Method of controlling selective four-wheel drive transmission system for all-terrain vehicle

摘要

A selective four-wheel drive transmission system includes a dog clutch (48) to be engaged and to be disengaged to set the selective four-wheel drive transmission system for a four-wheel drive mode and a two-wheel drive mode, respectively. The dog clutch (48) has a moving sleeve (52) provided with projections (51), and a coupling member (50) provided with recesses (57). An electric motor (53) internally provided with a potentiometer (54) shifts the moving sleeve (52) between a disengaging position (A₀) and an engaging position (A₂) to engage and disengage the dog clutch (48). A controller controls the electric motor (53) on the basis of a signal provided by the potentiometer (54) and indicating the position of the moving sleeve (52) to move the moving sleeve (52). If the projections (51) are unable to engage in the recesses (57) for a time exceeding a predetermined time, the moving sleeve (52) is returned to the disengaging position (A₀), and, after the passage of a predetermined time, the moving sleeve (52) is moved again toward the engaging position (A₂).