| 摘要 |
<p>PURPOSE:To prevent a working section from being swayed sidewards by the slight operation of a steering wheel during straight movement, by enabling control to steer rear wheels in the same direction as front wheels when the angle of steering is within a relatively narrow range. CONSTITUTION:In a four-wheeled vehicle such as a ridden-type rice planter, a steering mechanism for front wheels 8 is constructed so that the wheels are steered by the rotaion of a steering shaft 12 through a Pitman arm 13, tie rods 11 and knuckle arms 10. A steering mechanism for rear wheels 9 is constructed so that knuckle arms 14 provided at the rear wheels are connected to each other through a relay rod 15, and tie rods 17, 17' coupled to the knuckle arms 14 through elongation/contraction means 16, 16' made of hydraulic cylinders are connected to the Pitman arm 13. An oil feed/discharge system for the elongation/contraction means 16, 16' is shifted by a rotary valve 18 provided at the steering shaft 12, so that the rear wheels 9 can be steered in the same direction as the front wheels 8 when the angle of steering is within a prescribed range.</p> |
