EP1421358A2 - Method for predicting the maximum rolling distance in degraded mode of a mounted assembly - Google Patents

Method for predicting the maximum rolling distance in degraded mode of a mounted assembly

Info

Publication number
EP1421358A2
EP1421358A2 EP02759777A EP02759777A EP1421358A2 EP 1421358 A2 EP1421358 A2 EP 1421358A2 EP 02759777 A EP02759777 A EP 02759777A EP 02759777 A EP02759777 A EP 02759777A EP 1421358 A2 EP1421358 A2 EP 1421358A2
Authority
EP
European Patent Office
Prior art keywords
rolling
support
rim
crushing
value
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP02759777A
Other languages
German (de)
French (fr)
Inventor
Laurent Ferres
Daniel Thiallier
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Michelin Recherche et Technique SA Switzerland
Michelin Recherche et Technique SA France
Societe de Technologie Michelin SAS
Original Assignee
Michelin Recherche et Technique SA Switzerland
Michelin Recherche et Technique SA France
Societe de Technologie Michelin SAS
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 Michelin Recherche et Technique SA Switzerland, Michelin Recherche et Technique SA France, Societe de Technologie Michelin SAS filed Critical Michelin Recherche et Technique SA Switzerland
Publication of EP1421358A2 publication Critical patent/EP1421358A2/en
Withdrawn legal-status Critical Current

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
    • G01M17/02—Tyres
    • 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
    • G01M17/02—Tyres
    • G01M17/022—Tyres the tyre co-operating with rotatable rolls

Definitions

  • the present invention relates to a method of predicting the maximum driving distance in degraded mode, without substantial deterioration of the driving conditions, of a mounted assembly comprising a wheel rim, a safety support which is mounted on said rim and an envelope. tire which is mounted on said rim, said support supporting the tread of said casing during said rolling (rolling in “degraded mode” is a rolling at reduced or zero inflation pressure).
  • the invention also relates to an installation for implementing this method.
  • the safety supports for vehicle tires are intended to be mounted on a rim inside the tire, in order to be able to support the tread of this tire in the event of loss of inflation pressure.
  • These supports include in particular a base which is intended to be mounted on the rim, and a top which is intended to come into contact with the tread in the aforementioned case and which leaves a guard with respect to the latter at nominal pressure .
  • This annular body comprises a support element which is circumferentially continuous with a circumferential median plane, said support element comprising a plurality of partitions extending axially on either side of said circumferential median plane and distributed over the circumference of said support.
  • the stop criterion for this run test in degraded mode which is chosen by the operator in charge of the test, corresponds to the appearance of one or more specific damages concerning both the safety support and the tire cover.
  • the damage relating to the support can for example be materialized by cracks or breaks at the location of the partitions of the support due to a significant internal heating and the buckling stresses to which said support is subjected when running in degraded mode.
  • Damage to the envelope may, for example, be materialized by cuts at the location of the sides of the envelope, in particular due to the camber stresses to which said envelope is subjected on a more or less hazy circuit, or by pure rupture. and simple, making it impossible to continue driving in degraded mode.
  • this or these stopping criteria are parameters which can have a determining effect on the result of maximum driving distance in degraded mode without substantial deterioration of driving conditions, which is obtained at the end of this. circuit test.
  • the parameters relating to the ambient air (temperature) and to the coating of the circuit used can also influence the maximum driving distance obtained in degraded mode.
  • a major drawback of these circuit prediction tests lies in the difficulty of keeping the above parameters identical from one test to another because of their variability, as well as in the more or less restrictive nature of these parameters for the 'support and envelope during taxiing in degraded mode. This may in particular result in Difficulties in comparing the respective endurance in running of different assemblies mounted in degraded mode.
  • the aim of the present invention is to propose a method for predicting the maximum driving distance in degraded mode, without substantial deterioration of the driving conditions (that is to say without loss of control of the vehicle), of an assembly mounted comprising a wheel rim, a safety support which is mounted on said rim and a tire casing which is mounted on said rim around said support, said support supporting the tread of said casing during said rolling, which makes it possible to predict in a reliable and reproducible manner the maximum running distances in degraded mode of different mounted assemblies and to compare them with one another under identical experimental conditions.
  • said prediction method consists in rolling said assembled assembly at a reduced or zero inflation pressure, from an instant to, at a given temperature, under a determined load and with a constant speed V, on at least one rolling surface so that the center of said wheel rim is a substantially invariant point during said rolling (ie on a rolling wheel, typically), following the variation of a variable R representative of the radial crushing of the support as a function of the running time t at reduced or zero pressure, and in that this method consists, during this running, in implementing the sequence of steps ( i) to (iii) below:
  • said value ⁇ R which is adopted in step (ii) constitutes a criterion for stopping the rolling, beyond which the support is subjected to stresses and to heating capable of rendering it unfit for use. .
  • said method of predicting the maximum rolling distance of said assembly mounted at reduced or zero inflation pressure, without substantial deterioration of the rolling conditions consists in rolling, also at a given temperature. , under a determined load and with a constant speed V, said support mounted on said wheel rim directly in contact with said rolling surface so that the center of said rim is a substantially invariant point during said rolling, following the variation of said variable R representative of the radial crushing of the support as a function of the running time t at reduced or zero pressure, and in that this method consists, during this running, in implementing steps (i), (ii ) and (iii) above.
  • said support is mounted on the rim by clipping, in this second mode.
  • step (ii) above consists in monitoring the variation of said variable R from said time t ⁇ _ and predicting that it reaches said critical value R 2 at said critical time t 2 substantially when the instantaneous acceleration of the overwriting d R / dt of said support passes through a zero value.
  • this critical time t 2 is such that the graph of said variable R has a point of inflection substantially at said time t 2 , that is to say a reversal of the direction of variation of the slope dR / dt for t > t 2 translating an increasingly high crushing speed of the support which quickly leads to the aforementioned cracks or rupture of said support.
  • said variable R representative of the radial crushing of the support advantageously corresponds to the mean radius of said support during crushing (also called “crushed radius”), radius measured between a first point defining the center of said wheel rim and a second point defining the center of the contact surface between said tread and said rolling surface.
  • this variable R also corresponds to said radius during crushing, except that this radius is here measured between a first point defining the center of said wheel rim and a second point defining the center of the contact surface between the radially external face of said support and said rolling surface.
  • variable R could also correspond to the arrow relating to said support due to the crushing, or even to the relative crushing of the support
  • ratio of the arrow on the height of the support the direction of variation of this arrow or of this relative crushing being generally increasing as a function of said time t, beyond the stabilization time ti.
  • said prediction method also consists in estimating that said maximum driving distance without substantial deterioration of driving conditions is reached just before smoke is detected at the interior of said assembled assembly.
  • said rolling surface used has a geometry substantially cylindrical, and it is for example made up of a rolling wheel, ie whose rolling surface is a cylinder of circular section. It will be noted that this rolling surface can be convex or concave, depending on whether the exterior or interior face of the steering wheel is used, respectively. According to another exemplary embodiment of the invention common to the two abovementioned embodiments, said rolling surface used has a substantially planar geometry, for example of the treadmill type.
  • the running surface used can be smooth, or else have a plurality of projecting and / or re-entrant irregularities which are more or less regularly spaced. on its perimeter.
  • These irregularities can for example consist of obstacles of the bar type, intended to reproduce the rolling stresses due to manhole covers or other reliefs commonly encountered during an actual road rolling, or else of hollows, for example intended to reproduce the constraints inherent in rolling over potholes.
  • the wheel rim comprises in each of its two peripheral edges a rim seat intended to receive a bead of said casing, said rim comprising between its two seats, on the one hand, a bearing intended to receive said support and, on the other hand, a mounting groove connecting said bearing to an axially internal rim of one of said seats.
  • an annular body connecting said base and said vertex to each other, said body comprising a circumferentially continuous support element with a circumferential median plane, said support element comprising a plurality of partitions extending axially on either side of said median plane circumferential and distributed over the circumference of said support.
  • An installation according to the invention for implementing the aforementioned prediction method according to said first or second embodiments essentially comprises at least one rolling surface, and one or more rolling stations which are each intended for rolling on said surface a mounted assembly comprising a tire casing mounted on a wheel rim around a safety support with reduced or zero inflation pressure, or else when rolling on said surface of such a support mounted on a wheel rim, the center of said assembled assembly or of said support being a substantially invariant point during rolling on said or each rolling surface, this installation being characterized in that it also comprises: - detection means which are connected to said or to each rolling and which are intended to detect at each instant, during rolling on said or each surface, information representative of the effects in duits by this rolling comprising at least one item of information representative of the radial crushing of said support at each instant, and
