Planetary gearbox with integral service brake

A brake mechanism in combination with a planetary gear set, comprising:

• a fixed housing, said fixed housing includes a substantially cylindrical inner portion, and, said brake mechanism residing substantially within said substantially cylindrical inner portion of said fixed housing;
• a cylindrical member extending partially within said substantially cylindrical inner portion of said fixed housing;
• said brake mechanism includes a coupling;
• a motor shaft driven by a motor;
• said planetary gear set includes a rotating input drive and a rotating output drive;
• said motor shaft affixed to said coupling and said coupling affixed to said rotating input drive;
• said brake mechanism includes a service piston and a brake stack;
• said brake stack includes a plurality of stators and a plurality of rotors, said plurality of rotors are interleaved with said stators, and, each of said plurality of rotors resides interleaved between a pair of proximate stators;
• said rotors are affixed to said coupling and rotate therewith;
• said stators are affixed to said fixed housing;
• said rotating input drive imparting rotating input motion to said planetary gear set driving said rotating output drive of said planetary gear set, said output drive of said planetary gear set being rotatable with respect to said fixed housing;
• said service piston includes a brake stack engagement portion,
• said service piston and said brake stack engagement portion thereof movable between an initial home position and another position;
• said service piston being in said initial home position wherein said service piston is not actuated, and, said plurality of rotors and said plurality of stators are not engaged with each other;
• said another position being determined according to the wear of said brake stack, said initial another position being determined with no wear of said brake stack and before any actuation of said service piston;
• said service piston being in said another position when said service piston is actuated and said engagement portion of said service piston engages said brake stack forcing said plurality of rotors and said plurality of stators into engagement with each other;
• said engagement portion of said service piston spaced apart from said brake stack by a distance, G, when said engagement portion of said service piston is in said initial home position;
• said distance, G, being the distance between said engagement portion of said service piston in said initial home position and said initial another position;
• a wear adjuster, said wear adjuster being generally cylindrically shaped;
• said generally cylindrically shaped wear adjuster being press fit on said cylindrical member;
• said press-fit of said wear adjuster permitting said wear adjuster to move on said cylindrical member in engagement with, and under the force of, said service piston;
• said wear adjuster includes:
• a groove and a snap ring residing in said groove, and, a wall;
• said wear adjuster includes a spring, said spring resides between said wall of said adjuster and said snap ring;
• during actuation and movement of said service piston to said another position:
• said service piston engages said wear adjuster repositioning said wear adjuster to said another position to accommodate for loss of friction material;
• said service piston engages said spring compressing said spring between said service piston and said wall of said wear adjuster;
• and, said engagement portion of said service piston forcefully engages said brake stack wherein said plurality of stators and said plurality of rotors engage each other prohibiting rotation of said input drive with respect to said fixed housing;
• upon discontinuation of service piston actuation:
• said spring urges said service piston in a direction opposite said wall of said wear adjuster and repositions said service piston to second position due to loss of friction material;
• said service piston disengages said wear adjuster and said service piston is repositioned to said second position;
• and, said engagement portion of said service piston is returned to said second position and is spaced a distance, G, from said brake stack when it is next engaged.

A method for operating a brake mechanism in combination with a planetary gear set, comprising the steps of:

