Work vehicle and brake device thereof

A brake device for a work vehicle adapted to be disposed within an axle housing of the work vehicle, the brake device comprising:

• a brake unit including a brake disc plate, and a piston having a slide portion slidably supported by the axle housing and a pressure portion on which a pressure surface is formed for pressing the brake disc plate;
• and
• a slack adjuster mechanism that maintains a clearance between the piston and the brake disc plate at a predetermined clearance by mechanically adjusting a non-actuated position of the piston, the slack adjuster mechanism being formed by a member arranged on a piston rear surface side disposed on an opposite side from the brake disc plate and arranged further on an inner peripheral side than a slide portion of the piston, the member disposed further on the piston rear surface side than a pressure portion side end surface of the piston,
• wherein the slide portion of the piston is formed in a tubular shape and axially protruding from a lateral surface opposite to the pressure surface of the pressure portion,
• the slack adjuster mechanism includes
• a tubular carrier having a plurality of cases, the carrier being disposed on the inner peripheral side of the slide portion of the piston,
• a rod disposed within each of the cases and axially movable, the rod having a tip portion protruding from the case and being coupled to an inner peripheral part of the piston, the rod having a tip surface positioned further on the piston rear surface side than the pressure portion side end surface of the piston, and
• an adjustment portion disposed within each of the cases, the adjustment portion being configured to adjust a protruded amount of the rod from the case in a non-actuated state of the piston in accordance with an abrasion amount of the brake disc plate, and
• each of the cases includes sequentially from a brake unit side along an axial direction
• a first opening through which the rod penetrates,
• a second opening having a diameter greater than a diameter of the first opening, and
• a third opening in which the adjustment portion is disposed, the third opening having a diameter greater than the diameter of the second opening.