  • a unit for controlling the starting of the taxi according to predetermined taxi parameters comprising a speed V of the taxi and a load to be applied to the support during the taxi, for receiving said information from said detection means and memorizing it, and for command the halting of driving if at least one of said information reaches a predetermined critical value.
  • said detection means comprise a crushing sensor, for example of the potentiometric type, which is designed to supply at all times a value of support radius during crushing which is representative of the average radial crushing of said support during rolling, said radius being crushed being measured between a first point defining the center of the wheel rim and a second point defining the center of the contact surface between the casing, or the support as appropriate, and said rolling surface.
  • a crushing sensor for example of the potentiometric type, which is designed to supply at all times a value of support radius during crushing which is representative of the average radial crushing of said support during rolling, said radius being crushed being measured between a first point defining the center of the wheel rim and a second point defining the center of the contact surface between the casing, or the support as appropriate, and said rolling surface.
  • said detection means also comprise a smoke detector which is designed to detect the presence of smoke by internal heating inside said assembly assembled in progress of rolling at reduced or zero pressure, by means of suction means which are provided inside said rolling station to suck in the direction of said detector the air included inside said mounted assembly.
  • FIG. 3 is a block diagram illustrating the simplified structure of an installation according to the invention
  • FIG. 4 a schematic view of a rolling station of the installation of FIG. 3
  • FIG. 5 is a detail view in section of an internal part of the rolling station according to the plane IV-IV of FIG. 4
  • FIG. 6 is a graph illustrating the evolution over time, at the end of running flat, of two characteristics representative of the radial crushing of a support.
  • a support 1 which can be used to implement the prediction method according to the invention essentially comprises three parts:
  • a base 2 of generally annular shape, a crown 3, substantially annular, with on its radially outer wall (optionally) longitudinal grooves 5, and
  • annular body 4 for connection between the base 2 and the top 3.
  • Fig. 2 illustrates in particular the function of the support 1 when it is mounted on a wheel rim 6, which is to support the tread 7 of a tire casing 8 in the event of a fall in the inflation pressure at inside of the mounted assembly 9 comprising the rim 6, the support 1 and the casing 8.
  • the support 1 comprises a first solid part 4a of the annular body 4 as well as a second part 4b comprising recesses separated from each other by partitions 4a (see also Fig. 1) extending axially over substantially more than half of the annular body 4, opening on the outside in a substantially axial direction.
  • partitions 4a are regularly distributed over the entire circumference of the annular body 4.
  • the installation 10 essentially comprises: a rolling machine 20 comprising a flywheel 21 which is mounted on a motor shaft 22 for its rotational drive, one or more rolling stations 30 which are each intended for rolling on the steering wheel 21 d a mounted assembly 9, or else a safety support 1 mounted on a rim 6 (a single station 30 is shown in FIG. 3 for simplification purposes),
  • - Detection means 40 which are connected to said or to each taxiing station 30 and which are provided for detecting at each instant, during taxiing “flat” on the steering wheel 21, information representative of the effects induced by this taxiing on the 'mounted assembly 9 (or on the support 1, as the case may be), and - a unit 50 for controlling the start-up of said rolling according to predetermined rolling parameters, for receiving said information from said means 40 and storing it, and for command the stopping of said rolling if at least one of said information reaches a predetermined critical value.
  • the rolling station 30 is shown in more detail in FIG. 4.
  • This station 30 essentially consists of a frame 31 on which is mounted a hub 32 which is in this example intended to receive the assembled assembly 9 or the rim 6 provided with the support 1 (only the hub 32 is shown at for clarity) in order to roll the casing 8 or said support 1 on the steering wheel 21.
  • the hub 32 is mounted movable in translation on the frame 31 by displacement means 33, so as to allow the rolling of the casing 8 (or support 1, as the case may be) on the steering wheel 21 according to a given load.
  • the axis of symmetry of the hub 32 is provided parallel to said drive shaft 22 (not visible in FIG. 4) of the flywheel 21, and the hub 32 includes bearings (not visible) to allow rotation of the mounted assembly 9 or rim 6 provided with support 1 in contact with the steering wheel 21.
  • the rolling machine 20 is such that the steering wheel 21 has a smooth rolling surface.
  • the hub 32 is provided, at the location of its axis of symmetry, with a tube 34 or "valve nose", which projects axially at the front of the hub 32 and which is intended to be connected to the valve. wheel of the assembled assembly 9.
  • the displacement means 33 of the hub 32 comprise in this embodiment bellows 35 which are controlled by pneumatic type control means (not shown) to which they are connected, so that they can pass from one withdrawal position, in which the casing 8 or the support 1 are distant from the steering wheel 21, at various rolling positions, in which the casing 8 (or the support 1, as the case may be) are applied to the steering wheel 21 .
  • the means 40 for detecting the effects of rolling on the mounted assembly 9 essentially comprise a crushing sensor 41 which is designed to supply at all times a value of "crushed radius” which is representative of the average radial crushing of the support 1 during said rolling. This "crushed radius" is measured at each second of travel between a first point defining the center C of the wheel 6 and a second point defining the center of the contact surface between the tread 7 and the steering wheel 21.
  • this sensor 41 is of potentiometric type and it is provided with a wire (not shown in FIG. 4) which is connected to the displacement means 33 of the rolling station 30 so as to assign to each position of said station 30 a value of "radius overwritten".
  • sensor 41 As sensor 41, a sensor sold by the company ASM under the name "WL 10/250 / 10V / L 10" is used for example.
  • the means 40 further comprise a smoke detector 42 which is designed to detect any presence of smoke by internal heating inside the assembly mounted 9 during taxiing
  • This smoke detector 42 is connected to the unit 50 so as to be able to transmit an alarm signal to it in the event of smoke detection.
  • the smoke detector 42 is connected to the internal end of said tubing or “valve nose” 34 by suction means 43 which are provided inside the station 30 for sucking in the direction of the detector 42 the smoke generated at inside the assembled assembly 9. Part of these suction means 43 is shown in FIG. 5.
  • These means 43 essentially comprise, from said tubing 34, a tube 44 which is connected to the latter so as to communicate with the interior of the assembly mounted 9 in rotation, a rotary joint 45 which is connected to said tube 44 via an O-ring connector 46, and a pipe 48 which is connected to said rotary joint 45 via another connector 49 and which leads to the detector smoke 42.
  • a fan (not shown) is connected to this pipe 48 to allow the aforementioned suction.
  • the prediction method according to the invention can be implemented in the following manner, by means of the aforementioned installation.
  • the application on the steering wheel 21 is controlled of a mounted assembly 9 (or of a support 1 mounted on a rim 6, as the case may be), which has been previously mounted on the hub 32, by means of the automation provided for this purpose by the unit 50.
  • This automation has the effect of moving the rolling station 30 from a withdrawal position to a rolling position on the steering wheel 21, in such a way that the tread 7 of the casing 8 (or the support 1, as the case may be) is applied to said flywheel 21.
  • the unit 50 makes it possible to display the evolution of the average “crushed radius” R (in mm) of the support 1 as a function of the running time t (in s), thanks to the information it receives from the crushing sensor 41.
  • this crushed radius varies in an erratic and insignificant manner, essentially by creep due to its rotation at a relatively high speed and the stress resulting from the applied load. From this time ti, this crushed radius begins to decrease in a continuous and sensitive manner, essentially by buckling.
  • a stop criterion was used (ie the reduction ⁇ R of the crushed radius from the crushed radius corresponding to the stabilization time of approximately 15 min.) A reduction of this crushed radius 0.5 mm in 10 seconds after these 15 min. stabilization time, for a support having a height of 60 mm, a width of 110 mm and an internal diameter of 460 mm.
  • the suction means 43 also make it possible to suck up any air currents or vortices at the interior of the mounted assembly 9 which would not allow detect the presence of smoke, and also regulate the inflation air pressure to a zero or reduced value.
  • Fig. 6 contains such graphical characteristics obtained for running at zero internal pressure of two mounted assemblies tested identical (each comprising a support as described in patent document WO-A-00/76791).
  • the two graphs in FIG. 6 relate to the last 60 seconds before breaking of the supports (by buckling and excessive internal heating).
  • each assembled assembly is 225/700 R480, and the applied load of 430 daN.
  • the stopping criterion used was a reduction ⁇ R of the crushed radius by 0.5 mm in 10 seconds after 15 min. stabilization time.
  • the graph of the crushed radius relating to the 88 km / h test shows an inflection point II, beyond which the speed of decrease of the slope of the crushed radius suddenly increases until it breaks of the support that occurs ten seconds later.
  • This point II corresponds to a prediction of maximum driving distance, without substantial deterioration of driving conditions, equal to 384 km for the assembled assembly.
  • the graph of the crushed radius relating to the 100 km / h test presents an inflection point 12, which corresponds to a prediction of maximum driving distance, without substantial deterioration of the driving conditions, equal to 208 km for the assembled assembly.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Tires In General (AREA)

