1. Field of the Invention
The present invention relates to a tractor for mowing or earthing-up by attaching various work machines to the lower portion of a traveling vehicle body having front wheels and rear wheels.
2. Description of the Related Art
Tractors for mowing by attaching a work machine such as a mower to the lower portion of a traveling vehicle body have been generally known. For example, the tractor disclosed in Japanese Unexamined Patent Publication No. H09-272350 is constructed so that a mower is attached to the lower body portion between the front wheels and rear wheels, the driving force of the engine side is transmitted by a universal joint to the transmission case side, a mid PTO shaft projecting from the front face of the transmission case and an input shaft at the mower side are joined by other universal joints to drive mowing blades, and a front wheel driving shaft that also projects from the front face of the transmission case and a front wheel traveling input shaft provided at the rear portion of the front axle housing are joined by a universal joint so that the front wheels are also driven.
Generally, when a tractor travels across farm fields or roads after finishing mowing, a work machine such as a mower must be lifted high from the ground so as not to obstruct traveling. In the case of the abovementioned conventional tractor, to prevent the driving force transmission shaft for driving front wheels from obstructing lifting of the mower, the driving force transmission shaft is located close to the machine frame and extended forward parallel to the ground, the front end of the driving force transmission shaft is supported on the machine frame side by a special bearing, a transmission case for raising the position of the input shaft is provided at the front axle housing side, and the input shaft of this transmission case side and the front end of the driving force transmission shaft are joined to each other via a separate middle shaft, whereby the front wheels are driven.
Therefore, in this prior art, the structure for driving the front wheels is complicated and a bearing and a transmission case are required, resulting in an increase in the number of parts and manufacturing costs.