Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D53/00—Tractor-trailer combinations; Road trains
  • B62D53/04—Tractor-trailer combinations; Road trains comprising a vehicle carrying an essential part of the other vehicle's load by having supporting means for the front or rear part of the other vehicle
  • B62D53/06—Semi-trailers
  • B62D53/068—Semi-trailers having devices to equalise or modify the load between the fifth wheel and the rear wheels
• • 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
  • B60C19/001—Tyres requiring an asymmetric or a special mounting

Definitions

• the invention relates to a vehicle such as a truck type of transport vehicle, comprising at least two axles, none of them being directional and a method of distributing the load of said vehicle.
• a vehicle such as a truck type of transport vehicle, comprising at least two axles, none of them being directional and a method of distributing the load of said vehicle.
• the invention will be more particularly described with reference to a trailer type vehicle or semi trailer with three axles, each equipped with at least two tires.
• the circumferential direction of the tire is the direction corresponding to the periphery of the tire and defined by the rolling direction of the tire.
• the transverse or axial direction of the tire is parallel to the axis of rotation of the tire.
• the radial direction is a direction intersecting the axis of rotation of the tire and perpendicular thereto.
• the axis of rotation of the tire is the axis around which it rotates in normal use.
• a radial or meridian plane is a plane which contains the axis of rotation of the tire.
• a circumferential plane is a plane perpendicular to the axis of rotation of the tire.
• the circumferential mid-plane is a plane perpendicular to the axis of rotation of the tire and which divides the tire into two halves.
• Such vehicles generally intended to carry heavy loads, must meet certain obligations concerning in particular the spacing longitudinal between each of the axles. Indeed, the various regulations impose longitudinal distances between two axles of a trailer having three according to the load capacity of said vehicle.
• the current use of trailers with three axles is usually a distance of 1.3 meters.
• the current state of the market for these trailers goes towards a standardization of the design of these trailers and in particular of a given tire equipment and identical for all axles.
• the rolling curve results in load transfers on the tires on the outside of the curve and therefore a greater wear thereof.
• the tires fitted to the three axles suffer for some of them phenomena of shifting on the ground which accentuates the wear of the tires concerned by these phenomena.
• three axles each equipped with at least two tires fitted to the vehicle all the tires can not follow a curve trajectory corresponding to the course that follows the vehicle.
• the spacing between the axles is homogeneous, if the tires equipping the intermediate axle follow a trajectory substantially equivalent to that of the vehicle, the tires fitted to the other two axles undergo shifting phenomena on the ground leading to greater wear.
• the document FR 2 903 953 or else the document EP 1 640 247 propose solutions consisting of self-steering axles by passive or active turning of the axles of a trailer. These technologies if they provide solutions to the problem of shifting or different wear according to the tires are difficult to implement against and expensive. In addition, these technologies are operational because of their complexities only during maneuvers.
• a vehicle comprising at least two axles equipped with at least two tires whose axes of rotation are permanently parallel to each other from one axle to another, the tires of at least one axle having a drift rigidity greater than that of the tires of another axle.
• said at least two axles are not driving axles.
• the drift rigidities of the tires are defined as the slope on the plot of a curve expressing the force exerted by the tire on the ground as a function of the drift angle, measured for a pressure.
• the inventors have been able to demonstrate, in particular in the case of trailers with three axles, that the presence of tires having drift stiffnesses greater than those of the tires fitted to the other axles makes it possible to limit the wear of the tires during the crossing of round points or during maneuvers. More specifically, the wear of the tires equipping the front and rear axles is reduced.
• the drift stiffness of the tires equipping the intermediate axle is greater than those of the tires equipping the other axles, to limit at best the phenomena of shifting tires fitted to the other axles.
• the drift stiffness of the tires equipping the intermediate axle is at least 10% greater than those of the tires equipping the other axles.
• said vehicle having three axles, the drift rigidity of the tires equipping at least two axles are identical.
• said vehicle having three axles said vehicle having three axles, the drift stiffness of the tires equipping each axle is different.
• the choice of tires will be made according to the various parameters of the vehicle such as the size, the spacing between the axles, the load transported, etc.
• a first embodiment of the invention for obtaining tires with different drift rigidities from one axle to the other is to keep identical tire dimensions on all the axles, the tires of said at least an axle having a stiffness of drift greater than that of the tires of another axle having a different architecture.
• said tires may have working plies whose angles formed by the reinforcing elements with the circumferential direction are lower than those of the working plies of the tires equipping the other axles.
• the working plies are plies of reinforcing elements forming an angle with the circumferential direction, said reinforcing elements being crossed from one ply to the next.
• At least one axle comprises tires having a tread width greater than those of tires of at least one other axle, so that the drift rigidity of said tires. greater than those of other tires.
• At least one axle has more tires than at least one other axle.
• the tires equipping the set of axles are then advantageously identical and all of the tires of said at least one axle which has more tires has a rigidity of drift greater than that of the tires of the other axles.
