EP2082211A1 - Apparatus for the tribological evaluation of a lubricant - Google Patents

Apparatus for the tribological evaluation of a lubricant

Info

Publication number
EP2082211A1
EP2082211A1 EP07848360A EP07848360A EP2082211A1 EP 2082211 A1 EP2082211 A1 EP 2082211A1 EP 07848360 A EP07848360 A EP 07848360A EP 07848360 A EP07848360 A EP 07848360A EP 2082211 A1 EP2082211 A1 EP 2082211A1
Authority
EP
European Patent Office
Prior art keywords
cup
ball
load
installation according
lubricant
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Withdrawn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
EP07848360A
Other languages
German (de)
French (fr)
Inventor
Laurent Tiquet
Laurent Morisseau
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.)
Renault SAS
Original Assignee
Renault 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 Renault SAS filed Critical Renault SAS
Publication of EP2082211A1 publication Critical patent/EP2082211A1/en
Withdrawn legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N19/00—Investigating materials by mechanical methods
    • G01N19/02—Measuring coefficient of friction between materials
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/56—Investigating resistance to wear or abrasion
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/26—Oils; Viscous liquids; Paints; Inks
    • G01N33/28—Oils, i.e. hydrocarbon liquids
    • G01N33/30—Oils, i.e. hydrocarbon liquids for lubricating properties
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/02—Details not specific for a particular testing method
    • G01N2203/06—Indicating or recording means; Sensing means
    • G01N2203/067—Parameter measured for estimating the property
    • G01N2203/0676—Force, weight, load, energy, speed or acceleration

Definitions

  • the present invention relates to a lubricant evaluation system comprising a four-ball machine. It allows for example to follow the anti-wear or extreme-pressure characteristics of lubricants.
  • the operating time and the reliability of the machines and mechanisms in general are hardly limited by sudden organ failures caused by a lack of resistance of the materials.
  • the increased choice and performance of the latter, modern methods for calculating resistance, and room control techniques are increasingly eliminating the risk of serious incidents.
  • the mechanisms are limited in duration and in performance by phenomena of wear or failure of lubrication, such as seizing, abrasion, scratching, quilting, flaking, etc.
  • control means are defined by the choice of the bases which constitute the lubricant, the optimization of their hot viscosity and, above all, the incorporation of anti-wear additives, anti-corrosion, and additives improving the resistance to extreme pressures.
  • the lubricant keeps the surfaces with which it is in contact clean by removing unwanted products such as combustion soot, dust, wear debris and thermal or chemical degradation products.
  • test conditions are adapted to the properties that one wishes to reveal, namely the extreme pressure performance, or the anti-wear performance.
  • the wear plane of the three lower balls is dimensioned according to two perpendicular diameters.
  • Figures 1 and 2 announced, respectively in section, a general view of such a machine with four balls and in perspective with partial cutaway, a view of the cup that equips.
  • the machine 1 of Figure 1 comprises a frame 10 of vertical axis X-X ', on which is mounted a plate 11 which supports a cup 2 receiving three balls 20 (only two balls are visible in the figure).
  • the plate 11 rests itself by a ball bearing system on a support 4, movable in the vertical direction.
  • This support 4 is a kind of piston. It is slidably mounted relative to the frame 10 and is integral with a dynamometric arm 41, transverse axis, pivotally mounted about a horizontal axis Y-Y '. At the end of the arm opposite the support is mounted a pulling member 42. It is understood that the greater the traction on the member 42, in the direction of the arrow g, the more the plate 11, and thus the cup 2, are subjected to a large force, directed vertically in the opposite direction of the arrow g.
  • the fourth ball 30 of the machine is disposed at the end of a mandrel 31, itself driven in rotation about the vertical axis XX 'mentioned above, by means of a rotary motor 3.
  • the cup 2 is formed of a discoid bottom element 21 placed in a part 22 whose vertically rising edges have their threaded external wall.
  • the three balls 20, previously cleaned, are placed inside the cup 2 and are covered by a clamping ring 23 to keep them centered.
  • a lubricant H is poured inside the cup so that its level exceeds the top of the three balls 20.
  • the tightening torque is set at 11 daN.
  • the cup is then placed on the plate 11.
  • the clamping ring 23 is thus pressed firmly on the three balls 20 so that the ball / clamping ring / cup assembly forms an integral assembly.
  • a new ball 30 is placed in the mandrel 31 of the engine 3 and the assembly is put in place above the cup.
  • the machine is ready to use.
  • the four balls 20 and 30 are therefore arranged in a pyramidal arrangement with a triangular base.
  • the member 42 is integral with a jack.
  • the present invention aims at improving this technique according to which the effectiveness of the lubricant is determined as a function of the impressions of the balls and the friction applied, by proposing an installation including a machine with four ball that allows to automatically evaluate the tribological properties of this lubricant, depending on a number of parameters that are measured.
