US 5,665,901 AGranted

Shock absorber testing device

AssigneeFichtel & Sachs AG

InventorsFrank Ilzig, Norbert Omlor

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Abstract

At least one adjustable drive unit for a wheel support which can be set in oscillation, and electronic units which measure and evaluate the oscillating movement of the suspended vehicle with the following process steps: Acceleration of the wheel support by the drive unit to an oscillation measurement point A in an oscillation range above the resonance frequency of the wheel, and maintenance of the wheel support in this oscillating condition, until at measurement point B, the wheel has matched the oscillations of the wheel support with sufficient accuracy; A delayed reduction of the oscillation frequency with simultaneous measurement and storage of the oscillation amplitude to a reverse oscillation frequency at measurement point C, at which, during the reduction of the oscillation frequency, the oscillation amplitude has fallen below a first limit value which is considered an indicator of the faded, or decayed, resonance frequency; An increase in the oscillation frequency with simultaneous measurement and storage of the oscillation amplitude to a measurement point D, at which the oscillation amplitude has fallen below a second limit value which serves as an indicator for a faded resonance frequency; A deceleration of the oscillation movement of the wheel support unit it comes to a standstill; and A comparative measurement of the oscillation amplitude measured between measurement points C and D with an oscillation amplitude of a reference shock absorber.

Claims20

Dependent claims

A process for the in situ testing of the performance of at least one shock absorber being tested by comparison to the performance characteristics of a reference shock absorber, said at least one shock absorber being tested being mounted on a wheel of a vehicle during said testing process and said at least one shock absorber having at least one resonant frequency, said vehicle including said wheel, said at least one shock absorber being tested mounted on said wheel and a vehicle body, said process comprising the steps of:

providing a wheel support member;
providing means for oscillating said wheel support member over a range of oscillation frequencies;
disposing said wheel of said vehicle on said wheel support member;
oscillating said wheel support member at an oscillation frequency;
sensing the induced oscillations of at least one of said vehicle body and said wheel during at least a portion of said step of oscillating said wheel support member;
increasing said oscillation frequency of said wheel support member up to a first oscillation frequency at a measurement point A, said first oscillation frequency being greater than said at least one resonant oscillation frequency of said at least one shock absorber being tested;
maintaining said oscillation frequency of said wheel support member of said first oscillation frequency until a measurement point B, at which the induced oscillations of said wheel are substantially about matched to said first oscillation frequency;
decreasing said oscillation frequency of said wheel support member to a second oscillation frequency at a measurement point C, at which said sensed induced oscillations of said vehicle body are less than a first determined value, said second oscillation frequency being substantially less than said at least one resonant frequency of said at least one shock absorber being tested;
increasing said oscillation frequency of said wheel support member to a third oscillation frequency at a measurement point D, at which said sensed induced oscillations of said vehicle body are less than a second determined value;
and
comparing said sensed induced oscillations of said vehicle including said at least one shock absorber being tested between at least said measurement points C and D to the reference oscillations between at least said measurement points C and D of said reference shock absorber.

8 more elements

A shock absorber testing device for the in situ testing of the performance of at least one shock absorber being tested by comparison to the performance characteristics of a reference shock absorber, said at least one shock absorber being tested being mounted on a wheel of a vehicle during said testing process and having at least one resonant frequency, said vehicle including said wheel, said at least one shock absorber being tested mounted on said wheel and a vehicle body, said shock absorber testing device comprising:

