Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Vehicle subsystem or accessory control
Reexamination Certificate
2000-11-10
2003-04-29
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Vehicle subsystem or accessory control
C280S005500, C280S124100
Reexamination Certificate
active
06556907
ABSTRACT:
PRIORITY INFORMATION
This application is based on and claims priority to Japanese Patent Application numbers 11-320864, filed Nov. 11, 1999, and 2000-3385, filed Jan. 12, 2000.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a vehicle suspension system for use in four-wheeled vehicles having two or more interrelated damper units. More particularly, the present invention to the sizing and configuration of certain components within such a vehicle suspension system so as to provide improved interrelationships between the components for controlling vehicle movement.
2. Description of the Related Art
Vehicle suspension systems have been proposed that embody individual hydraulic dampers associated with each of the wheels for damping their respective motion. As a further improvement upon this arrangement, systems have been proposed wherein pairs or more of wheels may be interrelated to control the roll and/or pitch of a vehicle in addition to individual wheel damping when encountering objects. For instance, during rapid deceleration or emergency braking, the suspension system allows interaction between the front and rear suspended members. Moreover, during cornering, the vehicle suspension system allows interrelation between the suspended members to increase traction and control. Various systems have been proposed for accomplishing these effects, many of which have become quite complicated in nature and in construction. Often involving electronic sensors and complicated control strategies.
One particular advantageous type of system and numerous embodiments of it is disclosed in U.S. Pat. No. 5,486,018, issued Jan. 23, 1996. In this type of system, each wheel is associated with a hydraulic damper that is comprised of a cylinder in which a piston reciprocates. The cylinder is connected to either the wheel or the vehicle body and the piston is connected by a piston rod to the remaining vehicle component. The piston divides the cylinder into a pair of fluid chambers one of which may be considered to be a working chamber and the other of which may be considered to be a reservoir chamber. A damp valve arrangement is provided for controlling the flow between the working cylinder portion and the reservoir chamber thus, the individual units act like conventional shock absorbers.
However, the piston rod displaces a volume in one of the chambers and thus, it is necessary to provide a reservoir where the displaced fluid may be added and subtracted to compensate for the piston rod displacement amount. In accordance with the embodiments disclosed in that patent, pairs of wheels have a common reservoir arrangement which acts as a pressure control system. The makeup fluid from each unit is transferred to a respective variable volume chamber and the movable elements of those two chambers are interlinked to each other so as to provide additional suspension control between the two associated wheels for controlling vehicle body movement. This can be utilized to reduce roll and/or pitching.
For example, if the associated or interconnected wheels are at opposite sides of the vehicle when both wheels strike an obstacle, each piston and cylinder of the shock absorbing unit will undergo the same movement in the same direction. The differential fluids are transferred between the pressure control device and will cause equal displacements of the movable members that are interrelated and the system operates as a conventional suspension system. If, however, the vehicle is maneuvered around a curved path of travel, one suspension unit (i.e., the one on the outside) will tend to be compressed while that on the inside will tend to expand. Thus, there is a differential flow of fluid between the units and the interconnection provides further damping control resistance of such body motion.
The difficulty with this type of system is that the requirements in terms of size and capacity of the individual shock absorbers differ for optimum damping depending upon whether the displacement occurs during normal straight-ahead movement or when rounding a curve. Similar situations are true with respect to front and rear interconnected suspensions for damping pitching movements during acceleration or braking. That is, when the pressure control device is acting to damping body movements between the two wheels, the pressure control device works in combination with the respective shock absorbers because of this the individual wheel shock absorbers should be somewhat smaller to reduce the effect on the overall body control. Thus, the individual shock absorber design tends to be a compromise between the optimum for these two different damping conditions.
With reference now to
FIG. 1
, a vehicle suspension system of the interrelated type is disclosed therein. The suspension system indicated generally by the reference numeral comprises two mirrored halves in the illustrated arrangement each halve comprises a first damper
22
and a second damper
24
. In the illustrated arrangement, the first damper
22
and the second damper
24
are connected through a pressure regulator
26
. As indicated by the phantom lines in
FIG. 1
, a single pressure regulator
26
can be interconnected to the first damper
22
(i.e., a front damper) and a second damper (i.e., a rear damper). In some arrangements, a cross-relationship may arise such that a front left damper is connected to a rear right damper and a front right damper is connected to a rear left damper. Such a construction is illustrated with phantom lines in FIG.
1
. In other arrangements, a front left damper will be connected to a rear left damper while a front right damper will be connected to a rear right damper such as that illustrated in solid lines in FIG.
1
.
In the illustrated arrangement of
FIG. 1
, the first damper
22
is configured of a cylinder
28
in which a piston
30
is arranged to reciprocate. A piston rod
32
connects to the piston
30
at one end and to a component of the vehicle at the other end. As is known, the damper
22
is positioned between a sprung and unsprung number of the vehicle. For instance, as is generally known in a sprung portion of the vehicle (i.e., the vehicle body) differs from the unsprung portion of the vehicle (i.e., the suspension), in that a spring is positioned between the vehicle body and the operating surface whereas the unsprung portion of the vehicle does not have a spring interposed between its and the operating surface. In the illustrated arrangement, the piston rod
32
is connected to one of the vehicle body and the wheel whereas the cylinder
28
is connected to the other of the two members. Such a construction advantageously results in an upper fluid chamber
34
and a lower fluid chamber
36
that are segregated from each other by the piston
30
.
The piston
30
preferably has one or more passages
38
defined therethrough which allow communication between the upper fluid chamber
34
and the lower fluid chamber
36
. As will be appreciated, the term upper and lower are relative and used for ease of description but need not be an upper and lower chamber in all instances. A throttle valve
40
preferably is disposed along the passage
38
to control the flow of fluid between the upper fluid chamber
34
and the lower fluid chamber
36
. It should be noted that a similar construction is used for each of the dampers
22
,
24
in the illustrated arrangement of FIG.
1
. Accordingly, the components associated with each of these dampers
22
,
24
will not be further described.
The upper and lower fluid chambers
34
,
36
preferably are filled with a fluid or gas such as that known to those of ordinary skill in the art. As such, the first damper
22
and the second damper
24
are in fluid communication with one another through the pressure regulator
26
. The pressure regulator
26
in the arrangement illustrated in
FIG. 1
, comprises a first cylinder
42
and a second cylinder
44
. The first cylinder and the second cylinder
42
,
44
, generally are formed within a single outer body
Knobbe Martens Olson & Bear LLP
Yamaha Hatsudoki Kabushiki Kaisha
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