  • a tribological evaluation facility for a lubricant especially a motor oil or a transmission oil, which comprises a four-ball machine comprising:
  • This installation is remarkable in that it also comprises means for measuring at least the following parameters:
  • said measuring means comprise sensors and / or probes
  • said computer means are capable of controlling a gradual and continuous increase in the value of said load; said computer means are capable of driving a gradual increase in the value of said load, in successive stages;
  • said rotary drive means consist of a variable pitch motor
  • said means are capable of controlling a progressive and continuous increase in the rotational speed of said fourth ball; said computer means are capable of controlling a gradual and continuous increase in the speed of rotation of said fourth ball, in successive stages;
  • Said means are adapted to control, as a function of time, a variation of said temperature of the cup or bath;
  • said computer means are capable of establishing a graphical representation, as a function of time, of the various parameters measured.
  • FIG. 3 is a diagram showing an installation according to the invention
  • FIG. 4 is a graph which groups, as a function of time, representative curves of four parameters measured with the installation of FIG.
  • This installation comprises a machine 1 which has a physiognomy substantially identical to that described with reference to Figures 1 and 2.
  • the identical or similar elements bear identical references.
  • the member 42 is integral with the rod of a jack V, connected to the ground S, this jack being preferably an electropneumatic jack.
  • a set of sensors equip this machine.
  • a sensor Ei (of the typeK thermocouple type) measures the temperature of the cup 2.
  • a sensor E 2 (of the displacement type FGP) measures the value of the coefficient of friction applied to the cup 2.
  • the sensor E 3 (amperometric type) measures the speed of rotation of the motor 3.
  • the sensor E 4 (positioning type FGP) measures the displacement value of the dynamometric arm 41.
  • the sensor E 5 (displacement type FGP) measures the load applied by the jack V.
  • the values measured by all these sensors are sent to a computer F which records them by means of ACQ data acquisition software.
  • the various sensors will preferably be calibrated by comparing the values given by the software with calibrated values.
  • the computer means are advantageously able to drive a progressive increase in the value of the load applied to the cup and, at regular time intervals, to measure at least the following parameters:
  • Said progressive increase of the load can be done in successive stages.
  • the duration of the pulse ie the time during which the jack will pull on the arm
  • - pulse waiting time which is the time between two pulses
  • - the acquisition frequency which is the time between two measurements
  • the software is then able to interpret the saved parameters and to render them as tables and graphs.
  • Figure 4 gives an example of such a graphical interpretation.
  • This graphical representation makes it possible to evaluate the anti-wear properties of the lubricant, in particular from the curve C of displacement of the dynamometric arm.
  • This curve can also take a negative slope which corresponds to a dilation of the balls when one has a very rapid temperature rise.
  • the temperature curve is in direct relationship with the displacement curve. When microgrippings are formed, it follows an increase in temperature.
  • the coefficient of friction curve is in direct relation with the displacement curve of the dynamometric arm, and therefore of the wear.
  • actuator sensors of the jack can be installed in order to be able to control the speeds of rise in load.
  • the establishment of a temperature control unit via a cryostat may also be an additional variant.
  • This installation therefore allows, with a reduced operator time, to discriminate different types of lubricants, while allowing direct wear measurements on the balls, according to the known method according to the state of the art.

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Immunology (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Physics & Mathematics (AREA)
  • Pathology (AREA)
  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Food Science & Technology (AREA)
  • Medicinal Chemistry (AREA)
  • Testing Of Devices, Machine Parts, Or Other Structures Thereof (AREA)

Abstract

The present invention relates to an apparatus for the tribological evaluation of a lubricant, particularly an engine oil, which comprises a four-ball machine comprising: - a cup (2) containing three identical balls (20), kept fixed and immersed in a bath (4) of said lubricant; - a fourth ball (30) positioned on and in contact with the first three (20), this ball (30) being connected to means (3) of rotating it on itself, advantageously at variable speed; - said cup (2) being associated with a dynamometric arm (41) itself coupled to an actuator (V), particularly a pneumatic actuator, in order to vary the load applied by the three balls (20) to the fourth (30). This apparatus also comprises means (C1, C2, C3, C4, C5) of measuring at least the following parameters: - the magnitude of said load; - the temperature of the cup (2) or of the bath (4); - the displacement of the arm (41); - the friction force applied to the cup (2); - the rotation(al speed) of the fourth ball (30), and computerized means (F) capable, as a function of time, of driving a variation in said load and of recording, also as a function of time, the magnitudes of said parameters.

Description

INSTALLATION D'EVALUATION TRIBOLOGIQUE D'UN LUBRIFIANT TRIBOLOGICAL EVALUATION INSTALLATION OF A LUBRICANT
La présente invention est relative à une installation d'évaluation d'un lubrifiant comprenant une machine à quatre billes. Elle permet par exemple de suivre les caractéristiques anti-usure ou extrême-pression de lubrifiants.The present invention relates to a lubricant evaluation system comprising a four-ball machine. It allows for example to follow the anti-wear or extreme-pressure characteristics of lubricants.
