EP1578621A2 - Bandage elastique pour mesurer l adherence d un vehicul e qui en est equipe sur un sol - Google Patents
Bandage elastique pour mesurer l adherence d un vehicul e qui en est equipe sur un solInfo
- Publication number
- EP1578621A2 EP1578621A2 EP03706516A EP03706516A EP1578621A2 EP 1578621 A2 EP1578621 A2 EP 1578621A2 EP 03706516 A EP03706516 A EP 03706516A EP 03706516 A EP03706516 A EP 03706516A EP 1578621 A2 EP1578621 A2 EP 1578621A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- zone
- central zone
- rzz
- central
- elastic bandage
- 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- Withdrawn
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C19/00—Tyre parts or constructions not otherwise provided for
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/03—Tread patterns
-
- 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
- G01N19/00—Investigating materials by mechanical methods
- G01N19/04—Measuring adhesive force between materials, e.g. of sealing tape, of coating
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S152/00—Resilient tires and wheels
- Y10S152/03—Slits in threads
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S152/00—Resilient tires and wheels
- Y10S152/902—Non-directional tread pattern having no circumferential rib and having blocks defined by circumferential grooves and transverse grooves
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T152/00—Resilient tires and wheels
- Y10T152/10—Tires, resilient
- Y10T152/10495—Pneumatic tire or inner tube
- Y10T152/10513—Tire reinforcement material characterized by short length fibers or the like
Definitions
- the present invention relates to an elastic tire, such as a tire, provided with means making it possible to measure the grip of a vehicle which is equipped with it on a road surface, such as a roadway. It relates more particularly to the determination of the adhesion characteristics of such an elastic bandage when running, from obtaining physical parameters in the contact area between this elastic bandage and the rolling surface. It has already been proposed to carry out permanent measurements in the tread of a tire while a vehicle equipped with it is running, in order to know in real time the forces which develop between a tire and the ground. We can consult on this subject the patent document DE-A-3937966.
- the object of the present invention is to provide an elastic tire, such as a tire, comprising a tread which comprises at least one measuring block making it possible to effectively measure the grip of said tire on a road surface. , by providing as realistic information as possible about the safety margin that remains in driving the vehicle.
- an elastic bandage is such that this measuring block, which is intended to come into contact with the ground at each turn of said bandage, comprises, seen on a radially external face of the tread, a central zone and an encircling zone surrounding the central zone, a sensor sensitive to at least one tangential force exerted on the radially external vertex of said central zone being provided opposite said summit, the central zone and the encircling zone satisfying both of the following two conditions: a) Rzz c ⁇ Rzz e b) (i) Rxz c / Rzz c > Rxz e / Rzz e or (ii) Ryz c / Rzz c > Ryz e / Rzz e , where: x, y and z represent the circumferential, axial and radial directions respectively for said tire,
- Rzz c and Rzz e represent respectively the rigidities of said central zone and of said zone of encirclement at a force oriented perpendicular to said radially external face
- Rxz c and Rxz e represent respectively the rigidities of said central zone and of said zone encircling a force oriented tangentially to said radially external face in the circumferential direction of the tire
- Ryz c and Ryz e respectively represent the rigidities of said central zone and of said zone of encirclement at a force oriented tangentially to said radially external face in the axial direction of the tire.
- condition a) reflects the fact that the central zone has a “vertical” rigidity (ie in the radial direction of the tire) less than that of the encircling zone.
- condition b) it translates the fact that the ratio of the “tangential” stiffness (ie in the circumferential or axial direction of the tire) on the “vertical” stiffness is on the contrary higher for the central zone compared to the zone encirclement.
- the central zone can also have a grip potential which is lower than that of the encircling zone and that of the rest of the tread. To do this, this central zone may for example be made of a material different from that of the encircling zone and the rest of the tread.
- a sensor is installed to perform a measurement on this measurement block.
- the adaptation consists in providing a central measurement zone, surrounded by an encircling zone, which has properties identical to that which is used in a significant part of the tread.
- the term “properties” is understood to mean an overall evaluation having a contribution coming from the intrinsic characteristics of the material used, and possibly a contribution conditioned by the shape given by the molding of the material, the latter possibly even being dominant.
- the term “significant portion” is understood to mean a part of the tread designed solely as a function of the properties of use that the designer of the tire wanted to impart to the tire in question, as opposed to what is wanted to perform a measurement.
- the term “potential for adhesion of any element” is understood to mean the ratio between the maximum overall tangential force that this element, taken as a whole, can undergo during its contact with the ground, at a place given, and the normal force applied to this element.
- vibration potential denotes the ratio between the local tangential stress and the local vertical stress which are exerted at a given point on a tread element sliding on the ground.
- available grip margin The difference between the adhesion potential of an element and the ratio between the overall tangential force and the global vertical force actually applied to this element, taken as a whole, during its passage, is called "available grip margin". in the contact area.
- the invention relates to an elastic tire consisting of a tire, the tread of which is based on rubber.
- the tread of the elastic bandage comprises tread blocks separated from each other by grooves of width generally equal to or greater than 2 mm, the encircling zone being separated from the central zone by lamellae and / or incision (s) which have a substantially reduced width compared to that of said grooves and which are provided for decoupling the material of the central zone from that of the encircling zone.
- lamellae and / or incision (s) typically have widths of less than 2 mm and preferably less than 1 mm. Even more preferably, they have widths ranging from 0.3 mm to 0.8 mm.
- the area of the apex of the central area is less than 20% of the area of the radially outer face of the encircling area.
