Lift axle suspension system for a heavy-duty vehicle, which suspension system uses X-rod control arms for improved lateral stability

A suspension system for liftable steerable axles, comprising:

• laterally spaced left and right steerable knuckles;
• laterally spaced left and right pistonless bellows load air springs;
• laterally spaced left and right pistonless bellows lift air springs;
• a steerable axle structure that has, at a laterally spaced left and right end thereof, a respective left and right kingpin housing boss, and a respective left and right kingpin fixed into the respective left and right kingpin boss, wherein the respective left and right steerable knuckles rotate around the respective left and right kingpin and are supported by the respective left and right kingpin housing;
• wherein the steerable knuckles are connected to each other side to side by a tie rod assembly whereby the steerable knuckles respond to rotational inputs from each respective knuckle;
• left and right laterally spaced hanger brackets for mounting suspending under a frame or frame members of a heavy vehicle;
• left and right laterally spaced control arm sets extending between the respective left and right hanger brackets and the steerable axle;
• each control arm set comprising an upper control arm and a spaced lower control arm;
• each control arm extending between (1) a forward pivot-connection end adapted to receive a resilient bushing and pivot pin assemblage and (2) a rearward pivot-connection end adapted to receive a resilient bushing and pivot pin assemblage;
• each hanger bracket providing an upper pivot-connection set position and a lower pivot connection set position, wherein one or the other of the upper or lower pivot-connection set positions is inboard of the other of the lower or upper pivot-connection set positions and therein being relatively outboard;
• the axle providing four pivot-connection set positions comprising a laterally-spaced left and right lower pivot connection set position and a laterally-spaced left and right upper pivot connection set position;
• wherein one or the other of the axle-right upper or lower pivot-connection set positions is relatively inboard of the other of the axle-right lower or upper pivot-connection set positions and therein being relatively outboard;
• wherein one or the other of the axle-left upper or lower pivot-connection set positions is relatively inboard of the other of the axle-left lower or upper pivot-connection set positions;
• and
• wherein the lower and upper control arms of each control arm set respectively cross under and over each other X-configured or X-disposed relative each other in plan view.

A suspension system for liftable steerable axles, comprising:

• laterally spaced left and right steerable knuckles;
• laterally spaced left and right pistonless bellows load air springs;
• laterally spaced left and right pistonless bellows lift air springs;
• a steerable axle structure that has, at a laterally spaced left and right end thereof, a respective left and right kingpin housing boss, and a respective left and right kingpin fixed into the respective left and right kingpin boss, wherein the respective left and right steerable knuckles rotate around the respective left and right kingpin and are supported by the respective left and right kingpin housing;
• wherein the steerable knuckles are connected to each other side to side by a tie rod assembly whereby the steerable knuckles respond to rotational inputs from each respective knuckle;
• left and right laterally spaced hanger brackets for mounting suspending under a frame or frame members of a heavy vehicle;
• left and right laterally spaced control arm sets extending between the respective left and right hanger brackets and the steerable axle;
• each control arm set comprising an upper control arm and a spaced lower control arm;
• each control arm extending between (1) a forward pivot-connection end adapted to receive a resilient bushing and pivot pin assemblage and (2) a rearward pivot-connection end adapted to receive a resilient bushing and pivot pin assemblage;
• each hanger bracket providing an upper pivot-connection set position and a lower pivot connection set position, wherein one or the other of the upper or lower pivot-connection set positions is inboard of the other of the lower or upper pivot-connection set positions and therein being relatively outboard;
• and right lower pivot connection set position and a laterally-spaced left and right upper pivot connection set position;
• wherein one or the other of the axle-right upper or lower pivot-connection set positions is relatively inboard of the other of the axle-right lower or upper pivot-connection set positions and therein being relatively outboard;
• wherein one or the other of the axle-left upper or lower pivot-connection set positions is relatively inboard of the other of the axle-left lower or upper pivot-connection set positions;
• and
• further comprising a four-bar linkage arrangement that includes a given lateral span of the steerable axle;
• the four-bar linkage arrangement comprising a ground link, a left and right crank link, and a driven link;
• wherein:
• the ground link comprises the given lateral span of the steerable axle;
• the driven link comprises a given lateral span of the tie rod;
• the left and right crank links comprise left and right extensions of the left and right steerable knuckles respectively, which extensions are elongated and terminate in distal ends coupled to left and right laterally spaced positions relative to the tie rod.

A suspension package for liftable steerable axles for heavy vehicles, comprising:

• left and right laterally spaced hanger brackets adapted for mounting under a frame or frame members of a heavy vehicle;
• a laterally elongated axle having a central non-steerable portion flanked by laterally-spaced left and right steerable wheel hubs;
• left and right laterally spaced control arm sets extending longitudinally between the respective left and right hanger brackets and the axle;
• each control arm set comprising an upper control arm and a spaced lower control arm;
• each of the upper and lower control arm having a forward end or margin being connected in a pivotal load-bearing connection at respectively vertically-spaced set positions on the respective left or right hanger bracket;
• each of the upper and lower control arm having a trailing end or margin being connected in a pivotal load-bearing connection at respectively vertically-spaced set positions on the axle at respectively laterally spaced left or right set-position sets on the axle;
• wherein the lower and upper control arms of each control arm set respectively cross under and over each other X-configured or X-disposed relative each other in plan view.