Actuellement, la durée de fonctionnement et la fiabilité des machines et mécanismes en général ne sont guère limitées par des ruptures brutales d'organe provoquées par un défaut de résistance des matériaux. Le choix et les performances accrus de ces derniers, les méthodes modernes de calcul de résistance, et les techniques de contrôle des pièces éliminent de plus en plus les risques d'incidents graves. Par contre, les mécanismes sont limités en durée et en performances par des phénomènes d'usure ou de défaillance de graissage, tels que le grippage, l'abrasion, le rayage, le piquage, l'écaillage, etc.At present, the operating time and the reliability of the machines and mechanisms in general are hardly limited by sudden organ failures caused by a lack of resistance of the materials. The increased choice and performance of the latter, modern methods for calculating resistance, and room control techniques are increasingly eliminating the risk of serious incidents. On the other hand, the mechanisms are limited in duration and in performance by phenomena of wear or failure of lubrication, such as seizing, abrasion, scratching, quilting, flaking, etc.
On comprend donc aisément l'extrême importance des lubrifiants.It is therefore easy to understand the extreme importance of lubricants.
Ceux-ci ont, pour résumer, quatre fonctions principales. En premier lieu, ils permettent de réduire les pertes par frottements.These have, in short, four main functions. First, they reduce friction losses.
Cette propriété est la plus fondamentale. En effet, afin d'économiser de l'énergie et de réduire réchauffement des pièces induit par frottement, on insère un film d'huile pour éviter le contact rugueux métal/métal.This property is the most basic. Indeed, in order to save energy and reduce friction-induced parts heating, a film of oil is inserted to avoid rough metal / metal contact.
En deuxième lieu, ils permettent de combattre l'usure et la corrosion des surfaces frottantes. Ces moyens de lutte sont définis par le choix des bases qui constituent le lubrifiant, l'optimisation de leur viscosité à chaud et, surtout, l'incorporation d'additifs anti-usure, anti-corrosion, et d'additifs améliorant la résistance aux extrêmes pressions.Secondly, they make it possible to combat wear and corrosion of the friction surfaces. These control means are defined by the choice of the bases which constitute the lubricant, the optimization of their hot viscosity and, above all, the incorporation of anti-wear additives, anti-corrosion, and additives improving the resistance to extreme pressures.
En troisième lieu, ils permettent de refroidir les machines et d'évacuer les calories. Cette fonction réfrigérante est importante pour les moteurs thermiques, les mécanismes rapides comme les turbines, ou encore les réducteurs fonctionnant à grande vitesse.Thirdly, they allow machines to cool down and evacuate calories. This refrigerant function is important for thermal engines, fast mechanisms such as turbines, or gearboxes operating at high speed.
Enfin, ils permettent de neutraliser et d'évacuer les impuretés. Le lubrifiant permet de garder propres les surfaces avec lesquelles il est en contact, en évacuant les produits indésirables tels que les suies de combustion, les poussières, les débris d'usure ainsi que les produits de dégradation thermique ou chimique.Finally, they can neutralize and remove impurities. The lubricant keeps the surfaces with which it is in contact clean by removing unwanted products such as combustion soot, dust, wear debris and thermal or chemical degradation products.
La défaillance de graissage conduit à de l'usure qui est un phénomène évolutif et irréversible. Chaque état d'un système détruit définitivement l'état précédent, de sorte qu'il est très difficile, voire impossible de reconstituer le passé à partir du constat d'une dégradation.The failure of lubrication leads to wear which is an evolutionary and irreversible phenomenon. Each state of a system permanently destroys the previous state, so that it is very difficult, if not impossible, to reconstruct the past from the observation of a degradation.
La compréhension d'une situation de défaillance de graissage nécessite que l'on puisse enregistrer, si possible en continu, les divers paramètres permettant de caractériser l'état du système étudié au fil du temps.Understanding a grease failure situation requires that one can record, if possible continuously, the various parameters to characterize the state of the system studied over time.
Malheureusement, ces paramètres sont très nombreux et on estime par exemple qu'il en faut entre cent et deux cents pour définir les seules caractéristiques géométriques d'une des surfaces frottantes, sans compter l'état physico-chimique des matériaux, les facteurs thermiques et mécaniques, etc.Unfortunately, these parameters are very numerous and it is estimated for example that it takes between one hundred and two hundred to define the only geometric characteristics of one of the friction surfaces, not to mention the physico-chemical state of the materials, the thermal factors and mechanical, etc.
Tout ceci n'est réalisable que pour des essais en laboratoire, mais se révèle en général impossible pour un mécanisme réel en fonctionnement.All this is feasible only for laboratory tests, but is generally impossible for a real mechanism in operation.
On a cependant proposé d'évaluer l'efficacité des lubrifiants, par exemple des huiles-moteur et des huiles de transmission, en utilisant une machine dite "machine à quatre billes".However, it has been proposed to evaluate the effectiveness of lubricants, for example engine oils and transmission oils, using a so-called "four-ball machine".
