Variable wobbler plate for integrated drive generator

An integrated drive generator comprising:

• an input shaft connected to a differential, said differential connected to a generator, and said differential also being connected to a hydraulic unit, said hydraulic unit including a variable wobbler plate and a fixed wobbler plate, and each of said wobbler plates being associated with a set of pistons, and a fixed shaft associated with said fixed shaft plate, and connected to rotate with a cylinder block associated with said fixed wobbler plate, and said fixed shaft including a spline connection to drive a fixed block shaft, said fixed block shaft having gear teeth engaged to a ring gear in said differential;
• and
• said variable wobbler plate having a body with a cam surface on one face and an opposed non-working surface on an opposed face, a stub shaft extending at one side of said body and a pivot shaft extending at a diametrically opposed location on said body from said stub shaft, said pivot shaft having a smaller diameter portion and a larger diameter portion with said larger diameter portion spaced towards said stub shaft from said smaller diameter portion, and said smaller diameter portion having a generally cylindrical outer periphery with a flat over a limited circumferential extent and a diameter to opposed portions of said generally cylindrical portion defining a first distance, and a second distance being defined from an end of said smaller diameter portion spaced furthest from said stub shaft to an end of said larger diameter portion spaced closest to said stub shaft and measured along a central axis of said pivot shaft and defining a second distance, and a ratio of said first distance to said second distance being between 0.60 and 0.75.

A method of replacing a wobbler plate in an integrated drive generator comprising the steps of:

• a) removing an existing wobbler plate from an integrated drive generator having an input shaft connected to a differential, said differential connected to a generator, and said differential also being connected to a hydraulic unit, said hydraulic unit including said existing variable wobbler plate and a fixed wobbler plate, and each of said wobbler plates being associated with a set of pistons, and a fixed shaft associated with said fixed wobbler plate, and connected to rotate by a cylinder block associated with said fixed wobbler plate, and said fixed shaft including a spline connection to drive a fixed block shaft, said fixed block shaft having gear teeth engaged to a ring gear in said differential;
• and
• b) replacing said existing variable wobbler plate with a replacement variable wobbler plate having a body with a cam surface on one face and an opposed non-working surface on an opposed face, a stub shaft extending at one side of said body and a pivot shaft extending at a diametrically opposed location on said body from said stub shaft, said pivot shaft having a smaller diameter portion and a larger diameter portion with said larger diameter portion spaced towards said stub shaft from said smaller diameter portion, and said smaller diameter portion having a generally cylindrical outer periphery with a flat over a limited circumferential extent and a diameter to opposed portions of said generally cylindrical portion defining a first distance, and a second distance being defined from an end of said smaller diameter portion spaced furthest from said stub shaft to an end of said larger diameter portion spaced closest to said stub shaft and measured along a central axis of said pivot shaft and defining a second distance, and a ratio of said first distance to said second distance being between 0.60 and 0.75.