WO2017212038A1 - Procédé de vérification de l'assemblage correct d'un amortisseur hydraulique à deux tubes, en particulier pour une suspension de véhicule - Google Patents

Procédé de vérification de l'assemblage correct d'un amortisseur hydraulique à deux tubes, en particulier pour une suspension de véhicule Download PDF

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Publication number
WO2017212038A1
WO2017212038A1 PCT/EP2017/064152 EP2017064152W WO2017212038A1 WO 2017212038 A1 WO2017212038 A1 WO 2017212038A1 EP 2017064152 W EP2017064152 W EP 2017064152W WO 2017212038 A1 WO2017212038 A1 WO 2017212038A1
Authority
WO
WIPO (PCT)
Prior art keywords
cylindrical tube
outer cylindrical
absorber
shock
barkhausen noise
Prior art date
Application number
PCT/EP2017/064152
Other languages
English (en)
Inventor
Daniele Bussolino
Piero Antonio CONTI
Original Assignee
Sistemi Sospensioni S.P.A.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sistemi Sospensioni S.P.A. filed Critical Sistemi Sospensioni S.P.A.
Publication of WO2017212038A1 publication Critical patent/WO2017212038A1/fr

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M17/00—Testing of vehicles
    • G01M17/007—Wheeled or endless-tracked vehicles
    • G01M17/04—Suspension or damping
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G13/00—Resilient suspensions characterised by arrangement, location or type of vibration dampers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/32—Details
    • F16F9/3207—Constructional features
    • F16F9/3235—Constructional features of cylinders
    • F16F9/3242—Constructional features of cylinders of cylinder ends, e.g. caps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/32—Details
    • F16F9/3271—Assembly or repair
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/32—Details
    • F16F9/36—Special sealings, including sealings or guides for piston-rods
    • F16F9/362—Combination of sealing and guide arrangements for piston rods
    • F16F9/364—Combination of sealing and guide arrangements for piston rods of multi-tube dampers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2202/00—Indexing codes relating to the type of spring, damper or actuator
    • B60G2202/20—Type of damper
    • B60G2202/24—Fluid damper
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2206/00—Indexing codes related to the manufacturing of suspensions: constructional features, the materials used, procedures or tools
    • B60G2206/01—Constructional features of suspension elements, e.g. arms, dampers, springs
    • B60G2206/90—Maintenance
    • B60G2206/91—Assembly procedures