Abstract

The invention relates to a method for predicting the maximum rolling distance in degraded mode, without substantial rolling deterioration, of a mounted assembly (9) comprising a rim with a safety support and tyre mounted thereon. The inventive method consists in rolling the mounted assembly (9) at reduced or zero inflation pressure or rolling said rim-mounted support over at least one rolling surface (21) from one instant t0, under a determined load and at a constant speed V, in such a way that the centre (C) of the rim is a more or less invariant point during the rolling, following the variation of variable R, which is representative of the radial deflection of the support as a function of rolling time t. The inventive method also consists in: (i) determining a value R1 that variable R reaches at the end of a predetermined stabilisation time t1 such that the variation direction of variable R is representative of a radial deflection of the support that increases globally after time t1; (ii) determining a critical rolling time t2 (t2 > t1) at the end of which variable R reaches a critical value R2 such as R2=R1+ DELTA R, DELTA R being a representative value of a critical increase in the deflection of the support; and (iii) making a distance d2 correspond to said rolling time t2 with d2=V.(t2-t0), said distance representing a prediction of said maximum rolling distance.

Description

Méthode de prédiction de la distance maximale de roulage en mode dégradé d'un ensemble monté : Method for predicting the maximum driving distance in degraded mode of a mounted assembly:
La présente invention concerne une méthode de prédiction de la distance maximale de roulage en mode dégradé, sans détérioration substantielle des conditions de roulage, d'un ensemble monté comportant une jante de roue, un appui de sécurité qui est monté sur ladite jante et une enveloppe de pneumatique qui est montée sur ladite jante, ledit appui supportant la bande de roulement de ladite enveloppe lors dudit roulage (on appelle roulage « en mode dégradé » un roulage à pression de gonflage réduite ou nulle). L'invention concerne également une installation pour la mise en œuvre de cette méthode.The present invention relates to a method of predicting the maximum driving distance in degraded mode, without substantial deterioration of the driving conditions, of a mounted assembly comprising a wheel rim, a safety support which is mounted on said rim and an envelope. tire which is mounted on said rim, said support supporting the tread of said casing during said rolling (rolling in “degraded mode” is a rolling at reduced or zero inflation pressure). The invention also relates to an installation for implementing this method.
On sait que les appuis de sécurité pour pneumatique de véhicule sont destinés à être montés sur une jante à l'intérieur du pneumatique, en vue de pouvoir supporter la bande de roulement de ce pneumatique en cas de perte de pression de gonflage. Ces appuis comportent notamment une base qui est destinée à être montée sur la jante, et un sommet qui est destiné à entrer en contact avec la bande de roulement dans le cas précité et qui laisse une garde par rapport à celle-ci à la pression nominale.It is known that the safety supports for vehicle tires are intended to be mounted on a rim inside the tire, in order to be able to support the tread of this tire in the event of loss of inflation pressure. These supports include in particular a base which is intended to be mounted on the rim, and a top which is intended to come into contact with the tread in the aforementioned case and which leaves a guard with respect to the latter at nominal pressure .
Le document de brevet international WO-A-00/76791 présente un tel appui, dont la base et le sommet sont sensiblement cylindriques, et qui comporte en outre un corps annulaire reliant ladite base et ledit sommet.The international patent document WO-A-00/76791 presents such a support, the base and the top of which are substantially cylindrical, and which further comprises an annular body connecting said base and said top.
Ce corps annulaire comporte un élément de support qui est continu circonférentiellement avec un plan médian circonférentiel, ledit élément de support comprenant une pluralité de cloisons s 'étendant axialement de part et d'autre dudit plan médian circonférentiel et réparties sur la circonférence dudit appui.This annular body comprises a support element which is circumferentially continuous with a circumferential median plane, said support element comprising a plurality of partitions extending axially on either side of said circumferential median plane and distributed over the circumference of said support.
Les tests ou méthodes utilisées à ce jour pour prédire la distance maximale de roulage en mode dégradé, sans détérioration substantielle des conditions de roulage, d'un ensemble monté qui comporte une jante de roue pourvue d'un tel appui de sécurité et une enveloppe de pneumatique montée sur ladite jante consistent généralement :The tests or methods used to date for predicting the maximum driving distance in degraded mode, without substantial deterioration of the driving conditions, of a mounted assembly which comprises a wheel rim provided with such a safety support and an envelope of tire mounted on said rim generally consist of:
- à faire rouler en mode dégradé, à une vitesse constante prédéterminée (par exemple de l'ordre de 100 km/h) et à une température extérieure déterminée, un véhicule automobile équipé de tels ensembles montés sur un circuit de type routier ou autoroutier, puis à interrompre ce roulage lorsque le conducteur du véhicule détecte une telle détérioration substantielle des conditions de roulage rendant celui-ci très difficile en mode dégradé, détérioration qui est due à un endommagement significatif des ensembles montés et qui se traduit par exemple par une élévation sensible des vibrations dont le volant est le siège, ou bien suite à un examen de chaque ensemble monté suite à des roulages à plat sur des distances prédéterminées. Généralement, le critère d'arrêt de ce test de roulage en mode dégradé, qui est choisi par l'opérateur en charge du test, correspond à l'apparition d'un ou plusieurs dommages spécifiques concernant aussi bien l'appui de sécurité que l'enveloppe de pneumatique.to run in degraded mode, at a predetermined constant speed (for example of the order of 100 km / h) and at a determined outside temperature, a motor vehicle equipped with such assemblies mounted on a road or motorway type circuit, then to interrupt this taxiing when the driver of the vehicle detects such a substantial deterioration in the driving conditions making it very difficult in mode degraded, deterioration which is due to significant damage to the mounted assemblies and which results, for example, in a significant increase in the vibrations of which the steering wheel is the seat, or else following an examination of each assembled assembly following running on flat on predetermined distances. Generally, the stop criterion for this run test in degraded mode, which is chosen by the operator in charge of the test, corresponds to the appearance of one or more specific damages concerning both the safety support and the tire cover.
Les dommages concernant l'appui peuvent par exemple être matérialisés par des fissures ou cassures à l'emplacement des cloisons de l'appui en raison d'un échauffement interne important et des contraintes de flambage auquel est soumis ledit appui en roulage en mode dégradé.The damage relating to the support can for example be materialized by cracks or breaks at the location of the partitions of the support due to a significant internal heating and the buckling stresses to which said support is subjected when running in degraded mode.
Les dommages concernant l'enveloppe peuvent par exemple être matérialisés par des coupures à l'emplacement des flancs de l'enveloppe, notamment en raison des contraintes de carrossage auxquelles est soumise ladite enveloppe sur un circuit plus ou moins virageux, ou par une rupture pure et simple de celle-ci rendant impossible toute continuation du roulage en mode dégradé.Damage to the envelope may, for example, be materialized by cuts at the location of the sides of the envelope, in particular due to the camber stresses to which said envelope is subjected on a more or less hazy circuit, or by pure rupture. and simple, making it impossible to continue driving in degraded mode.
Or, l'expérience montre que ce ou ces critères d'arrêt sont des paramètres pouvant avoir un effet déterminant sur le résultat de distance maximale de roulage en mode dégradé sans détérioration substantielle des conditions de roulage, qui est obtenu à l'issu de ce test sur circuit.However, experience shows that this or these stopping criteria are parameters which can have a determining effect on the result of maximum driving distance in degraded mode without substantial deterioration of driving conditions, which is obtained at the end of this. circuit test.
Il en est de même pour les paramètres caractérisant le roulage qui sont propres au véhicule, tels que la vitesse choisie pour le roulage ou la charge à laquelle est soumis chaque ensemble monté lors du roulage.The same applies to the parameters characterizing the running which are specific to the vehicle, such as the speed chosen for running or the load to which each assembled assembly is subjected during running.
Bien entendu, les paramètres relatifs à l'air ambiant (température) et au revêtement du circuit utilisé (rugosité, sol sec ou humide) peuvent également influer sur la distance maximale de roulage obtenue en mode dégradé.Of course, the parameters relating to the ambient air (temperature) and to the coating of the circuit used (roughness, dry or wet ground) can also influence the maximum driving distance obtained in degraded mode.
Un inconvénient majeur de ces tests de prédiction sur circuit réside dans la difficulté de conserver à l'identique les paramètres précités d'un test à un autre en raison de leur variabilité, ainsi que dans le caractère plus ou moins contraignant de ces paramètres pour l'appui et l'enveloppe lors du roulage en mode dégradé. Il peut notamment en résulter des difficultés pour comparer entre elles les endurances respectives en roulage de différents ensembles montés en mode dégradé.A major drawback of these circuit prediction tests lies in the difficulty of keeping the above parameters identical from one test to another because of their variability, as well as in the more or less restrictive nature of these parameters for the 'support and envelope during taxiing in degraded mode. This may in particular result in Difficulties in comparing the respective endurance in running of different assemblies mounted in degraded mode.
Le but de la présente invention est de proposer une méthode de prédiction de la distance maximale de roulage en mode dégradé, sans détérioration substantielle des conditions de roulage (c'est-à-dire sans perte de contrôle du véhicule), d'un ensemble monté comportant une jante de roue, un appui de sécurité qui est monté sur ladite jante et une enveloppe de pneumatique qui est montée sur ladite jante autour dudit appui, ledit appui supportant la bande de roulement de ladite enveloppe lors dudit roulage, qui permette de prédire d'une manière fiable et reproductible les distances maximales de roulage en mode dégradé de différents ensembles montés et de les comparer entre elles dans des conditions expérimentales identiques.The aim of the present invention is to propose a method for predicting the maximum driving distance in degraded mode, without substantial deterioration of the driving conditions (that is to say without loss of control of the vehicle), of an assembly mounted comprising a wheel rim, a safety support which is mounted on said rim and a tire casing which is mounted on said rim around said support, said support supporting the tread of said casing during said rolling, which makes it possible to predict in a reliable and reproducible manner the maximum running distances in degraded mode of different mounted assemblies and to compare them with one another under identical experimental conditions.
