HEAD REST DEVICE

• US 20090160235A1
• Filed: 11/15/2006
• Published: 06/25/2009
• Est. Priority Date: 11/17/2005
• Status: Active Grant

• Current Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.), Toyota Boshoku Kabushiki Kaisha, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.), Toyota Boshoku Kabushiki Kaisha, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Ito, Koji, Hirota, Koichi, Akaike, Fumitoshi, Okawa, Tatsuhiro, Iyoda, Motomi, Nishimura, Seiya
• Granted Patent: US 7,770,967 B2
• Time in Patent Office: Days
• US Class Current: 297/391
• 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 2/0244 with logic circuits
• CPC Class Codes: B60N 2/0268 using sensors or detectors for adapting the seat or seat part, e.g. to the position of an occupant
• CPC Class Codes: B60N 2/862 with means for maintaining a desired position when the seat-back is adjusted, e.g. parallelogram mechanisms
• CPC Class Codes: B60N 2/888 with arrangements for protecting against abnormal g-forces, e.g. by displacement of the head-rest

Abstract

A head rest device that improves reliability of detecting a head on the basis of a change in capacitance without complicating a wiring structure. A head rest device is provided with a head rest rear portion configured to be supported to a seat back, and a head rest front portion freely moving forward and backward between a fully-closed position coming close to the head rest rear portion and a fully-open position separated from the head rest rear portion. The head rest front portion is moved by an actuator. The head rest front portion has a sensor electrode structured such that its capacitance is changed as a head of an occupant approaches, and an ECU controlling the actuator so as to move the head rest front portion and detecting the approach of the head of the occupant on the basis of a change of the capacitance of the sensor electrode thereon.

Claims

1. A head rest device comprising:

a head rest rear portion configured to be supported to a seat back;

a head rest front portion freely moving forward and backward between a fully-closed position coming close to the head rest rear portion and a fully-open position separated from the head rest rear portion;

a driving device moving the head rest front portion;

a control circuit controlling the driving device so as to move the head rest front portion;

a sensor electrode structured such that a capacitance is changed in accordance as a head of an occupant approaches the sensor electrode; and

a capacitance detecting circuit detecting the approach of the head of the occupant on the basis of a change in the capacitance of the sensor electrode,

wherein the sensor electrode is mounted to the head rest front portion,

wherein the driving device, the control circuit, and the capacitance detecting circuit are mounted together to one of the head rest front portion and the head rest rear portion.

2. The head rest device according to claim 1, wherein the capacitance detecting circuit is mounted to the head rest front portion.

3. The head rest device according to claim 2, wherein the control circuit is mounted to the head rest front portion.

4. The head rest device according to claim 2, wherein the sensor electrode is provided on a sensor mat, and a cable extends from a lower portion of the sensor mat.

5. The head rest device according to claim 4, wherein the sensor mat is arranged between a cushion retention member having a recess for accommodating a cushion, and the cushion accommodated in the recess, wherein the capacitance detecting circuit is located on a side of the cushion retention member that is opposite to the side on which the cushion is provided.

6. The head rest device according to claim 4, wherein each of the cushion retention member and a base member supporting the cushion retention member has an insertion hole, and the cable is connected to the control circuit via the insertion hole.

7. The head rest device according to claim 2, wherein an extensible mechanism moving the head rest front portion is provided between the head rest front portion and the head rest rear portion, and the driving device is provided in the extensible mechanism.

8. The head rest device according to claim 7, wherein the capacitance detecting circuit is fixed to a front portion of the extensible mechanism.