Patent ID: 7040445
Filing Date: 2006-05-09
Classification: B60K,B60Y,B62D

Abstract:
1. A hydraulic driving apparatus for a wheeled vehicle including a prime mover and a pair of wheels, comprising; a stepless transmission mechanism for traveling which transmits driving force from said prime mover to said drive wheels so as rotate said drive wheels in a common forward or rearward direction; 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 said hydraulic motor is divided into opposite directive rotations transmitted to said respective drive wheels; traveling operation means for changing speed of said common rotation of said drive wheels and for switching said common rotational direction of said drive wheels between a forward direction and a rearward direction; steering operation means for changing the rotational speed of said hydraulic motor and switching the rotational direction of said hydraulic motor between opposite directions; a switching valve disposed between said variable hydraulic pump and said hydraulic motor in said steering transmission mechanism, wherein said switching valve is controlled based on setting of said traveling operation means; a neutral position for location of said switching valve, wherein said switching valve is located in said neutral position so as to isolate said hydraulic motor from said variable hydraulic pump when said traveling operation means is set for stopping said drive wheels; a forward traveling position for location of said switching valve, wherein said switching valve is located in said forward traveling position so as to fluidly connect said hydraulic motor with said variable hydraulic pump when said traveling operation means is set for rotating said drive wheels in a forward direction; and a rearward traveling position for location of said switching valve, wherein said switching valve is located in said rearward traveling position so as to fluidly connect said hydraulic motor with said variable hydraulic pump when said traveling operation means is set for rotating said drive wheels rearward, and wherein, in relation to the discharge direction of said variable hydraulic pump, the rotational direction of said hydraulic motor when said switching valve is located in said rearward traveling position is reversed in comparison with the rotational direction of said hydraulic motor when said switching valve is located in said forward traveling position.