OCCUPANCY DETECTION DEVICE FOR DETECTING OCCUPANCY OF A SEAT IN A MOTOR VEHICLE

• US 20140132042A1
• Filed: 03/13/2012
• Published: 05/15/2014
• Est. Priority Date: 03/15/2011
• 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: Midderhoff, Robert, Hellerforth, Thomas
• Granted Patent: US 9,650,064 B2
• Time in Patent Office: Days
• US Class Current: 297/180.12
• CPC Class Codes: A47C 7/748 for heating
• 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: B60N 2/5685 Resistance
• CPC Class Codes: B60R 21/01532 using electric or capacitive field sensors
• CPC Class Codes: B60R 21/0154 in combination with seat heating
• CPC Class Codes: B62D 1/06 Rims, e.g. with heating means; Rim covers B62D1/11 takes precedence
• CPC Class Codes: H05B 1/0238 For seats
• CPC Class Codes: Y10T 74/20834 Hand wheels

Abstract

The invention relates to an occupancy detection device for detecting an occupancy of a seat of a motor vehicle. The occupancy detection device comprises

• • an electric resonant circuit which includes a first and a second inductance and at least one sensor element;
  • means for charging the resonant circuit with an alternating voltage;
  • means for determining at least one electrical parameter in the resonant circuit (2), wherein the electric resonant circuit experiences a change due to a change of the surroundings of the sensor element, so that with reference to the determined electrical parameter an occupancy of the seat can be detected; and
  • a first and a second terminal, via which a heater control can be connected with the occupancy detection device, in order to be able to simultaneously operate the sensor element as heater. The first and the second terminal are arranged such that a direct current provided at these terminals by the heater control is supplied to the sensor element via the first and the second inductance.

Claims

1. An occupancy detection device for detecting an occupancy of a seat of a motor vehicle, comprising

an electric resonant circuit which includes a first and a second inductance and at least one sensor element;

means for charging the resonant circuit with an alternating voltage;

means for determining at least one electrical parameter in the resonant circuit, wherein the electric resonant circuit experiences a change due to a change of the surroundings of the sensor element, so that with reference to the determined electrical parameter an occupancy of the seat can be detected; and

a first and a second terminal, via which a heater control can be connected with the occupancy detection device, in order to be able to simultaneously operate the sensor element as heater, wherein the first and the second terminal are arranged such that a direct current provided at these terminals by the heater control is supplied to the sensor element via the first and the second inductance.

2. The occupancy detection device according to claim 1, wherein an input terminal of the first inductance is connected with the first terminal and an input terminal of the second inductance is connected with the second terminal.

3. The occupancy detection device according to claim 2, wherein the sensor element includes a first terminal, which is connected with the output terminal of the first inductance, and a second terminal, which is connected with an output terminal of the second inductance.

4. The occupancy detection device according to claim 2, further comprising a first capacitance, which is connected with the input terminal of the first inductance, and a second capacitance, which is connected with the input terminal of the second inductance.

5. The occupancy detection device according to claim 4, wherein the first and the second capacitance each include a first terminal which is connected with the first and the second inductance, respectively, and a second terminal which is connectable with a reference potential.

6. The occupancy detection device according to claim 1, wherein the sensor element includes an electrically conductive structure which can be integrated into a vehicle seat and/or a steering wheel of the vehicle.

7. The occupancy detection device according to claim 1, wherein the first and the second inductance are formed by a first and a second coil.

8. The occupancy detection device according to claim 7, wherein the d.c. resistance of the two coils each is not more than one tenth or not more than one hundredth of the d.c. resistance of the sensor element.

9. The occupancy detection device according to claim 1, wherein the electric resonant circuit includes a capacitance connected in series with a further inductance.

10. The occupancy detection device according to claim 1, wherein the means for charging the resonant circuit with an alternating voltage include a voltage-controlled oscillator.

11. The occupancy detection device according to claim 10, wherein the means for charging the resonant circuit with an alternating voltage include a sine shaper cooperating with the voltage-controlled oscillator.

12. The occupancy detection device according to claim 1, wherein the means for determining an electrical parameter are formed for determining the resonance frequency and/or the resonance amplitude of the electric resonant circuit.

13. The occupancy detection device according to claim 12, wherein the means for determining an electrical parameter include a peak-to-peak detector with which a voltage in the resonant circuit is determined.

14. A vehicle seat arrangement for a motor vehicle, comprising a vehicle seat and an occupancy detection device according to claim 1, wherein the sensor element is arranged in the vehicle seat.

15. A steering wheel arrangement for a motor vehicle, comprising a steering wheel and an occupancy detection device according to claim 1, wherein the sensor element is arranged in or at the steering wheel.