Test rig and process for testing motor vehicle assemblies, in particular independent wheel suspension

Claim 1

Test rig for testing motor-vehicle assemblies of the type including spring means under operational loading conditions comprising: a frame for rigidly supporting the motor-vehicle assembly; modifying means for modifying the spring means of the motor-vehicle assembly for linearising a spring characteristic of said spring means; loading means for inducing vertical forces F Z , lateral forces F Y , longitudinal forces F X and braking or driving forces F XB in the motor-vehicle assembly; and control means for controlling the loading means in such a way that the vertical forces F Z , lateral forces F Y , longitudinal forces F X and braking or driving forces F XB are induced, in accordance with a predetermined control loading program, by means of which different loading cases which are realistic in relation to actual motoring physics and combined to form loading blocks are repeatedly and in temporary consecutive sequence simulated in the motor vehicle assembly, wherein said control loading program comprises as loading cases driving straight ahead, cornering, braking and accelerating and according to which actual forces in accordance with the formula F.sub.Ri (t.sub.j)=B.sub.Ri (t.sub.j)·a.sub.Ri ·P.sub.r are applied during a corresponding time t j to the motor vehicle assembly; wherein i denotes the loading case with i=1 for driving straight ahead, i=2 when cornering, i=3 for braking and i=4 for accelerating; wherein further R denotes the load direction with R=z for the vertical force, R=x for the longitudinal force, R=xB for the braking and driving force and R=y for the lateral force; so that the forces to be applied are as follows: ______________________________________ Forces to be applied in the different loading cases: Type of Straight force ahead Cornering Braking Accelerating ______________________________________ F.sub.Z F.sub.Z1 (t.sub.j) F.sub.Z2 (t.sub.j) F.sub.Z3(t.sub.j) F.sub.Z4 (t.sub.j) (vertical force) | F.sub.X F.sub.X1 (t.sub.j) F.sub.X2 (t.sub.j) F.sub.X3(t.sub.j) F.sub.X4 (t.sub.j) (longitudinal force) F.sub.XB F.sub.XB1 (t.sub.j) F.sub.XB2 (t.sub.j) F.sub.XB3(t.sub.j) F.sub.XB4 (t.sub.j) (braking or driving force) F.sub.Y F.sub.Y1 (t.sub.j) F.sub.Y2 (t.sub.j) F.sub.Y3(t.sub.j) F.sub.Y4 (t.sub.j) (lateral force) ______________________________________ with B R1 (t j ) in the above formula being basic forces which are for the corresponding loading cases as follows: ______________________________________ Basic forces for the different loading cases: Type of Straight force ahead Cornering Braking Accelerating ______________________________________ F.sub.Z B.sub.Z1 (t.sub.j) B.sub.Z2 (t.sub.j) B.sub.Z3(t.sub.j) B.sub.Z4 (t.sub.j) (vertical force) F.sub.X B.sub.X1 (t.sub.j) B.sub.X2 (t.sub.j) B.sub.X3(t.sub.j) B.sub.X4 (t.sub.j) (longitudinal force) F.sub.XB B.sub.XB1 (t.sub.j) B.sub.XB2 (t.sub.j) B.sub.XB3(t.sub.j) B.sub.XB4 (t.sub.j) (braking or driving force) F.sub.Y B.sub.Y1 (t.sub.j) B.sub.Y2 (t.sub.j) B.sub.Y3(t.sub.j) B.sub.Y4 (t.sub.j) (lateral force) ______________________________________ and with a R1 being at least one of vehicle- and axle specific conversion factors and P R being test-rig-specific conversion factors which are as follows for the different loading cases: ______________________________________ Vehicle- and[/or] axle-specific conversion factors for the Test-rig- different loading cases specific Type of Straight Corner- Brak- Accel- conversion force ahead ing ing erating factor ______________________________________ F.sub.Z a.sub.Z1 a.sub.Z2 a.sub.Z3 a.sub.Z4 P.sub.Z (vertical force) F.sub.X a.sub.X1 a.sub.X2 a.sub.X3 a.sub.X4 P.sub.X (longitudinal force) F.sub.XB a.sub.XB1 a.sub.XB2 a.sub.XB3 a.sub.XB4 P.sub.XB (braking or driving force) F.sub.Y a.sub.Y1 a.sub.Y2 a.sub.Y3 a.sub.Y4 P.sub.Y (lateral force) ______________________________________ so that a given force F R1 (t j ) according to the control loading program equals a basic force B R1 (t j ) modified by multiplication with a vehicle-and/or axle-specific conversion factor a R1 and a test-rig-specific conversion factor P r .