Land vehicles – Wheeled – Running gear
Reexamination Certificate
2000-04-19
2001-08-21
Culbreth, Eric (Department: 3618)
Land vehicles
Wheeled
Running gear
C280S124128, C280S124159, C280S124160, C280S124161, C280S683000, C280S676000
Reexamination Certificate
active
06276710
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to suspensions for tandem axles and more particularly to high articulation suspensions for driven tandem axles.
2. Description of the Prior Art
A tandem axle is commonly employed to a support a heavy load such as the rear sections of heavy duty vehicles. Among suspensions commonly used with tandem axles are systems which provide a leaf or air spring for each end of the leading and trailing axles of the tandem pair and suspensions based on walking or equalizing beams. Walking beam suspensions for a tandem axle typically include two beams, each mounted perpendicularly to the axles and riding on the axles toward the outside ends of the axles. A single spring, which may be a rubber spring or steel spring, is mounted above the walking beam and below the vehicle frame and is displaced only by the average of movement of the two axles. Walking beam suspensions provide for greater axle articulation and improved traction over rough surfaces than common suspension systems and are favored for driven tandem axles used with vehicles intended for off road use. However, walking beam suspensions are inferior at maintaining a good ride for loaded and unloaded vehicles than are more commonly used systems, particularly air spring suspensions.
Good roll stability is an important factor in any vehicle suspension system. Roll stability is a particularly important factor in the design of suspensions for off road applications. The primary way to reduce roll and thereby improve roll stability is to increase the suspension's spring rate. However, simply increasing the suspension spring rate produces an increasingly harsh and uncomfortable ride. In order to keep the vertical spring rate low enough for reasonable levels of comfort it has become common practice to add auxiliary stabilizing elements to suspensions. This approach works well until the wheels on one side of a vehicle need to move independently of the roll coupled member. When this occurs the result is an increase in the effective vertical spring rate and a loss of suspension articulation. The loss of articulation in turn results in a loss of traction in rough terrain. High axle articulation and anti-roll stability have been partially incompatible objectives.
Air springs have given suspension designers some advantages in handling the problem of providing a good ride with roll stability in a single suspension design. Air can be added or released from an air spring on demand to adjust the spring's deflection as desired and keep the vehicle from listing due to uneven loading. Air springs alone, however, provide no inherent mechanism for stabilizing axle orientation and have tended to require extensive auxiliary stabilizing elements for the axles.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a tandem axle suspension system which retains axle orientational stability while achieving good suspension articulation for off road applications.
It is another object of the invention to improve tandem axle suspension articulation in an air spring based suspension system.
It is still another object to achieve anti-roll stability while maintaining good axle articulation and a comfortable ride.
According to the invention there is provided a suspension system for a vehicle's tandem axle. The tandem axle supports from the axle outside ends, a vehicle having two major sides. For each end of the axles there is a lead air spring and a trailing air spring mounted in tandem along each major side of the vehicle. First and second lead air springs are anchored to support the vehicle from a lead axle of the tandem axle and first and second trailing air springs are anchored to support the vehicle from a trailing axle of the tandem axle. A fluid transfer channel connects the lead and trailing air springs associated on each major side. An averaging rod connects the ends of the lead and trailing axles of the tandem axle substantially adjacent the major sides.
An air spring pressurization controller is installed for each major side, with the air spring pressurization controller being responsive to displacement of the averaging rod for its respective side and further being in fluidic communication with the fluid transfer channel for the side.
Additional effects, features and advantages will be apparent in the written description that follows.
REFERENCES:
patent: 4030738 (1977-06-01), Willetts
patent: 4132433 (1979-01-01), Willetts
patent: 4705294 (1987-11-01), Raidel
patent: 4993729 (1991-02-01), Payne
patent: 5052712 (1991-10-01), Raidel
patent: 5058917 (1991-10-01), Richardson
patent: 5458360 (1995-10-01), Raidel, Sr.
patent: 5464245 (1995-11-01), Vogler
patent: 5560641 (1996-10-01), Vogler
patent: 5588665 (1996-12-01), Pierce et al.
patent: 5615906 (1997-04-01), Raidel, Sr.
patent: 5882031 (1999-03-01), VanDenberg
patent: 6149142 (2000-11-01), Penzotti
patent: 6193266 (2001-02-01), Cortez et al.
Goodyear, Super Cushion Air Springs, Vehicular Applications Engineering Manual, Jun. 1997, pp. 3 + 38 + front and back covers, reprinted from SAE Publication HS1576, Society of Automotive Engineers, INc.
Calfa Jeffrey P.
Culbreth Eric
Dennis Kelly Sullivan
Draper Deanna
Hernandez Gilberto
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