Suspended drive axle and agricultural tractor with same

An agricultural tractor comprising:

• a frame;
• an engine;
• a transmission driven by the engine;
• a drive axle assembly driven by the transmission, the axle assembly including differential case having left and right planetary final drives, the final drives having an output member, left and right inner suspension housings fixed to the differential case, left and right upper and lower control arms pivotally coupled to the inner suspension housings and extending outward to distal ends, left and right axle housings pivotally coupled to the distal ends of the control arms for up and down movement of the axle housings relative to the inner suspension housings, left and right axle shafts rotatably carried by the left and right axle housings, left and right universal joints drivingly coupling the output members of the left and right final drives to the left and right axle shafts respectively, and left and right spring members extending between the left and right inner suspension housings and the left and right axle housings to resiliently transmit loads from the frame to the axle housings;
• and
• left and right wheel and tire assemblies coupled to the left and right axle shafts respectively.

A universal joint for transmitting rotary power:

• a drive member rotatably supported in a first housing by a first bearing set for rotation about a first longitudinal axis;
• a driven member rotatably supported in a second housing by a second bearing set for rotation about a second longitudinal axis;
• a drive yoke fixed to the drive member;
• a first journal member coupled to the drive yoke for pivotal motion about a first joint pivot axis transverse to a longitudinal axis of the drive member;
• a coupling yoke joined to the first journal member for pivotal motion about a second joint pivot axis transverse to the longitudinal axis of the drive member and to the first joint pivot axis and lying in the same plane as the first joint pivot axis;
• a driven yoke fixed to the driven member;
• a second journal member coupled to the driven yoke for pivotal motion about a third joint pivot axis transverse to the second longitudinal axis;
• and
• the second journal member being joined to the coupling yoke for pivotal motion about a fourth joint pivot axis transverse to the second longitudinal axis and to the third joint pivot axis and lying in the same plane as the third joint pivot axis;
• and
• at least a portion of the first and second bearing sets being located between the plane of the first and second joint pivot axes and the plane of the third and fourth joint pivot axes.

A suspended drive axle for a work vehicle comprising:

• a differential case having left and right planetary final drives, the final drives having each having an output member;
• left and right inner suspension housings fixed to the differential case;
• left and right upper and lower control arms pivotally carried by the inner suspension housings and extending outward to distal ends;
• left and right axle housings pivotally coupled to the distal ends of the control arms for up and down movement of the axle housings relative to the inner suspension housings;
• left and right axle shafts rotatably carried by the left and right axle housings;
• left and right universal joints drivingly coupling the output members of the left and right final drives to the left and right axle shafts respectively;
• and
• left and right spring members extending between the left and right inner suspension housings and the left and right axle housings to resiliently transmit loads therebetween.

An agricultural tractor comprising:

• a frame;
• an operator's platform;
• rear wheels;
• a rear axle carrying the rear wheels and including a suspension system coupling the rear wheels to the frame for vertical motion of the rear wheels relative to the frame, the suspension system including a hydro-pneumatic spring system including at least one hydraulic cylinder on each side of the tractor, the extension of the cylinder rod determining the position of the rear wheels relative to the frame;
• and
• a switch at the operator's platform for actuation by an operator to raise and lower the rear end of the tractor by extending or retracting the cylinder rod of the hydraulic cylinders.