- the "vertical" rigidity of the central zone is minimized to such an extent that the tire according to the invention also satisfies the following condition: a bis ) Rzz c / ⁇ 0.2. Rzz e .
- the ratio (“tangential” stiffness / “vertical” stiffness) for the central zone is maximized to such an extent that said bandage also satisfies the following condition: ba ) (i) Rxz c / Rzz c > 1.5. Rxz e / Rzz e or (ii) Ryz c / Rzz c > 1.5. Ryz e / Rzz e .
- the central zone consists of a compressible and isotropic material, such as a cellular rubber composition (ie cellular, for example with closed cells, which is obtained in a manner known in the art. area of a blowing agent), which contributes to significantly minimizing the “vertical” rigidity Rzz c of the central zone and therefore to maximizing the stiffness ratio Rxz c / Rzz c or Ryz c / Rzz c , hence the desired optimization of the sliding of said central area.
- a compressible and isotropic material such as a cellular rubber composition (ie cellular, for example with closed cells, which is obtained in a manner known in the art. area of a blowing agent), which contributes to significantly minimizing the “vertical” rigidity Rzz c of the central zone and therefore to maximizing the stiffness ratio Rxz c / Rzz c or Ryz c / Rzz c , hence the desired optimization of the sliding of said central area.
- said central zone has an orthotropic character, and it consists of composite layers which are superimposed either in the axial direction or in the circumferential direction of the bandage (respectively when said condition b) is satisfied by said inequality (i) or by said inequality (ii)) and which are each based on a rubber composition in which are oriented reinforcements of organic or mineral type, for example metallic or textile reinforcements, substantially parallel to the median circumferential plane of said bandage or else perpendicular to this plane (superposition of said layers in the circumferential and axial directions, respectively).
- said composite layers which are two by two adjacent respectively comprise textile fibers which are oriented at opposite angles with the circumferential or axial direction of the bandage.
- these angles are substantially between ⁇ 20 ° and ⁇ 45 ° and, even more preferably, they are substantially equal to ⁇ 30 °.
- Each composite layer preferably has a thickness ranging from 0.5 mm to 3 mm and, even more preferably, ranging from 0.5 mm to 1 mm.
- This orthotropic composite structure of the central zone makes it possible to increase the “tangential” rigidity Rxz or Ryz of this zone for a given “vertical” rigidity, which contributes to further maximizing the abovementioned stiffness ratio Rxz c / Rzz c or Ryz c / Rzz c and therefore to optimize the sliding of said central area.
- the anisotropy ratio in extension or in compression of such a central composite zone according to the invention can vary from 3 to 7 and, preferably, from 3 to 4.
- said central zone substantially admits as an element of symmetry the median circumferential plane of said bandage, and said condition b) is satisfied by said inequality (i).
- said central area has an elongated shape (for example rectangular or ellipsoidal) in said circumferential direction of said bandage. It will be noted that this reduced width of the central zone (in the axial direction of the tire for this first embodiment) contributes to minimizing the “vertical” rigidity Rzz of the central zone and, consequently, to specifically maximizing the stiffness ratio Rxz c / Rzz c , hence the desired optimization of the sliding of the central area.
- said apex of said central zone which is in the form of a parallelepiped, has its sides respectively opposite four elements of parallelepipedal sculpture forming said encircling zone.
- at least one of the lateral faces of said central zone which extends from a short side of said vertex is inclined at an angle ranging from -45 ° at + 45 ° (for example ⁇ 30 °) relative to a plane perpendicular to said vertex containing said short side. This inclination of the or each lateral face of the central zone extending from a short side of said vertex contributes to optimizing the sliding of said central zone in the contact area.
- the tread of the tire has tread blocks separated from each other by grooves of width generally equal to or greater than 2 mm, the encircling zone being separated from the central zone by lamellae or incision (s) which have a substantially reduced width compared to that of said grooves and which are provided for decoupling the material of the central zone from that of the encircling zone, each long side of said vertex being connected to one of said sculpture elements located opposite by one of said strips and at least one of the short sides of said apex being connected to the sculpture element opposite by one of said incision (s).
- these strips and / or incision (s) typically have widths of less than 2 mm and preferably less than 1 mm.
- the incision which connects the or each short side of the apex of the central zone to the corresponding sculpture element of the encircling zone has the effect of optimizing the "flattening" of the measurement block comprising this central zone in the area of contact with the road surface.
- said central area is located in the shoulder area of the bandage and said condition b) is satisfied by said inequality (ii).
- said central zone has an elongated shape (for example rectangular or ellipsoidal) in the axial direction of the tire.
- this reduced width of the central zone contributes to minimizing the “vertical” rigidity Rzz of said central zone and, consequently, to specifically maximizing the stiffness ratio Ryz c / Rzz c , hence the sought-after optimization of the sliding of the central zone.
- the central zone of parallelepiped shape, is housed between the wings of a first sculpture element of the zone of encirclement having a substantially "U" section in a plane perpendicular to the radial direction. of the tire, said wings extending parallel to said axial direction and having their respective ends practically aligned with one of the short sides of said apex of the central zone, which short side faces a second element of parallelepipedal sculpture of the zone d 'encirclement.
- At least one of the lateral faces of said central zone which extends from a short side of said vertex is inclined at an angle ranging from -45 ° at + 45 ° (for example ⁇ 30 °) relative to a plane perpendicular to said vertex containing said short side.
- This inclination of the or each lateral face of the central zone extending from a short side of said vertex contributes to optimizing the sliding of said central zone in the contact area.
