STEERING WHEEL GRIP DETECTION DEVICE

• US 20180022374A1
• Filed: 02/25/2016
• Published: 01/25/2018
• Est. Priority Date: 03/13/2015
• Status: Active Grant

• Current Assignee: Panasonic Automotive Systems Company of America (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Inventors: FUJIKAWA, SHINJI, OKAZAKI, YUTA, NAITOU, HIROSHI, NISHIO, TSUYOSHI, KATSUKI, NOBUHARU
• Granted Patent: US 10,640,138 B2
• Time in Patent Office: Days
• CPC Class Codes: B60R 16/037 for occupant comfort , e.g. for automatic adjustment of appliances according to personal settings, e.g. seats, mirrors, steering wheel
• CPC Class Codes: B62D 1/046 Adaptations on rotatable parts of the steering wheel for accommodation of switches
• CPC Class Codes: B62D 1/065 Steering wheels with heating and ventilating means heating and ventilation of steering wheel when connected to vehicle HVAC B60H1/00292
• CPC Class Codes: G01V 3/08 operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices with electromagnetic waves G01V3/12
• CPC Class Codes: H03K 17/962 Capacitive touch switches

Abstract

A steering wheel grip detection device includes a series circuit including an inductance element, a thermostat incorporated into a steering wheel, and a heater incorporated into the steering wheel; an electrostatic sensor circuit that detects a grip of the steering wheel by means of an electric or electromagnetic field; and a voltage detecting circuit that detects an open/closed state of the thermostat.

Claims

1. A steering wheel grip detection device comprising:

a series circuit electrically connected to between a positive electrode and a negative electrode of a power supply and including a first inductance element, a thermostat incorporated into a steering wheel, and a heater incorporated into the steering wheel; and

an electrostatic sensor circuit electrically connected to an end of the heater to which the first inductance element is electrically connected, or to a middle of a wiring path of the heater, the electrostatic sensor circuit detecting a contact with the steering wheel by means of an electric or electromagnetic field,

wherein the steering wheel grip detection device includes a voltage detecting circuit electrically connected;

to between a wiring path of the positive electrode and any one of connecting points between the first inductance element, the thermostat, and the heater;

to between a wiring path of the negative electrode and any one of connecting points between the first inductance element, the thermostat, and the heater;

to two ends of the first inductance element;

to two ends of the heater;

or to two ends of the thermostat,

wherein output of the voltage detecting circuit is electrically connected to the electrostatic sensor circuit, and

wherein the electrostatic sensor circuit corrects output of the electrostatic sensor circuit based on an open or closed state of the thermostat obtained from output of the voltage detecting circuit.

2. The steering wheel grip detection device of claim 1, further comprising a second inductance element electrically connected to an end of the heater opposite to the end to which the first inductance element is connected,

wherein the voltage detecting circuit is connected

to two ends of one of circuit components including the first inductance element, the thermostat, the heater, and the second inductance element,

to two ends of any two of the circuit components directly series-connected, or

to two ends of any three of the circuit components directly series-connected.

3. The steering wheel grip detection device of claim 1, wherein a first switch is electrically connected in parallel with the first inductance element.

4. The steering wheel grip detection device of claim 2, wherein a second switch is electrically connected in parallel with the second inductance element.

5. The steering wheel grip detection device of claim 1, further comprising a second switch electrically connected to an end of the heater opposite to the end to which the first inductance element is connected,

6. The steering wheel grip detection device of claim 1,

wherein the electrostatic sensor circuit updates a reference value which is output of the electrostatic sensor circuit when a hand is not in contact with the steering wheel.

7. The steering wheel grip detection device of claim 1,

wherein the electrostatic sensor circuit corrects output of the electrostatic sensor circuit based on an open or closed state of the thermostat obtained from output of the voltage detecting circuit wherein the electrostatic sensor circuit retains an offset value at a sensor value detected by electrostatic sensor circuit, based on an open/closed state of the thermostat obtained from output of the voltage detecting circuit, and adds the offset value to the sensor value or subtracts the offset value from the sensor value, in response to change of the open/closed state.

8. The steering wheel grip detection device of claim 1, further comprising a current detecting circuit electrically series-connected to a wiring path of the series circuit.

9. The steering wheel grip detection device of claim 8, wherein output of the voltage detecting circuit and output of the current detecting circuit are electrically connected to the electrostatic sensor circuit, and

wherein the electrostatic sensor circuit updates a reference value based on an open/closed state of the thermostat obtained from output of the voltage detecting circuit and output of the current detecting circuit, the reference value being output of the electrostatic sensor circuit when a hand is not in contact with the steering wheel.

10. The steering wheel grip detection device of claim 8, wherein output of the voltage detecting circuit and output of the current detecting circuit are electrically connected to the electrostatic sensor circuit, and

wherein the electrostatic sensor circuit retains an offset value at a sensor value detected by the electrostatic sensor circuit, based on an open/closed state of the thermostat obtained from output of the voltage detecting circuit and output of the current detecting circuit, and adds the offset value to the sensor value or subtracts the offset value from the sensor value, in response to change of the open/closed state.

14. The steering wheel grip detection device of claim 7, wherein the offset value is determined based on an actual measured value of the offset value generated by change of the sensor value due to previous opening and closing of the thermostat.

15. The steering wheel grip detection device of claim 10, wherein the offset value is determined based on an actual measured value of the offset value generated by change of the sensor value due to previous opening and closing of the thermostat.

11. A steering wheel grip detection device comprising:

a series circuit electrically connected to between a positive electrode and a negative electrode of a power supply and including a first inductance element, a thermostat incorporated into a steering wheel, and a heater incorporated into the steering wheel; and

an electrostatic sensor circuit electrically connected to an end of the heater to which the first inductance element is electrically connected, or to a middle of a wiring path of the heater, the electrostatic sensor circuit detecting a contact with the steering wheel by means of an electric or electromagnetic field,

wherein the steering wheel grip detection device includes a current detecting circuit electrically series-connected to a wiring path of the series circuit,

wherein output of the current detecting circuit is electrically connected to the electrostatic sensor circuit, and

wherein the electrostatic sensor circuit corrects output of the electrostatic sensor circuit based on an open/closed state of the thermostat obtained from output of the current detecting circuit.

12. The steering wheel grip detection device of claim 11,

wherein the electrostatic sensor circuit updates a reference value which is output of the electrostatic sensor circuit when a hand is not in contact with the steering wheel.

13. The steering wheel grip detection device of claim 11, wherein the electrostatic sensor circuit corrects output of the electrostatic sensor circuit based on an open or closed state of the thermostat obtained from output of the voltage detecting circuit

wherein the electrostatic sensor circuit retains an offset value at a sensor value detected by the electrostatic sensor circuit, based on an open/closed state of the thermostat obtained from output of the current detecting circuit, and adds the offset value to the sensor value or subtracts the offset value from the sensor value, in response to change of the open/closed state.

16. The steering wheel grip detection device of claim 13, wherein the offset value is determined based on an actual measured value of the offset value generated by change of the sensor value due to previous opening and closing of the thermostat.