Sensor system for a motor vehicle

• US 9,810,727 B2
• Filed: 10/19/2012
• Issued: 11/07/2017
• Est. Priority Date: 10/20/2011
• Status: Active Grant

• Current Assignee: Joyson Safety Systems Germany GmbH (Ningbo Junsheng Investment Group Co., Ltd.)
• Original Assignee: Takata AG (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Kandler, Marcus, Kretzschmar, Albrecht
• Primary Examiner(s): Nguyen, Tung X
• Assistant Examiner(s): HAWKINS, DOMINIC E
• Application Number:
  US14/353,109
• Publication Number:
  US 20140253151A1
• Time in Patent Office: 1,845 Days
• Field of Search: 324686, 324687, 74552, 7311702
• CPC Class Codes: B60N 2/002 Seats provided with an occupancy detection means mounted therein or thereon detection means responsive to presence or absence of children B60N2/266
• CPC Class Codes: B62D 1/046 Adaptations on rotatable parts of the steering wheel for accommodation of switches
• CPC Class Codes: B62D 1/06 Rims, e.g. with heating means; Rim covers B62D1/11 takes precedence
• CPC Class Codes: G01L 1/142 using capacitors
• CPC Class Codes: G01L 1/144 with associated circuitry G01L1/146 and G01L1/148 take precedence
• CPC Class Codes: G01L 1/26 Auxiliary measures taken, or devices used, in connection with the measurement of force, e.g. for preventing influence of transverse components of force, for preventing overload
• CPC Class Codes: G01L 5/221 to steering wheels, e.g. for power assisted steering
• CPC Class Codes: G01R 27/2605 Measuring capacitance capacitive sensors G01D5/24

Abstract

A sensor system for a motor vehicle is provided. The sensor system comprises a flat shielding element which is electrically conductive and to which an electric potential can be applied, and at least one capacitive sensor element which includes an electrically conducting structure which is arranged on one side of the shielding element. As electrically conducting structure the sensor element includes at least one sensor conductor which forms a sewing thread and is sewn onto the one side of the shielding element.

Claims

1. A sensor system for a motor vehicle, which comprises:

a flat shielding element comprising a fabric of metal threads which is electrically conductive and to which a first electric potential is applied, and

at least one capacitive sensor element, which includes an electrically conducting structure which is arranged on a first side of the shielding element, wherein as electrically conducting structure, the at least one capacitive sensor element includes at least one sensor conductor which forms a sewing thread and is sewn onto the first side of the shielding element,

wherein a second potential is applied to the at least one sensor conductor, such that the fabric of metal threads of the shielding element masks any parasitic capacitance between the at least one sensor conductor and any electrically conductive material disposed adjacent a second side of the shielding element, wherein the second side of the shielding element is opposite and spaced apart from the first side of the shielding element,

a holding thread,

wherein the sensor conductor and the holding thread together form a seam, wherein the sensor conductor and/or the holding thread at least partially extend through the shielding element.

2. The sensor system according to claim 1, wherein the sensor conductor forms the bottom thread or face thread of the seam which is formed in the shielding element.

3. The sensor system according to claim 1 wherein the shielding element includes a plurality of interconnected layers of different materials, wherein at least one of the layers is the fabric of metal threads.

4. The sensor system according to claim 3, wherein in addition to the fabric of metal threads, the shielding element includes at least one non-conducting layer selected from the group consisting of an adhesive material, a foam material and a fleece.

5. The sensor system according to claim 4, wherein the fabric of metal threads is arranged between at least two non-conducting layers or adjacent to at least two non-conducting layers of the shielding element in a sandwich construction.

6. The sensor system according to claim 1, wherein the fabric of metal threads comprises a wire fabric with warp threads and weft threads, which are offset with respect to heating conductors and/or sensor conductors by an angle unequal to 90°

.

7. The sensor system according to claim 1, wherein for measuring a quantity to be measured a modulated measurement signal is applied to the sensor element and a change in the phase and/or amplitude of the measurement signal is evaluated.

8. The sensor system according to claim 1, wherein the first potential and the second potential are the same, the sensor system further comprising a circuit arrangement which drives the first potential and the second potential.

9. The sensor system according to claim 8, wherein the second potential is a modulated measurement signal, and for measuring a quantity to be measured, the modulated measurement signal is applied to the sensor element and a change in the phase and/or amplitude of the measurement signal is evaluated, and wherein the first potential applied to the shielding element has the same phase as the measurement signal applied to the sensor element.

10. The sensor system according to claim 9, wherein the measurement signal for the sensor element also is applied to the shielding element.

11. The sensor system according to claim 1, wherein the sensor system is provided and formed to be integrated into a vehicle steering wheel or into a vehicle seat.

12. The sensor system according to claim 1, wherein the sensor system includes at least one heating element which is arranged on the second side of the shielding element.

13. The sensor system according to claim 12, wherein the heating element includes at least one heating conductor which is sewn onto the second side of the shielding element.

14. The sensor system according to claim 13, wherein the heating conductor itself forms a sewing thread which is interlaced with the shielding element and/or at least one further sewing thread.

15. The sensor system according to claim 13, wherein the heating conductor is sewn onto the second side of the shielding element by means of the holding thread which fixes the heating conductor on the other side of the shielding element.

16. The sensor system according to claim 15, wherein the holding thread is made of a non-conducting material.

17. The sensor system according to claim 1, wherein the sensor conductor is interlaced with at least one further sewing thread.

18. The sensor system according to claim 15, wherein the sensor conductor is interlaced with at least one further sewing thread and the sensor conductor and the holding thread form at least one seam and in doing so form bottom thread and face thread of the seam.

19. The sensor system according to claim 1, wherein the first and second potentials are the same.