Parking brake for drum type brakes with electronic lining wear sensor and adjuster

An electrically actuated strut actuator subassembly for an electro-hydraulically applied parking brake in an automotive drum brake for use in engaging or disengaging a parking brake, sensing brake lining wear and adjusting brake shoe-to-drum clearance that has a backing plate, brake shoes that are supported on said backing plate, a brake drum disposed about said brake shoes, a hydraulic wheel cylinder mounted to said backing plate, return springs connecting said brake shoes at upper portions and lower portions and a strut actuator subassembly located parallel to said wheel cylinder and mounted between webs in slots that interconnects said upper portions between ends, wherein said strut actuator subassembly comprises, a strut tube having female threads and tapering to a fork at another end, a power screw having male threads and a rod portion at one end, a connector fork having a female portion at one end suitable for receiving said rod portion of said power screw and a fork at another end, a low power electric motor having a driveshaft at one end, and a position encoder, that are all in a common axial relationship with one another and wherein said strut tube and said power screw are connected by said female and male threads and said rod portion of said power screw is connected to said connector fork at said female portion to define the transverse structure of said strut actuator subassembly, and further wherein said electric motor and said position encoder are connected to one another and located within the interior of said strut tube and said electric motor is further connected to said power screw by said driveshaft, so that upon actuation of said electric motor, said driveshaft turns said power screw that advances said connector fork in one direction and said strut tube in an opposing direction along the axis of connection to engage or disengage said brake shoes with said brake drum for activating or deactivating said parking brake, sensing brake lining wear, or adjusting brake shoe-to-drum clearance.