Four wheel-drive anti-locking braking

Claim 2

A four-wheel-drive vehicle, comprising: a set of front wheels; a set of rear wheels; brakes on all of said wheels; an axle for each of said wheels; a front differential providing motive power to each of said axles of said front wheels; a rear differential providing motive power to each of said axles of said rear wheels, said front and rear differentials being normally connected together in four wheel drive; anti-locking means for preventing the locking of at least one of said set of rear wheels; and a motive power transmission system linking said front differential and said rear differential, whereby braking torque applied to said front wheels is transmitted to said rear wheels; wherein said power transmission system includes a lockable central differential disposed between said front and rear differentials, and means for reducing braking torque transmitted from said front wheels to said rear wheels through said motive power transmission system when said anti-locking means are operating; wherein said reducing means comprises means for disconnecting said front and rear differentials; and wherein said disconnecting means comprises means for releasing locking of said central differential.

Claim 3

A four-wheel-drive vehicle comprising: a set of front wheels; a set of rear wheels; brakes on all of said wheels; a pair of front axles providing motive power to said front wheels; a pair of rear axles providing motive power to said rear wheels; a motive power unit coupled to one of said pair of axles; anti-locking means for preventing locking of at least one of said set of rear wheels; and a motive power transmission system linking said front wheels and said rear wheels, whereby braking torque applied to said front wheels is transmitted to said rear wheels; wherein said power transmission system includes means for reducing braking torque transmitted from said front wheels to said rear wheels when said anti-locking means are operating, and said motive power transmission system includes a clutch disposed between said front wheels and said rear wheels, said clutch being usable as said means for reducing transmitted braking torque; wherein said motive power transmission system further includes a first viscous coupling and a second viscous coupling in series with said first viscous coupling, said clutch being disposed between said first and second viscous couplings.

Claim 4

A four-wheel-drive vehicle comprising: a set of front wheels; a set of rear wheels; brakes on all of said wheels; a pair of front axles providing motive power to said front wheels; a pair of rear axles providing motive power to said rear wheels; a motive power unit coupled to one of said pair of axles; anti-locking means for preventing locking of at least one of said set of rear wheels; and a motive power transmission system linking said front wheels and said rear wheels, whereby braking torque applied to said front wheels is transmitted to said rear wheels; wherein said power transmission system includes means for reducing braking torque transmitted from said front wheels to said rear wheels when said anti-locking means are operating, and said motive power transmission system includes a clutch disposed between said front wheels and said rear wheels, said clutch being usable as said means for reducing transmitted braking torque; wherein said motive power transmission system further includes a first viscous coupling and a second viscous coupling in series with said first viscous coupling, said clutch being disposed between said first and second viscous couplings.

Claim 5

A four-wheel-drive vehicle as recited in claim 2, wherein each of said viscous couplings comprises a plurality of clutch disks spline-coupled alternately to an input member and to an output member of said each viscous coupling and disposed in a sealed oil-filled chamber.

Claim 6

A four-wheel-drive vehicle as recited in claim 2, wherein power transmission efficiency of said second viscous coupling is higher than that of said first viscous coupling.

Claim 7

A four-wheel-drive vehicle comprising: a set of front wheels; a set of rear wheels; brakes on all of said wheels; an axle for each of said wheels; a front differential providing motive power to each of said axles of said front wheels; a rear differential providing motive power to each of said axles of said rear wheels, said front and rear differentials being normally connected together in four wheel drive; and anti-locking means for preventing the locking of at least one of said set of rear wheels, a motive power transmission system linking said front differential and said rear differential, whereby braking torque applied to said front wheels is transmitted to said rear wheels; wherein said power transmission system includes means for reducing braking torque transmitted from said front wheels to said rear wheels when said anti-locking means are operating; wherein said reducing means comprises means for disconnecting said front and rear differentials; and wherein said disconnecting means comprises two power transmitting members arranged coaxially, a first one of said two power transmitting members being connected to said front differential and a second one of said two power transmitting members being connected to said rear differential, a freely rotatable member, a brake for braking said freely rotatable member, and a gear mechanism connected to said freely rotatable member so that said two power transmitting members are connected by said gear mechanism in response to braking of said rotatable member.

Claim 8

A four-wheel-drive vehicle comprising: a set of front wheels; a set of rear wheels; brakes on all of said wheels; an axle for each of said wheels; a front differential providing motive power to each of said axles of said front wheels; a rear differential providing motive power to each of said axles of said rear wheels, said front and rear differentials being normally connected together in four wheel drive; and anti-locking means for preventing the locking of at least one of said set of rear wheels, a motive power transmission system linking said front differential and said rear differential, whereby braking torque applied to said front wheels is transmitted to said rear wheels; wherein said power transmission system includes means for reducing braking torque transmitted from said front wheels to said rear wheels when said anti-locking means are operating; wherein said reducing means comprises means for disconnecting said front and rear differentials; and wherein said disconnecting means comprises two power transmitting members arranged coaxially, a first one of said two power transmitting members being connected to said front differential and a second one of said two power transmitting members being connected to said rear differential, a freely rotatable member, a brake for braking said freely rotatable member, and a gear mechanism connected to said freely rotatable member so that said two power transmitting members are connected by said gear mechanism in response to braking of said rotatable member.

Claim 9

A four-wheel-drive vehicle as recited in claim 5, wherein said gear mechanism comprises a first large gear connected to one of said power transmitting members, a second large gear connected to the other power transmitting member, first and second small gears in meshing engagement with said first and second large gears, and a rotary member connected to a rotary shaft of said first and second small gears.