FR2872087A1 - On-board assembly for monitoring and adjusting vehicle tyre pressures has radio signal receiver controlling information emitter - Google Patents

Abstract

The on-board assembly (12) for monitoring vehicle tyre pressures consists of a pressure sensor (18) in fluid communication with the interior of each tyre (14), an emitter (20) to transmit pressure measurements to an on-board computer (16), and a fluid communication link (39) with an air-transmitting bearing (41) and a solenoid valve (42) between each tyre and an inflation/deflation circuit. It also incorporates a receiver for a radio signal to trigger the emitter.

Description

The present invention relates to a mounted assembly of a wheel and a

  pneumatic system and a system comprising such an assembly.

  More specifically, the invention relates to a mounted assembly of a wheel and a tire, of the type comprising: a pressure sensor in fluid communication with the inside of the tire, able to provide a measurement of the pressure prevailing at the inside the tire, means for transmitting the pressure measurement to an on-board computer on a vehicle, and a fluidic communication pathway between the inside of the tire and a fitting arranged so as to be able to connect to an inflation circuit and deflation embedded on the vehicle.

  Some manufacturers of motor vehicles, trucks, military.

  equip vehicles with tire pressure control systems. These control systems conventionally comprise means for measuring the pressure of each of the tires and the means of inflating and deflating each tire ... DTD: The regulation system of a vehicle monitors the pressure of the tires and adjusts this pressure around an optimal operating pressure. Such a system contributes effectively to optimizing the performance of the vehicle, in particular by improving the comfort of the occupants, adhesion for example on wet surfaces, traction on soft ground, behavior, consumption, as well as safety; the life of the tires can also be significantly increased.

  The pressure measurement of a tire is conventionally carried out by means of a pressure sensor integrated in a wheel valve. The pressure measurements of a tire are generally interpreted by a vehicle calculator.

  In order to allow the transmission of pressure measurements from the tire to the vehicle computer, advantageously a transmission is used over the air. For this, the pressure sensor onboard the tire is coupled to radio transmission means of the pressure measurement.

  To ensure inflation or deflation of the tire, each mounted assembly of a wheel and a tire comprises a fluidic communication path between the inside of the tire and a fitting arranged so as to be able to connect to an inflation circuit and deflation embedded on the vehicle. In this way, it is possible to act on the pressure of a tire even when the tire is moving.

  As the assembly composed of the pressure sensor and the transmission means is not connected to the computer by wire links, the power supply of this set is an autonomous power supply conventionally made by means of a battery.

  The aforementioned assembly emits, at regular intervals, for example every minute, tire pressure measurements. In what follows, transmission frequency means the frequency defined by these intervals. These pressure measurements make it possible to control, while driving, that the tires are correctly inflated and that they do not leak air.

  Pressure measurements are also used when inflating or deflating the tire to stop the inflation or deflation action when the tire pressure recommended by the manufacturers is reached. In this case, it is preferable that the emission frequency of the pressure measurement is high so that the set pressure is not exceeded.

  There are other modes of use of the pressure measurement each using a specific emission frequency.

  For the pressure measurement system to be usable in all possible modes of use, the emission frequency of the pressure measurement must be at least equal to the highest required frequency.

  However, a high transmission frequency considerably solicits the pressure sensor battery, which discharges rapidly.

  In addition, it may happen that the computer suddenly needs a measurement of the pressure of the tire, for example when a leak or a puncture has been detected. In the case of a mounted assembly of the state of the art, the computer must wait for the pressure measurement to be emitted spontaneously by the pressure sensor. There can therefore be a significant time between the need and the reception of the pressure measurement.

  The present invention proposes an assembly mounted on a wheel and a tire of the aforementioned type, which makes it possible to avoid these disadvantages.

  For this purpose, the subject of the invention is a mounted assembly of a wheel and a tire, comprising: a pressure sensor in fluid communication with the inside of the tire, capable of providing a measurement of the pressure prevailing at inside the tire, means for transmitting the pressure measurement to a computer on board a vehicle, and a fluid communication path between the inside of the tire and a fitting arranged so as to be able to connect to an inflation circuit and deflation embedded on the vehicle, characterized in that it further comprises means for receiving a radio trigger signal, carrying a triggering information transmitting means.

