Planetary gearbox with integral service brake

• US 8,662,277 B2
• Filed: 12/22/2011
• Issued: 03/04/2014
• Est. Priority Date: 12/22/2011
• Status: Active Grant

• Current Assignee: Fairfield Manufacturing Company, Inc. (Dana, Inc.)
• Original Assignee: Fairfield Manufacturing Company, Inc. (Dana, Inc.)
• Inventors: Schoon, Benjamin Warren
• Primary Examiner(s): Holmes, Justin
• Assistant Examiner(s): MANLEY, MARK ALAN
• Application Number:
  US13/335,378
• Publication Number:
  US 20130161148A1
• Time in Patent Office: 803 Days
• Field of Search: 192/221.1
• US Class Current: 192/221.1
• CPC Class Codes: B60K 17/046 with planetary gearing having orbital motion
• CPC Class Codes: B60K 2007/0092 the motor axle being coaxial to the wheel axle
• CPC Class Codes: B60K 7/0015 the motor being hydraulic
• CPC Class Codes: B60T 1/062 acting on transmission parts
• CPC Class Codes: B60T 13/22 Brakes applied by springs or weights and released hydraulically
• CPC Class Codes: F16D 2121/06 for releasing a normally applied brake
• CPC Class Codes: F16D 55/38 mechanically actuated
• CPC Class Codes: F16D 65/186 with full-face force-applying member, e.g. annular
• CPC Class Codes: F16D 65/64 by means of direct linear adjustment
• CPC Class Codes: F16H 57/10 Braking arrangements

Abstract

A brake mechanism includes a fixed housing in which the brake mechanism substantially resides. A plate closes the fixed housing and includes a cylindrical portion extending partially within the fixed housing. A parking piston and a service piston are employed to act against a brake stack which includes a plurality of stators and rotors interleaved together. A wear adjuster is press-fit onto the cylindrical portion of the plate and engages the service piston during actuation of the service piston and compensates for wear of friction material from the rotors or stators such that the distance between the service piston and the brake stack is substantially the same during the life of the brake mechanism. If neither the service piston nor the parking piston engage the brake stack prohibiting rotation of the input drive, the planetary gear set drives the rotating output drive with respect to the fixed housing.

Claims

1. 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 plate;

said plate includes a flange portion and a cylindrical portion extending partially within said substantially cylindrical inner portion of said fixed housing;

said flange portion of said plate substantially encloses 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;

each of said rotors includes friction material affixed thereto;

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, a piston portion, a first shoulder, a second shoulder and a piston cavity;

said piston cavity of said service piston formed by said piston portion of said service piston and said cylindrical portion of said plate;

said service piston 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 includes;

a groove, a snap ring, said snap ring residing in said groove, a wall, a spring, said spring resides between said wall of said adjuster and said snap ring, and, said wear adjuster being generally cylindrically shaped;

said generally cylindrically shaped wear adjuster being press fit on said cylindrical portion of said plate;

said press-fit of said wear adjuster permitting said wear adjuster to move on said cylindrical portion of said plate in engagement with, and under the force of, said piston portion of said service piston;

during actuation and movement of said service piston to said another position;

said first shoulder of said piston portion of said service piston engages said wear adjuster repositioning said wear adjuster position to accommodate for loss of friction material;

said second shoulder of said service piston engages said spring compressing said spring between said second shoulder of 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 second shoulder of said service piston in a direction opposite said wall of said wear adjuster and repositions said service piston to a second position due to a loss of friction material;

said first shoulder of said service piston disengages said wear adjuster; 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.

2. A brake mechanism in combination with a planetary gear set as claimed in claim 1, wherein:

said spring of said wear adjuster is a wave spring.

3. A brake mechanism in combination with a planetary gear set as claimed in claim 1, wherein:

said cylindrical portion of said plate includes a mark thereon; and

, said wear adjuster is initially located on said mark or distally with respect to said mark and said brake stack.