• arranging a brake stack within a housing, said brake stack includes a plurality of stators and a plurality of rotors, said brake stack having a thickness when said plurality of stators and rotators are in engagement with each other;
• affixing said rotors to a rotating input drive such that said rotors rotate with said rotating input drive;
• affixing said stators to a fixed housing;
• interleaving a plurality of rotors interleaved with said stators such that each of said plurality of rotors resides interleaved between a pair of proximate stators;
• positioning a generally cylindrically shaped service piston concentrically around said cylindrical member;
• press fitting a wear adjuster on a cylindrical member at a desired location, said wear adjuster includes:
• a groove, a snap ring residing in said groove, a wall, a spring, said spring resides between said wall of said adjuster and said snap ring, said wear adjuster being generally cylindrically shaped, said press-fit of said wear adjuster permitting said wear adjuster to move on said cylindrical member in engagement with, and under the force of, said service piston;
• engaging said service piston with said spring of said wear adjuster defining the home position of said service piston;
• defining an initial home position of said service piston before actuation of said service piston;
• determining said initial another position of said service piston based upon said brake stack thickness;
• rotating an input drive imparting rotating input motion to said planetary gear set driving said rotating output drive of said planetary gear set, said output drive of said planetary gear set being rotatable with respect to said fixed housing;
• said initial home position of said service piston is spaced apart from said brake stack by a distance, G, said distance, G, being the distance between said service piston in said initial home position and said service piston in said initial another position;
• moving said service piston between an initial home position and another position, said another position of said service piston being determined according to the wear of said brake stack, and, said service piston being in said another position when said service piston is actuated and said service piston engages said brake stack forcing said plurality of rotors and said plurality of stators into engagement with each other;
• during actuation and movement of said service piston to said another position:
• said service piston engages said wear adjuster repositioning said wear adjuster;
• said service piston engages said spring compressing said spring between said service piston and said wall of said wear adjuster;
• said service piston moves to said another position;
• and, said service piston forcefully engages said brake stack wherein said plurality of stators and said plurality of rotors engage each other prohibiting rotation of said input drive with respect to said fixed housing;
• and,
• discontinuing actuation of said service piston results in:
• said spring urges said service piston in a direction opposite said wall of said wear adjuster and repositions said service piston to a new home position;
• said service piston disengages said wear adjuster;
• and, said service piston is and is spaced a distance, G, wherein G is the distance from the new home position of said service piston to said another position of said service piston at the end of the previous brake actuation.

A method for operating a brake mechanism in combination with a planetary gear set, comprising the steps of:

• arranging a brake stack within a housing, said brake stack includes a plurality of stators and a plurality of rotors;
• affixing said rotors to a rotating input drive such that said rotors rotate with said rotating input drive;
• affixing said stators to a fixed housing;
• interleaving a plurality of rotors interleaved with said stators such that each of said plurality of rotors resides interleaved between a pair of proximate stators, said rotors or stators include friction material affixed thereto;
• press-fitting a wear adjuster on a cylindrical member to a pre-set location on said cylindrical member, said wear adjuster includes:
• a groove, a snap ring residing in said groove, a wall, a spring, said spring resides between said wall of said adjuster and said snap ring, said wear adjuster being generally cylindrically shaped, said press-fit of said wear adjuster permitting said wear adjuster to move on said cylindrical member in engagement with, and under the force of, said service piston;
• engaging and positioning said service piston with said spring of said wear adjuster to an initial position, I0;
• spacing apart said service piston from said brake stack by a distance, G, according to said pre-set location of said wear adjuster on said cylindrical member and the brake stack thickness when said rotors and stators are in engagement,
• rotating an input drive imparting rotating input motion to said planetary gear set driving said rotating output drive of said planetary gear set, said output drive of said planetary gear set being rotatable with respect to said fixed housing;
• moving said service piston between said initial position, I0, wherein said service piston abuts said spring of said wear adjuster, and another position, AN, with N being a positive integer equal to the number of service piston actuations;
• determining said another position AN according to the wear of said brake stack, said service piston being in said another position, AN, when said service piston is actuated and said service piston engages said brake stack forcing said plurality of rotors and said plurality of stators into engagement with each other;
• actuating and moving said service piston to said another position AN results in:
• said service piston engaging said wear adjuster repositioning said wear adjuster;
• said service piston engaging said spring compressing said spring between said service piston and said wall of said wear adjuster;
• and, said service piston forcefully engaging said brake stack wherein said plurality of stators and said plurality of rotors engage each other prohibiting rotation of said input drive with respect to said fixed housing;
• and,
• discontinuing actuation of said service piston results in:
• said spring urging said service piston in a direction opposite said wall of said wear adjuster, said service piston disengaging said wear adjuster, and, said service piston being repositioned to a position, IN and spaced a distance, G, from said worn brake stack when it is next engaged by said service position.