  The emission of the pressure measurement of an assembly mounted according to the invention is controllable by a computer of a vehicle provided with the assembled assembly. In particular, the computer can control an increase in the transmission frequency of the pressure measurement during an inflation or deflation phase of the tire, so as to reach quickly and without exceeding the pressure value recommended by the manufacturers .

  The use of a mounted assembly according to the invention therefore reduces the consumption of the battery of the pressure sensor.

  Thanks to an assembly mounted according to the invention, a user can further know the pressure of the tire without having to wait for the automatic emission of the pressure sensor, on simple control of the computer. In particular, it is interesting to check the pressure of the tires of a vehicle from its start.

  Optionally, the fluidic communication path includes an air passage bearing.

  According to a particular embodiment, the fluidic communication path comprises a wheel valve.

  A wheel valve is a valve for bidirectional fluid communication, the opening or closing of which is controlled by a pressure difference between the upstream pressure and the downstream pressure of the valve. In particular, when the pressure prevailing inside the tire is much greater than the pressure prevailing in the inflation and deflation circuit, the wheel valve is closed.

  A mounted assembly of a wheel and a tire provided with such a wheel valve can therefore be disconnected from the inflation and deflation circuit without the tire being deflated, which is desirable in case of a change of wheel.

  In addition, the joint use of a wheel valve and an air-flow bearing makes it possible to solve any problems related to air leaks from the air-passage bearing since the latter is no longer constantly under pressure. As the air passage bearing is at atmospheric pressure, its service life is significantly increased.

  Optionally, the wheel valve comprises removable means for closing the fluidic communication path and means for returning the closure means to the closed position, the return means being dimensioned so that the closing means are in the closed position when the pressure inside the tire is lower than a predetermined pressure. These return means, which comprise for example a spring, avoid that a handling error does not result in total deflation of the tire.

  The invention also relates to a system comprising: at least one assembly mounted according to the invention, means for inflating and deflating the tire of the mounted assembly, intended to be loaded onto the vehicle, and transmission means the radio trigger signal.

  Optionally, the inflation and deflation means of the system according to the invention comprise: a compressor, an inflation and deflation circuit connecting the compressor to the coupling, so as to ensure fluid communication between the compressor and the interior of the pneumatic, and a solenoid valve controlled by the computer, interposed in the inflation and deflation circuit.

  The invention will be better understood on reading the following description given solely by way of example, with reference to the appended drawings in which: FIG. 1 is a diagram of the front of a car seen from above fitted with assemblies according to a first embodiment of the invention, FIG. 2 is a detailed diagram of an assembly mounted according to a second embodiment of the invention, and FIG. 3 is a detailed diagram of a wheel valve of the assembly of Figure 2.

  The car 10 shown in FIG. 1 comprises four mounted assemblies 12 of a wheel 13 and a tire 14 of which only the front-left and front-right assemblies 12 are shown.

  The car 10 includes a multifunction computer 16 used for example by a traction control device or anti-lock wheels.

  Each mounted assembly 12 comprises a pressure sensor 18 in fluid communication with the inside of the tire 14, able to provide a measurement of the pressure prevailing inside the tire. The pressure sensor 18 is conventionally integrated with a wheel inflation valve.

  The pressure sensor 18 is connected to radio transmission means 20 housed in the tire and comprising a wheel transmitter 22 and a wheel emitting antenna 24. The transmission means 20 over the air are intended to emit a radio signal S carrying a pressure value measured by the pressure sensor 18 towards the computer 16.

  The computer 16 comprises an antenna 26 for receiving radio signals S from the four wheel emitters 22.

  The transmission means 20 can be activated by triggering means 28, controlled by the computer 16. The triggering means are also called initiators 28.

  Each initiator 28 comprises a radio-frequency initiator transmitter 30 and an initiator antenna 32. The radio-frequency initiator transmitter 30 is connected to the computer 16 by means of electric cables 33.

  The initiator 28 is intended to emit a triggering radio I signal, also called an initiation signal, carrying a triggering information of the transmission means 20. This initiation signal I is a low frequency signal.

  Since each initiator 28 is relative to a given tire, it is advantageous for it to be placed close to the corresponding tire. For example, the initiator 28 may be carried by a wheel well.

