Land vehicles – Suspension modification enacted during travel – Including condition or parameter adjustment occurring at...
Reexamination Certificate
2000-01-12
2001-06-26
Dickson, Paul N. (Department: 3618)
Land vehicles
Suspension modification enacted during travel
Including condition or parameter adjustment occurring at...
C280S124106, C701S038000
Reexamination Certificate
active
06250649
ABSTRACT:
BACKGROUND OF THE INVENTION
The application claims priority of DE 197 17 418.3 filed Apr. 25, 1999, now German Patent DE 197 17 418, patented Oct. 22, 1998; the disclosure of which is expressly incorporated by reference herein.
The present invention relates to a multi-track tilting-body vehicle, the body of which, when travelling on curves, can be tilted in an active manner to the inside of the curve by an actuator operated by an automatic control system, in particular a three-wheel vehicle having two front wheels—preferably following the body tilt—and a rear wheel following the body tilt.
Such vehicles are known in principle. For example, railway carriages whose body, when travelling on curves, tilts towards the inside of the curve in order to compensate for the centrifugal forces acting on the passengers are already in regular use. In this way, passenger comfort can be substantially increased. Reference may be made in this connection to EP 0 528 783 A1.
In vehicles having a small gauge track compared with the vehicle size, the tilting of the body on curves as well as a wheel slanting position, controlled in accordance with the body tilt, also serve to ensure the requisite side-tilt stability of the vehicle at higher speeds on curves. Such vehicles are described, for example, in non-published DE 196 08 578 A1.
SUMMARY OF THE INVENTION
An object of the present invention, then, is to ensure a high degree of safety even if a malfunction occurs in the automatic control of the tilting on curves.
To this end, provision is made according to the invention that
the control system, which continuously checks for correct operational function, is automatically cut off/disconnected from the actuator in the event of a malfunction,
if the control system is disconnected from the actuator, a continuously working emergency system, which, however, is disconnected from the actuator during normal operation, is connected to the actuator,
this emergency system has an inertia mass which reacts to transverse accelerations of the vehicle and assumes a center position when transverse accelerations disappear,
in each case one of two parallel control devices of the emergency system is rendered effective by this inertia mass in such a way that the first control device comes into effect when transverse accelerations are significant and the second control device comes into effect when transverse accelerations disappear, and
the first control device produces a maximum body tilt in the direction of the transverse acceleration and the second control device retracts the body tilt when the emergency system is connected to the actuator.
The invention is based on the general recognition of providing an emergency control system with its own energy supply in case of an emergency, so that at least some driving maneuvres with tilting of the body on curves can still be carried out or continued before the vehicle can continue to travel, in particular in curves, if need be with the body fixed in an upright position and at reduced travelling speed. In this way, even the worst conceivable emergency, i.e. starting to travel on a curve at high speed, can be coped with, since the body can still be tilted by the emergency control system.
Furthermore, the concept of using especially reliable mechanical elements, i.e., an inertia mass or an inertia pendulum, for the emergency control is realized by the invention. The control members actuated by these elements are rendered ineffective during normal operation but work continuously in the same way as in an emergency. The reliability is further increased owing to the fact that parallel control circuits with, in each case, functionally separate tasks are provided.
At the same time, the system according to the invention is distinguished by desirable simplicity by virtue of the fact that, in emergencies, when transverse acceleration of the vehicle is significant, in each case the maximum body tilt is set in the direction of the transverse acceleration. As a result, maximum side-tilt stability of the vehicle when travelling on curves is ensured on the one hand, and considerable constructional simplicity and corresponding reliability are ensured on the other hand. Only a loss of comfort for the occupants has to be accepted.
In a currently preferred embodiment of the invention, a double-acting fluidic actuator for setting the body tilt is provided and an accumulator is provided as energy storage device for an emergency. The accumulator is shut off from the actuator during normal operation by a shut-off valve continuously spring-loaded in the opening direction.
The first control circuit, in the case of a fluidic actuator, can have a valve arrangement which is actuated by the inertia mass, is arranged between the accumulator and the actuator. When transverse acceleration is slight or disappears, the valve arrangement disconnects both sides of the actuator from the accumulator and, when transverse acceleration is significant, in each case connects one side of the actuator to the accumulator and the other side of the actuator to a relatively pressureless outlet. In the case of a hydraulic system, this outlet can lead to a relatively pressureless hydraulic reservoir.
The second control circuit can have a shut-off valve controlled by the inertia mass and opened when transverse acceleration disappears and, in series with said shut-off valve, a control valve. The control valve is controlled by the body tilt and, depending on the direction of the body tilt, connects the one or the other side of the actuator to the accumulator and connects the respectively remaining side of the actuator to the relatively pressureless outlet in such a way that the body tilt is retracted.
In an especially preferred embodiment of the invention, the inertia mass as well as the control elements or valves actuated by the mass may be arranged on a platform, which is continuously approximately horizontal or is held horizontal, in order to be able to utilize the inertia effects in an especially effective manner.
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Crowell & Moring , L.L.P.
Daimler-Chrysler AG
Dickson Paul N.
Fischmann Bryan
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