Pour résumer, dans une telle machine, trois billes maintenues fixes dans une coupelle sont immergées dans un échantillon d'huile, et une quatrième bille tourne sur les trois autres dans des conditions données de vitesse, de charge, de température et de durée. Les conditions d'essais sont adaptées aux propriétés que l'on souhaite révéler, soit les performances extrême pression, soit les performances anti-usure.To summarize, in such a machine, three balls held fixed in a cup are immersed in an oil sample, and a fourth ball rotates on the other three under given conditions of speed, load, temperature and duration. The test conditions are adapted to the properties that one wishes to reveal, namely the extreme pressure performance, or the anti-wear performance.
Après chaque essai, le plan d'usure des trois billes inférieures est coté suivant deux diamètres perpendiculaires.After each test, the wear plane of the three lower balls is dimensioned according to two perpendicular diameters.
On a représenté aux figures 1 et 2 annoncées, respectivement en coupe, une vue générale d'une telle machine à quatre billes et en perspective avec arrachement partiel, une vue de la coupelle qui l'équipe.There is shown in Figures 1 and 2 announced, respectively in section, a general view of such a machine with four balls and in perspective with partial cutaway, a view of the cup that equips.
La machine 1 de la figure 1 comporte un bâti 10 d'axe vertical X-X', sur lequel est monté un plateau 11 qui supporte une coupelle 2 recevant trois billes 20 (deux billes seulement sont visibles sur la figure). Le plateau 11 repose lui-même par un système de roulement à billes sur un support 4, mobile dans le sens vertical.The machine 1 of Figure 1 comprises a frame 10 of vertical axis X-X ', on which is mounted a plate 11 which supports a cup 2 receiving three balls 20 (only two balls are visible in the figure). The plate 11 rests itself by a ball bearing system on a support 4, movable in the vertical direction.
Ce support 4 constitue en quelque sorte un piston. Il est monté coulissant par rapport au bâti 10 et est solidaire d'un bras dynamométrique 41, d'axe transversal, monté pivotant autour d'un axe horizontal Y-Y'. A l'extrémité du bras qui est opposée au support est monté un organe de traction 42. On comprend que plus on exerce une traction importante sur l'organe 42, dans le sens de la flèche g, plus le plateau 11 , et par là même la coupelle 2, sont soumis à une force importante, dirigée verticalement dans le sens inverse de la flèche g. La quatrième bille 30 de la machine est disposée à l'extrémité d'un mandrin 31, lui-même entraîné en rotation autour de l'axe vertical X-X' précité, par l'intermédiaire d'un moteur rotatif 3.This support 4 is a kind of piston. It is slidably mounted relative to the frame 10 and is integral with a dynamometric arm 41, transverse axis, pivotally mounted about a horizontal axis Y-Y '. At the end of the arm opposite the support is mounted a pulling member 42. It is understood that the greater the traction on the member 42, in the direction of the arrow g, the more the plate 11, and thus the cup 2, are subjected to a large force, directed vertically in the opposite direction of the arrow g. The fourth ball 30 of the machine is disposed at the end of a mandrel 31, itself driven in rotation about the vertical axis XX 'mentioned above, by means of a rotary motor 3.
Plus précisément et en se reportant à la figure 2, on constate que la coupelle 2 est formée d'un élément de fond discoïde 21, placé dans une pièce 22 dont les bords, remontant verticalement, ont leur paroi externe filetée.More precisely and with reference to FIG. 2, it can be seen that the cup 2 is formed of a discoid bottom element 21 placed in a part 22 whose vertically rising edges have their threaded external wall.
Les trois billes 20, préalablement nettoyées, sont placées à l'intérieur de la coupelle 2 et on les recouvre par une bague de serrage 23 afin de les maintenir centrées.The three balls 20, previously cleaned, are placed inside the cup 2 and are covered by a clamping ring 23 to keep them centered.
Un lubrifiant H est versé à l'intérieur de la coupelle de manière que son niveau dépasse le sommet des trois billes 20.A lubricant H is poured inside the cup so that its level exceeds the top of the three balls 20.
On met alors en place sur cet ensemble un tenon de serrage supérieur 24, dont le filetage coopère avec celui de la pièce 22.An upper clamping pin 24 is then installed on this assembly, the threading of which cooperates with that of the part 22.
A titre indicatif, le couple de serrage est fixé à 11 daN.As an indication, the tightening torque is set at 11 daN.
La coupelle est alors placée sur le plateau 11. La bague de serrage 23 est ainsi appuyée fermement sur les trois billes 20 de telle sorte que l'ensemble billes / bague de serrage / coupelle forme un ensemble solidaire.The cup is then placed on the plate 11. The clamping ring 23 is thus pressed firmly on the three balls 20 so that the ball / clamping ring / cup assembly forms an integral assembly.
Une bille neuve 30 est placée dans le mandrin 31 du moteur 3 et l'ensemble est mis en place au-dessus de la coupelle. La machine est alors prête à être utilisée. Les quatre billes 20 et 30 sont donc disposées selon un arrangement pyramidal à base triangulaire.A new ball 30 is placed in the mandrel 31 of the engine 3 and the assembly is put in place above the cup. The machine is ready to use. The four balls 20 and 30 are therefore arranged in a pyramidal arrangement with a triangular base.