  The transmitter of the airwheel 22 is connected to a receiving antenna 34 of the radio signal I of initiation. The receiving antenna 34 may be confused with the transmitting antenna 24.

  Optionally, the transmission means 20 carried by the wheel are connected to a temperature sensor or tire identification means so that the radio signal S carrying a pressure value of the tire is also a carrier. the temperature of the tire measured by the temperature sensor and / or an identifier of the tire.

  The car 10 comprises an onboard compressor 35, provided with a channel 36 for fluid communication with the outside air, controlled by the computer 16 by means of an electric cable 37. The compressor 35 is intended to ensure the inflation or the deflation of the tires 14 mounted assemblies 12. It is for this purpose connected to each tire 14 via an inflation and deflation circuit 38, also called inflation circuit 38, so as to ensure fluid communication between the compressor 35 and the interior of each tire 14.

  Each mounted assembly 12 comprises a channel 39 for fluid communication between the inside of the tire 14 and a fitting 40 arranged to be able to connect to the inflation circuit 38. The channel 39 of fluid communication comprises a bearing 41 with air passage. The air passage bearing 41 makes it possible to pass air between the inside of the tire 14, which is rotating, and the inside of the inflation circuit 38, which is fixed to the chassis of the vehicle.

  Each inflation circuit 38 comprises a solenoid valve 42 controlled by the computer 16 via a cable 43. When the solenoid valve 42 is at rest, the inflation circuit 38 no longer ensures the fluid communication between the compressor 35 and inside each tire.

  According to a second embodiment of the assembled assembly, shown in FIG. 2, the fluidic communication path 39 further comprises a wheel valve 44 interposed in the path 39 for fluid communication between the tire and the thrust bearing. air.

  The wheel valve 44 is shown in more detail in FIG. 3. It comprises a membrane 46 separating the valve 44 at first 48 and second 50 cavities.

  The first cavity 48 forms part of the fluidic communication path 39. The fluidic communication path 39 comprises an upstream channel 52 for access to the first cavity 48 and a downstream channel 54 for access to the first cavity 48.

  The wheel valve 44 comprises, in the first cavity 48, removable means 56 for closing the fluidic communication path 39 carried by the diaphragm 46. These sealing means 56 comprise a seal 58 for closing the downstream channel 54. .

  The wheel valve 44 comprises, in the second cavity 50, return means 60, constituted by a spring 60, in the closed position of the closure means 56.

  We will now describe how the various elements defined above cooperate with each other during an inflation, then a deflation of a tire of an assembly mounted according to the first embodiment.

  Consider first the case where a user of the car 10 controls the computer 16, via a man-machine interface (not shown), inflating a tire 14 to a first predetermined target pressure.

  In this case, to increase the inflation accuracy, the computer 16 increases the transmission frequency of the pressure measurements. It therefore commands the initiator 28 of the tire 14 concerned to frequently transmit a low frequency initiation signal I.

  On receiving an initiation signal I, the transmission means 20 emit a radio signal S carrying a pressure value measured by the pressure sensor 18 to the receiving antenna 26 of the computer 16.

  To inflate the tire, the computer actuates the compressor 35 which sends air into the inflation circuit 38 towards the tire 14. Simultaneously with the action on the compressor 35, the computer actuates the solenoid valve 42 of the tire concerned for that the air can flow in the inflation circuit 38 from the outside to the inside of the tire.

  Thanks to the frequent knowledge of the pressure values, the computer can follow accurately and in real time the increase of the pressure of the tire.

  As soon as the first target pressure is reached, the computer closes solenoid valve 42 and stops compressor 35.

  Consider the case where the user wishes to deflate the tire 14 to a second predetermined target pressure. In this case, the computer 16 actuates only the solenoid valve 42 and not the compressor 35, which has the effect of allowing the air contained in the tire to escape outside via the channel 36 fluidic communication with the outside air.

  As before, the computer 16 benefits from the precise and almost real-time knowledge of the pressure prevailing in the tire, thanks to the action of the initiators 28 which trigger the transmission means 20 sufficiently frequently to monitor the failure to exceed the set value.

  In a particular operating mode, the tripping frequency is all the greater as the real pressure is close to the target pressure.