• the intermediate axle may for example comprise two pairs of twin wheels, the other axles each having two individual wheels, the tires being the same on all wheels.
• At least one other axle comprises tires of different geometrical dimensions from those of tires of at least one other axle, in particular associated with rims of wheels of diameters smaller than that of the rims of at least one other axle.
• each axle carries at least 10% of the load of the vehicle and, in rolling, said at least one axle whose tires have a rigidity of drift greater than that of the tires of a another axle carries a load different from those carried by the other axles.
• At least one axle whose tires have a drift rigidity greater than that of the tires of another axle carries a load at least 15% greater than that carried by another axle.
• the inventors were able to highlight, particularly in the case of trailers with three axles, a different load distribution on the axles can help to homogenize the tire wear speed when crossing round points or during maneuvers. More specifically, the wear speed of the tires fitted to the front and rear axles is reduced. More and more vehicles and, especially trailers with three axles, are today equipped with air suspension pot type suspension. Currently, the suspension pots are all at the same pressure.
• a modification of the device for managing the pressure of the air pots may make it possible to confer different pressures from one pot to the other and so from one axle to another.
• Such a change in the pressure of the air suspension pots makes it possible to achieve a different load distribution between at least two axles.
• the pressure management in the various air suspension pots can be performed immediately after loading the vehicle and kept during the rolling thereof.
• This embodiment is more particularly adapted to the case of vehicles traveling with loads less than their maximum load capacity. Indeed, the loss in terms of the behavior of the tires equipping the axles whose load is lightened has no consequence insofar as the vehicle has a load less than its maximum load capacity.
• This first embodiment is satisfactory in many cases.
• This embodiment is, as previously stated particularly well suited to the case of vehicles having an axle with more wheels and able to carry a larger load or also in the case of an axle comprising tires with a tread of greater width, which can also generally carry a larger load.
• this pressure management in the air suspension pots is made in real time so as not to penalize rolling in a straight line and ensure different loads between at least two axles only in curveways corresponding to roundabouts or maneuvering phases.
• Another method to perform this management in real time can be done using a microprocessor from measured data on the vehicle.
• a microprocessor for example, it is possible to use data accessible by the anti-lock braking systems associated with each of the wheels. Indeed, these systems make it possible to know precisely the speed of rotation of each of the wheels and thus to deduce on the one hand the speed of the vehicle by an average of the different speeds and on the other hand the radius of rotation followed, s' it exists, by differences between the wheel speeds of the same axle.
• the different load distributions are preserved during the rolling.
• said vehicle having three axles, at least two axles carry identical loads.
• the load carried by the intermediate axle is different from that of the other axles to best limit the phenomena of shifting tires on other axles.
• said vehicle having three axles, each axle carries a different load.
• the choice of distribution will be made according to the various parameters of the vehicle such as the size, the spacing between the axles, the load transported, etc.
• the load carried by the intermediate axle is advantageously greater than those of the other axles.
• the intermediate axle advantageously carries a load greater than those of the other two axles so as to minimize the phenomena of shifting tires fitted to these two front and rear axles either when passing roundabouts or during maneuvers.
• the load carried by the intermediate axle is between 35 and 70% of the vehicle load.
• the load carried by the front axle and / or the rear axle is between 10 and 33% of the vehicle load.
• the tires mainly used on trailers with three axles are type 385 / 65R22.5.
• Such tires have a load capacity of 4.5 tonnes, as defined by ETRTO.
• some legislation on trailers has, for example, set a maximum load of these trailers at 24 tonnes. It can be seen from these figures that even when the trailer is fully loaded, the six tires on all three axles are overcapacity with respect to the load being transported. In theory, these six tires could carry a load of 27 tons.
• FIG. 1 a diagram of a vehicle comprising a trailer with three axles
• FIG. 2 a schematic representation seen from above of a vehicle according to a first embodiment of the invention
• FIG. 3 a schematic representation seen from above of a vehicle according to a second embodiment of the invention.
• the figures are not represented in scale to simplify understanding.
• FIG 1 is shown schematically a vehicle 1 consisting on the one hand of a tractor 2 and a trailer 3.
• the tractor 2 comprises a first steering axle 4 and a second driving axle 5.
• the trailer 3 comprises three axles carrier 6, 7, 8. These three axles 6, 7,
• the overall weight of the vehicle 1 in load is equal to the maximum of 40 tons, which corresponds to a maximum transport load of 24 tons.
• the distribution of the masses on the various axles when the vehicle 1 is at its maximum load, the latter being distributed homogeneously in the trailer 3 is distributed as follows:
• the tires of the intermediate axle 7 have a rigidity of drift greater than those of the tires equipping the axles 6 and 8.
• this upper drift rigidity can be obtained by an architecture and in particular a different crown reinforcement, the external dimensions of the tires being the same.
• FIG. 2 schematically illustrates an alternative embodiment of the invention on which the vehicle 21 is viewed from above in semi-transparency to observe all the tires and axles of the tractor 22 and the trailer 23.