- the tread of the bandage comprises tread blocks separated from each other by grooves, the encircling zone being separated from the central zone by strips or incision (s) which have a width substantially reduced compared to that of said grooves and which are provided for decoupling the material of the central zone from that of the encircling zone, the other short side of said vertex which faces the core of said the first U-shaped sculpture element being connected to the latter by a lamella, while said short side which is aligned with the ends of said wings is connected to said second sculpture element by an incision.
- this incision has the effect of optimizing the "flattening" of the measurement block comprising this central zone in the area of contact with the rolling ground.
- Fig. 1 is a plan view of a sector of a tire tread comprising a measuring block according to a first embodiment of the invention, with reference to a schematic view in axial section of this tread,
- - Fig. 2 is a plan view of a sector of a tire tread comprising a measuring block according to a second embodiment of the invention, still with reference to a schematic view in axial section of this tread, - Figs. 3 and 4 are respectively views in section along the planes ILT-i ⁇ and IV-iV of FIG. 1 of the tread shown in this FIG. 1
- FIG. 5 and 6 are respectively views in section along the planes V-V and VI-VI of FIG. 2 of the tread shown in this FIG. 2
- Fig. 7 is a schematic perspective view illustrating the structure of a composite measuring block according to the invention comprising reinforcements oriented in the circumferential direction of the tire at a given angle with this direction, and
- Fig. 8 is a graph illustrating the variation, as a function of the angle of the fibers for a measuring block according to FIG. 7, on the one hand, of the ratio (stiffness Rzz c to a force oriented perpendicular to the surface of the tread / stiffness Rxz c to a force oriented tangentially to said surface) and, on the other hand, of the force applied to said measurement block.
- Fig. 1 a tread sector 1 of a tire according to a first exemplary embodiment of the invention comprising tread blocks 2 and, facing this sector, this tread 1 viewed in axial section which admits for axis of symmetry the median circumferential plane P of the tire.
- the tread 1 comprises a measuring block 3 which extends locally from the radially internal face 4 to the radially external face 5 of this tread 1. In the example of FIG. 1, this measurement block 3 is centered on said median circumferential plane P.
- block is meant in the present description a sculpture element 2 of parallelepipedal shape or not, such as a rubber “bread”, which is surrounded on its periphery by a groove or groove 6 connecting it to other blocks. This groove is relatively deep and has a width typically equal to or greater than 2 mm.
- the measuring block 3 of FIG. 1 forms a cross substantially in the shape of a "+".
- This measuring block 3 comprises a central zone 10 and a surrounding zone 20 of the same height in the radial direction Z of the tire (see Figs. 3 and 4), the surrounding zone 20 surrounding the central zone 10 and being connected to the latter by strips and / or incision (s) 30, 31, 32, 33 of reduced width compared to that of a groove as mentioned above.
- These strips and / or incision (s) 30 to 33 which are visible in Figs. 3 and 4 and which typically have widths less than 2 mm and preferably less than 1 mm, are intended to ensure mechanical decoupling of the materials from the central zone 10 and the encircling zone 20 for the adhesion measurements.
- the central zone 10 has in this example a shape of a parallelepiped whose rectangular apex 11 (ie the radially outer face) has its sides 12, 13, 14, 15 respectively opposite four sculpture elements 21, 22, 23, 24, also in the form of a parallelepiped, which form the encircling zone 20.
- a sensor 40 sensitive to at least one tangential force exerted on said apex 11, which can measure stresses or displacements.
- the sensor 40 is housed in the mass of the central zone 10, radially outside the internal face 4 of the tread 1 and close to this internal face 4, so that this sensor 40 is not affected by tread wear 1 in rolling. It is a question of measuring one or more states correlated to the deformations or the stresses which the tire undergoes during rolling, at the contact surface opposite this location, in the longitudinal and transverse directions.
- This sensor 40 may for example be of the Hall effect type, comprising in a known manner a magnetic element and at least one Hall effect device.
- this sensor 40 is a nail type force sensor as described in European patent application EP-A-1 275 949 in the name of the applicant, the content of which is incorporated into the present description by reference.
- this nail type sensor is a force sensor comprising a rigid rod intended to be stressed by a force and a head, said head comprising an element integral with the rod intended to be deformed or stressed when said rod is stressed, said element carrying means for measuring deformation or stress and comprising anchor points which have a position relative to said rod at rest and which substantially maintain this position, when said rod is stressed, said anchor points being discrete or else continuous on the edge of said deformable element.
- Said deformable element can be a solid membrane, such as a circular membrane, and said deformable element comprises for example radiating arms connected together in a central part at the level of which said rod is fixed, said anchor points being located at ends of said arms.
- each large side 12, 13 of said apex 11 is connected to the sculpture element 21, 22 facing one another by a strip 30, 31 of width, for example equal to 0.8 mm.
- one of the short sides 14 of said apex 11 is connected to the trimming element 23 opposite by another strip 32 of width similar to those of the strips 30, 31, while the other short side 15 of said apex 11 is connected to the sculpting element 24 opposite by an incision 33 whose width is less than that of the lamellae 30 to 32 (the width of the incision 33 can for example vary from 0.3 to 0.8 mm ).
- the incision 33 is such that it does not reach the radially internal face 4 of the tread 1, so that it does not completely separate the central area 10 and the trimming element 24.
- one of the legs of the cross formed by the measuring block 3 comprises in the axial direction Y of the tire, on the one hand and on the other side of the central zone 10 and in a manner practically aligned with the latter, the two sculpture elements 21, 22 situated opposite the long sides 12, 13.