A cet effet et selon un premier mode de réalisation de l'invention, ladite méthode de prédiction consiste à faire rouler ledit ensemble monté à une pression de gonflage réduite ou nulle, à partir d'un instant to, à une température donnée, sous une charge déterminée et avec une vitesse V constante, sur au moins une surface de roulage de telle manière que le centre de ladite jante de roue soit un point sensiblement invariant lors dudit roulage (i.e. sur un volant de rouleuse, typiquement), en suivant la variation d'une variable R représentative de l'écrasement radial de l'appui en fonction du temps t de roulage à pression réduite ou nulle, et en ce que cette méthode consiste, pendant ce roulage, à mettre en oeuvre la séquence d'étapes (i) à (iii) suivantes :To this end and according to a first embodiment of the invention, said prediction method consists in rolling said assembled assembly at a reduced or zero inflation pressure, from an instant to, at a given temperature, under a determined load and with a constant speed V, on at least one rolling surface so that the center of said wheel rim is a substantially invariant point during said rolling (ie on a rolling wheel, typically), following the variation of a variable R representative of the radial crushing of the support as a function of the running time t at reduced or zero pressure, and in that this method consists, during this running, in implementing the sequence of steps ( i) to (iii) below:
(i) déterminer une valeur Ri qu'atteint ladite variable R au bout d'un temps de stabilisation ti prédéterminé qui est tel que le sens de variation de ladite variable R est représentatif d'un écrasement radial dudit appui globalement croissant au-delà dudit temps de stabilisation ti, puis(i) determining a value Ri that said variable R reaches after a predetermined stabilization time ti which is such that the direction of variation of said variable R is representative of a radial crushing of said generally increasing support beyond said stabilization time ti, then
(ii) déterminer un temps de roulage critique t2 (t > ti) au bout duquel ladite variable R atteint une valeur critique R2 telle que R = Ri+ΔR, ΔR étant une valeur représentative d'un accroissement critique de l'écrasement de l'appui par rapport à la valeur Ri à l'issue du temps de stabilisation tj, puis (iii) faire correspondre audit temps de roulage t2 une distance d2 avec d2 = V. (t2 - t0), représentant une prédiction de distance maximale de roulage sans détérioration substantielle des conditions de roulage. On notera que ladite valeur ΔR qui est retenue à l'étape (ii) constitue un critère d'arrêt du roulage, au-delà duquel l'appui est soumis à des contraintes et à un échauffement susceptibles de le rendre impropre à l'usage.(ii) determining a critical rolling time t 2 (t> ti) at the end of which said variable R reaches a critical value R 2 such that R = Ri + ΔR, ΔR being a value representative of a critical increase in the crushing support with respect to the value Ri at the end of the stabilization time tj, then (iii) make correspond to said running time t 2 a distance d 2 with d 2 = V. (t 2 - t 0 ), representing a prediction of maximum driving distance without substantial deterioration of driving conditions. It will be noted that said value ΔR which is adopted in step (ii) constitutes a criterion for stopping the rolling, beyond which the support is subjected to stresses and to heating capable of rendering it unfit for use. .
On notera également que l'on pourrait choisir au moins une nouvelle valeur critique ΔR' supérieure ou inférieure à ΔR en fonction de l'absence ou de la présence de dommages substantiels dans l'appui au bout dudit temps t2, et mettre à nouveau en œuvre ladite séquence d'étapes (i) à (iii) en remplaçant ΔR par ΔR', de manière à obtenir au bout de n itérations une prédiction encore améliorée de la distance maximale de roulage de l'appui sans détérioration substantielle des conditions de roulage.It will also be noted that one could choose at least one new critical value ΔR 'greater or less than ΔR as a function of the absence or the presence of substantial damage in the support after said time t 2 , and set again implementing said sequence of steps (i) to (iii) by replacing ΔR with ΔR ', so as to obtain, after n iterations, a further improved prediction of the maximum rolling distance of the support without substantial deterioration of the conditions of rolling.
Selon un second mode de réalisation de l'invention, ladite méthode de prédiction de la distance maximale de roulage dudit ensemble monté à pression de gonflage réduite ou nulle, sans détérioration substantielle des conditions de roulage, consiste à faire rouler, également à une température donnée, sous une charge déterminée et avec une vitesse V constante, ledit appui monté sur ladite jante de roue directement au contact de ladite surface de roulage de manière que le centre de ladite jante soit un point sensiblement invariant lors dudit roulage, en suivant la variation de ladite variable R représentative de l'écrasement radial de l'appui en fonction du temps t de roulage à pression réduite ou nulle, et en ce que cette méthode consiste, pendant ce roulage, à mettre en œuvre les étapes (i), (ii) et (iii) précitées. De préférence, ledit appui est monté sur la jante par clipage, dans ce second mode.According to a second embodiment of the invention, said method of predicting the maximum rolling distance of said assembly mounted at reduced or zero inflation pressure, without substantial deterioration of the rolling conditions, consists in rolling, also at a given temperature. , under a determined load and with a constant speed V, said support mounted on said wheel rim directly in contact with said rolling surface so that the center of said rim is a substantially invariant point during said rolling, following the variation of said variable R representative of the radial crushing of the support as a function of the running time t at reduced or zero pressure, and in that this method consists, during this running, in implementing steps (i), (ii ) and (iii) above. Preferably, said support is mounted on the rim by clipping, in this second mode.
Selon un exemple préférentiel de mise en œuvre de l'invention qui est commun à ces deux modes de réalisation, ladite valeur prédéterminée ΔR est telle qu'au temps t2, la vitesse d'accroissement |dR/dt| de l'écrasement dudit appui est supérieure à un seuil critique donné. Selon une autre caractéristique de l'invention commune à ces deux modes de réalisation (i.e. roulage de l'ensemble monté ou seulement de l'appui sur la surface de roulage), l'étape (ii) ci-dessus consiste à suivre la variation de ladite variable R à partir dudit temps tι_ et à prédire qu'elle atteint ladite valeur critique R2 audit temps critique t2 sensiblement lorsque l'accélération instantanée de l'écrasement d R/dt dudit appui passe par une valeur nulle. On notera que ce temps critique t2 est tel que le graphe de ladite variable R présente un point d'inflexion sensiblement audit temps t2, c'est-à-dire un inversement du sens de variation de la pente dR/dt pour t > t2 traduisant une vitesse d'écrasement de l'appui de plus en plus élevée qui conduit rapidement aux fissurations ou à la rupture précitées dudit appui.According to a preferred example of implementation of the invention which is common to these two embodiments, said predetermined value ΔR is such that at time t 2 , the rate of increase | dR / dt | of the crushing of said support is greater than a given critical threshold. According to another characteristic of the invention common to these two embodiments (ie rolling of the assembled assembly or only of the support on the rolling surface), step (ii) above consists in monitoring the variation of said variable R from said time tι_ and predicting that it reaches said critical value R 2 at said critical time t 2 substantially when the instantaneous acceleration of the overwriting d R / dt of said support passes through a zero value. It will be noted that this critical time t 2 is such that the graph of said variable R has a point of inflection substantially at said time t 2 , that is to say a reversal of the direction of variation of the slope dR / dt for t > t 2 translating an increasingly high crushing speed of the support which quickly leads to the aforementioned cracks or rupture of said support.
Concernant ledit premier mode de réalisation de l'invention, ladite variable R représentative de l'écrasement radial de l'appui correspond avantageusement au rayon moyen dudit appui en cours d'écrasement (encore appelé « rayon écrasé »), rayon mesuré entre un premier point définissant le centre de ladite jante de roue et un second point définissant le centre de la surface de contact entre ladite bande de roulement et ladite surface de roulage.Concerning said first embodiment of the invention, said variable R representative of the radial crushing of the support advantageously corresponds to the mean radius of said support during crushing (also called “crushed radius”), radius measured between a first point defining the center of said wheel rim and a second point defining the center of the contact surface between said tread and said rolling surface.
Concernant ledit second mode de réalisation de l'invention, cette variable R correspond également audit rayon en cours d'écrasement, à ceci près que ce rayon est ici mesuré entre un premier point définissant le centre de ladite jante de roue et un second point définissant le centre de la surface de contact entre la face radialement externe dudit appui et ladite surface de roulage.Concerning said second embodiment of the invention, this variable R also corresponds to said radius during crushing, except that this radius is here measured between a first point defining the center of said wheel rim and a second point defining the center of the contact surface between the radially external face of said support and said rolling surface.
On notera que le sens de variation de ces rayons en cours d'écrasement est globalement décroissant en fonction du temps t de roulage, au-delà dudit temps de stabilisation t[.It will be noted that the direction of variation of these radii during crushing is generally decreasing as a function of the running time t, beyond said stabilization time t [.
On notera également que ladite variable R pourrait également correspondre à la flèche relative audit appui du fait de l'écrasement, ou encore à l'écrasement relatif de l'appuiIt will also be noted that said variable R could also correspond to the arrow relating to said support due to the crushing, or even to the relative crushing of the support
(rapport de la flèche sur la hauteur de l'appui), le sens de variation de cette flèche ou de cet écrasement relatif étant globalement croissant en fonction dudit temps t, au-delà du temps de stabilisation ti.(ratio of the arrow on the height of the support), the direction of variation of this arrow or of this relative crushing being generally increasing as a function of said time t, beyond the stabilization time ti.
Selon une autre caractéristique avantageuse de l'invention concernant uniquement le premier mode de réalisation précité, ladite méthode de prédiction consiste également à estimer que ladite distance maximale de roulage sans détérioration substantielle des conditions de roulage est atteinte juste avant que de la fumée soit détectée à l'intérieur dudit ensemble monté.According to another advantageous characteristic of the invention relating only to the first aforementioned embodiment, said prediction method also consists in estimating that said maximum driving distance without substantial deterioration of driving conditions is reached just before smoke is detected at the interior of said assembled assembly.