wheel support means for receiving and supporting said wheel of said vehicle;
oscillation means for oscillating said wheel support means at an oscillation frequency within a range of oscillation frequencies, said range of oscillation frequencies including said at least one resonant oscillation frequency of said at least one shock absorber being tested;
sensing means for sensing the induced oscillations of at least one of said vehicle body and said wheel during at least a portion of said oscillation of said wheel support member;
and
control means for determining and controlling said oscillation of said wheel support means, said control means comprising:
means for increasing said oscillation frequency of said wheel support member up to a first oscillation frequency at a measurement point A, said first oscillation frequency being greater than said at least one resonant oscillation frequency of said at least one shock absorber being tested;
means for maintaining said oscillation frequency of said wheel support member at said first oscillation frequency until a measurement point B, at which the induced oscillations of said wheel are substantially about matched to said first oscillation frequency;
means for decreasing said oscillation frequency of said wheel support member to a second oscillation frequency at a measurement point C, at which said sensed induced oscillations of said vehicle body are less than a first determined value, said second oscillation frequency being substantially less than said at least one resonant frequency of said at least one shock absorber being tested;
means for increasing said oscillation frequency of said wheel support member to a third oscillation frequency at a measurement point D, at which said sensed induced oscillations of said vehicle body are less than a second determined value;
and
means for comparing said sensed induced oscillations of said vehicle including said at least one shock absorber being tested between at least said measurement points C and D to the reference oscillations between at least said measurement points C and D of said reference shock absorber.

8 more elements

A process for the in situ testing of the performance of at least one shock absorber being tested by comparison to the performance characteristics of a reference shock absorber, said at least one shock absorber being tested being mounted on a wheel of a vehicle during said testing process and having at least one resonant frequency, said vehicle including said wheel, said at least one shock absorber being tsted mounted on said wheel and a vehicle body, said vehicle being positioned on a shock absorber testing device during said testing process, said shock absorber testing device comprising:

wheel support means for receiving and supporting said wheel of said vehicle;
oscillation means for oscillating said wheel support means at an oscillation frequency within a range of oscillation frequencies, said range of oscillation frequencies including said at least one resonant oscillation frequency of said at least one shock absorber being tested;
sensing means for sensing the induced oscillations of at least one of said vehicle body and said wheel during at least a portion of said oscillation of said wheel support member;
and
control means for determining and controlling said oscillation of said wheel support means, said control means comprising:
means for increasing said oscillation frequency of said wheel support member up to a first oscillation frequency at a measurement point A, said first oscillation frequency being greater than said at least one resonant oscillation frequency of said at least one shock absorber being tested;
means for maintaining said oscillation frequency of said wheel support member at said first oscillation frequency until a measurement point B, at which the induced oscillations of said wheel are substantially about matched to said first oscillation frequency;
means for decreasing said oscillation frequency of said wheel support member to a second oscillation frequency at a measurement point C, at which said sensed induced oscillations of said vehicle body are less than a first determined value, said second oscillation frequency being substantially less than said at least one resonant frequency of said shock absorber being tested;
means for increasing said oscillation frequency of said wheel support member to a third oscillation frequency at a measurement point D, at which said sensed induced oscillations of said vehicle body are less than a second determined value;
and
means for comparing said sensed induced oscillations of said vehicle including said at least one shock absorber being tested between at least said measurement point C and D to the reference oscillations between at least said measurement points C and D of the reference shock absorber;
said process comprising the steps of:
disposing said wheel of said vehicle on said wheel support means;
oscillating said wheel support means at an oscillation frequency;
sensing the induced oscillations of at least one of said vehicle body and said wheel during at least a portion of said step of oscillating said wheel support means;
increasing said oscillation frequency of said wheel support means up to a first oscillation frequency at a measurement point A, said first oscillation frequency being greater than said at least one resonant oscillation frequency of said at least one shock absorber being tested;
maintaining said oscillation frequency of said wheel support means at said first oscillation frequency until a measurement point B, at which the induced oscillations of said wheel are substantially about matched to said first oscillation frequency;
decreasing said oscillation frequency of said wheel support means to a second oscillation frequency at a measurement point C, at which said sensed induced oscillations of said vehicle body are less than a first determined value, said second oscillation frequency being substantially less than said at least one resonant frequency of said at least one shock absorber being tested;
increasing said oscillation frequency of said wheel support means to a third oscillation frequency at a measurement point D, at which said sensed induced oscillations of said vehicle body are less than a second determined value;
and
comparing said sensed induced oscillations of said vehicle including said at least one shock absorber being tested between at least said measurement points C and D to the reference oscillations between at least said measurement points C and D of said reference shock absorber.

18 more elements

Dependencies are inferred from the claim text.