Vehicle improved steering

A lawn tractor improved in steering, comprising:

• an integral transaxle apparatus for driving and steering a lawn tractor, including,
• a housing,
• a driving hydrostatic transmission having a variable displacement first hydraulic pump and a first hydraulic motor fluidly connected with each other, said driving hydrostatic transmission being disposed in said housing, wherein said first hydraulic pump receives power of a prime mover and has a first movable swash plate,
• a steering hydrostatic transmission having a variable displacement second hydraulic pump and a variable displacement second hydraulic motor fluidly connected with each other, said steering hydrostatic transmission being disposed in said housing, wherein said second hydraulic pump receives power of said prime mover independently of said first hydraulic pump and has a second movable swash plate, and wherein said second hydraulic motor has a third movable swash plate including a neutral position,
• a pair of axles disposed co-axially with each other and supported said housing, and
• a differential unit differentially connecting said axles with each other, said differential unit being disposed in said housing, wherein said differential unit is driven regularly or reversely by the output of said driving hydrostatic transmission and differentially drives said axles while receiving the output of said steering hydrostatic transmission;
• a forward/backward accelerator pedal for slanting operation of said first movable swash plate so as to switch the traveling direction of the lawn tractor between forward and backward and change the traveling speed, wherein said forward/backward accelerator pedal is operatively connected to said third movable swash plate so that the slanting direction of said third movable swash plate is changed oppositely with respect to said neutral position according to the traveling direction switching operation of said forward/backward accelerator pedal;
• a steering wheel for slanting operation of said second movable swash plate so as to determine the leftward and rightward traveling direction of the lawn tractor, wherein said lawn tractor turns laterally in the same direction of leftward and rightward steering operation of said steering wheel whether said lawn tractor travels forward or backward;
• and
• a caster interlocking with said steering wheel so as to be swivelled in relation to said lawn tractor by operation of said steering wheel, wherein said caster is swivelled laterally in the same direction of leftward and rightward steering operation of said steering wheel whether said lawn tractor travels forward or backward, and wherein said caster is restricted in its range where it can be freely swivelled.

A lawn tractor improved in steering, comprising:

• an integral transaxle apparatus for driving and steering a lawn tractor, including,
• a housing,
• a driving hydrostatic transmission having a variable displacement first hydraulic pump and a first hydraulic motor fluidly connected with each other, said driving hydrostatic transmission being disposed in said housing, wherein said first hydraulic pump receives power of a prime mover and has a first adjusting member,
• a steering hydrostatic transmission having a variable displacement second hydraulic pump and a variable displacement second hydraulic motor fluidly connected with each other, said steering hydrostatic transmission being disposed in said housing, wherein said second hydraulic pump receives power of said prime mover independently of said first hydraulic pump and has a second adjusting member, and wherein said second hydraulic motor has a third adjusting member so that the rotational direction of said second hydraulic motor is switched between first and second opposite directions by movement of said third adjusting member,
• a pair of axles disposed co-axially with each other and supported in said housing, and
• a differential unit differentially connecting said axles with each other, said differential unit being disposed in said housing, wherein said differential unit is driven regularly or reversely by the output of said driving hydrostatic transmission and differentially drives said axles while receiving the output of said steering hydrostatic transmission;
• a single manually operable driving operating means for operation of said first adjusting member so as to switch the traveling direction of the lawn tractor between forward and backward and change the traveling speed, wherein said single driving operating means is operatively connected to said third adjusting member;
• and
• a single manually operable steering operating means for operation of said second adjusting member so as to determine the leftward and rightward traveling direction of the lawn tractor, wherein said lawn tractor turns laterally in the same direction of leftward and rightward steering operation of said single steering operating means whether said lawn tractor travels forward or backward.

A lawn tractor improved in steering, comprising:

• an integral transaxle apparatus for driving and steering a lawn tractor, including,
• a housing,
• a driving hydrostatic transmission having a variable displacement first hydraulic pump and a first hydraulic motor fluidly connected with each other, said driving hydrostatic transmission being disposed in said housing, wherein said first hydraulic pump receives power of a prime mover and has a first adjusting member,
• a steering hydrostatic transmission having a variable displacement second hydraulic pump and a variable displacement second hydraulic motor fluidly connected with each other, said steering hydrostatic transmission being disposed in said housing, wherein said second hydraulic pump receives power of said prime mover independently of said first hydraulic pump and has a second adjusting member, and wherein said second hydraulic motor has a third adjusting member,
• a pair of axles disposed co-axially with each other and supported in said housing, and
• a differential unit differentially connecting said axles with each other, said differential unit being disposed in said housing, wherein said differential unit is driven regularly or reversely by the output of said driving hydrostatic transmission and differentially drives said axles while receiving the output of said steering hydrostatic transmission;
• a single manually operable driving operating means for operation of said first adjusting member so as to switch the traveling direction of the lawn tractor between forward and backward and to change the traveling speed, wherein said single driving operating means is operable between first and second opposite sides and operatively connected to said third adjusting member so that the output force of said second hydraulic motor is adjusted by operation of said single driving operating means;
• and
• a single manually operable steering operating means for operation of said second adjusting member so as to determine the leftward and rightward traveling direction of the lawn tractor.

A lawn tractor improved in steering, comprising:

• an integral transaxle apparatus for driving and steering a lawn tractor, including,
• a housing,
• a driving hydrostatic transmission having a variable displacement first hydraulic pump and a first hydraulic motor fluidly connected with each other, said driving hydrostatic transmission being disposed in said housing, wherein said first hydraulic pump receives power of a prime mover and has a first adjusting member,
• a steering hydrostatic transmission having a variable displacement second hydraulic pump and a variable displacement second hydraulic motor fluidly connected with each other, said steering hydrostatic transmission being disposed in said housing, wherein said second hydraulic pump receives power of said prime mover independently of said first hydraulic pump and has a second adjusting member,
• a pair of axles disposed co-axially with each other and supported in said housing, and
• a differential unit differentially connecting said axles with each other, said differential unit being disposed in said housing, wherein said differential unit is driven regularly or reversely by the output of said driving hydrostatic transmission and differentially drives said axles while receiving the output of said steering hydrostatic transmission;
• a single manually operable driving operating means for operation of said first adjusting member so as to switch the traveling direction of the lawn tractor between forward and backward and to change the traveling speed;
• a single manually operable steering means for operation of said second adjusting member so as to determine the leftward and rightward traveling direction of said lawn tractor, wherein said lawn tractor turns laterally in the same direction of leftward and rightward steering operation of said single steering operating means whether said lawn tractor travels forward or backward;
• and
• a caster interlocking with said single steering operating means so as to be swivelled in relation to said lawn tractor by operation of said single steering operating means, wherein said caster is swivelled laterally in the same direction of leftward and rightward steering operation of said single steering operating means whether said lawn tractor travels forward or backward.