• the set of tires 261, 262, 281, 282 equipping the axles 26 and 28 of the trailer 23 are identical and type 385 / 65R22.5.
• the intermediate axle 27 comprises tires 271, 272 having a much wider tread and are of the type 495 / 45R22.5.
• These tires 271, 272 with an enlarged tread give a rigidity of drift of the tires of the intermediate axle 27 greater than those of the tires 261, 262, 281, 282 of the two other axles 26 and 28.
• FIG 3 schematically illustrates an alternative embodiment of the invention on which the vehicle 31 is viewed from above in semi-transparency to observe all the tires and axles of the tractor 32 and the trailer 33.
• all the tires equipping the axles 36, 37, 38 of the trailer 33 of the vehicle 31 are identical and the intermediate axle 37 comprises two pairs of twin wheels. These twin wheels thus give a drift rigidity of the tires 371a, 371b, 372a, 372b of the intermediate axle 37 greater than those of the tires 361, 362, 381, 382 of the two other axles 26 and 28.
• the load capacity of the intermediate axle 27, 37 is actually greater than the load capacity of the other axles 26, 28; 36, 38 of the trailer 23, 33.
• each of the axles 26, 27, 28; 36, 37, 38 is associated with a suspension, not shown in the figure, the air suspension pot type whose pressure can be adjusted for each of the axles.
• the vehicle 21, 31 is still equipped with a system for modifying the pressure of each of the air suspension jars. This pressure regulation is, for example, carried out using electro valves associated with each of the air circuits of the various axles 26, 27, 28; 36, 37, 38.
• the greater load on the axle 27, 37 also contributes to limiting the wear of the tires of the axles 26, 36 and 28, 38 when they are caused to skid on the ground when the vehicle 21, 31 turns around. roundabouts or when maneuvering.
• Tests have been made with the vehicle 1, the latter carrying a load of 24 tons, worn as explained above for 21.6 tons on the three axles of the trailer.
• the tests were carried out on the one hand with a reference vehicle comprising identical tires on all the axles of the trailer and on the other hand with vehicles according to the invention including the tires equipping the intermediate axle.
• Different tires have been designed to see the influence of drift stiffness differences between different tires.
• the tests were thus carried out on the one hand with tires equipping the intermediate axle with a rigidity of drift greater than 1.2 times that of the tires of the two other axles (Test A) and on the other hand with tires equipping the axle.
• the test is to roll the vehicle for a period of 250 hours and to characterize the absolute wear by a measurement in grams of tire material lost per 100 km of each of the tires fitted to the three axles of the trailer and an average of these wear being established between the two tires equipping the same axle.
• the test is to roll the vehicle for a period of 250 hours and to characterize the absolute wear by a measurement in grams of tire material lost per 100 km of each of the tires on the three axles of the trailer and an average of these wear being established between the two tires equipping the same axle.
• a third type of test was carried out by rolling two identical vehicles and one of them being in accordance with the vehicle 1 according to the invention on identical paths and representative of a type of conventional use for trucks carrying goods.
• the test consisted in determining the life of the tires on each of the axles, this being expressed in kilometers traveled before total wear (indicated by the wear indicators). The results are shown in the table below.
• axles 6 and 8 each carry a load equal to 6.3 tons.
• the results are shown in the tables below; the first table corresponds to the tests allowing to simulate the wear due to rollings in zone the second table corresponds to the tests to simulate the wear due to running further comprising maneuvers and the third table corresponds to the tests for determining the life of the tires on each of the axles.
• Test A shows that it was possible to achieve identical mileage for the tires of the axles 1 and 2 and therefore limit the usual permutations for this type of vehicle as described above.
• the combination of the invention with a choice of materials constituting the different tread for the tires of the axle 3 could be used to balance the mileage traveled between the three axles. Such a change of materials is quite conceivable since it bears only on the axle 3 without risk of disturbing the behavior of the vehicle while driving.
• the invention has essentially been described with reference to trailers having three axles forming part of five-axle vehicles.
• the invention also makes it possible to reduce tire wear on trailers with two axles, which are part of vehicles with three or five axles or even trailers with two or three axles associated with vehicles up to eight axles for weights of up to eight axles. up to 60 tons.
• the invention also applies to vehicles combining on the same axles a distribution of the axle load according to the invention with axles that can optionally be raised when the load is zero.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Transportation (AREA)
• Vehicle Body Suspensions (AREA)
• Tires In General (AREA)

Priority Applications (6)

Applications Claiming Priority (2)

Publications (1)

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Citations (6)

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• 2009
  • 2009-07-29 FR FR0955307A patent/FR2948622B1/fr not_active Expired - Fee Related
• 2010
  • 2010-07-06 CN CN201080032456.6A patent/CN102470710B/zh not_active Expired - Fee Related
  • 2010-07-06 JP JP2012522068A patent/JP2013500196A/ja active Pending
  • 2010-07-06 RU RU2012107309/11A patent/RU2012107309A/ru not_active Application Discontinuation
  • 2010-07-06 US US13/388,041 patent/US8770601B2/en not_active Expired - Fee Related
  • 2010-07-06 WO PCT/EP2010/059606 patent/WO2011012408A1/fr not_active Ceased
  • 2010-07-06 BR BR112012001995A patent/BR112012001995A8/pt not_active Application Discontinuation
  • 2010-07-06 EP EP10730774.6A patent/EP2459399B1/fr not_active Not-in-force

Patent Citations (6)

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