Selon un exemple avantageux de réalisation de l'invention commun aux deux modes de réalisation précités, ladite surface de roulage utilisée présente une géométrie sensiblement cylindrique, et elle est par exemple constituée d'un volant de rouleuse, i.e. dont la surface de roulage est un cylindre de section circulaire. On notera que cette surface de roulage peut être convexe ou concave, selon que l'on utilise la face extérieure ou intérieure du volant, respectivement. Selon un autre exemple de réalisation de l'invention commun aux deux modes de réalisation précités, ladite surface de roulage utilisée présente une géométrie sensiblement plane, par exemple du type tapis roulant.According to an advantageous embodiment of the invention common to the two above-mentioned embodiments, said rolling surface used has a geometry substantially cylindrical, and it is for example made up of a rolling wheel, ie whose rolling surface is a cylinder of circular section. It will be noted that this rolling surface can be convex or concave, depending on whether the exterior or interior face of the steering wheel is used, respectively. According to another exemplary embodiment of the invention common to the two abovementioned embodiments, said rolling surface used has a substantially planar geometry, for example of the treadmill type.
Concernant l'un ou l'autre de ces exemples de réalisation de l'invention, on notera que la surface de roulage utilisée peut être lisse, ou bien présenter une pluralité d'irrégularités saillantes et/ou rentrantes qui sont plus ou moins régulièrement espacées sur son périmètre.Concerning one or other of these exemplary embodiments of the invention, it will be noted that the running surface used can be smooth, or else have a plurality of projecting and / or re-entrant irregularities which are more or less regularly spaced. on its perimeter.
Ces irrégularités peuvent par exemple être constituées d'obstacles du type barettes, destinées à reproduire les contraintes de roulage dues à des plaques d'égouts ou à d'autres reliefs couramment rencontrés lors d'un roulage réel sur route, ou bien de creux, par exemple destinés à reproduire les contraintes inhérentes à un roulage sur des nids-de-poule.These irregularities can for example consist of obstacles of the bar type, intended to reproduce the rolling stresses due to manhole covers or other reliefs commonly encountered during an actual road rolling, or else of hollows, for example intended to reproduce the constraints inherent in rolling over potholes.
Selon un exemple avantageux de réalisation de l'invention, la jante de roue comporte en chacun de ses deux bords périphériques un siège de jante destiné à recevoir un bourrelet de ladite enveloppe, ladite jante comportant entre ses deux sièges, d'une part, une portée destinée à recevoir ledit appui et, d'autre part, une gorge de montage reliant ladite portée à un rebord axialement interne de l'un desdits sièges.According to an advantageous embodiment of the invention, the wheel rim comprises in each of its two peripheral edges a rim seat intended to receive a bead of said casing, said rim comprising between its two seats, on the one hand, a bearing intended to receive said support and, on the other hand, a mounting groove connecting said bearing to an axially internal rim of one of said seats.
On pourra se référer au document de brevet français FR-A-2 720 977 pour une description détaillée du montage de l'enveloppe sur la jante.Reference may be made to French patent document FR-A-2 720 977 for a detailed description of the mounting of the casing on the rim.
Quant à l'appui selon l'invention, il est avantageusement du type comportant:As for the support according to the invention, it is advantageously of the type comprising:
- une base sensiblement cylindrique destinée à être montée sur la jante, - un sommet sensiblement cylindrique destiné à entrer en contact avec la bande de roulement de l'enveloppe en cas de chute de pression, et laissant une garde par rapport à ladite bande à la pression nominale, et- a substantially cylindrical base intended to be mounted on the rim, - a substantially cylindrical summit intended to come into contact with the tread of the casing in the event of a pressure drop, and leaving a guard with respect to said band at the nominal pressure, and
- un corps annulaire reliant ladite base et ledit sommet entre eux, ledit corps comportant un élément de support continu circonférentiellement avec un plan médian circonférentiel, ledit élément de support comprenant une pluralité de cloisons s'étendant axialement de part et d'autre dudit plan médian circonférentiel et réparties sur la circonférence dudit appui. Une installation selon l'invention pour la mise en œuvre de la méthode de prédiction précitée selon lesdits premier ou second modes de réalisation comporte essentiellement au moins une surface de roulage, et un ou plusieurs postes de roulage qui sont chacun destinés au roulage sur ladite surface d'un ensemble monté comportant une enveloppe de pneumatique montée sur une jante de roue autour d'un appui de sécurité à pression de gonflage réduite ou nulle, ou bien au roulage sur ladite surface d'un tel appui monté sur une jante de roue, le centre dudit ensemble monté ou dudit appui étant un point sensiblement invariant lors du roulage sur ladite ou chaque surface de roulage, cette installation étant caractérisée en ce qu'elle comporte également : - des moyens de détection qui sont reliés audit ou à chaque poste de roulage et qui sont prévus pour détecter à chaque instant, lors du roulage sur ladite ou chaque surface, des informations représentatives des effets induits par ce roulage comprenant au moins une information représentative de l'écrasement radial dudit appui à chaque instant, etan annular body connecting said base and said vertex to each other, said body comprising a circumferentially continuous support element with a circumferential median plane, said support element comprising a plurality of partitions extending axially on either side of said median plane circumferential and distributed over the circumference of said support. An installation according to the invention for implementing the aforementioned prediction method according to said first or second embodiments essentially comprises at least one rolling surface, and one or more rolling stations which are each intended for rolling on said surface a mounted assembly comprising a tire casing mounted on a wheel rim around a safety support with reduced or zero inflation pressure, or else when rolling on said surface of such a support mounted on a wheel rim, the center of said assembled assembly or of said support being a substantially invariant point during rolling on said or each rolling surface, this installation being characterized in that it also comprises: - detection means which are connected to said or to each rolling and which are intended to detect at each instant, during rolling on said or each surface, information representative of the effects in duits by this rolling comprising at least one item of information representative of the radial crushing of said support at each instant, and
- une unité pour commander la mise en marche du roulage selon des paramètres de roulage prédéterminés comprenant une vitesse V de roulage et une charge à appliquer sur l'appui lors du roulage, pour recevoir lesdites informations desdits moyens de détection et les mémoriser, et pour commander l'arrêt du roulage si au moins l'une desdites informations atteint un valeur critique prédéterminée.a unit for controlling the starting of the taxi according to predetermined taxi parameters comprising a speed V of the taxi and a load to be applied to the support during the taxi, for receiving said information from said detection means and memorizing it, and for command the halting of driving if at least one of said information reaches a predetermined critical value.
Selon une autre caractéristique de l'invention, lesdits moyens de détection comportent un capteur d'écrasement, par exemple de type potentiométrique, qui est prévu pour fournir à chaque instant une valeur de rayon d'appui en cours d'écrasement qui est représentative de l'écrasement radial moyen dudit appui lors du roulage, ledit rayon en cours d'écrasement étant mesuré entre un premier point définissant le centre de la jante de roue et un second point définissant le centre de la surface de contact entre l'enveloppe, ou l'appui selon le cas, et ladite surface de roulage.According to another characteristic of the invention, said detection means comprise a crushing sensor, for example of the potentiometric type, which is designed to supply at all times a value of support radius during crushing which is representative of the average radial crushing of said support during rolling, said radius being crushed being measured between a first point defining the center of the wheel rim and a second point defining the center of the contact surface between the casing, or the support as appropriate, and said rolling surface.
De préférence, dans le cas d'un roulage dudit ensemble monté sur ladite surface de roulage, lesdits moyens de détection comportent également un détecteur de fumée qui est prévu pour détecter la présence de fumée par échauffement interne à l'intérieur dudit ensemble monté en cours de roulage à pression réduite ou nulle, par l'intermédiaire de moyens d'aspiration qui sont prévus à l'intérieur dudit poste de roulage pour aspirer en direction dudit détecteur l'air compris à l'intérieur dudit ensemble monté. Les caractéristiques précitées de la présente invention, ainsi que d'autres, seront mieux comprises à la lecture de la description suivante de plusieurs exemples de réalisation de l'invention, donnés à titre illustratif et non limitatif, ladite description étant réalisée en relation avec les dessins joints, dans lesquels : la Fig. 1 est une vue de côté d'un appui de sécurité utilisable dans la méthode de prédiction selon l'invention, la Fig. 2 est une vue en coupe axiale d'un ensemble monté qui comporte l'appui de la Fig. 1 et qui est utilisable dans la méthode de prédiction selon l'invention, la Fig. 3 est un schéma à blocs illustrant la structure simplifiée d'une installation selon l'invention, la Fig. 4 une vue schématique d'un poste de roulage de l'installation de la Fig. 3, la Fig. 5 est une vue de détail en coupe d'une partie interne du poste de roulage selon le plan IV-IV de la Fig. 4, et la Fig. 6 est un graphique illustrant l'évolution en fonction du temps, en fin de roulage à plat, de deux caractéristiques représentatives de l'écrasement radial d'un appui.Preferably, in the case of a rolling of said assembly mounted on said rolling surface, said detection means also comprise a smoke detector which is designed to detect the presence of smoke by internal heating inside said assembly assembled in progress of rolling at reduced or zero pressure, by means of suction means which are provided inside said rolling station to suck in the direction of said detector the air included inside said mounted assembly. The aforementioned characteristics of the present invention, as well as others, will be better understood on reading the following description of several embodiments of the invention, given by way of illustration and not limitation, said description being made in relation to the attached drawings, in which: FIG. 1 is a side view of a safety support usable in the prediction method according to the invention, FIG. 2 is an axial section view of a mounted assembly which includes the support of FIG. 1 and which can be used in the prediction method according to the invention, FIG. 3 is a block diagram illustrating the simplified structure of an installation according to the invention, FIG. 4 a schematic view of a rolling station of the installation of FIG. 3, FIG. 5 is a detail view in section of an internal part of the rolling station according to the plane IV-IV of FIG. 4, and FIG. 6 is a graph illustrating the evolution over time, at the end of running flat, of two characteristics representative of the radial crushing of a support.
