Rack and pinion steering system for four wheel drive vehicle

An apparatus comprising:

• first and second steerable drive wheels of a vehicle;
• a drive axle assembly interconnecting said first and second steerable wheels and a drive shaft extending from the drive axle assembly, the drive axle assembly including a differential gear housing containing gears for transmitting rotational force from the drive shaft to the steerable wheels to drive the steerable wheels for rotation about a drive axis extending along the drive axle assembly;
• first and second steering arms associated with said first and second steerable wheels, respectively, for receiving steering force for effecting turning movement of said first and second steerable wheels, a steering linkage axis extending between said first and second steering arms;
• a rack and pinion steering gear assembly including an elongate rack having a longitudinal axis and extending axially through a rack housing, said rack being movable axially in said rack housing, a first end portion of said rack projecting axially from said rack housing;
• a drag link structurally connected between said first end portion of said rack and one of said first and second steering arms for transmitting steering force to said one steering arm;
• and
• a second steering link for transmitting steering force from said drag link to the other one of said first and second steering arms;
• said drag link having a kinematic axis which extends generally parallel to said rack axis;
• said drag link having a non-linear configuration to clear said steering gear assembly and its operating envelope.

An apparatus comprising:

• first and second steerable drive wheels of a vehicle;
• a drive axle assembly interconnecting said first and second steerable wheels and a drive shaft extending from the drive axle assembly, the drive axle assembly including a differential gear housing containing gears for transmitting rotational force from the drive shaft to the steerable wheels to drive the steerable wheels for rotation about a drive axis extending along the drive axle assembly;
• first and second steering arms associated with said first and second steerable wheels, respectively, for receiving steering force for effecting turning movement of said first and second steerable wheels, a steering linkage axis extending between said first and second steering arms;
• a rack and pinion steering gear assembly including an elongate rack having a longitudinal axis and extending axially through a rack housing, said rack being movable axially in said rack housing in response to rotation of the vehicle steering wheel, a first end portion of said rack projecting axially from said rack housing;
• a drag link structurally connected between said first end portion of said rack and one of said first and second steering arms for transmitting steering force to said one steering arm;
• a second steering link for transmitting steering force from said drag link to the other one of said first and second steering arms;
• and
• a pivot connection interconnecting said drag link with said rack at a location on said rack axis;
• said drag link extending from said pivot connection toward said one of said first and second steering arms.

An apparatus comprising:

• first and second steerable drive wheels of a vehicle;
• a drive axle assembly interconnecting said first and second steerable wheels and a drive shaft extending from the drive axle assembly, the drive axle assembly including a differential gear housing containing gears for transmitting rotational force from the drive shaft to the steerable wheels to drive the steerable wheels for rotation about a drive axis extending along the drive axle assembly;
• first and second steering arms associated with said first and second steerable wheels, respectively, for receiving steering force for effecting turning movement of said first and second steerable wheels, a steering linkage axis extending between said first and second steering arms;
• a rack and pinion steering gear assembly including an elongate rack having a longitudinal axis and extending axially through a rack housing, said rack being movable axially in said rack housing, a first end portion of said rack projecting axially from said rack housing;
• a drag link structurally connected between said first end portion of said rack and one of said first and second steering arms for transmitting steering force to said one steering arm;
• a second steering link for transmitting steering force from said drag link to the other one of said first and second steering arms;
• and
• a Hooke joint interconnecting said drag link and said first end portion of said rack.