  Of course, it is possible to regulate the pressure of several tires 14. The computer 16 then actuates the initiators 28 and the solenoid valves 42 of the tires 14 concerned.

  Consider now the case of a car 10 equipped with a mounted assembly 12 according to the second embodiment described above. The operation of the initiators 28 is unchanged from the first embodiment, only the means for inflating or deflating the tire differ.

  To inflate the tire to a first target pressure, the computer actuates the compressor 35 which sends air into the inflation circuit 38 towards the tire 14. Simultaneously with the action on the compressor, the computer actuates the tire. solenoid valve 42 of the tire concerned so that air can circulate in the inflation circuit 38 to the inside of the tire.

  The air then enters the first cavity 48 of the wheel valve 44 through the upstream channel 52. When the pressure prevailing in the first cavity 48 becomes sufficient to exert on the diaphragm 46 a force greater than that exerted by the spring 60. the spring compresses and the seal 58 moves to release the downstream channel 54.

  If the pressure imposed by the compressor 35 is greater than the pressure in the tire, air is transferred in the path 39 of fluid communication to the tire which has the effect of inflating it.

  As soon as the first target pressure is reached, the computer stops the compressor 35 and closes the solenoid valve 42. An unrepresented exhaust channel then makes it possible to put at atmospheric pressure at the same time the air-passage bearing 41, the channel upstream 52 and therefore the first cavity 48. The pressure in the first cavity is then insufficient to withstand the pressure imposed by the spring 60. The diaphragm 46 therefore moves until the seal 58 closes the track 39 of fluidic communication.

  Consider the case where the user wishes to deflate the tire 14 to a second predetermined target pressure. In this case, the computer 16 actuates the solenoid valve 42 and the compressor 35 as during an inflation so as to disengage the seal 58 from the downstream channel 54.

  When channel 39 of fluid communication is open, the compressor is stopped, and the computer controls the opening of the solenoid valve 42 so as to control the flow of air escaping from the tire.

  With this flow control, the pressure in the first cavity is sufficient to maintain the seal in the open position, and the pressure in the tire is greater than the pressure in the upstream channel 52 so as to generate a flow of air coming out of the tire.

  When the second target pressure is reached, one proceeds in the same way as during inflation to close the channel 39 of fluid communication.

  By acting on the resistance of the spring 60, one can control the minimum pressure in the tire below which the seal 58 closes the channel 39 of fluid communication.

Claims (7)

  A mounted assembly (12) of a wheel (13) and a tire (14), comprising: a pressure sensor (18) in fluid communication with the interior of the tire (14), capable of providing a measurement the pressure inside the tire (14), means (20) for transmitting the pressure measurement to a computer (16) on a vehicle (10), and a fluidic communication path (39) between the inside of the tire (14) 10 and a coupling (40) arranged to be able to connect to an inflation and deflation circuit (38) on board the vehicle (10), characterized in that it comprises in in addition to means (34) for receiving a radio trigger signal (I), carrying a triggering information of the transmission means (20).   The mounted assembly (12) of claim 1, wherein the fluid communication path (39) comprises an air flow bearing (41).   The mounted assembly (12) of claim 1 or 2, wherein the fluid communication path (39) comprises a wheel valve.   4. Mounted assembly (12) according to claim 3, wherein the wheel valve comprises removable closure means of the fluidic communication path and return means in the closed position of the closure means, the return means being sized so that the closing means are in the closed position when the pressure prevailing inside the tire is less than a predetermined pressure.   25 .. The mounted assembly (12) of claim 4, wherein the biasing means comprises a spring.   6. System comprising: at least one mounted assembly (12) according to any one of the preceding claims, means (36, 38, 42) for inflating and deflating the tire (14) of the mounted assembly (12), intended to be embedded on the vehicle (10), means (28) for transmitting the radio signal (I).   The system of claim 6, wherein the inflation and deflation means (36,38,42) comprises: a compressor (36), an inflation and deflation circuit (38) connecting the compressor (36) to the connector (41), so as to ensure fluid communication between the compressor (36) and the inside of the tire (14), and a solenoid valve (42) controlled by the computer (16) of the vehicle (10), interposed in the circuit (38) inflation and deflation.