En référence aux Figs. 1 et 2, un appui 1 qui est utilisable pour mettre en œuvre la méthode de prédiction selon l'invention comprend essentiellement trois parties:With reference to Figs. 1 and 2, a support 1 which can be used to implement the prediction method according to the invention essentially comprises three parts:
- une base 2, de forme généralement annulaire, - un sommet 3, sensiblement annulaire, avec sur sa paroi radialement extérieure (de façon optionnelle) des rainures longitudinales 5, eta base 2, of generally annular shape, a crown 3, substantially annular, with on its radially outer wall (optionally) longitudinal grooves 5, and
- un corps annulaire 4 de liaison entre la base 2 et le sommet 3.an annular body 4 for connection between the base 2 and the top 3.
La Fig. 2 illustre notamment la fonction de l'appui 1 lorsqu'il est monté sur une jante de roue 6, qui est de supporter la bande de roulement 7 d'une enveloppe de pneumatique 8 en cas de chute de la pression de gonflage à l'intérieur de l'ensemble monté 9 comprenant la jante 6, l'appui 1 et l'enveloppe 8.Fig. 2 illustrates in particular the function of the support 1 when it is mounted on a wheel rim 6, which is to support the tread 7 of a tire casing 8 in the event of a fall in the inflation pressure at inside of the mounted assembly 9 comprising the rim 6, the support 1 and the casing 8.
Comme on peut le voir à la Fig. 2, l'appui 1 comporte une première partie massive 4a du corps annulaire 4 ainsi qu'une seconde partie 4b comprenant des évidements séparés entre eux par des cloisons 4a (voir également Fig. 1) s'étendant axialement sur sensiblement plus de la moitié du corps annulaire 4, en débouchant du côté extérieur dans une direction sensiblement axiale. Ces cloisons 4a sont régulièrement répartis sur toute la circonférence du corps annulaire 4. Les parties principales d'une installation 10 selon l'invention pour prédire la distance de roulage à plat, sans détérioration substantielle des conditions de roulage, de l'ensemble monté 9 sont schématisées à la Fig. 3. L'installation 10 comporte essentiellement : une rouleuse 20 comportant un volant 21 qui est monté sur un arbre moteur 22 en vue de son entraînement en rotation, un ou plusieurs postes de roulage 30 qui sont chacun destinés au roulage sur le volant 21 d'un ensemble monté 9, ou bien d'un appui de sécurité 1 monté sur une jante 6 (un seul poste 30 est représenté à la Fig. 3 à des fins de simplification),As can be seen in Fig. 2, the support 1 comprises a first solid part 4a of the annular body 4 as well as a second part 4b comprising recesses separated from each other by partitions 4a (see also Fig. 1) extending axially over substantially more than half of the annular body 4, opening on the outside in a substantially axial direction. These partitions 4a are regularly distributed over the entire circumference of the annular body 4. The main parts of an installation 10 according to the invention for predicting the running distance flat, without substantial deterioration of the driving conditions, of the mounted assembly 9 are shown diagrammatically in FIG. 3. The installation 10 essentially comprises: a rolling machine 20 comprising a flywheel 21 which is mounted on a motor shaft 22 for its rotational drive, one or more rolling stations 30 which are each intended for rolling on the steering wheel 21 d a mounted assembly 9, or else a safety support 1 mounted on a rim 6 (a single station 30 is shown in FIG. 3 for simplification purposes),
- des moyens de détection 40 qui sont reliés audit ou à chaque poste de roulage 30 et qui sont prévus pour détecter à chaque instant, lors du roulage « à plat » sur le volant 21, des informations représentatives des effets induits par ce roulage sur l'ensemble monté 9 (ou sur l'appui 1, selon le cas), et - une unité 50 pour commander la mise en marche dudit roulage selon des paramètres de roulage prédéterminés, pour recevoir lesdites informations desdits moyens 40 et les mémoriser, et pour commander l'arrêt dudit roulage si au moins l'une desdites informations atteint une valeur critique prédéterminée.- Detection means 40 which are connected to said or to each taxiing station 30 and which are provided for detecting at each instant, during taxiing “flat” on the steering wheel 21, information representative of the effects induced by this taxiing on the 'mounted assembly 9 (or on the support 1, as the case may be), and - a unit 50 for controlling the start-up of said rolling according to predetermined rolling parameters, for receiving said information from said means 40 and storing it, and for command the stopping of said rolling if at least one of said information reaches a predetermined critical value.
Le poste de roulage 30 est représenté plus en détail à la Fig. 4.The rolling station 30 is shown in more detail in FIG. 4.
Ce poste 30 est essentiellement constitué d'un bâti 31 sur lequel est monté un moyeu 32 qui est dans cet exemple destiné à recevoir l'ensemble monté 9 ou la jante 6 pourvue de l'appui 1 (seul le moyeu 32 est représenté à des fins de clarté) en vue de faire rouler l'enveloppe 8 ou ledit appui 1 sur le volant 21. Le moyeu 32 est monté mobile en translation sur le bâti 31 par des moyens de déplacement 33, de manière à permettre le roulage de l'enveloppe 8 (ou de l'appui 1, selon le cas) sur le volant 21 selon une charge donnée.This station 30 essentially consists of a frame 31 on which is mounted a hub 32 which is in this example intended to receive the assembled assembly 9 or the rim 6 provided with the support 1 (only the hub 32 is shown at for clarity) in order to roll the casing 8 or said support 1 on the steering wheel 21. The hub 32 is mounted movable in translation on the frame 31 by displacement means 33, so as to allow the rolling of the casing 8 (or support 1, as the case may be) on the steering wheel 21 according to a given load.
A cet effet, l'axe de symétrie du moyeu 32 est prévu parallèle audit arbre moteur 22 (non visible à la Fig. 4) du volant 21, et le moyeu 32 comporte des roulements (non visibles) pour permettre la rotation de l'ensemble monté 9 ou de la jante 6 pourvue de l'appui 1 au contact du volant 21.To this end, the axis of symmetry of the hub 32 is provided parallel to said drive shaft 22 (not visible in FIG. 4) of the flywheel 21, and the hub 32 includes bearings (not visible) to allow rotation of the mounted assembly 9 or rim 6 provided with support 1 in contact with the steering wheel 21.
Dans cet exemple de réalisation de l'invention, la rouleuse 20 est telle que le volant 21 présente une surface de roulement lisse. Le moyeu 32 est pourvu, à l'emplacement de son axe de symétrie, d'une tubulure 34 ou « nez de valve », qui fait saillie axialement à l'avant du moyeu 32 et qui est destiné à être relié à la valve de roue de l'ensemble monté 9.In this exemplary embodiment of the invention, the rolling machine 20 is such that the steering wheel 21 has a smooth rolling surface. The hub 32 is provided, at the location of its axis of symmetry, with a tube 34 or "valve nose", which projects axially at the front of the hub 32 and which is intended to be connected to the valve. wheel of the assembled assembly 9.
Comme on peut le voir à la Fig. 4, les moyens de déplacement 33 du moyeu 32 comportent dans cet exemple de réalisation des soufflets 35 qui sont commandés par des moyens de commande de type pneumatique (non représentés) auxquels ils sont reliés, de telle manière qu'ils peuvent passer d'une position de retrait, dans laquelle l'enveloppe 8 ou l'appui 1 sont distants du volant 21, à diverses positions de roulage, dans lesquelles l'enveloppe 8 (ou l'appui 1, selon le cas) sont appliqués sur le volant 21.As can be seen in Fig. 4, the displacement means 33 of the hub 32 comprise in this embodiment bellows 35 which are controlled by pneumatic type control means (not shown) to which they are connected, so that they can pass from one withdrawal position, in which the casing 8 or the support 1 are distant from the steering wheel 21, at various rolling positions, in which the casing 8 (or the support 1, as the case may be) are applied to the steering wheel 21 .
Les moyens de détection 40 des effets du roulage sur l'ensemble monté 9 (ou sur l'appui 1, selon le cas) comportent essentiellement un capteur d'écrasement 41 qui est prévu pour fournir à chaque instant une valeur de « rayon écrasé » qui est représentative de l'écrasement radial moyen de l'appui 1 lors dudit roulage. Ce « rayon écrasé » est mesuré à chaque seconde de roulage entre un premier point définissant le centre C de la roue 6 et un second point définissant le centre de la surface de contact entre la bande de roulement 7 et le volant 21.The means 40 for detecting the effects of rolling on the mounted assembly 9 (or on the support 1, as the case may be) essentially comprise a crushing sensor 41 which is designed to supply at all times a value of "crushed radius" which is representative of the average radial crushing of the support 1 during said rolling. This "crushed radius" is measured at each second of travel between a first point defining the center C of the wheel 6 and a second point defining the center of the contact surface between the tread 7 and the steering wheel 21.
Plus précisément, ce capteur 41 est de type potentiométrique et il est pourvu d'un fil (non représenté à la Fig. 4) qui est relié aux moyens de déplacement 33 du poste 30 de roulage de manière à affecter à chaque position dudit poste 30 une valeur de « rayon écrasé ».More precisely, this sensor 41 is of potentiometric type and it is provided with a wire (not shown in FIG. 4) which is connected to the displacement means 33 of the rolling station 30 so as to assign to each position of said station 30 a value of "radius overwritten".
A titre de capteur 41 , on utilise par exemple un capteur commercialisé par la société ASM sous la dénomination « WL 10/250/ 10V/L 10 ».As sensor 41, a sensor sold by the company ASM under the name "WL 10/250 / 10V / L 10" is used for example.
Dans le cas d'un roulage de l'ensemble monté 9 sur le volant 21, les moyens 40 comportent en outre un détecteur de fumée 42 qui est prévu pour détecter toute présence de fumée par échau fement interne à l'intérieur de l'ensemble monté 9 en cours de roulageIn the case of rolling of the assembly mounted 9 on the steering wheel 21, the means 40 further comprise a smoke detector 42 which is designed to detect any presence of smoke by internal heating inside the assembly mounted 9 during taxiing
(c'est-à-dire entre la jante 6 et l'enveloppe 8). Ce détecteur de fumée 42 est relié à l'unité 50 de manière à pouvoir lui transmettre un signal d'alarme en cas de détection de fumée.(that is to say between the rim 6 and the casing 8). This smoke detector 42 is connected to the unit 50 so as to be able to transmit an alarm signal to it in the event of smoke detection.
Le détecteur de fumée 42 est relié à l'extrémité interne de ladite tubulure ou « nez de valve » 34 par des moyens d'aspiration 43 qui sont prévus à l'intérieur du poste 30 pour aspirer en direction du détecteur 42 la fumée générée à l'intérieur de l'ensemble monté 9. Une partie de ces moyens d'aspiration 43 est représentée à la Fig. 5.The smoke detector 42 is connected to the internal end of said tubing or “valve nose” 34 by suction means 43 which are provided inside the station 30 for sucking in the direction of the detector 42 the smoke generated at inside the assembled assembly 9. Part of these suction means 43 is shown in FIG. 5.