- the other leg of this cross which s extends in the circumferential direction X of the tire, it is such that the two tread elements 23, 24 situated opposite the short sides 14, 15 have a width greater than that of the latter, so that these elements 23, 24 are extend beyond the central zone 10 in said direction Y.
- each strip 30, 31, 32 contributes, during the passage of the measuring block 3 in the area of contact with the running floor, to reduce the rigidity Rzz c of the central zone 10 to a force oriented perpendicular to the radially external face 5 of the tread 1 with respect to the corresponding stiffness Rzz e of the encircling zone 20.
- the incision 33 contributes, when passing through the cont area act, increasing the rigidity Rxz c of the central zone 10 to a force oriented tangentially to said radially external face 5 in the circumferential direction X of the tire with respect to the corresponding rigidity Rxz e of the encircling zone 20.
- the area of the apex 11 of the central zone 10 is provided for much less than that of the radially external face of the sculpture elements 21, 22, 23, 24 forming the encircling zone 20, so that during the rolling of the tire according to the invention, this central zone 10 is surrounded over a significant area by the encircling zone 20 which is by definition much more compact than the central zone 10 (ie of vertical rigidity greater than that of the latter), which results in the fact that said central zone 10 does not "take up" all of the forces exerted on the crown reinforcement of the tire.
- the apex 11 of the central zone 10 has a length of 20 mm (in the circumferential direction X), a width of 8 mm (in the axial direction Y) and a height of 8 mm (in the radial direction Z), and the area of said apex 11 is less than 10% of the area of the encircling area 20.
- a tread sector 101 of a tire comprising tread blocks 102 and, facing this sector, this tread 101 seen in axial section.
- the tread 101 comprises a measuring block 103 which extends locally from the radially inner face 104 to the radially outer face 105 of the tread 101.
- this measurement block 103 is located in the area of the shoulder of the tire. It will be noted that the relative dimensions of the different sculpture blocks 102 are also respected in this FIG. 2.
- the measurement block 103 of FIG. 2 includes a central zone 110 and a surrounding zone 120 of the same height in the radial direction Z of the tire (see FIGS. 5 and 6), the surrounding zone 120 surrounding the central zone 110 and being connected to the latter by lamellae and / or incisions 130, 131, 132, 133 of reduced width compared to that of a groove 106 as mentioned above with reference to FIG. 1.
- the lamellae and / or incision (s) 130 to 133 which are visible in FIGS. 5 and 6 and which typically have widths of less than 2 mm and preferably less than 1 mm, are intended to ensure mechanical decoupling of the materials from the central zone 110 and from the encircling zone 120 for the adhesion measurements.
- the central area 110 has in this example a shape of a parallelepiped which is elongated in the axial direction Y of the tire and which is housed between the wings 121a and 121b of a tread element 121, which forms part of the encircling area 120 and has a section perpendicular to the radial direction Z of the tire which is practically in the shape of a "U". More specifically, the wings 121a and 121b of the element 121 extend parallel to this direction Y and have their respective ends which are aligned with one of the short sides 114 of the rectangular top 111 of the central area 110.
- a sensor 140 for example of the Hall effect type comprising a magnetic element and at least one Hall effect device, this sensor 140 being sensitive to at least one tangential force exerted on said vertex 111, which can measure constraints or displacements, in exactly the same way as the sensor 40 described above with reference to Figs. 3 and 4.
- the other short side 115 of the top 111 facing the core 121c of the "U" of the sculpture element 121 is connected to the latter by a strip 132 of width similar to that of the aforementioned strip 32
- said short side 114 of the apex 111 is connected to another element of parallelepiped sculpture 122 also forming part of the encirclement zone 120 by an incision 133 similar to the aforementioned incision 33.
- the incision 133 is thus such that it does not reach the radially internal face 104 of the tread 101, so that it does not completely separate the central area 110 and the trimming element 122.
- each large side 112, 113 of the top 111 is connected to the sculpture element 121 by a strip 130, 131 similar to said strips 30 and 31 above.
- the tread element 122 extends in the axial direction Y of the tire practically in the extension of the wings 121a, 121b of the tread element 121.
- two other tread elements 123 and 124 parallelepiped complete the encircling zone 120 in such a way that they are respectively connected to said wings 121a and 121b of the element 121 by strips 134 and 135, these elements 123, 124 having a length in the axial direction Y which is practically identical to that of said element 122.
- each strip 130, 131, 132 contributes to reducing, during the passage through the contact area, the rigidity Rzz c of the central zone 110 to a force oriented perpendicular to the radially external face 105 of the tread 101 with respect to the corresponding rigidity Rzz e of the encirclement zone 120.
- the incision 133 contributes to increase, when passing through the air e of contact, the rigidity Ryz c of the central zone 110 to a force oriented tangentially to said radially external face 105 in the circumferential direction X of the tire with respect to the corresponding rigidity Ryz e of the encircling zone 120.
- the area of the summit 111 of the central area 110 is provided for much less than that of the radially external face of the sculpture elements 121, 122, 123, 124 forming the surrounding area 120, so that during the rolling of the tire according to the invention, this central area 110 is surrounded over a significant area by the surrounding area 120 which is by definition much more compact than the central area 110 (ie of vertical rigidity greater than that of the latter), which results in the fact that said central zone 110 does not "take up" all of the forces exerted on the crown reinforcement of the tire.
- the apex 111 of the central zone 110 has a length of 20 mm (in the axial direction Y), a width of 8 mm (in the circumferential direction X) and a height of 8 mm (in the radial direction Z), and the area of said vertex 111 is also less than 10% of the total area of the encirclement area 120.
- Fig. 7 illustrates an example of the structure of the central zone 10, 110 of a measuring block 3, 103 according to the invention.
