Trim ring gear for integrated drive generator

An integrated drive generator comprising:

• an input shaft for driving a carrier shaft in a differential, a carrier shaft, said carrier shaft driving two sets of planet gears, a first set of said planet gears for driving a first ring gear;
• a second set of said planet gears for driving a trim ring gear portion;
• said trim ring gear extending between a first end and a second end, and having an inner bore and an outer peripheral surface, a plurality of outer gear teeth on said outer peripheral surface and a plurality of inner gear teeth on an inner surface of said inner bore;
• wherein said outer teeth have a profile defined by roll angles at A-D and wherein said outer tooth roll angle at A is between 16.0 and 17.5°, said outer tooth roll angle B is between 17.5 and 19.0°, said outer tooth roll angle at C is between 22.0 and 23.5°, and said outer tooth roll angle at D is between 23.0 and 24.5°;
• and
• said inner gear teeth having a profile defined by inner tooth roll angles at A-D, with said inner tooth roll angle at A being between 31.5 and 33.0°, said inner tooth roll angle at B being between 30.0 and 31.5°, said inner tooth roll angle at C being between 25.5 and 27.0°, and said inner tooth roll angle at D being between 24.0 and 25.5°.

A method of replacing a trim ring gear in an integrated drive generator comprising the steps of:

• removing an existing trim ring gear from an integrated drive generator having an input shaft connected for driving a carrier shaft in a differential, said carrier shaft connected for driving two sets of planet gears, a first set of said planet gears for driving a first ring gear portion, which in turn is connected to drive a generator rotor, a second set of said planet gears for driving said existing trim ring gear;
• inserting a replacement trim ring gear for the existing trim ring gear, the replacement trim ring gear having a ring gear body extending between a first end and a second end, and having an inner bore and an outer peripheral surface, and a plurality of outer gear teeth on said outer peripheral surface and a plurality of inner gear teeth on an inner surface of said inner bore;
• said outer gear teeth having a profile defined by roll angles at A-D and wherein said outer tooth roll angle at A is between 16.0 and 17.5°, said outer tooth roll angle at B is between 17.5 and 19.0°, said outer tooth roll angle at C is between 22.0 and 23.5°, and said outer tooth roll angle at D is between 23.0 and 24.5°;
• and
• said inner gear teeth having a profile defined by inner tooth roll angles at A-D, with said inner tooth roll angle at A being between 31.5 and 33.0°, said inner tooth roll angle at B being between 30.0 and 31.5°, said inner tooth roll angle at C being between 25.5 and 27.0°, and said inner tooth roll angle at D being between 24.0 and 25.5°.