4. A brake mechanism in combination with a planetary gear set as claimed in claim 1, further comprising:

a fluid source, said fluid source being pressurized;

said fixed housing includes a first passageway therethrough;

said plate includes a first passageway in communication with said first passageway of said fixed housing; and

,

said first passageway of said plate communicates with said piston cavity of said service piston pressurizing said cavity when said service piston is actuated.

5. A brake mechanism in combination with a planetary gear set as claimed in claim 1, further comprising:

a hydraulic oil source, said hydraulic oil source being pressurized;

said fixed housing includes a second passageway therethrough;

said second passageway includes a discharge end;

said discharge end of said second passageway includes an orifice therein; and

,

said hydraulic oil is communicated from said hydraulic oil pressure source through said second passageway and said orifice in said discharge end of said second passageway and into said substantially cylindrical inner portion of said fixed housing.

6. A brake mechanism in combination with a planetary gear set as claimed in claim 4, further comprising:

a hydraulic oil source, said hydraulic oil source being pressurized;

said fixed housing includes a second passageway therethrough;

said second passageway includes a discharge end;

said discharge end of said second passageway includes an orifice therein; and

,

said hydraulic oil is communicated from said hydraulic oil pressure source through said second passageway and said orifice in said discharge end of said second passageway and into said substantially cylindrical inner portion of said fixed housing.

7. A brake mechanism in combination with a planetary gear set as claimed in claim 5, further comprising:

said fixed housing includes an exterior;

a vacuum pump;

said fixed housing includes a third passageway;

said third passageway in communication with said vacuum pump; and

,

said third passageway communicating hydraulic oil from said substantially cylindrical inner portion of said fixed housing to said vacuum pump.

8. A brake mechanism in combination with a planetary gear set as claimed in claim 6, further comprising:

said fixed housing includes an exterior;

a vacuum pump;

said fixed housing includes a third passageway;

said third passageway in communication with said vacuum pump; and

,

said third passageway communicating hydraulic oil from said substantially cylindrical inner portion of said fixed housing to said vacuum pump.

9. A brake mechanism in combination with a planetary gear set as claimed in claim 1, further comprising:

said service piston is generally cylindrically shaped and concentric with said substantially cylindrical portion of said plate; and

,

said service piston slidingly engages said substantially cylindrical portion of said plate.

10. A brake mechanism in combination with a planetary gear set as claimed in claim 9, further comprising:

said brake mechanism includes a parking piston;

said parking piston being substantially cylindrically shaped and concentric with said service piston;

said parking piston includes a spring, a spring cavity and a brake stack engagement portion;

said spring resides in said spring cavity;

said spring operable between said flange portion of said plate and said spring cavity;

said parking piston slidingly engages said substantially cylindrical inner portion of said fixed housing;

a cavity end piece;

said fixed housing includes a shoulder;

said cavity end piece restrained from movement in one direction by said shoulder of said fixed housing;

said parking piston includes a pressure actuation surface;

said cavity end piece includes a pressure actuation surface;

said pressure actuation surface of said parking piston and said pressure actuation surface of said cavity end piece forming a pressure cavity therebetween; and

,

when said pressure cavity is pressurized said parking piston engagement portion is not in engagement with said brake stack, and, when said pressure cavity is not pressurized said parking piston engagement portion engages said brake stack and said plurality of stators and said plurality of rotors engage each other prohibiting rotation of said input drive with respect to said fixed housing.