Tel est donc l'état de la technique représenté notamment par le document US-A-6,857,306.This is therefore the state of the art represented in particular by US-A-6,857,306.
Dans un mode de réalisation décrit dans ce document, l'organe 42 est solidaire d'un vérin.In an embodiment described in this document, the member 42 is integral with a jack.
Avec une telle machine, on s'attache essentiellement à déterminer l'efficacité du lubrifiant en fonction des diamètres d'empreinte des billes et des traces d'usure qu'elles comportent.With such a machine, it is essentially a matter of determining the effectiveness of the lubricant as a function of the impression diameters of the balls and the traces of wear that they comprise.
La présente invention vise à améliorer cette technique selon laquelle on détermine l'efficacité du lubrifiant en fonction des empreintes des billes et du frottement appliqué, en proposant une installation incluant une machine à quatre billes qui permet d'évaluer automatiquement les propriétés tribologiques de ce lubrifiant, en fonction d'un certain nombre de paramètres que l'on mesure.The present invention aims at improving this technique according to which the effectiveness of the lubricant is determined as a function of the impressions of the balls and the friction applied, by proposing an installation including a machine with four ball that allows to automatically evaluate the tribological properties of this lubricant, depending on a number of parameters that are measured.
Il s'agit donc d'une installation d'évaluation tribologique d'un lubrifiant, notamment d'une huile-moteur ou d'une huile de transmission, qui comporte une machine à quatre billes comprenant :It is therefore a tribological evaluation facility for a lubricant, especially a motor oil or a transmission oil, which comprises a four-ball machine comprising:
- une coupelle contenant trois billes identiques, maintenues fixes et immergées dans un bain dudit lubrifiant ;a cup containing three identical balls, held stationary and immersed in a bath of said lubricant;
- une quatrième bille disposée sur et en contact avec les trois premières, cette bille étant reliée à des moyens d'entraînement en rotation sur elle- même ;a fourth ball disposed on and in contact with the first three, this ball being connected to rotating drive means on itself;
- ladite coupelle étant associée à un bras dynamométrique, lui- même couplé à un vérin, notamment pneumatique, pour faire varier la charge appliquée par les trois billes sur la quatrième.- Said cup being associated with a torque arm, itself coupled to a cylinder, in particular pneumatic, to vary the load applied by the three balls on the fourth.
Cette installation est remarquable par le fait qu'elle comporte également des moyens de mesure d'au moins les paramètres suivants :This installation is remarkable in that it also comprises means for measuring at least the following parameters:
- valeur de ladite charge ;- value of said load;
- température de la coupelle ou du bain ;- temperature of the cup or bath;
- valeur de déplacement du bras ;- value of movement of the arm;
- force de frottement appliqué à la coupelle ; - valeur de rotation (vitesse) de la quatrième bille. ainsi que des moyens informatiques aptes à piloter, en fonction du temps, une variation de ladite charge et à enregistrer, également en fonction du temps, les valeurs desdits paramètres.- friction force applied to the cup; - rotation value (speed) of the fourth ball. as well as computer means able to control, as a function of time, a variation of said load and to record, also as a function of time, the values of said parameters.
Ainsi, selon d'autres caractéristiques avantageuses et non limitatives de ce procédé :Thus, according to other advantageous and nonlimiting features of this process:
- lesdits moyens de mesure comprennent des capteurs et/ou des sondes ;said measuring means comprise sensors and / or probes;
- lesdits moyens informatiques sont aptes à piloter une augmentation progressive et continue de la valeur de ladite charge ; - lesdits moyens informatiques sont aptes à piloter une augmentation progressive de la valeur de ladite charge, par paliers successifs ;said computer means are capable of controlling a gradual and continuous increase in the value of said load; said computer means are capable of driving a gradual increase in the value of said load, in successive stages;
- lesdits moyens d'entraînement en rotation consistent en un moteur à pas variable ;said rotary drive means consist of a variable pitch motor;
- lesdits moyens sont aptes à piloter une augmentation progressive et continue de la vitesse de rotation de ladite quatrième bille ; - lesdits moyens informatiques sont aptes à piloter une augmentation progressive et continue de la vitesse de rotation de ladite quatrième bille, par paliers successifs ;said means are capable of controlling a progressive and continuous increase in the rotational speed of said fourth ball; said computer means are capable of controlling a gradual and continuous increase in the speed of rotation of said fourth ball, in successive stages;
- lesdits moyens sont aptes à piloter, en fonction du temps, une variation de ladite température de la coupelle ou du bain ;- Said means are adapted to control, as a function of time, a variation of said temperature of the cup or bath;
- lesdits moyens informatiques sont aptes à établir une représentation graphique, en fonction du temps, des différents paramètres mesurés.said computer means are capable of establishing a graphical representation, as a function of time, of the various parameters measured.
