Annular single piston brake arrangement

An annular single piston brake arrangement, for selective holding engagement of a rotatable member of a drive train, comprising:

• a support structure;
• an annular brake piston mounted for axial movement within the support structure and defining therewith a service brake actuation chamber, a parking brake retraction chamber, and a separate spring chamber;
• spring means disposed within the spring chamber and connected to the support structure for biasing the brake piston concentrically toward peripheral brake holding engagement of the rotatable member;
• retraction means for supplying fluid to the parking brake retraction chamber for biasingly overcoming the force of the spring means and holding the brake piston in a disengaged position;
• actuating means for supplying fluid to the service brake actuation chamber for selectively biasing the brake piston concentrically toward peripheral brake holding engagement of the rotatable member;
• seal means disposed intermediate the support structure and the rotatable member for defining an internal chamber therebetween;
• means for continually supplying a cooling fluid to the internal chamber for cooling the brake arrangement, with such fluid acting to bias the brake piston toward the disengaged position;
• and
• means for communicating a fluid to the separate spring chamber for biasing the brake piston toward engagement in opposition to the effect of the cooling fluid in the internal chamber urging the brake piston toward disengagement.