Spreader unit for a motor vehicle drum brake

A spreader unit for a drum brake, comprising:

• a housing;
• a first and second brake shoe holders that are rotationally secured to the housing, and actuatable linearly along an axis, respectively away from one another in a spreading direction and respectively toward one another in a release direction;
• a first and a second brake shoe provided respectively with a brake lining;
• a readjustment device arranged between the actuating pistons, wherein the readjustment device changes the spacing of the actuating pistons in at least one readjustment step when an actuating travel of the first and second brake shoe holders has exceeded a travel setpoint value;
• and
• a thermally actuable blocking device mechanically prevents the execution of the readjustment step by the readjustment device at a temperature above a temperature setpoint value;
• wherein the readjustment device further comprises a freewheel clutch having two claws, wherein the claws carry out a relative stroke during freewheeling and wherein one claw is rotationally secured to the first brake shoe holder and the other claw is connected to the second actuating piston via a threaded spindle, and wherein the blocking device is arranged operatively parallel to the clutch to keep the claws apart in the activated state;
• wherein the blocking device has a bimetallic element, and a blocking space is located between and is laterally delimited by the claws, wherein at least a portion of the bimetallic element passes into the blocking space at least when the maximum claw stroke has been reached.

A spreader unit for a drum brake comprising:

• a housing;
• a first and second brake shoe holders that are rotationally secured to the housing, and actuatable linearly along an axis, respectively away from one another in a spreading direction and respectively toward one another in a release direction;
• a first and a second brake shoe provided respectively with a brake lining, having at least one rotation-translation converter mechanism;
• a readjustment device arranged between the actuating pistons, wherein the readjustment device changes the spacing of the actuating pistons in at least one readjustment step when an actuating travel of the first and second brake shoe holders has exceeded a travel setpoint value;
• and
• a thermally actuable blocking device which mechanically prevents the execution of the readjustment step by the readjustment device at a temperature above a temperature setpoint value;
• wherein the spreader is electromechanically drivable with the aid of an electromechanical actuator comprising an electric motor;
• and
• wherein the spreader is equipped indirectly or directly with an electric load measurement device.