11. A brake mechanism in combination with a planetary gear set as claimed in claim 8, further comprising:

said brake mechanism includes a parking piston;

said parking piston being substantially cylindrically shaped and concentric with said service piston;

said parking piston includes a spring, a spring cavity and a brake stack engagement portion;

said spring resides in said spring cavity;

said spring operable between said flange portion of said plate and said spring cavity;

said parking piston slidingly engages said substantially cylindrical inner portion of said fixed housing;

a cavity end piece;

said fixed housing includes a shoulder;

said cavity end piece restrained from movement in one direction by said shoulder of said fixed housing;

said parking piston includes a pressure actuation surface;

said cavity end piece includes a pressure actuation surface;

said pressure actuation surface of said parking piston and said pressure actuation surface of said cavity end piece forming a pressure cavity therebetween; and

,

when said pressure cavity is pressurized said parking piston engagement portion is not in engagement with said brake stack, and, when said pressure cavity is not pressurized said parking piston engagement portion engages said brake stack and said plurality of stators and said plurality of rotors engage each other prohibiting rotation of said input drive with respect to said fixed housing.

12. A brake mechanism in combination with a planetary gear set as claimed in claim 11, further comprising:

a hydraulic oil source, said hydraulic oil source being pressurized;

said fixed housing includes a fourth passageway therethrough; and

,

said fourth passageway in said fixed housing in communication with said hydraulic oil source and said parking piston pressure cavity.

13. A brake mechanism in combination with a planetary gear set as claimed in claim 11, further comprising:

said planetary gear set includes a motor shaft, an input shaft, and a coupling affixed to said motor shaft and to said input shaft transferring the rotary motion of said motor shaft to said input shaft;

said input shaft includes a sun gear;

said planetary gear set includes an input planetary stage and an output planetary stage;

a ring gear and a hub, said ring gear and said hub affixed together;

said input sun gear drives input planet gears which interengage with said ring gear;

and input planet carrier and an output sun gear;

said input planet carrier drives said output sun gear;

said output sun gear drives said output planet gears, said output planet gears mounted on said fixed housing and rotatable with respect to said fixed housing, and, said output planet gears interengaged with said ring gear and driving said ring gear and said hub with respect to said housing; and

,

bearings interposed between said hub and said fixed housing enabling said hub to rotate with respect to said fixed housing.

14. A brake mechanism in combination with a planetary gear set as claimed in claim 1, further comprising:

said planetary gear set includes a motor shaft, an input shaft, and a coupling affixed to said motor shaft and to said input shaft transferring the rotary motion of said motor shaft to said input shaft;

said input shaft includes a sun gear;

said planetary gear set includes an input planetary stage and an output planetary stage;

a ring gear and a hub, said ring gear and said hub affixed together;

said input sun gear drives input planet gears which interengage with said ring gear;

an input planet carrier and an output sun gear;

said input planet carrier drives said output sun gear;

said output sun gear drives said output planet gears, said output planet gears mounted on said fixed housing and rotatable with respect to said fixed housing, and, said output planet gears interengaged with said ring gear and driving said ring gear and said hub with respect to said housing; and

,

bearings interposed between said hub and said fixed housing enabling said hub to rotate with respect to said fixed housing.

19. A brake mechanism in combination with a planetary gear set as claimed in claim 1, wherein said another position changes each time said service piston is actuated.

15. 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.

16. A brake mechanism in combination with a planetary gear set as claimed in claim 15, wherein:

friction material resides on said rotors.

17. A brake mechanism in combination with a planetary gear set as claimed in claim 15, wherein:

friction material resides on said stators.

18. A brake mechanism in combination with a planetary gear set as claimed in claim 15, wherein said another position changes each time said service piston is actuated.

20. 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.

21. A method for operating a brake mechanism in combination with a planetary gear set as claimed in claim 20 wherein:

said another position changes each time said service piston is actuated due to loss of said friction material; and

,

said home position changes each time said service piston is actuated due to loss of said friction material.

22. 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, A_N, with N being a positive integer equal to the number of service piston actuations;

determining said another position A_N according to the wear of said brake stack, said service piston being in said another position, A_N, 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 A_N 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, I_N and spaced a distance, G, from said worn brake stack when it is next engaged by said service position.

23. A method for operating a brake mechanism in combination with a planetary gear set, as claimed in claim 22, wherein said wear of said brake stack is equal to I_N minus I_N-1, the change in position of said service piston.