- the central zone 10, 110 of FIG. 7 consists of a parallelepiped "bread” comprising a plurality of identical rectangular layers 16, 116 which are superimposed in the axial direction Y of the tire.
- This “bread” 10, 110 has a composite structure giving it an orthotropic character, because each of the layers 16, 116 is based on the same rubber composition reinforced by reinforcements 17, 117 textiles or metals.
- Test blocks 3, 103 were tested in which each layer 16, 116 of the central zone 10, 110 is reinforced by textile fibers, for example polyester, which are oriented relative to the circumferential direction X at an angle ⁇ ⁇ given, so that two adjacent layers 16, 116 respectively comprise these fibers 17, 117 oriented at opposite angles ⁇ and - ⁇ .
- textile fibers for example polyester
- Fig. 8 gives an account of the tests carried out on orthotropic “breads” for central zone 10, 110 which all comprise eight layers 16, 116 each having a thickness of approximately 1 mm. These “breads” 10, 110 tested are characterized by an anisotropy equal to 3 and by the arrangement of the fibers at opposite angles ⁇ ⁇ in two adjacent layers 16, 116. We measured the variation, as a function of the absolute value ⁇ of these angles:
- the graph in Fig. 8 shows that a "bread" of central zone 10, 110 characterized by, angles ⁇ practically equal to ⁇ 30 ° alternately in the layers 16, 116 has a stiffness ratio Rxz c / Rzz c which is maximized, which contributes, in accordance with the present invention, to optimizing the sliding in the contact area of the measuring block 10, 110 incorporating this "bread" 10, 110.
- This“ witness ”sculpture element has a length of 25 mm, a width of 20 mm and a height of 8 mm, and is made up of a composition of crosslinked rubber for tread 1, 101.
- This “control” tread element has a rigidity Rzz e at a force oriented perpendicular to its radially external face which is equal to 186 DaN / mm.
- a first “bread” of central zone 10, 110 differs from this “witness” sculpture element in that, on the one hand, it is made up of a rubber composition having a rigidity Rzz c at a force oriented perpendicular to the apex 11, 111 of the “bread” 10, 110 which is equal to 17.59 DaN / mm, value much lower than that of said “witness” sculpture element and, on the other hand, in that it has a width of only 5 mm for a length of 15 mm.
- a second “bread” of central zone 10, 110 according to the invention differs from said first “bread” according to the invention in that it consists of a composition of composition of compressible rubber in the crosslinked and expanded state, which has a closed cell cellular structure (ie rubber “foam”) giving it a rigidity Rzz c equal to 11.90 DaN / mm.
- This second “bread” also has the same dimensions as said first "bread” according to the invention.
- a third "bread” in the central zone 10, 110 according to the invention differs from these two “breads” according to the invention in that it has the above-mentioned structure with reference to FIG. 7, this structure comprising eight layers 16, 116 of thickness equal to 1 mm.
- Each layer 16, 116 comprises a rubber composition which is reinforced by the above-mentioned polyester fibers at angles of ⁇ 45 °, which gives this third “bread” a stiffness Rzz c equal to 17.58 DaN / mm.
- the stiffness Rxz was measured for said “witness” tread element and these three “loaves” 10, 110 according to the invention at a force oriented tangentially to the radially external face 5, 105 of the tread 1, 101 , to deduce the Rxz / Rzz ratio.
- the table below shows the results obtained.
- Tires comprising a tread 1, 101 as described with reference to FIGS. 1 to 7 are such that, in a wide range of stresses developed in contact with the tire on the ground during normal operation, a large part, or even all of the central zone 10, 110 of the measuring block 3, 103 slides on the ground. It has been found that this occurs even in free rolling (no torque) at low speed, including on soils with strong grip.
- This phenomenon of sliding of the central zone 10, 110 occurs at least during part of each passage of the measuring block in the contact area on the ground. The guarantee that there is this sliding phenomenon in the measuring block 3, 103 makes it possible to measure the potential for friction on the ground.
- the decoupling provided by the strips and incisions 30 to 33 and 130 to 133 makes it possible to carry out the envisaged measurement in a very acceptable manner, and it is believed that this is because the central zone 10, 110 verifies the conditions a) and b) according to the invention which have been set out in the preamble to the present description in relation to the encircling zone 20, 120. This makes it possible to avoid the appearance of contact pressures on the ground which are too high to allow the sliding of the central zone 10, 110.
- An advantage of the invention is thus being able to apprehend the margin of grip available until total wear of the tire, by means of a measurement of the friction potential made as indicated above.
- the tire thus adapted will make it possible to estimate the "adhesion potential", a concept defined above and used essentially in conjunction with the whole of the tread 1, 101. this tire can also make it possible to estimate the "potential for friction ", a concept also defined above.
- these measurements can be obtained throughout the life of the tire. It is of course desirable that the measurement block 3, 103 be as small as possible relative to the volume of the tread 1, 101, or more fundamentally that this block 3, 103 does not degrade the performance of the tire.
- the desired information can be obtained by making a single measurement per revolution of the tire.
- the tire can include enough measurement blocks 3, 103 so that there is always at least one in the area of contact with the ground. As for the vehicle, it is thought that it is superfluous that all of its tires are affected by such measurements, one tire per side may be sufficient.