Definitions

  • the present invention relates to a method for checking the correct assembling of a twin- tube hydraulic shock-absorber, particularly for a vehicle suspension.
  • a twin-tube hydraulic shock- absorber for use in particular on a vehicle suspension, is generally indicated 10 and comprises, in per-se-known manner:
  • an outer cylindrical tube 12 with a closed bottom end and an open top end, the bottom end being closed by a cover 12a which may be a piece separate from the outer cylindrical tube 12 and attached to this tube (for example, by welding) or, alternatively, may be integrally formed by the outer cylindrical tube 12 itself;
  • an inner cylindrical tube 14 which is arranged coaxially with the outer cylindrical tube 12 and defines with the latter a reservoir chamber 16;
  • a piston 18 slidably received in the inner cylindrical tube 14 so as to split the internal volume of this tube into an upper working chamber 20, or rebound chamber, and a lower working chamber 22, or compression chamber;
  • valve assembly 26 arranged at the bottom end of the inner cylindrical tube 14; a guide body 28 interposed between the top end of the inner cylindrical tube 14 and the top end of the outer cylindrical tube 12 to guide the rod 24 in the sliding movement thereof along a longitudinal axis of the cylindrical tubes 12 and 14; and
  • sealing member 30 arranged to sealingly close the outer cylindrical tube 12 at the top end thereof.
  • a hydraulic shock-absorber of the above-mentioned type is assembled first by inserting the various components of the shock-absorber (valve assembly 26, inner cylindrical tube 14, piston 18 with relating rod 24, guide body 28, sealing member 30 etc.) into the outer cylindrical tube 12 and finally by closing the outer cylindrical tube 12 at the top end thereof, for example by folding radially inwards a top edge 12b (or at least a portion of the top edge 12b) of the side wall of the outer cylindrical tube 12 or, more generally, by deforming at least a portion of the top edge 12b, so as to lock the sealing member 30 in its position and thus ensure that the outer cylindrical tube 12 is sealingly closed at its top end.
  • FIGS 3 and 4 of the attached drawings show the top end of the shock-absorber 10 before and after the aforesaid final closing step, respectively.
  • the sealing member 30 is clamped with a given axial load against the guide body 28, which is in abutment against the top end of the inner cylindrical tube 14, the latter being in turn in abutment against the valve assembly 26.
  • the invention is based on the idea of measuring, in either static or dynamic mode, the so-called Barkhausen noise on the outer cylindrical tube of the shock-absorber, both before and after the final closing step, and checking, once the final closing step has been carried out, whether the difference between the Barkhausen noise measured before the final closing step and the Barkhausen noise measured after the final closing step is higher than a given minimum level (in which case, the shock-absorber is to be regarded as being correctly assembled, in that the outer cylindrical tube has been properly closed at its top end) or not.
  • the final closing step leads to a change in the Barkhausen noise that can be measured on the outer cylindrical tube, which change is due to the stress state (namely, the tensile stress state) that is generated in the outer cylindrical tube of the shock-absorber as a result of the reaction force applied by the sealing member on that tube once the sealing member is compressed by the folded top edge of the outer cylindrical tube.
  • the stress state namely, the tensile stress state
  • the Applicant has experimentally checked the existence of a correlation between the amount of change in the Barkhausen noise measured on the outer cylindrical tube of the shock-absorber as a result of the final closing step and the correct or non-correct assembling condition of the shock-absorber, in that a change (namely, an increase) in the Barkhausen noise lower than a given minimum level means that the shock-absorber has not been correctly assembled, and more specifically that the outer tube has not been correctly closed at the top end thereof.
  • Figures 1 and 2 are a perspective view and an axial section view, respectively, of a twin-tube hydraulic shock-absorber, in particular for a vehicle suspension, to which the checking method of the present invention is applicable;
  • Figures 3 and 4 are axial section views showing in detail the top end portion of the shock-absorber of Figures 1 and 2 before and after the final closing step, respectively;
  • Figure 5 is a graph showing the values of the Barkhausen noise measured along the outer cylindrical tube of a shock-absorber before and after the final closing step.
  • Figure 6 indicates, for each shock-absorber of a batch of thirty shock-absorbers on which the Applicant has carried out tests, the value of the difference between the Barkhausen noise measured in a given point of the outer cylindrical tube of the shock-absorber after the final closing step and the Barkhausen noise measured in that point before the final closing step.
  • the graph shown therein illustrates the change over time of the Barkhausen noise, measured by a suitable detection probe (not shown, but of per-se-known type) moving at a constant speed along the outer cylindrical tube 12 of a shock-absorber 10, such as the one described above with reference to Figures 1 and 2, both before the final closing step (line designated by CI) and after the final closing step (line designated by C2).
  • the Barkhausen noise is indicated in the graph in terms of the physical quantity known as magneto -elastic parameter (mp).
  • the measure path along which the values of the Barkhausen noise as shown in the graph of Figure 5 have been measured is indicated with p in Figure 1.
  • the measure path p is preferably a straight path extending parallel to the longitudinal axis (indicated z in Figures 2 to 4) of the shock-absorber along a non-occupied portion of the outer cylindrical tube 12 of the shock-absorber, between a mounting bracket 32 and a spring plate 34 which are welded to the outer cylindrical tube 12 at the bottom and top ends thereof, respectively.
  • the length of the measure path p may be selected depending for example on the length of the outer cylindrical tube 12.
  • the Barkhausen noise measured after the final closing step (hereinafter simply referred to as "final noise”) is higher than the Barkhausen noise measured before the final closing step (hereinafter simply referred to as "initial noise”). More specifically, the final noise is higher than the initial noise both in the starting point and in the end point (indicated Pi and Pf in Figure 1 , respectively) of the measure path p. Furthermore, the maximum value of the final noise along the measure path p is higher than the maximum value of the initial noise along the measure path p.
  • the Applicant has realized that the condition of correct assembling of the shock-absorber, i.e. of correct closure of the outer cylindrical tube, de- pends on the difference between the final noise and the initial noise (which difference is indicated with Amp in the graph of Figure 6), in that a difference lower than a given minimum level means that the outer cylindrical tube of the shock-absorber has not been correctly closed, and that therefore the shock-absorber has not been properly assembled.
  • the checking method of the invention comprises therefore the following steps:
  • step d) a fourth step wherein the difference calculated at step c) is compared with the above-mentioned minimum level to determine whether the outer cylindrical tube of the shock-absorber has been correctly closed or not.
  • the Barkhausen noise on the outer cylindrical tube of the shock-absorber is measured by means of a measurement apparatus of per-se-known type, which will not be described herein.
  • a measurement apparatus of per-se-known type, which will not be described herein.
  • Any suitable measurement apparatus may there- fore be used to carry out the method of the invention.
  • the Barkhausen noise may be indifferently measured in static or dynamic mode.
  • the Barkhausen noise is measured before and after the final closing step along the whole measure path p and the difference Amp between the final noise and the initial noise is calculated considering for example the maximum value of the final noise and the maximum value of the initial noise.
  • a difference Amp lower than a given minimum level (which minimum level, as already explained, may be determined by carrying out a number of tests on the shock- absorber) means that the shock-absorber has not been correctly assembled and does not therefore comply with the prescribed requirements.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Fluid-Damping Devices (AREA)
  • Vehicle Body Suspensions (AREA)

