a first bumper on a first side of the at least one bridge extends from the radially inner portion and a second bumper on a second side of the at least one bridge extends from the radially outer portion.
9. The air turbine starter of claim 1 , wherein the output is a carrier shaft and the input is a turbine shaft.
10. A planetary gear system, comprising:
a sun gear;
a set of planetary gears configured to mesh with the sun gear;
a flexible ring gear including a radially inner portion defining a gear face configured to mesh with the set of planetary gears and a radially outer portion and where the radially inner portion is spaced from the radially outer portion via a set of slots, where the flexible ring gear includes a set of bridges located between the set of slots and coupling the radially inner portion and the radially outer portion; and
at least one bumper extending from one of the radially inner portion or the radially outer portion into a slot of the set of slots proximate and separate from the set of bridges at a location where the bridge meets the radially inner portion or the radially outer portion where the bumper engages the other of the of the radially inner portion or the radially outer portion during abnormal loading;
wherein at least one bridge of the set of bridges is configured to deflect under loading from at least one of the set of planetary gears.
11. The planetary gear system of claim 10 wherein the at least one bridge is configured to deflect without closing a slot of the set of slots during normal loading of the planetary gear system.
12. The planetary gear system claim 10 wherein the at least one bridge is configured to deflect to close at least a portion of the slot during abnormal loading of the planetary gear system.
13. The planetary gear system of claim 12 , wherein when the bumper engages the other of the of the radially inner portion or the radially outer portion the at least a portion of the slot becomes closed.
14. The planetary gear system of claim 13 , wherein the at least one bumper is adjacent the at least one bridge.
15. The planetary gear system of claim 14 , wherein the at least one bumper comprises a first bumper on a first side of the at least bridge extends from the radially inner portion and a second bumper on a second side of the at least bridge extends from the radially outer portion.
16. A planetary gear system, comprising:
a sun gear operably coupled to an input;
a set of planetary gears configured to mesh with the sun gear;
a flexible ring gear operably coupled to an output and including a radially inner portion defining a gear face configured to mesh with the set of planetary gears and a body defining a radially outer portion mounted to a gear box where a cantilever axially projects from the body and at least partially defines the radially inner portion;
wherein the cantilever is configured to flex and deflect under loading and absorb eccentricity from movement of at least one of the planet gears of the set of planetary gears.