- This recalibration procedure is useful because the pressure under the central zone 10, 110 of a measuring block 3, 103 can change during the use of the tire, for example as a function of the wear of the tire, for conditions identical tire load and inflation pressure and this change in pressure introduces a variable which modifies the relationship between the shear stress exerted on the central zone 10, 110 of a measuring block 3, 103 and the potential of grip of the tire. If the central zone 10, 110 of a measuring block 3, 103 is additionally equipped with a measurement of the vertical stress at the same point, it is possible to calculate the coefficient of friction between the central zone 10, 110 of a measuring block 3, 103 and the ground by making the ratio between the shear stress and the vertical stress. In this case, it may not be useful to perform regular recalibration to assess the grip potential of the tire.
- a) provide in the tread at least one measuring block 3, 103 which is intended to come into contact with the ground at each turn of the tire, the measuring block 3, 103 comprising, seen on a radially external face of the tread, a central zone and an encircling zone surrounding the central zone 10, 110, which is adapted to slide on the ground at a level of stresses parallel to the ground surface substantially lower than the level of stresses parallel to the surface of the ground beyond which the encircling zone 20, 120 slides on the ground; b) placing a sensor 40, 140 so as to carry out a measurement in said central zone, said sensor 40, 140 being sensitive at least to a parameter reflecting a tangential force exerted on the surface of said central zone 10, 110; c) producing a first signal, representative of a tangential force in said contact surface of the central zone 10, 110; d) detecting a variation of said first signal, characteristic of a loss of adhesion; e) producing an estimate of the friction potential in said contact surface of the central zone 10, 110; f) produce an
- the invention of course makes it possible to estimate the "available grip margin" by the difference between the adhesion potential of the elastic bandage and the ratio between the tangential force and the vertical force actually applied to the bandage.
- the tangential force for example in the longitudinal direction, as well as the vertical force by means of what is described in US Pat. No. 5,913,240. But we can also estimate the tangential force and the vertical force from ready-made measurements in the tread. Further details are given below.
- the steps aimed at detecting a variation of said first signal and at producing an estimate of the adhesion potential in said contact surface of the tire include the following operations: a ) producing a second signal, representative of a vertical force in said contact surface of said central area; b) producing from the first and second signals a third signal, representative of the ratio between the tangential force and the vertical force; c) detecting a variation of said third signal characteristic of a loss of adhesion; d) producing an estimate of the friction potential in said contact surface of the central zone; and e) from the friction potential, producing an estimate of the adhesion potential of said tread.
- the method proposed by the invention then further comprises the following steps: a) placing a sensor facing an area of the contact surface of the outer tread with one or more measuring blocks, said sensor being sensitive at least to a parameter reflecting a tangential force exerted on the surface of said external zone; b) producing a first functional tread signal, representative of a tangential force in an area of the contact surface of the tread outside the measurement block (s); c) producing a second functional tread signal, representative of a vertical force in an area of the contact surface of the outer tread at or at the measuring elements; d) produce a characteristic indication of the tangential force applied to the tire, from the integration of said first functional tread signal, between the instants of start and end of contact with the ground of said external zone, and on the full width of the bandage; e) producing a characteristic indication of the vertical
- the invention provides a method of detecting a characteristic of adhesion between an elastic bandage having a deformable tread and a running surface, comprising the following steps: a) provide in the tread at least one measuring block which is intended to come into contact with the ground at each turn of the tire, the measuring block comprising, seen on a radially external face of the tread, a zone central and an encircling zone surrounding the central zone, which is adapted to slide on the ground at a level of stresses parallel to the ground surface substantially lower than the level of stresses parallel to the ground surface beyond which the encirclement area slides on the ground; b) placing a sensor so as to carry out a measurement in said central zone, said sensor being sensitive at least to a parameter reflecting a tangential force exerted on the surface of said central zone; c) producing a first measuring block which is intended to come into contact with the ground at each turn of the tire, the measuring block comprising, seen on a radially external face of the tread, a zone central and an encircling zone surrounding
- said function of the first signal is the ratio between the average value of the first derivative of said signal with respect to time and the value of the signal at the point characteristic of a loss of adhesion.
- said function of the first signal is the time interval separating said detections.
- the invention proposes a method for detecting a characteristic of adhesion between an elastic tire having a deformable tread and a running surface, comprising the following steps: a) provide in the tread at least one measuring block which is intended to come into contact with the ground at each turn of the tire, the measuring block comprising, seen on a radially external face of the tread, a zone central and an encircling zone surrounding the central zone, which is adapted to slide on the ground at a level of stresses parallel to the ground surface substantially lower than the level of stresses parallel to the ground surface beyond which the encirclement area slides on the ground; b) placing a sensor so as to carry out a measurement in said central zone, said sensor being sensitive at least to a parameter reflecting a tangential force exerted on the surface of said central zone; c) placing a sensor facing an area of the contact surface of the outer tread with or to the measuring elements, said sensor being sensitive to at least one parameter reflecting a tangential force exerted on the surface of said outer area
- the adhesion potential of the elastic bandage on the roadway directly conditions the maximum level of guidance, braking and traction forces that can be transmitted to the vehicle. It is a determining factor in the mobility and handling of vehicles.
- the principle of design of the elastic bandage presented here represents an important interest from this point of view. In fact, it makes it possible to evaluate the level of the grip potential even when the tire is in free rolling, which amounts to saying that it is possible to determine this potential in all the running conditions of the vehicle, from the situation driving in a straight line at constant speed to the maximum braking and acceleration situations, or turns taken to the limit of grip.
- the adhesion potential available can therefore be assessed continuously. From the measures described, it is also possible to know the part of the adhesion potential actually used. The following table illustrates applications permitted by knowledge of this information.
