Spreader unit for a drum brake, comprising wear travel adjustment, and the drum brake

An electromechanically drivable spreader unit for a drum brake, comprising:

• a housing and
• two first and second brake shoe holders, which are arranged in a manner secured against rotation in relation to the housing and which can be actuated linearly along an axis, respectively away from one another in a spreading direction and toward one another in a release direction, and act respectively on a first and second brake shoe, each of which is provided with a brake lining,
• wherein the linear motion of the brake shoe holders is produced by two ball-ramp devices,
• wherein a first ball-ramp device comprises a first actuation piston arranged for rotation about the axis and a second ball-ramp device comprises a second actuation piston arranged for rotation about the axis,
• wherein an adjustment apparatus for compensating an actuation travel that increases as a result of wear on the friction linings is arranged in an axially centered position and substantially between the actuation pistons within the housing,
• wherein the adjustment apparatus comprises an adjustment piston, which is in the same force transmission path as the first actuation piston, and a latching sleeve, which is in engagement with the adjustment piston via axial toothed rings, and
• wherein the latching sleeve is secured against rotation relative to the second brake shoe holder, can be moved axially to a limited extent relative to the second actuation piston and is arranged under elastic preload against the adjustment piston.