Abstract

La présente invention concerne un procédé de vérification de l'assemblage correct d'un amortisseur hydraulique à deux tubes, en particulier pour une suspension de véhicule. Le procédé comprend les étapes de : a) mesure du bruit de Barkhausen sur le tube cylindrique externe (12) de l'amortisseur (10) avant une étape de fermeture finale par laquelle le tube cylindrique externe (12) est fermé à son extrémité supérieure de façon à verrouiller un élément d'étanchéité (30) dans sa position, en le serrant avec une charge de compression axiale donnée ; b) mesure du bruit de Barkhausen sur le tube cylindrique externe (12) une fois que l'étape de fermeture finale a été effectuée ; c) calcul de la différence (Δmp) entre le bruit de Barkhausen mesuré à l'étape b) et le bruit de Barkhausen mesuré à l'étape a) ; et d) comparaison de la différence (Δmp) calculée à l'étape c) avec un niveau de différence minimal donné, ledit niveau minimal étant choisi à l'avance de telle manière que ladite différence (Δmp) soit supérieure audit niveau minimal lorsque l'amortisseur (10) est correctement assemblé, c'est-à-dire lorsque le tube cylindrique externe (12) est correctement fermé à son extrémité supérieure, alors que ladite différence (Δmp) est inférieure audit niveau minimal lorsque l'amortisseur (10) n'est pas correctement assemblé, c'est-à-dire lorsque le tube cylindrique externe (12) n'est pas correctement fermé à son extrémité supérieure.
PCT/EP2017/064152 2016-06-09 2017-06-09 Procédé de vérification de l'assemblage correct d'un amortisseur hydraulique à deux tubes, en particulier pour une suspension de véhicule WO2017212038A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT102016000059080 2016-06-09
ITUA2016A004223A ITUA20164223A1 (it) 2016-06-09 2016-06-09 Procedimento per la verifica della corretta chiusura di un ammortizzatore idraulico a doppio tubo, particolarmente per sospensione di veicolo.

Publications (1)

Publication Number Publication Date
WO2017212038A1 true WO2017212038A1 (fr) 2017-12-14

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PCT/EP2017/064152 WO2017212038A1 (fr) 2016-06-09 2017-06-09 Procédé de vérification de l'assemblage correct d'un amortisseur hydraulique à deux tubes, en particulier pour une suspension de véhicule

Country Status (2)

Country Link
IT (1) ITUA20164223A1 (fr)
WO (1) WO2017212038A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19631311A1 (de) * 1996-08-02 1998-02-05 Fraunhofer Ges Forschung Verfahren und Vorrichtung zur zerstörungsfreien Materialprüfung
EP2098748A2 (fr) * 2008-03-07 2009-09-09 Kayaba Industry Co., Ltd. Absorbeur de choc de fluides
EP2101172A1 (fr) * 2008-03-12 2009-09-16 Scania CV AB Procédé et dispositif à utiliser en connexion avec la fabrication d'un véhicule ou une pièce de véhicule
WO2014134500A1 (fr) * 2013-02-28 2014-09-04 Tenneco Automotive Operating Company Inc. Amortisseur avec électronique intégrée

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19631311A1 (de) * 1996-08-02 1998-02-05 Fraunhofer Ges Forschung Verfahren und Vorrichtung zur zerstörungsfreien Materialprüfung
EP2098748A2 (fr) * 2008-03-07 2009-09-09 Kayaba Industry Co., Ltd. Absorbeur de choc de fluides
EP2101172A1 (fr) * 2008-03-12 2009-09-16 Scania CV AB Procédé et dispositif à utiliser en connexion avec la fabrication d'un véhicule ou une pièce de véhicule
WO2014134500A1 (fr) * 2013-02-28 2014-09-04 Tenneco Automotive Operating Company Inc. Amortisseur avec électronique intégrée

Also Published As

Publication number Publication date
ITUA20164223A1 (it) 2017-12-09

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