D'autres caractéristiques et avantages de la description apparaîtront de la description détaillée qui va suivre. Cette description sera faite en référence aux dessins annexés dans lesquels :Other features and advantages of the description will become apparent from the following detailed description. This description will be made with reference to the appended drawings in which:
- la figure 3 est un schéma montrant une installation selon l'invention,FIG. 3 is a diagram showing an installation according to the invention,
- la figure 4 est un graphique qui regroupe, en fonction du temps, des courbes représentatives de quatre paramètres mesurés avec l'installation de la figure 3.FIG. 4 is a graph which groups, as a function of time, representative curves of four parameters measured with the installation of FIG.
Cette installation comporte une machine 1 qui présente une physionomie sensiblement identique à celle décrite en référence aux figures 1 et 2. Ainsi, les éléments identiques ou similaires portent des références identiques. On notera ici que l'organe 42 est solidaire de la tige d'un vérin V, relié au sol S, ce vérin étant de préférence un vérin électropneumatique.This installation comprises a machine 1 which has a physiognomy substantially identical to that described with reference to Figures 1 and 2. Thus, the identical or similar elements bear identical references. It will be noted here that the member 42 is integral with the rod of a jack V, connected to the ground S, this jack being preferably an electropneumatic jack.
Un ensemble de capteurs équipe cette machine.A set of sensors equip this machine.
En premier lieu, un capteur Ei (du genre thermocouple TypeK) mesure la température de la coupelle 2. Un capteur E2 (du type FGP de déplacement) mesure la valeur du coefficient de frottement appliqué à la coupelle 2.In the first place, a sensor Ei (of the typeK thermocouple type) measures the temperature of the cup 2. A sensor E 2 (of the displacement type FGP) measures the value of the coefficient of friction applied to the cup 2.
Le capteur E3 (de type ampérométrique) mesure la vitesse de rotation du moteur 3.The sensor E 3 (amperometric type) measures the speed of rotation of the motor 3.
Le capteur E4 (de type FGP de positionnement) mesure la valeur de déplacement du bras dynamométrique 41.The sensor E 4 (positioning type FGP) measures the displacement value of the dynamometric arm 41.
Enfin, le capteur E5 (de type FGP de déplacement) mesure la charge appliquée par le vérin V.Finally, the sensor E 5 (displacement type FGP) measures the load applied by the jack V.
Les valeurs mesurées par l'ensemble de ces capteurs sont envoyées à un ordinateur F qui les enregistre au moyen d'un logiciel d'acquisition de données ACQ. Préalablement, on aura de préférence étalonné les différents capteurs en comparant les valeurs données par le logiciel à des valeurs étalonnées.The values measured by all these sensors are sent to a computer F which records them by means of ACQ data acquisition software. Beforehand, the various sensors will preferably be calibrated by comparing the values given by the software with calibrated values.
Les moyens informatiques sont avantageusement aptes à piloter une, augmentation progressive de la valeur de la charge appliquée à la coupelle et, à intervalles de temps réguliers, à mesurer au moins les paramètres suivants :The computer means are advantageously able to drive a progressive increase in the value of the load applied to the cup and, at regular time intervals, to measure at least the following parameters:
- valeur de cette charge ;- value of this load;
- température de la coupelle ou du bain ;- temperature of the cup or bath;
- valeur de déplacement du bras ;- value of movement of the arm;
- force de frottement appliqué à la coupelle ; - valeur de rotation (vitesse) de la quatrième bille.- friction force applied to the cup; - rotation value (speed) of the fourth ball.
Ladite augmentation progressive de la charge peut se faire par paliers successifs.Said progressive increase of the load can be done in successive stages.
Avantageusement, ces paliers sont de mêmes valeurs et à intervalles de temps identiques. On aura pris soin, préalablement, de régler les paramètres suivants :Advantageously, these steps are of the same values and at identical time intervals. We will have taken care, previously, to adjust the following parameters:
- la durée d'impulsion, c'est à dire le temps pendant lequel le vérin va tirer sur le bras ;the duration of the pulse, ie the time during which the jack will pull on the arm;
- le temps d'attente impulsion, qui est le temps entre deux impulsions ; - la fréquence d'acquisition, qui est le temps entre deux mesures ;- pulse waiting time, which is the time between two pulses; - the acquisition frequency, which is the time between two measurements;
- le nombre de phases.- the number of phases.
Ainsi, on peut avantageusement réaliser une acquisition de données à partir d'une valeur initiale de charge de 20 daN, avec une valeur finale de 110 daN, une montée en charge par paliers de 10 daN et une durée de paliers de 10 mn. Ainsi, il faut 1 h 40 mn pour engranger l'ensemble des données.Thus, one can advantageously perform a data acquisition from an initial load value of 20 daN, with a final value of 110 daN, a load increase in increments of 10 daN and a duration of steps of 10 minutes. Thus, it takes 1 h 40 min to gather all the data.
Mais on pourrait aussi atteindre une valeur finale de 500 daN.But we could also reach a final value of 500 daN.
Ledit logiciel est alors en mesure d'interpréter les paramètres enregistrés et de les restituer sous forme de tableaux et de graphiques.The software is then able to interpret the saved parameters and to render them as tables and graphs.
