Brake system for mine trucks

A piece of equipment comprising:

• a frame;
• a shaft rotatable relative to the frame;
• and
• a brake system comprising:
• a series of rotors and stators, including a plurality of rotors operatively coupled to the shaft and rotatable with the shaft relative to the frame, and a plurality of stators operatively coupled to the frame and fixed against rotation relative to the frame;
• a service brake system including an annular service piston positioned to extend continuously around the series of rotors and stators such that pressurization of fluid in the service brake system acts on the service piston opposite the series of rotors and stators and drives the service brake piston to continuously engage around the series of rotors and stators such that the series of rotors and stators are compressed together and thereby create braking torque;
• and
• a parking brake system including an annular parking piston positioned to extend continuously around the series of rotors and stators, at least one parking piston spring creating a parking piston spring bias acting on the parking piston to drive the parking piston to continuously engage around the series of rotors and stators such that the rotors and stators are compressed together and thereby create braking torque,
• wherein the service piston is configured for nesting with the parking piston such that the service piston is positioned between the parking piston and the series of rotors and stators,
• wherein the parking piston and the service piston are configured to continuously engage together around the series of rotors and stators to thereby create the braking torque,
• wherein at least one of the rotors or stators comprises carbon-carbon,
• wherein the shaft includes a longitudinal axis about which the rotors are configured to rotate, the rotors and stators being movable along the longitudinal axis between a free position in which the rotors and stators are spaced apart from each other and a braking position in which the rotors and stators are clamped together,
• wherein the service piston is positioned between the parking piston and the series of rotors and stators such that a line parallel to the longitudinal axis intersects each of the parking piston, the service piston, and the series of rotors and stators, and
• wherein at least one service piston spring creating a service piston spring bias on the service piston is positioned coaxially with the at least one parking piston spring creating the parking piston spring bias acting on the parking piston.

A brake system for a piece of equipment having a frame and a shaft rotatable relative to the frame, the brake system comprising:

• a series of rotors and stators, including a plurality of rotors configured to be operatively coupled to the shaft and configured to rotate with the shaft relative to the frame, and a plurality of stators configured to be operatively coupled to the frame and configured to be fixed against rotation relative to the frame;
• a service brake system including an annular service piston positioned to extend continuously around the series of rotors and stators such that pressurization of fluid in the service brake system acts on the service piston opposite the series of rotors and stators and drives the service piston to continuously engage around the series of rotors and stators such that the rotors and stators are compressed together and thereby create braking torque;
• and
• a parking brake system including an annular parking piston positioned to extend continuously around the series of rotors and stators, at least one parking piston spring creating a parking piston spring bias acting on the parking piston to drive the parking piston to continuously engage around the series of rotors and stators such that the rotors and stators are compressed together and thereby create braking torque,
• wherein the service piston is configured for nesting with the parking piston such that the service piston is positioned between the parking piston and the series of rotors and stators,
• wherein the parking piston and the service piston are configured to continuously engage together around the series of rotors and stators to thereby create the braking torque,
• wherein the brake system is configured such that the series of rotors and stators is free from oil flow,
• wherein the service piston is positioned between the parking piston and the series of rotors and stators such that when a braking force is applied to the parking piston, the braking force is applied by the parking piston to the service piston and by the service piston to the series of rotors and stators, and
• wherein a parking piston fluid inlet port supplies fluid to a parking piston chamber on a same side of the parking piston as the series of rotors and stators such that pressurization of the parking piston chamber is configured to overcome the parking piston spring bias acting on the parking piston.