Comme on peut le voir sur cette Fig., ces moyens 43 comportent essentiellement, à partir de ladite tubulure 34, un tube 44 qui est relié à cette dernière de manière à communiquer avec l'intérieur de l'ensemble monté 9 en rotation, un joint tournant 45 qui est relié audit tube 44 par l'intermédiaire d'un raccord 46 à joint torique 47, et un tuyau 48 qui est relié audit joint tournant 45 par l'intermédiaire d'un autre raccord 49 et qui débouche sur le détecteur de fumée 42.As can be seen in this FIG., These means 43 essentially comprise, from said tubing 34, a tube 44 which is connected to the latter so as to communicate with the interior of the assembly mounted 9 in rotation, a rotary joint 45 which is connected to said tube 44 via an O-ring connector 46, and a pipe 48 which is connected to said rotary joint 45 via another connector 49 and which leads to the detector smoke 42.
Un ventilateur (non représenté) est connecté à ce tuyau 48 pour permettre l'aspiration précitée.A fan (not shown) is connected to this pipe 48 to allow the aforementioned suction.
On peut mettre en œuvre la méthode de prédiction selon l'invention de la manière suivante, au moyen de l'installation précitée.The prediction method according to the invention can be implemented in the following manner, by means of the aforementioned installation.
Dans un premier temps, on commande l'application sur le volant 21 d'un ensemble monté 9 (ou d'un appui 1 monté sur une jante 6, selon le cas), qui a été préalablement monté sur le moyeu 32, au moyen de l'automatisme prévu à cet effet de l'unité 50. Cet automatisme a pour effet de déplacer le poste de roulage 30 d'une position de retrait à une position de roulage sur le volant 21, de telle manière que la bande de roulement 7 de l'enveloppe 8 (ou l'appui 1, selon le cas) soit appliquée sur ledit volant 21.Firstly, the application on the steering wheel 21 is controlled of a mounted assembly 9 (or of a support 1 mounted on a rim 6, as the case may be), which has been previously mounted on the hub 32, by means of the automation provided for this purpose by the unit 50. This automation has the effect of moving the rolling station 30 from a withdrawal position to a rolling position on the steering wheel 21, in such a way that the tread 7 of the casing 8 (or the support 1, as the case may be) is applied to said flywheel 21.
On se reportera au document de brevet précité WO- A-00/76791 pour la description d'un exemple d'appui 1 utilisé.Reference is made to the aforementioned patent document WO-A-00/76791 for the description of an example of support 1 used.
Dans un second temps, on commande à un instant to la mise en marche du roulage de cet ensemble monté 9 ou de cet appui 1 sur le volant 21 à une vitesse V et sous une charge données, par un autre automatisme de l'unité 50.In a second step, the rolling of this mounted assembly 9 or of this support 1 on the flywheel 21 is commanded at an instant to start running of the wheel 21 at a speed V and under a given load, by another automation of the unit 50 .
L'unité 50 permet de visualiser l'évolution du « rayon écrasé » moyen R (en mm) de l'appui 1 en fonction du temps t de roulage (en s), grâce aux informations qu'elle reçoit du capteur d'écrasement 41.The unit 50 makes it possible to display the evolution of the average “crushed radius” R (in mm) of the support 1 as a function of the running time t (in s), thanks to the information it receives from the crushing sensor 41.
Pendant une temps de roulage de stabilisation ti, il apparaît que ce « rayon écrasé » varie d'une manière erratique et peu significative, essentiellement par fluage du fait de sa rotation à une vitesse relativement élevée et de la contrainte résultant de la charge appliquée. A partir de ce temps ti, ce rayon écrasé commence à décroître d'une manière continue et sensible, essentiellement par flambage. Sur la base du rayon écrasé « stabilisé » Ri correspondant à ce temps ti de stabilisation, on continue le roulage jusqu'à ce que l'unité 50 indique que le rayon écrasé R de l'appui 1 atteint une valeur R2 telle que R2 = Ri + ΔR, ou ΔR est une valeur critique prédéterminée de décroissance du rayon écrasé au-delà de laquelle l'appui 1 est soumis à des contraintes et à un échauffement susceptibles de fissurer ses cloisons ou de les rompre.During a rolling rolling time ti, it appears that this “crushed radius” varies in an erratic and insignificant manner, essentially by creep due to its rotation at a relatively high speed and the stress resulting from the applied load. From this time ti, this crushed radius begins to decrease in a continuous and sensitive manner, essentially by buckling. On the basis of the “stabilized” crushed radius Ri corresponding to this stabilization time ti, rolling is continued until the unit 50 indicates that the crushed radius R of the support 1 reaches a value R 2 such that R 2 = Ri + ΔR, or ΔR is a predetermined critical value for the decrease of the crushed radius beyond which the support 1 is subjected to stresses and to heating capable of cracking or breaking its partitions.
Selon un mode préférentiel de réalisation de l'invention, on a utilisé comme critère d'arrêt (i.e. la diminution ΔR du rayon écrasé à partir du rayon écrasé correspondant au temps de stabilisation d'environ 15 min.) une diminution de ce rayon écrasé de 0,5 mm en 10 secondes suite à ces 15 min. de temps de stabilisation, pour un appui présentant une hauteur de 60 mm, une largeur de 110 mm et un diamètre intérieur de 460 mm.According to a preferred embodiment of the invention, a stop criterion was used (ie the reduction ΔR of the crushed radius from the crushed radius corresponding to the stabilization time of approximately 15 min.) A reduction of this crushed radius 0.5 mm in 10 seconds after these 15 min. stabilization time, for a support having a height of 60 mm, a width of 110 mm and an internal diameter of 460 mm.
En d'autres termes, il s'agit d'une vitesse de diminution de ce rayon écrasé « stabilisé » sur un intervalle de temps donné.In other words, it is a rate of decrease of this "stabilized" overwritten radius over a given time interval.
A partir de la valeur de temps t2 correspondant à ce rayon R qui est fournie par l'unité 50, on calcule la distance de roulage d2 de l'ensemble monté 9 (ou de l'appui 1, selon le cas) par la formule d2 = V. (t2 - 10), qui représente ainsi une prédiction de la distance maximale de roulage, sans détérioration substantielle des conditions de roulage, de l'ensemble monté 9.From the time value t 2 corresponding to this radius R which is supplied by the unit 50, the running distance d 2 of the mounted assembly 9 (or of the support 1, as the case may be) is calculated by the formula d 2 = V. (t 2 - 1 0 ), which thus represents a prediction of the maximum driving distance, without substantial deterioration of the driving conditions, of the mounted assembly 9.
L'expérience montre que les caractéristiques graphiques de rayon écrasé de l'appui en fonction du temps de roulage présentent, juste avant l'apparition de dommages substantiels dans l'appui 1, tels que des ruptures des cloisons 4a, un point d'inflexion sensiblement audit temps critique t2, c'est-à-dire un inversement du sens de variation de la pente de la caractéristique graphique pour t > t2 traduisant une vitesse d'écrasement de l'appui 1 de plus en plus élevée qui conduit rapidement à la rupture dudit appui 1.Experience shows that the graphical characteristics of the crushed radius of the support as a function of the running time present, just before the appearance of substantial damage in the support 1, such as ruptures of the partitions 4a, an inflection point substantially at said critical time t 2 , that is to say a reversal of the direction of variation of the slope of the graphical characteristic for t> t 2 translating an increasingly high speed of crushing of the support 1 which leads quickly at the breaking of said support 1.
Parallèlement à ce suivi de l'évolution du rayon écrasé de l'appui 1, on surveille au moyen de l'unité 50 les informations reçues du détecteur de fumée 42 et l'on commande au moyen de ladite unité 50 l'arrêt du roulage, lorsque ladite unité 50 adresse le signal d'alarme indiquant la présence de fumée à l'intérieur de l'ensemble monté 9. On notera que les moyens d'aspiration 43 permettent également d'aspirer les éventuels courants d'air ou tourbillons à l'intérieur de l'ensemble monté 9 qui ne permettraient pas de détecter la présence de fumée, et également de réguler la pression de l'air de gonflage à une valeur nulle ou réduite.In parallel with this monitoring of the evolution of the crushed radius of the support 1, the information received from the smoke detector 42 is monitored by means of the unit 50 and the halting of driving is controlled by means of the said unit 50 , when said unit 50 sends the alarm signal indicating the presence of smoke inside the mounted assembly 9. It will be noted that the suction means 43 also make it possible to suck up any air currents or vortices at the interior of the mounted assembly 9 which would not allow detect the presence of smoke, and also regulate the inflation air pressure to a zero or reduced value.
La Fig. 6 contient de telles caractéristiques graphiques obtenues pour un roulage à pression interne nulle de deux ensembles montés testés identiques (comportant chacun un appui tel que décrit dans le document de brevet WO-A-00/76791).Fig. 6 contains such graphical characteristics obtained for running at zero internal pressure of two mounted assemblies tested identical (each comprising a support as described in patent document WO-A-00/76791).
On a testé ces deux ensembles montés à deux vitesses différentes, l'une de 100 km/h et l'autre de 88 km/h.We tested these two assemblies mounted at two different speeds, one of 100 km / h and the other of 88 km / h.
Plus précisément, les deux graphes de la Fig. 6 concernent les 60 dernières secondes avant la rupture des appuis (par flambage et échauffement interne excessif).More specifically, the two graphs in FIG. 6 relate to the last 60 seconds before breaking of the supports (by buckling and excessive internal heating).
Les dimensions de chaque ensemble monté sont 225 / 700 R480, et la charge appliquée de 430 daN.The dimensions of each assembled assembly are 225/700 R480, and the applied load of 430 daN.
On a utilisé dans ces essais une rouleuse comportant un volant lisse « 2 P/N » caractérisé par un développement (circonférence) de 5 mètres. La température ambiante pour ces essais était de 25° C.We used in these tests a rolling machine comprising a smooth flywheel "2 P / N" characterized by a development (circumference) of 5 meters. The ambient temperature for these tests was 25 ° C.
Le critère d'arrêt utilisé était une diminution ΔR du rayon écrasé de 0,5 mm en 10 secondes suite à 15 min. de temps de stabilisation.The stopping criterion used was a reduction ΔR of the crushed radius by 0.5 mm in 10 seconds after 15 min. stabilization time.
Le graphe du rayon écrasé relatif à l'essai à 88 km/h (essai n°l) présente un point d'inflexion II, au-delà duquel la vitesse de décroissance de la pente du rayon écrasé augmente soudainement jusqu'à la rupture de l'appui qui se produit une dizaine de secondes plus tard.The graph of the crushed radius relating to the 88 km / h test (test No. 1) shows an inflection point II, beyond which the speed of decrease of the slope of the crushed radius suddenly increases until it breaks of the support that occurs ten seconds later.
Ce point II correspond à une prédiction de distance maximale de roulage, sans détérioration substantielle des conditions de roulage, égale à 384 km pour l'ensemble monté.This point II corresponds to a prediction of maximum driving distance, without substantial deterioration of driving conditions, equal to 384 km for the assembled assembly.
D'une manière analogue, le graphe du rayon écrasé relatif à l'essai à 100 km/h (essai n°2) présente un point d'inflexion 12, qui correspond à une prédiction de distance maximale de roulage, sans détérioration substantielle des conditions de roulage, égale à 208 km pour l'ensemble monté. In an analogous manner, the graph of the crushed radius relating to the 100 km / h test (test No. 2) presents an inflection point 12, which corresponds to a prediction of maximum driving distance, without substantial deterioration of the driving conditions, equal to 208 km for the assembled assembly.

