Portal box assemblies and wet brake systems for vehicles

A portal box assembly for mounting a wheel of a vehicle having a drive axle, comprising:

• a portal box housing configured for mounting on the vehicle, the portal box housing having a housing interior;
• a lift kit and gear reduction system in the housing interior of the portal box housing, the lift kit and gear reduction system including:
• an input gear configured to be drivingly engaged by the drive axle on the vehicle;
• an output gear drivingly engaged by the input gear, the output gear disposed in offset or spaced-apart relationship to the input gear;
• and
• a spindle drivingly engaged by the output gear, the spindle configured to drivingly engage the wheel of the vehicle;
• and
• a wet brake system in the housing interior of the portal box housing, the wet brake system deployable between a brake release configuration and a braking configuration applying a braking force to the spindle, the wet brake system including:
• a rotatable cam plate disposed for axial movement with respect to the spindle;
• a pressure plate carried by the portal box housing in fixed relationship to the spindle and in spaced-apart relationship to the cam plate;
• at least one clamp plate disposed for axial movement with respect to the spindle between the cam plate and the pressure plate;
• at least one friction disk splined to the spindle between the at least one clamp plate and the pressure plate;
• at least one spring guide pin spanning the at least one clamp plate and the pressure plate;
• and
• a brake release spring on the at least one spring guide pin, the brake release spring normally biasing the at least one clamp plate in the brake release configuration;
• and
• a brake actuator engaging the cam plate of the wet brake system, the brake actuator configured to actuate the wet brake system between the brake release configuration and the braking configuration by rotation of the cam plate.

A portal box assembly for mounting a wheel of a vehicle having a drive axle, comprising:

• a portal box housing configured for mounting on the vehicle, the portal box housing including:
• a rear housing wall;
• a side housing wall extending from the rear housing wall;
• a housing cover on the side housing wall in offset or spaced-apart relationship to the rear housing wall;
• and
• a housing interior;
• a lift kit and gear reduction system in the housing interior of the portal box housing, the lift kit and gear reduction system including:
• an input gear configured to be drivingly engaged by the drive axle on the vehicle;
• an output gear drivingly engaged by the input gear, the output gear disposed in offset or spaced-apart relationship to the input gear;
• and
• a spindle drivingly engaged by the output gear, the spindle configured to drivingly engage the wheel of the vehicle;
• and
• a wet brake system in the housing interior of the portal box housing, the wet brake system deployable between a brake release configuration and a braking configuration applying a braking force to the spindle, the wet brake system including:
• a rotatable cam plate disposed for axial movement with respect to the spindle;
• a plurality of ball bearing openings in the cam plate, the plurality of ball bearings having a plurality of seat bevels, respectively;
• a plurality of ball bearings in the plurality of ball bearing openings, respectively, the plurality of ball bearings engaging the housing cover of the portal box housing;
• a pressure plate carried by the portal box housing in fixed relationship to the spindle and in spaced-apart relationship to the cam plate;
• an outer clamp plate adjacent to the cam plate, the outer clamp plate disposed for axial movement with respect to the spindle;
• first and second inner clamp plates between the outer clamp plate and the pressure plate, the first and second inner clamp plates disposed for axial movement with respect to the spindle;
• a first outer friction disk splined to the spindle between the outer clamp plate and the first inner clamp plate;
• a second friction disk splined to the spindle between the first inner clamp plate and the second inner clamp plate;
• a third friction disk splined to the spindle between the second inner clamp plate and the pressure plate;
• at least one spring guide pin spanning the outer clamp plate and the pressure plate;
• and
• a brake release spring on the at least one spring guide pin, the brake release spring normally biasing the outer clamp plate and the first and second inner clamp plates in the brake release configuration;
• a brake actuator engaging the cam plate of the wet brake system, the brake actuator configured to actuate the wet brake system between the brake release configuration and the braking configuration by rotation of the cam plate, whereby the plurality of ball bearings are displaced from the plurality of ball bearing openings, respectively, to the plurality of seat bevels, respectively, and apply the cam plate against the outer clamp plate against bias imparted by the brake release spring on the at least one spring guide pin;
• and
• brake cooling fluid in the housing interior of the portal box housing.

A wet brake system for mounting a wheel of a vehicle having a drive axle, comprising:

• a brake housing configured for mounting on the vehicle;
• a wet brake system in the brake housing, the wet brake system deployable between a brake release configuration and a braking configuration and configured to apply a braking force to the drive axle and including:
• a piston slidably disposed in the brake housing between a brake release position and a braking position;
• a pressure plate carried by the brake housing in fixed and spaced-apart relationship to the piston;
• at least one clamp plate disposed for axial movement between the piston and the pressure plate;
• and
• at least one friction disk configured to be splined to the drive axle between the at least one clamp plate and the pressure plate.