Ainsi, à titre d'exemple, on représente graphiquement l'évolution des paramètres dont il a été fait état plus haut, en fonction du temps.Thus, by way of example, the evolution of the parameters mentioned above, as a function of time, is graphically represented.
La figure 4 donne un exemple d'une telle interprétation graphique.Figure 4 gives an example of such a graphical interpretation.
Il y est donné, en fonction du temps :It is given, depending on the time:
- sur la courbe A, l'évolution de la température de la coupelle ;on the curve A, the evolution of the temperature of the cup;
- sur la courbe B, l'évolution de la charge appliquée à la coupelle ; - sur la courbe C, l'évolution du déplacement du bras dynamométrique ; - et sur la courbe D, l'évolution du coefficient de frottement des billes.- on curve B, the evolution of the load applied to the cup; on the curve C, the evolution of the displacement of the dynamometric arm; and on the curve D, the evolution of the coefficient of friction of the balls.
Cette représentation graphique permet d'évaluer les propriétés antiusure du lubrifiant, notamment à partir de la courbe C de déplacement du bras dynamométrique.This graphical representation makes it possible to evaluate the anti-wear properties of the lubricant, in particular from the curve C of displacement of the dynamometric arm.
Ainsi, dans la zone supérieure C2, on constate que la courbe de l'évolution de déplacement du bras prend une pente positive, de sorte qu'il s'en déduit une augmentation de l'usure.Thus, in the upper zone C 2 , it can be seen that the curve of the evolution of movement of the arm takes a positive slope, so that an increase in wear results.
Entre chaque palier, lors de la montée en charge, on a une forte augmentation du déplacement, qui est due à la déformation élastique des billes causée par la montée en charge.Between each landing, during the climb, there is a strong increase in the displacement, which is due to the elastic deformation of the balls caused by the increase in load.
Cette déformation élastique est décroissante lorsque les charges augmentent.This elastic deformation decreases as the loads increase.
Cette courbe peut également prendre une pente négative qui correspond à une dilatation des billes lorsque l'on a une élévation de température très rapide.This curve can also take a negative slope which corresponds to a dilation of the balls when one has a very rapid temperature rise.
Elle peut également prendre une pente nulle qui équivaut à peu ou pas d'usure. C'est la partie inférieure Ci de la courbe C.It can also take a zero slope that equates to little or no wear. This is the lower part Ci of the curve C.
On remarque par ailleurs que la courbe de température est en relation directe avec la courbe de déplacement. Lorsque des microgrippages se forment, il s'en suit une augmentation de la température.Note also that the temperature curve is in direct relationship with the displacement curve. When microgrippings are formed, it follows an increase in temperature.
De même, la courbe de coefficient de frottement est en relation directe avec la courbe de déplacement du bras dynamométrique, donc de l'usure.Similarly, the coefficient of friction curve is in direct relation with the displacement curve of the dynamometric arm, and therefore of the wear.
Selon une variante de réalisation, des capteurs de guidage du vérin peuvent être installés afin de pouvoir piloter les vitesses de montée en charge.According to an alternative embodiment, actuator sensors of the jack can be installed in order to be able to control the speeds of rise in load.
La mise en place d'une unité de pilotage de la température par l'intermédiaire d'un cryostat peut également constituer une variante supplémentaire.The establishment of a temperature control unit via a cryostat may also be an additional variant.
Cette installation permet donc, avec un temps opérateur réduit, de discriminer différents types de lubrifiants, tout en autorisant des mesures directes d'usure sur les billes, conformément à la méthode connue selon l'état de la technique. This installation therefore allows, with a reduced operator time, to discriminate different types of lubricants, while allowing direct wear measurements on the balls, according to the known method according to the state of the art.

Claims

REVENDICATIONS
1. Installation d'évaluation tribologique d'un lubrifiant, notamment d'une huile-moteur, qui comporte une machine à quatre billes comprenant :A tribological evaluation apparatus for a lubricant, especially an engine oil, comprising a four-ball machine comprising:
- une coupelle (2) contenant trois billes identiques (20), maintenues fixes et immergées dans un bain (4) dudit lubrifiant ; - une quatrième bille (30) disposée sur et en contact avec les trois premières (20), cette bille (30) étant reliée à des moyens (3) d'entraînement en rotation sur elle-même, avantageusement à vitesse variable ;- a cup (2) containing three identical balls (20), held stationary and immersed in a bath (4) of said lubricant; - A fourth ball (30) disposed on and in contact with the first three (20), this ball (30) being connected to means (3) for driving in rotation on itself, preferably at variable speed;
- ladite coupelle (2) étant associée à un bras dynamométrique (41), lui-même couplé à un vérin (V), notamment pneumatique, pour faire varier la charge appliquée par les trois billes (20) sur la quatrième (30), caractérisée par le fait qu'elle comporte également des moyens de mesure (C1, C2, C3, C4, C5) d'au moins les paramètres suivants :said cup (2) being associated with a dynamometric arm (41), itself coupled to a jack (V), in particular pneumatic, to vary the load applied by the three balls (20) on the fourth (30), characterized in that it also comprises measuring means (C 1 , C 2 , C 3 , C 4 , C 5 ) of at least the following parameters:
- valeur de ladite charge ;- value of said load;
- température de la coupelle (2) ou du bain (4) ; - valeur de déplacement du bras (41) ;- temperature of the cup (2) or the bath (4); - displacement value of the arm (41);
- force de frottement appliqué à la coupelle (2) ;- friction force applied to the cup (2);
- valeur de rotation (vitesse) de la quatrième bille (30). ainsi que des moyens informatiques (F) aptes à piloter, en fonction du temps, une variation de ladite charge et à enregistrer, également en fonction du temps, les valeurs desdits paramètres.- rotation value (speed) of the fourth ball (30). as well as computer means (F) able to control, as a function of time, a variation of said load and to record, also as a function of time, the values of said parameters.