Claims

REVENDICATIONS
1) Méthode de prédiction de la distance maximale de roulage sans détérioration substantielle des conditions de roulage, à pression de gonflage réduite ou nulle, d'un ensemble monté (9) comportant une jante de roue (6), un appui de sécurité (1) qui est monté sur ladite jante (6) et une enveloppe de pneumatique (8) qui est montée sur ladite jante (6) autour dudit appui (1), ledit appui (1) supportant la bande de roulement (7) de ladite enveloppe (8) lors dudit roulage, caractérisée en ce que ladite méthode de prédiction consiste à faire rouler sur au moins une surface de roulage (21), à partir d'un instant to, à une température donnée, sous une charge déterminée et avec une vitesse V constante, ledit ensemble monté (9) à une pression de gonflage réduite ou nulle ou ledit appui (1) monté sur ladite jante (6), de telle manière que le centre (C) de ladite jante (6) soit un point sensiblement invariant lors dudit roulage, en suivant la variation d'une variable R représentative de l'écrasement radial de l'appui (1) en fonction du temps t de roulage à pression réduite ou nulle, et en ce que cette méthode consiste, pendant ce roulage, à mettre en œuvre la séquence d'étapes (i) à (iii) suivantes :1) Method for predicting the maximum driving distance without substantial deterioration of the driving conditions, at reduced or zero inflation pressure, of a mounted assembly (9) comprising a wheel rim (6), a safety support (1 ) which is mounted on said rim (6) and a tire casing (8) which is mounted on said rim (6) around said support (1), said support (1) supporting the tread (7) of said casing (8) during said rolling, characterized in that said prediction method consists in rolling on at least one rolling surface (21), from an instant to, at a given temperature, under a determined load and with a constant speed V, said assembled assembly (9) at a reduced or zero inflation pressure or said support (1) mounted on said rim (6), so that the center (C) of said rim (6) is a point substantially invariant during said rolling, following the variation of a variable R re presentation of the radial crushing of the support (1) as a function of the running time t at reduced or zero pressure, and in that this method consists, during this running, in implementing the sequence of steps (i) to (iii) following:
(i) déterminer une valeur Ri qu'atteint ladite variable R au bout d'un temps de stabilisation ti prédéterminé qui est tel que le sens de variation de ladite variable R est représentatif d'un écrasement radial dudit appui (1) globalement croissant au-delà du temps de stabilisation ti, puis(i) determining a value Ri that said variable R reaches after a predetermined stabilization time ti which is such that the direction of variation of said variable R is representative of a radial crushing of said support (1) generally increasing at beyond the stabilization time ti, then
(ii) déterminer un temps de roulage critique t2 (t2 > ti) au bout duquel ladite variable R atteint une valeur critique R2 telle que R2 = Ri+ΔR, ΔR étant une valeur représentative d'un accroissement critique de l'écrasement de l'appui (1) par rapport à la valeur Rj à l'issue du temps de stabilisation ti, puis (iii) faire correspondre audit temps de roulage t2 une distance d2 avec d2 = V. (t2 - t0), représentant une prédiction de distance maximale de roulage sans détérioration substantielle des conditions de roulage dudit ensemble monté (9).(ii) determining a critical rolling time t 2 (t 2 > ti) at the end of which said variable R reaches a critical value R 2 such that R 2 = Ri + ΔR, ΔR being a value representative of a critical increase in l crushing of the support (1) with respect to the value Rj at the end of the stabilization time ti, then (iii) making correspond to said running time t 2 a distance d 2 with d 2 = V. (t 2 - t 0 ), representing a prediction of maximum driving distance without substantial deterioration of the driving conditions of said mounted assembly (9).
2) Méthode de prédiction selon la revendication 1 , caractérisée en ce que ladite valeur ΔR est telle qu'au temps t2, la vitesse d'accroissement |dR/dt| de l'écrasement dudit appui (1) est supérieure à un seuil critique donné. 3) Méthode de prédiction selon la revendication 1 ou 2, caractérisée en ce qu'elle consiste à faire rouler ledit ensemble monté (9) sur ladite ou lesdites surfaces de roulage (21).2) Prediction method according to claim 1, characterized in that said value ΔR is such that at time t 2 , the rate of increase | dR / dt | of the crushing of said support (1) is greater than a given critical threshold. 3) Prediction method according to claim 1 or 2, characterized in that it consists in rolling said mounted assembly (9) on said one or said rolling surfaces (21).
4) Méthode de prédiction selon la revendication 1 ou 2, caractérisée en ce qu'elle consiste à faire rouler l'appui (1) monté sur ladite jante (6) sur ladite ou lesdites surfaces de roulage (21).4) Prediction method according to claim 1 or 2, characterized in that it consists in rolling the support (1) mounted on said rim (6) on said or said rolling surfaces (21).
5) Méthode de prédiction selon une des revendications précédentes, caractérisée en ce qu'elle consiste à mettre en œuvre l'étape (ii) en suivant la variation de ladite variable R à partir dudit temps t\, et à prédire qu'elle atteint ladite valeur critique R2 audit temps critique t2 sensiblement lorsque l'accélération instantanée de l'écrasement d R/dt dudit appui (1) passe par une valeur nulle.5) Prediction method according to one of the preceding claims, characterized in that it consists in implementing step (ii) by following the variation of said variable R from said time t \ , and in predicting that it reaches said critical value R 2 at said critical time t 2 substantially when the instantaneous acceleration of the crushing d R / dt of said support (1) passes through a zero value.
6) Méthode de prédiction selon une des revendications précédentes, caractérisée en ce que ladite variable R représentative de l'écrasement radial de l'appui (1) correspond au rayon moyen dudit appui (1) en cours d'écrasement, rayon mesuré entre un premier point définissant le centre (C) de ladite jante (6) et un second point définissant le centre de la surface de contact entre ladite surface de roulage (21) et ladite bande de roulement (7) ou la face radial ement externe (3) dudit appui (1), selon le cas.6) Prediction method according to one of the preceding claims, characterized in that said variable R representative of the radial crushing of the support (1) corresponds to the mean radius of said support (1) during crushing, radius measured between a first point defining the center (C) of said rim (6) and a second point defining the center of the contact surface between said rolling surface (21) and said tread (7) or the radially external face (3 ) of said support (1), as the case may be.
7) Méthode de prédiction selon une des revendications 3, 5 ou 6, caractérisée en ce qu'elle consiste également à estimer que ladite distance maximale de roulage, sans détérioration substantielle des conditions de roulage, est atteinte juste avant que de la fumée soit détectée à l'intérieur dudit ensemble monté (9).7) Prediction method according to one of claims 3, 5 or 6, characterized in that it also consists in estimating that said maximum driving distance, without substantial deterioration of the driving conditions, is reached just before smoke is detected inside said mounted assembly (9).
8) Méthode de prédiction selon une des revendications précédentes, caractérisée en ce qu'elle consiste à utiliser une surface de roulage (21) en forme de cylindre de section circulaire, telle qu'un volant (21) de rouleuse (20).8) Prediction method according to one of the preceding claims, characterized in that it consists in using a rolling surface (21) in the form of a cylinder of circular section, such as a steering wheel (21) of rolling machine (20).
9) Méthode de prédiction selon la revendication 8, caractérisée en ce qu'elle consiste à utiliser un volant (21) dont la surface de roulage est lisse. 10) Méthode de prédiction selon la revendication 8, caractérisée en ce qu'elle consiste à utiliser un volant (21) dont la surface de roulage présente une pluralité d'irrégularités saillantes et/ou rentrantes sur sa circonférence.9) Prediction method according to claim 8, characterized in that it consists in using a flywheel (21) whose rolling surface is smooth. 10) Prediction method according to claim 8, characterized in that it consists in using a steering wheel (21) whose rolling surface has a plurality of projecting and / or re-entrant irregularities around its circumference.
11) Installation (10) pour la mise en œuvre d'une méthode de prédiction selon une des revendications précédentes, caractérisée en ce qu'elle comporte essentiellement au moins une surface de roulage (21) et un ou plusieurs postes de roulage (30) qui sont chacun destinés au roulage sur ladite surface (21) d'un ensemble monté (9) comportant une enveloppe de pneumatique (8) montée sur une jante de roue (6) autour d'un appui de sécurité (1) à pression de gonflage réduite ou nulle, ou bien au roulage sur ladite surface (21) d'un tel appui (1) monté sur une jante de roue (6), le centre (C) de ladite jante (6) étant un point sensiblement invariant lors dudit roulage sur ladite ou chaque surface (21), ladite installation comportant également : - des moyens de détection (40) qui sont reliés au ou à chaque poste de roulage (30) et qui sont prévus pour détecter à chaque instant, lors du roulage sur ladite ou lesdites surfaces (21), des informations représentatives des effets induits par ce roulage comprenant au moins une information représentative de l'écrasement radial dudit appui (1) à chaque instant, et une unité (50) pour commander la mise en marche du roulage selon des paramètres de roulage prédéterminés comprenant une vitesse de roulage et une charge à appliquer sur l'appui (1) lors du roulage, pour recevoir lesdites informations desdits moyens de détection (40) et les mémoriser, et pour commander l'arrêt du roulage si au moins l'une desdites informations atteint un valeur critique prédéterminée.11) Installation (10) for the implementation of a prediction method according to one of the preceding claims, characterized in that it essentially comprises at least one rolling surface (21) and one or more rolling stations (30) which are each intended for rolling on said surface (21) a mounted assembly (9) comprising a tire casing (8) mounted on a wheel rim (6) around a safety support (1) at pressure of reduced or zero inflation, or else on rolling on said surface (21) of such a support (1) mounted on a wheel rim (6), the center (C) of said rim (6) being a substantially invariant point during of said rolling on said or each surface (21), said installation also comprising: - detection means (40) which are connected to or to each rolling station (30) and which are provided for detecting at all times during rolling on said surface (s) (21), information representative of the effects s induced by this rolling comprising at least one item of information representative of the radial crushing of said support (1) at each instant, and a unit (50) for controlling the starting of the rolling according to predetermined rolling parameters comprising a rolling speed and a load to be applied on the support (1) during taxiing, to receive said information from said detection means (40) and store it, and to control the halting of taxiing if at least one of said information reaches a value predetermined criticism.
12) Installation (10) selon la revendication 11, caractérisée en ce que lesdits moyens de détection (40) comportent un capteur d'écrasement (41) qui est prévu pour fournir à chaque instant une valeur de rayon d'appui (1) en cours d'écrasement qui est représentative de l'écrasement radial moyen dudit appui (1) lors du roulage, ledit rayon en cours d'écrasement étant mesuré entre un premier point définissant le centre (C) de la jante (6) et un second point définissant le centre de la surface de contact entre ladite surface de roulage (21) et l'enveloppe (8) ou l'appui (1). 13) Installation (10) selon la revendication 11 ou 12, caractérisée en ce que lesdits moyens de détection (40) comportent un détecteur de fumée (42) qui est prévu pour détecter la présence de fumée à l'intérieur dudit ensemble monté (9) en cours de roulage à pression réduite ou nulle, par l'intermédiaire de moyens d'aspiration (43) qui sont prévus à l'intérieur dudit ou chaque poste de roulage (30) pour aspirer en direction dudit détecteur (42) l'air compris à l'intérieur dudit ensemble monté (9). 12) Installation (10) according to claim 11, characterized in that said detection means (40) comprise a crushing sensor (41) which is designed to provide at all times a value of bearing radius (1) in crushing course which is representative of the average radial crushing of said support (1) during rolling, said radius during crushing being measured between a first point defining the center (C) of the rim (6) and a second point defining the center of the contact surface between said rolling surface (21) and the casing (8) or the support (1). 13) Installation (10) according to claim 11 or 12, characterized in that said detection means (40) comprise a smoke detector (42) which is designed to detect the presence of smoke inside said mounted assembly (9 ) during driving at reduced or zero pressure, by means of suction means (43) which are provided inside said or each taxiing station (30) for sucking towards said detector (42). air included inside said mounted assembly (9).
EP02759777A 2001-04-05 2002-03-22 Method for predicting the maximum rolling distance in degraded mode of a mounted assembly Withdrawn EP1421358A2 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR0104764A FR2823303A1 (en) 2001-04-05 2001-04-05 METHOD FOR PREDICTING THE MAXIMUM DISTANCE OF DEGRADE MODE RUNWAY FOR A MOUNTED ASSEMBLY FOR A MOTOR VEHICLE
FR0104764 2001-04-05
PCT/EP2002/003230 WO2002082039A2 (en) 2001-04-05 2002-03-22 Method for predicting the maximum rolling distance in degraded mode of a mounted assembly

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EP1421358A2 true EP1421358A2 (en) 2004-05-26

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EP02759777A Withdrawn EP1421358A2 (en) 2001-04-05 2002-03-22 Method for predicting the maximum rolling distance in degraded mode of a mounted assembly

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US (1) US6820015B2 (en)
EP (1) EP1421358A2 (en)
JP (1) JP2004529028A (en)
KR (1) KR20030020291A (en)
CA (1) CA2410811A1 (en)
FR (1) FR2823303A1 (en)
WO (1) WO2002082039A2 (en)

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US7055381B2 (en) * 2004-07-08 2006-06-06 The Goodyear Tire & Rubber Company Method of testing tires for durability

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KR20030020291A (en) 2003-03-08
WO2002082039A2 (en) 2002-10-17
CA2410811A1 (en) 2002-10-17
US6820015B2 (en) 2004-11-16
JP2004529028A (en) 2004-09-24
US20040002820A1 (en) 2004-01-01
WO2002082039A3 (en) 2004-03-25
FR2823303A1 (en) 2002-10-11

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