Hydraulically actuated brake assembly for an off-highway implement

A hydraulically actuated brake assembly for an off-highway implement, comprising:

• a shaft mounted for rotation about a fixed axis in a stationary housing;
• an actuator assembly and a series of annular and intermixed friction brake members operative to effect a braking action on said shaft in response to said actuator assembly applying a force thereto, with some of said brake members rotating with the shaft while others remain stationary relative to said housing, each annular brake member having wetted brake surfaces on opposite sides thereof, said actuator assembly including a first annular brake piston that combines with said housing to define a first fluid receiving cavity, said first piston being movable through a path of travel along the axis of said shaft between a released position, wherein a fixed clearance is provided between said first piston and the brake members thereby relieving the brake force on said shaft, and an engaged position, wherein said first piston applies a force against said brake members to impart a braking action to said shaft, and a resiliently biased second annular brake piston that combines with said housing to define a second fluid receiving cavity and which is mounted in axial alignment with and for axial movement toward said first piston for yieldingly moving said first piston to apply a force against said brake members when the fluid pressure in said second cavity is at a lower pressure and for moving away from said first piston when the fluid pressure in said second cavity is adequately increased to relieve the braking force applied to the brake members and thereby the shaft;
• and
• a series of self-compensating brake release assemblies peripherally disposed about said actuator assembly for urging said first piston into a released position wherein said fixed clearance is provided between said first piston and the brake members, each brake release assembly comprising a mounting member that extends axially from one of the pistons of said actuator assembly, a spring mechanism arranged coaxially about and radially from said mounting member for yieldingly moving said first piston toward its released position, and a spring retainer assembly for captively maintaining the spring mechanism between opposite ends thereof and in operative association with a respective mounting member while permitting compression of said spring mechanism in response to axial movement of said fast piston toward an engaged position, and wherein the spring retainer assembly is axially movable along the length of the mounting member to compensate for wear of the friction brake surfaces on the brake members while maintaining said fixed clearance between the fast piston and the brake members following the return of said first piston to its released position.

A hydraulically actuated brake assembly for an off-highway implement, comprising:

• a shaft mounted for rotation about a fixed axis in a stationary housing;
• an actuator assembly and a plurality of annular and intermixed friction brake members operative to effect a braking action on said shaft in response to said actuator assembly applying a force to said brake members, with alternate friction brake members being adapted to rotate with the shaft while other friction brake members remain stationary relative to said housing, each annular brake ring having wetted brake surfaces on opposite sides thereof, said actuator assembly including a first annular brake piston that combines with said housing to define a first fluid receiving cavity and that is mounted in said housing for axial movement along a path of travel toward and away from said brake members, springs operatively associated with and for moving said first piston away from a released position and into an engaged position whereat said first piston is operatively associated with and forces said brake members to apply a braking action to said shaft as long as the fluid pressure in said first fluid receiving cavity is less than the pressure applied to the fast piston by said springs, and wherein said first piston is retained in said released position as long as the fluid pressure in said first fluid receiving cavity is greater than the pressure exerted by said springs against said first piston, a second annular brake piston that combines with said housing to define a second fluid receiving cavity, said second piston being coaxially mounted in said housing about said axis and for movement along a path of travel between a released position, wherein a fixed clearance is provided between said second piston and said brake members thereby relieving the braking force applied to said shaft, and an engaged position, wherein said second piston applies a force against said brake members to impart a braking action to said shaft, said second piston being operatively disposed between said first piston and said brake members for effecting a braking action on said shaft either through said first piston being moved into its engaged position or through selective pressurization of said second fluid receiving cavity whereby effecting movement of the second piston toward said brake members independent of the action of said first piston;
• and
• a series of self-compensating brake release assemblies peripherally disposed about said actuator assembly for urging said second piston into its released position wherein said fixed clearance is provided between said second piston and the brake members, each release assembly comprising a mounting member that extends axially from one of the pistons of said actuator assembly, a spring mechanism arranged coaxially about and radially from said mounting member for yieldingly moving said second piston toward its released position, and a spring retainer assembly for captively maintaining the spring mechanism between opposite ends thereof and in operative association with the mounting member while permitting compression of said spring mechanism in response to axial movement of said second piston toward an engaged position, and wherein the spring retainer assembly axially moves along the length of the mounting member to compensate for wear of the friction brake surfaces on the brake members while maintaining said fixed clearance between the second piston and the brake members following the return of said second piston to its released position.

A hydraulically actuated brake assembly for an off-highway implement including a transmission having a housing, comprising:

• a transmission output shaft mounted for turning movement about a fixed axis in a stationary housing affixed to the transmission housing;
• an actuator assembly and a pack of annular and intermixed friction plates operative to effect a braking action to said transmission output shaft in response to said actuator assembly applying a force to said brake members, with some of friction plates being adapted to rotate with the shaft while others remain stationary relative to said housing, each annular friction plate having wetted brake surfaces on opposite sides thereof, and wherein a surface on the transmission housing serves as a reaction surface for the annular friction plates, said actuator assembly including a first annular brake piston that combines with said stationary housing to define a first fluid receiving cavity, said first piston being movable along the axis of said shaft between a released position, wherein a fixed clearance is provided between said first piston and the brake members thereby relieving the brake force on said shaft, and an engaged position, wherein said first piston applies a force against said brake members to impart a braking action to said shaft, and a resiliently biased second annular brake piston that combines with said stationary housing to define a second fluid receiving cavity and which is mounted in axial alignment with and for axial movement toward said first piston for yieldingly moving said first piston to apply a force against said brake members when the fluid pressure in said second cavity is at a lower pressure and for moving away from said first piston when the fluid pressure in said second cavity is adequately increased to relieve the braking force applied to the brake members and thereby the shaft;
• and
• a series of self-compensating brake release assemblies peripherally disposed about said actuator assembly for urging said first piston into a released position wherein said fixed clearance is provided between said first piston and the brake members, each brake release assembly comprising a mounting member that extends axially from one of the pistons of said actuator assembly, a spring mechanism arranged coaxially about and radially from said mounting member for yieldingly moving said first piston toward its released position, and a spring retainer assembly for captively maintaining the spring mechanism between opposite ends thereof and in operable association with the mounting member while permitting compression of said spring mechanism in response to axial movement of said first piston toward an engaged position, and wherein the spring retainer assembly axially moves along the length of the mounting member to compensate for wear of the friction brake surfaces on the brake members while maintaining said fixed clearance between the first piston and the brake members following the return of said first piston to its released position.

A hydraulically actuated brake assembly for yielding both a service brake function and a park brake function to an off-highway implement having a transmission including a housing, comprising:

• a stationary housing mounted in an aligned and surrounding relationship relative to an output shaft of the transmission;
• an actuator assembly and a pack of annular friction brake members coaxially arranged about the shaft and operative to effect a braking action on said transmission shaft in response to said actuator assembly applying a force to said brake members, said friction brake members being arranged in an intermixed and stacked relationship relative to each other with alternating friction brake members rotating with the transmission shaft while others remain stationary relative to said housing, each annular brake member having wetted brake surfaces on opposite sides thereof, and wherein the transmission housing serves as a reaction surface for the annular brake members, said actuator assembly including an annular park brake piston that combines with said stationary housing to define a first fluid receiving cavity and that is mounted in said stationary housing for axial movement along said shaft toward and away from said brake members, a series of springs operatively associated with and for moving said park brake piston away from a released position thereby relieving the braking force applied to said transmission shaft and into an engaged position whereat said park brake piston is operatively associated with and forces said brake members to apply a braking action to said transmission shaft as long as the fluid pressure in said first fluid receiving cavity is less than the pressure applied to the park brake piston by said springs, and wherein said park brake piston is retained in said released position as long as the fluid pressure in said fist fluid receiving cavity is greater than the pressure exerted by said springs against said park brake piston, an annular service brake piston that combines with said stationary housing to define a second fluid receiving cavity, said service brake piston being coaxially mounted in said stationary housing about and for movement along said shaft between a released position wherein a fixed clearance is provided between said service brake piston and said brake members thereby relieving the braking force applied to said transmission shaft and an engaged position wherein said service brake piston applies a force against said brake members to impart a braking action to said transmission shaft, said service brake piston being operatively disposed between said park brake piston and said brake members for effecting a braking action on said transmission shaft either through said park brake piston being moved from its released position or through selective pressurization of said second fluid receiving cavity whereby effecting movement of the service brake piston toward said brake members independent of the action of said park brake piston;
• and
• a series of self-compensating brake release assemblies peripherally disposed about said actuator assembly for normally urging said service brake piston into its released position wherein said fixed clearance is provided between said service brake piston and the brake members, each release assembly comprising a mounting member that extends axially from one of the pistons of said actuator assembly, a spring mechanism arranged coaxially about and radially from said mounting member for yieldingly moving said service brake piston toward its released position, and a spring retainer assembly for captively maintaining the spring mechanism between opposite ends thereof and in operative association with a respective mounting member while permitting compression of said spring mechanism in response to axial movement of said service brake piston toward an engaged position, and wherein the spring retainer assembly axially shifts along the length of the mounting member under the influence of said service piston to compensate for wear of the friction broke surfaces on the brake members while maintaining said fixed clearance between the service brake piston and the brake members following the return of said service brake piston to its released position.

A hydraulically actuated brake assembly for an off-highway implement, comprising:

• a stationary housing that surrounds a turning shaft to which a braking action is to be applied by the brake assembly;
• an actuator assembly and a pack of intermixed brake plates, with some of said brake plates being adapted to turn with the shaft while others remain in nonrotatable association with the housing, each brake plate having wetted friction brake surfaces on opposite sides thereof, said actuator assembly including an annular brake piston that combines with said housing to define a fluid receiving cavity, said piston being movable along an axis of the shaft between a released position, wherein a fixed clearance is provided between the piston and the brake plates thereby relieving the braking force on said shaft, and an engaged position, wherein said piston applies a force against the brake plates to impart a braking action to the brake plates and thereby to the shaft;
• and
• a brake release mechanism including a plurality of self-compensating brake release assemblies peripherally disposed about said actuator assembly for urging said brake piston toward its released position, each brake release assembly comprising a mounting member that extends generally parallel to the shaft, a spring mechanism arranged coaxially about and radially from said mounting member for yieldingly moving said brake piston toward its released position, and a spring retainer assembly for captively entrapping the spring mechanism between first and second axially spaced surfaces disposed at opposite ends of said spring mechanism, with said spring retainer assembly being arranged in operable association with the mounting member while permitting compression of said spring mechanism in response to axial movement of said brake piston toward an engaged position, and wherein the spring retainer assembly including said first and second surfaces being axially movable along the length of said mounting member to compensate for wear of the friction brake surfaces on the brake members while maintaining the fixed clearance between the brake piston and the brake members following the return of the brake piston to its released position.