A hydraulic driving apparatus for a wheeled vehicle including a prime mover and
a pair of wheels comprises a stepless transmission mechanism for traveling which
transmits driving force from the prime mover to the drive wheels so as rotate the
drive wheels in a common forward or rearward direction, and a steering transmission
mechanism including a hydrostatic stepless transmission including a variable hydraulic
pump and a hydraulic motor fluidly connected to each other, wherein a rotational
force of the hydraulic motor is divided into opposite directive rotations transmitted
to the respective drive wheels. A switching valve is disposed between the variable
hydraulic pump and the hydraulic motor in the steering transmission mechanism.
The switching valve reverses the rotational direction of the motor relative to
the discharge direction from the pump according to a change in the traveling direction
of the vehicle between forward and rearward, and divides a pair of oil passages
between the pump and the motor into independent circuits which include the pump
and the motor, respectively.