- the information taken continuously, when the vehicle is moving can feed a database located in a computer system linked to the vehicle or external to the vehicle (centralized database with which the vehicle would communicate); moreover, this information can be compared with the statistical population already stored in the database to determine which percentile of the population it corresponds to; this result can be converted into simple information delivered to the driver (for example by indicating a conventional level qualifying the available grip: strong, medium, weak, very weak);
- a magnetic element can be incorporated in the central zone of a measuring element, at a place such that this element undergoes a relative displacement with respect to Hall effect sensors placed in the tread when said measuring element is subjected to a tangential force or to a normal force.
- Hall effect sensors are arranged to measure the displacement of the magnetic element to the minimum under the effect of a tangential force applied to the surface of a measuring element, or even to measure its displacement in addition separate.
- US Patent 5,864,056 or US 5,50243 could also perform a measurement as taught by US Patent 5,864,056 or US 5,502433.
- the signals thus measured are sent to a calculation unit which determines the adhesion potential and the available margin of adhesion according to one of the methods proposed.
- a calculation unit which determines the adhesion potential and the available margin of adhesion according to one of the methods proposed.
- current technology allows the transmission, preferably the remote transmission of signals from one or more measurement units located in the tread and the vehicle itself, that it is not the object of this invention to deal with this aspect, which is relatively independent of the measurement aspects which are treated here.
- This calculated information is addressed itself, for example to a device making it possible to inform the driver, or else is sent, for example by hertzian way, to a system external to the vehicle, making it possible to centralize the information relating to the grip potential of the ground and intended to inform all road users, or else are used to regulate systems or bodies of the vehicle on which the elastic bandage is mounted.
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Abstract
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR0202504A FR2836418A1 (fr) | 2002-02-22 | 2002-02-22 | Bandage elastique pour mesurer l'adherence d'un vehicule qui en est equipe sur un sol de roulage |
FR0202504 | 2002-02-22 | ||
PCT/EP2003/001558 WO2003070492A2 (fr) | 2002-02-22 | 2003-02-17 | Bandage elastique pour mesurer l'adherence d'un vehicule qui en est equipe sur un sol |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1578621A2 true EP1578621A2 (fr) | 2005-09-28 |
EP1578621A3 EP1578621A3 (fr) | 2005-10-05 |
Family
ID=27676143
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP03706516A Withdrawn EP1578621A3 (fr) | 2002-02-22 | 2003-02-17 | Bandage elastique pour mesurer l adherence d un vehicul e qui en est equipe sur un sol |
Country Status (9)
Country | Link |
---|---|
US (1) | US7377300B2 (fr) |
EP (1) | EP1578621A3 (fr) |
JP (1) | JP4624677B2 (fr) |
KR (1) | KR20040088503A (fr) |
CN (1) | CN1326715C (fr) |
AU (1) | AU2003208861A1 (fr) |
BR (1) | BR0307614A (fr) |
FR (1) | FR2836418A1 (fr) |
WO (1) | WO2003070492A2 (fr) |
Families Citing this family (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7267148B2 (en) * | 1999-08-10 | 2007-09-11 | Michelin Recherche Et Technique S.A. | Measurement of adherence between a vehicle wheel and the roadway |
DE10324505A1 (de) * | 2003-05-28 | 2004-12-16 | Continental Aktiengesellschaft | Verwendung eines miniaturisierten 3-Komponenten-Kraftsensors im Zusammenhang mit Fahrzeugluftreifen, damit ausgerüsteter Reifenprüfstand und mit dem 3-Komponenten-Kraftsensor ausgestatteter Fahrzeugluftreifen |
FR2904260B1 (fr) * | 2006-07-27 | 2012-03-23 | Michelin Soc Tech | Pneumatique avec un element de bande de roulement calibre |
FR2909946B1 (fr) * | 2006-12-13 | 2010-09-17 | Soc Tech Michelin | Procede d'estimation d'un risque de defaut de liaison au sol d'un vehicule automobile |
JP5191163B2 (ja) * | 2007-04-27 | 2013-04-24 | 株式会社ブリヂストン | タイヤ接地状態推定方法、及び、タイヤ接地状態推定装置 |
FR2918478B1 (fr) * | 2007-07-04 | 2009-08-21 | Michelin Soc Tech | Procede d'estimation de la marge d'adherence disponible d'un pneumatique en roulage. |
JP4388569B2 (ja) * | 2007-08-01 | 2009-12-24 | 住友ゴム工業株式会社 | 空気入りタイヤ |
US9616773B2 (en) | 2015-05-11 | 2017-04-11 | Uber Technologies, Inc. | Detecting objects within a vehicle in connection with a service |
FR3042441A1 (fr) | 2015-10-20 | 2017-04-21 | Michelin & Cie | Pneumatique avec bande de roulement comportant des secteurs renforces et des gorges auto-entretenues |