2. Installation selon la revendication 1, caractérisée par le fait que lesdites moyens de mesure (C1, C2, C3, C4, C5) comprennent des capteurs et/ou des sondes.2. Installation according to claim 1, characterized in that said measuring means (C 1 , C 2 , C 3 , C 4 , C 5 ) comprise sensors and / or probes.
3. Installation selon la revendication 1 ou 2, caractérisée par le fait que lesdits moyens informatiques (F) sont aptes à piloter une augmentation progressive et continue de la valeur de ladite charge.3. Installation according to claim 1 or 2, characterized in that said computer means (F) are adapted to drive a gradual and continuous increase in the value of said load.
4. Installation selon la revendication 3, caractérisée par le fait que lesdits moyens informatiques (F) sont aptes à piloter une augmentation progressive de la valeur de ladite charge, par paliers successifs. 4. Installation according to claim 3, characterized in that said computer means (F) are adapted to drive a gradual increase in the value of said load, in successive stages.
5. Installation selon l'une des revendications 1 à 4, caractérisée par le fait que lesdits moyens d'entraînement en rotation consistent en un moteur (3) à pas variable. 5. Installation according to one of claims 1 to 4, characterized in that said rotary drive means consist of a motor (3) variable pitch.
6. Installation selon l'une des revendications 1 à 5, caractérisée par le fait que lesdits moyens informatiques (F) sont aptes à piloter une augmentation progressive et continue de la vitesse de rotation de ladite quatrième bille.6. Installation according to one of claims 1 to 5, characterized in that said computer means (F) are adapted to drive a gradual and continuous increase in the rotational speed of said fourth ball.
7. Installation selon l'une des revendications 1 à 6, caractérisée par le fait que lesdits moyens informatiques (F) sont aptes à piloter une augmentation progressive et continue de la vitesse de rotation de ladite quatrième bille, par paliers successifs.7. Installation according to one of claims 1 to 6, characterized in that said computer means (F) are adapted to drive a gradual and continuous increase in the speed of rotation of said fourth ball, in successive stages.
8. Installation selon l'une des revendications 1 à 7, caractérisée par le fait que lesdits moyens sont aptes à piloter, en fonction du temps, une variation de ladite température de la coupelle (2) ou du bain (4).8. Installation according to one of claims 1 to 7, characterized in that said means are adapted to control, as a function of time, a variation of said temperature of the cup (2) or the bath (4).
9. Installation selon l'une des revendications 1 à 8, caractérisée par le fait que lesdits moyens informatiques (F) sont aptes à établir une représentation graphique, en fonction du temps, des différents paramètres mesurés. 9. Installation according to one of claims 1 to 8, characterized in that said computer means (F) are able to establish a graphical representation, as a function of time, of the various measured parameters.
EP07848360A 2006-10-27 2007-09-21 Apparatus for the tribological evaluation of a lubricant Withdrawn EP2082211A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR0609458A FR2907903B1 (en) 2006-10-27 2006-10-27 TRIBOLOGICAL EVALUATION INSTALLATION OF A LUBRICANT
PCT/FR2007/051989 WO2008050015A1 (en) 2006-10-27 2007-09-21 Apparatus for the tribological evaluation of a lubricant

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CN102004054B (en) * 2010-09-21 2012-02-29 同济大学 Three-way loading mechanical property test system of multifunctional lining segment joint
RU2454654C1 (en) * 2011-02-25 2012-06-27 Федеральное государственное автономное образовательное учреждение высшего профессионального образования Сибирский федеральный университет (СФУ) Method of determining quality of lubricating oil
CN102768208B (en) * 2012-07-16 2014-06-25 清华大学 Device for measuring microstructure and components of contact area in superlubric state
US10281388B2 (en) 2015-12-18 2019-05-07 Ducom Instruments Pvt. Ltd. Tester to estimate co-efficient of friction and determine properties of a sample lubricant
CN105890997A (en) * 2016-04-12 2016-08-24 中国建筑股份有限公司 External three-ring integrated type loading frame of shield segment mechanical property testing machine
JP6453816B2 (en) * 2016-06-29 2019-01-16 エイスインターナショナルトレード株式会社 Simple type dynamic friction tester and simple test method for dynamic friction force

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