System and method for determining at least one parameter of at least one rotating member by means of a position signal

• US 20050110624A1
• Filed: 11/08/2004
• Published: 05/26/2005
• Est. Priority Date: 11/21/2003
• Status: Active Grant

• Current Assignee: SNR Roulements
• Original Assignee: SNR Roulements
• Inventors: Duret, Christophe, Nicot, Christophe
• Granted Patent: US 7,196,615 B2
• Time in Patent Office: Days
• US Class Current: 340/445
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
• CPC Class Codes: B60C 23/044 Near field triggers, e.g. magnets or triggers with 125 KHz

Abstract

The invention concerns a system for determining at least one parameter of at least one member (1) rotating with respect to a fixed structure (2), comprising, for each rotating member (1), an assembly comprising a transponder (3), a coder (5), a position sensor (6) and a device (4) for detecting the parameter or parameters issuing from the transponder (3); the said system also comprising a synchronisation unit (7) which is connected to each sensor (6) and to each detection device (4), the said unit comprising a device (7a) for determining an activation position of the detection device (4) of an assembly when the transponder (3) of the assembly is in the transmission/reception cone of the communication means of the said detection device, and an activation device (7b) able, by comparing the position of the coder (5) with the activation position, to activate the detection device (4) of the assembly in order to measure the parameter or parameters.

Claims

1. A system for determining at least one parameter of at least one member (1) rotating with respect to a fixed structure (2), the said system comprising, for each rotating member (1), an assembly comprising:

a transponder (3) rotationally fixed to the rotating member (1), the said transponder being able to measure the parameter or parameters to be determined;

a coder (5) rotationally fixed to the rotating member (1);

a sensor (6) fixed to the fixed structure (2), the said sensor being disposed opposite to and at a reading distance from the coder (5), the said sensor comprising an electronic circuit able to deliver a signal representing the angular position of the coder (5) with respect to the fixed structure (2);

a device (4) for detecting the parameter or parameters issuing from the transponder (3), the said device being fixed to the fixed structure (2) and comprising a communication means able to transmit an excitation signal to the transponder (3) and to receive the measurement or measurements;

the said system also comprising;

a synchronisation unit (7) which is connected to each sensor (6) and to each detection device (4), the said unit comprising a device (7a) for determining an activation position of the detection device (4) of an assembly when the transponder (3) of the assembly is in the transmission/reception cone of the communication means of the said detection device, and an activation device (7b) able, by comparing the position of the coder (5) with the activation position, to activate the detection device (4) of the assembly in order to measure the parameter or parameters.

2. A system according to claim 1, characterised in that the activation device (7b) comprises means of resetting the position signal of the coder (5) with respect to the activation position.

3. A system according to claim 1 or 2, characterised in that the coder (5) is formed from a magnetic ring comprising on its surface a track formed by a succession of North and South poles.

4. A method of determining at least one parameter of at least one member (1) rotating with respect to a fixed structure (2) by means of a system according to claim 1, characterised in that it comprises an initial procedure of determining an activation position and then, when the position of the coder (5) is equal to the said activation position, the activation device (7b) activates or enables the activation of the detection device (4).

5. A method of determining at least one parameter of at least one member (1) rotating with respect to a fixed structure (2) by means of a system according to claim 2, characterised in that it comprises an initial procedure of determining an activation position, after which the position signal of the coder (5) is reset with respect to the said activation position in order, according to the reset position of the coder (5), to allow or enable the activation of the detection device (4).

6. A method according to claim 4 or 5, characterised in that the initial determination procedure is implemented by activating the detection device (4) at a fixed frequency and, when the signal measured by the said device is satisfactory, determining the activation position which is equal to the position of the coder (5).

7. A method according to claim 4 or 5, characterised in that it comprises an iterative procedure of optimising the activation position in which the quality of the signal issuing from the detection device (4) is analysed and, if the quality is lower than a first threshold, the activation position is incremented and/or decremented by a given step in order to determine a new optimised position which is used subsequently by the activation device (7b) as the new activation position.

8. A method according to claim 7, in which, if the quality of the signal is below a second threshold which is below the first threshold, the procedure of determining an activation position is implemented in place of the optimisation procedure.

9. A method according to claim 4 or 5, characterised in that, when the activation device (7b) enables activation, this is effected at variable interrogation periods which are determined according to operating conditions of the rotating member (1).

10. A motor vehicle comprising a system according to claim 1 or 2, each assembly being disposed so as to determine at least one parameter of a tyre (1) of the said vehicle.

11. A vehicle according to claim 10, characterised in that the communication means is housed in the arch of the wheel on which the tyre (1) is mounted and in that the transponder (3) is housed in the valve of the tyre (1).

12. A method according to claim 6, characterised in that it comprises an iterative procedure of optimising the activation position in which the quality of the signal issuing from the detection device (4) is analysed and, if the quality is lower than a first threshold, the activation position is incremented and/or decremented by a given step in order to determine a new optimised position which is used subsequently by the activation device (7b) as the new activation position.

13. A method according to claim 12, in which, if the quality of the signal is below a second threshold which is below the first threshold, the procedure of determining an activation position is implemented in place of the optimisation procedure.

14. A motor vehicle comprising a system according to claim 3, each assembly being disposed so as to determine at least one parameter of a tyre (1) of the said vehicle.

15. A vehicle according to claim 14, characterised in that the communication means is housed in the arch of the wheel on which the tyre (1) is mounted and in that the transponder (3) is housed in the valve of the tyre (1).