US20170166216A1 (en) * | 2015-12-10 | 2017-06-15 | Uber Technologies, Inc. | Motion planning for a vehicle using traction information |
US10712160B2 (en) | 2015-12-10 | 2020-07-14 | Uatc, Llc | Vehicle traction map for autonomous vehicles |
US9841763B1 (en) | 2015-12-16 | 2017-12-12 | Uber Technologies, Inc. | Predictive sensor array configuration system for an autonomous vehicle |
US9840256B1 (en) | 2015-12-16 | 2017-12-12 | Uber Technologies, Inc. | Predictive sensor array configuration system for an autonomous vehicle |
US9990548B2 (en) | 2016-03-09 | 2018-06-05 | Uber Technologies, Inc. | Traffic signal analysis system |
JP2017161477A (ja) * | 2016-03-11 | 2017-09-14 | 株式会社ブリヂストン | タイヤ荷重推定方法及びタイヤ荷重推定装置 |
US20180003511A1 (en) | 2016-07-01 | 2018-01-04 | Uber Technologies, Inc. | Autonomous vehicle localization using submaps |
JP6899752B2 (ja) * | 2017-10-17 | 2021-07-07 | Toyo Tire株式会社 | タイヤ接地面における摩擦係数の余裕度を算出する方法、システム及びプログラム |
US11334753B2 (en) | 2018-04-30 | 2022-05-17 | Uatc, Llc | Traffic signal state classification for autonomous vehicles |
Family Cites Families (16)
Publication number | Priority date | Publication date | Assignee | Title |
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US1537456A (en) * | 1920-09-10 | 1925-05-12 | Brown John | Wear and strain resisting fabric |
US1948311A (en) * | 1931-12-14 | 1934-02-20 | Gen Tire & Rubber Co | Vehicle tire |
US4249588A (en) * | 1978-04-27 | 1981-02-10 | The Goodyear Tire & Rubber Company | Pneumatic tire |
DE3005651A1 (de) * | 1980-02-15 | 1981-08-20 | Continental Gummi-Werke Ag, 3000 Hannover | Laufflaechengestaltung fuer fahrzeugluftreifen |
JPH0446194Y2 (fr) * | 1985-06-27 | 1992-10-29 | ||
JPS626802A (ja) * | 1985-07-03 | 1987-01-13 | Bridgestone Corp | ウエツト性に優れた空気入りタイヤ |
DE3937966C2 (de) * | 1989-11-15 | 1994-02-03 | Bert Prof Dr Ing Breuer | Verfahren und Vorrichtung zur Bestimmung der Kraftschlußverhältnisse zwischen Fahrzeugreifen und Fahrbahn |
DE3939917A1 (de) * | 1989-12-02 | 1991-06-06 | Bosch Gmbh Robert | Vorrichtung zum bestimmen der haftreibung zwischen fahrzeugreifen und fahrbahndecke |
JPH06171321A (ja) * | 1992-12-09 | 1994-06-21 | Sumitomo Rubber Ind Ltd | 空気入りタイヤ |
US5864056A (en) * | 1998-02-17 | 1999-01-26 | Bell; Larry D. | Method and apparatus for monitoring the coefficient of friction between a tire and rolling surface, particularly to provide the vehicle operator with coefficient of friction, tire tread wear out and skid warning indications |
DE19807004A1 (de) * | 1998-02-19 | 1999-09-09 | Siemens Ag | Sensorsystem und Verfahren für Überwachung/Messung des Kraftschlusses eines Fahrzeugreifens mit der Fahrbahn und weiterer physikalischer Daten des Reifens |
FR2820501A1 (fr) * | 2001-02-07 | 2002-08-09 | Michelin Soc Tech | Mesure d'adherence entre une roue de vehicule et la chaussee |
US7267148B2 (en) | 1999-08-10 | 2007-09-11 | Michelin Recherche Et Technique S.A. | Measurement of adherence between a vehicle wheel and the roadway |
BR0002924A (pt) * | 1999-08-10 | 2000-10-17 | Michelin Soc Tech | Pneumático e processo de detecção de uma caracterìstica de aderência entre uma roda que possui uma banda de rodagem deformável e um solo de rodagem |
DE19945264A1 (de) * | 1999-09-21 | 2001-03-29 | Daimler Chrysler Ag | Reifen, insbesondere Luftreifen, für Fahrzeuge |
EP1617197B8 (fr) * | 2001-07-10 | 2009-04-15 | Commissariat A L'energie Atomique | Dispositif de mesure de forces, notamment pour pneumatique |
-
2002
- 2002-02-22 FR FR0202504A patent/FR2836418A1/fr active Pending
-
2003
- 2003-02-17 KR KR10-2004-7012738A patent/KR20040088503A/ko not_active Application Discontinuation
- 2003-02-17 JP JP2003569424A patent/JP4624677B2/ja not_active Expired - Fee Related
- 2003-02-17 AU AU2003208861A patent/AU2003208861A1/en not_active Abandoned
- 2003-02-17 CN CNB038044005A patent/CN1326715C/zh not_active Expired - Fee Related
- 2003-02-17 WO PCT/EP2003/001558 patent/WO2003070492A2/fr active Application Filing
- 2003-02-17 EP EP03706516A patent/EP1578621A3/fr not_active Withdrawn
- 2003-02-17 BR BR0307614-8A patent/BR0307614A/pt not_active IP Right Cessation
-
2004
- 2004-08-18 US US10/920,550 patent/US7377300B2/en not_active Expired - Fee Related
Non-Patent Citations (1)
Title |
---|
See references of WO03070492A2 * |
Also Published As
Publication number | Publication date |
---|---|
BR0307614A (pt) | 2004-12-21 |
WO2003070492A3 (fr) | 2005-08-18 |
US7377300B2 (en) | 2008-05-27 |
KR20040088503A (ko) | 2004-10-16 |
JP2005531448A (ja) | 2005-10-20 |
JP4624677B2 (ja) | 2011-02-02 |
AU2003208861A8 (en) | 2003-09-09 |
FR2836418A1 (fr) | 2003-08-29 |
CN1326715C (zh) | 2007-07-18 |
EP1578621A3 (fr) | 2005-10-05 |
AU2003208861A1 (en) | 2003-09-09 |
US20050155685A1 (en) | 2005-07-21 |
CN1638982A (zh) | 2005-07-13 |
WO2003070492A2 (fr) | 2003-08-28 |
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