Measuring and testing – Testing of shock absorbing device
Reexamination Certificate
1998-04-03
2001-06-19
Fuller, Benjamin R. (Department: 2855)
Measuring and testing
Testing of shock absorbing device
C073S117020, C073S118040
Reexamination Certificate
active
06247348
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for and a method of testing-running characteristics of a part of a vehicle as an object to be tested on a test bench.
Related Art
A flat belt type chassis dynamo has been proposed in order to evaluate the maneuvering stability of the vehicle, instead of a conventional drum type chassis dynamo. For example, Japanese Patent Unexamined Publication No. 6-249753 discloses a method wherein support parts are provided, corresponding to wheels of the vehicle, on the upper surfaces of movable parts which can be swung by first hydraulic jacks actuated independent from one another, and which can be swung widthwise of the vehicle by second hydraulic jacks actuated independent from one another, and flat belts making contact with the wheels of the vehicle are provided respectively to the support parts, the movable parts being inclined so as to reproduce a climbing slope and a ramp and the support parts being inclined so as to variously change ground contact conditions of the wheels of the vehicle so as to reproduce various disturbances exhibited by the road surface, thereby precisely testing the maneuverability of the vehicle in various road surface conditions over a wide range.
Dynamic load variation occurs at each of wheels of a vehicle during acceleration or turning during actual running of vehicle, in addition to static load variation caused by a climbing slope or a ramp as mentioned above. For example, during acceleration, loads at rear wheels become larger, while during deceleration, loads at front wheels become larger, and during turning, loads at outer wheels become larger. These occur irrespective of a load configuration such as a flat road or a ramp. During acceleration, an inertia force is exerted to the gravitational center of the vehicle while a drive force is exerted to the ground contact points of the tires, and accordingly, moments are generated around the pitching axis. Load displacement from the front wheels to the rear wheels occurs, corresponding to forces balancing the above-mentioned pitching moments. Similarly, a centrifugal force is exerted to the gravitational center of the vehicle during turning while a cornering force is exerted to a ground contact point, and accordingly, a rolling moment is effected. A displacement of a load from an outer wheel to an inner wheel occurs, corresponding to a force balancing with the rolling moment.
Further, the wheels stroke vertically while they are guided by suspension links. Since the links have a limited length, the alignment with respect to the road surface is always changed as the wheels stroke.
The variation in load and variation in the alignment intricately influence upon each other so as to excessively affect the friction forces between the tires and the road surfaces, and are influence factors which are not negligible for analyzing the maneuverability of the vehicle, in particular abrupt changes in maneuvering.
Further, in the case of testing a vehicle on actual running, variations in the attitude of the vehicle continuously affect constraint conditions with respect to inputs to the four wheels. However, in the case of testing a suspension for a single wheel as a module, influence caused by variation in the attitude of an overall vehicle cannot be taken into account, that is, it has been impossible to evaluate how the suspension for a single wheel affects the maneuvering of an overall vehicle.
SUMMARY OF THE INVENTION
One object of the present invention is to provide an apparatus for testing dynamic characteristics of a vehicle component, that is, a part of a vehicle to be tested, and a module, which can be evaluated and analyzed on a test bench, in consideration with a variation in load and a variation in alignment during running of the vehicle.
In a method of causing respective functional components of a vehicle, which relate to the maneuvering performance of a vehicle, as an object to be tested, to reproduce, on a test bench, a condition in consideration with variation in load and variation in alignment, which occur during actual running of a vehicle, it is required to subject a dummy chassis on which functional components and a module are installed, to an attitude change or a load variation by forces represented by an inertia force upon acceleration and a centrifugal force upon turning during actual running of a vehicle, and accordingly, it is also required to adjust these forces in accordance a load variation and an alignment variation resulting therefrom.
Thus, according to one aspect of the present invention, there is provided a vehicle component dynamic test apparatus for testing running characteristics of respective vehicle components relating to maneuvering performances of a vehicle, and a module on a test bench, comprising a frame, a dummy chassis supported by a plurality of actuators connected to the frame, for setting up thereon components including at least one wheel, a dummy road surface simulating a road surface on which the vehicle runs, reaction force measuring means for measuring a reaction force produced when the wheel among the components makes contact with the dummy road surface, an attitude measuring means for measuring an attitude of the dummy chassis with respect to the frame, control means for the actuators, control means for the dummy road surface, numerical model storage means for storing numerical models of the vehicle on which the above-mentioned components will be installed, and a digital computer for computing an attitude of the vehicle and a load applied to the road surface from each of wheels of the vehicle, from a measured reaction force value measured by the reaction force measuring means and the numerical models stored in the numerical model storage means, and for delivering instruction signals to the control means for the actuators and the control means for the dummy road surface so as to decrease a difference between the attitude of the dummy chassis measured by the attitude measuring means and the calculated attitude, and a difference between a load applied to the dummy road surface, which is computed from a reaction force of the wheel corresponding to the component to be tested, which has been measured by the reaction force measuring means, and a load applied to a road surface by the wheel.
Further, in such a case that the number of wheels, constituted by the number of functional components and the number of modules is smaller than the number of wheels of a vehicle on which the functional components and the module are installed, there may be provided a digital computer for computing an attitude of the vehicle and loads applied to a road surface by the wheels from a preset test condition, a measured reaction force measured by the reaction force measuring means, and the numerical models stored in the numerical model storage means.
Further, the reaction force measuring means preferably measures a reaction force from decomposed components longitudinal, crosswise and vertical with respect to the dummy road surface.
Further, if the reaction force measuring means measures a longitudinal component from the dummy road surface, a rotational displacement about a rotary axis crosswise of the dummy road surface may preferably be applied to the dummy chassis by the actuators.
Further, if the reaction force measuring means measures a crosswise component from the dummy road surface, a rotational displacement about a rotary axis longitudinal of the dummy road surface may preferably be applied to the chassis by the actuators.
Further, the attitude measuring means may computes an attitude of the dummy chassis from displacements of the actuators, which are measured by actuator displacement sensors incorporated in the actuators.
Further, the dummy road surface may preferably be composed of a flat-belt type chassis dynamo, and the reaction force measuring means may measure a longitudinal reaction force of the dummy road surface as a value which is computed from rotational data including a rotational inertia of the flat-belt type ch
Horiuchi Toshihiko
Konno Takao
Yamagishi Wataru
Yamakado Makoto
Antonelli Terry Stout & Kraus LLP
Fuller Benjamin R.
Hitachi , Ltd.
Thompson Jewel V.
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