Tractor

A tractor, comprising:

• a front axle case which extends in the lateral direction and is mounted on a body frame,
• a pair of left and right front wheels respectively mounted on left and right end portions of the front axle case by way of left and right gear casings,
• the front axle case being constituted of a center casing forming body and left and right casing forming bodies which have respective proximal end portions thereof connected to left and right end portions of the center casing forming body,
• proximal end portions of the left and right casing forming bodies having mounting positions thereof which are arranged to be adjustable about axes with respect to the left and right end portions of the center casing forming body, and
• cylinder stays being mounted on the left and right casing forming bodies, respectively, and a power steering cylinder is interposed between both cylinder stays,
• left and right end portions of the power steering cylinder being respectively, interlockingly connected with left and right gear casings thereof which are connected, respectively, to distal end portions of the left and right casing forming bodies by knuckle arms,
• the left and right gear casings being constituted of fixed-side casing forming bodies and rotation-side casing forming bodies, in which the fixed-side casing forming bodies are connected to the distal end portions of the left and right casing forming bodies, and proximal end portions of the knuckle arms are rotatably and pivotally connected to upper end portions of the fixed-side casing forming bodies, distal end portions of connecting members of the knuckle arms being connected to upper end portions of the rotation-side casing forming bodies, and lower end portions of the fixed-side casing forming bodies and lower end portions of the rotation-side casing forming bodies are pivotally connected with each other, and
• rotation restricting members are mounted on outer peripheral surfaces of the fixed-side casing forming bodies so that the rotation restricting members project toward the rotation-side casing forming bodies, and driven rotation restricting members are mounted on the connecting members of the knuckle arms so that the driven rotation restricting members project toward the fixed-side casing forming bodies, the driven rotation restricting members being integrally rotated with the knuckle arms and with the rotation-side casing forming bodies and engageable with the rotation restricting members to restrict rotation of the rotation-side casing forming bodies.