1. Field of the Invention
The invention relates to a transaxle disposed above a grass-discharging duct of a mower unit equipped on a lawn tractor.
2. Related Art
As disclosed in U.S. Pat. No. 6,390,227, there is a conventional well-known rear discharge lawn tractor equipped with a mower unit including a mower deck and a grass-discharging duct. The mower deck is provided with rotary blades and a blower which blows grass mowed by the rotary blades into the duct. A grass collection box is disposed behind a rear end of the lawn tractor and connected to the duct so as to catch grass sent from the mower deck through the duct.
In the conventional rear discharge lawn tractor, left and right drive wheels are disposed on left and right sides of the duct. A transaxle having left and right lateral output shafts is disposed on one lateral side of the duct. Left and right final transmission devices (e.g., chains and sprockets, belts and pulleys, or gears) are disposed on respective lateral opposite sides of the duct so that each of the final transmission devices is drivingly interposed between the output shaft and the drive wheel. The transaxle includes a transaxle housing, which incorporates a hydraulic pump, a hydraulic motor fluidly connected to the hydraulic pump, and the left and right output shafts driven by the hydraulic motor.
Further, the conventional rear discharge lawn tractor is equipped with an engine having a vertical output shaft, and the transaxle includes a vertical input shaft (serving as a pump shaft of the hydraulic pump) projecting upward from the transaxle housing. An input pulley is provided on an upper portion of the input shaft projecting upward from the transaxle housing so as to be drivingly connected to a pulley provided on the vertical output shaft of the engine through a belt.
Since the transaxle housing has to be low as to ensure a space for the input shaft with the input pulley projecting upward from the transaxle housing, the transaxle housing is laterally offset from the duct (i.e., disposed on one lateral side of the duct as mentioned above) so as to be prevented from interfering with the duct, thereby restricting the lateral width of the duct. Further, a lateral shaft extended from the output shaft of the transaxle to one of the left and right final transmission devices is passed through a space above the duct, thereby restricting the vertical width of the duct. Consequently, the grass-discharging duct of the conventional lawn tractor is restricted in volume, thereby restricting the grass discharging (collection) speed of the mower unit.
If the transaxle is disposed above the grass-discharging duct, the problem regarding the restriction of the lateral width of the duct is solved. However, another problem arises because the input pulley on the input shaft projecting upward from the transaxle housing becomes too high to be drivingly connected to the pulley on the engine output shaft through a horizontal belt.