Headrest apparatus

Abstract

A headrest apparatus comprising a headrest rear portion supported at a seatback, a headrest front portion movable between a fully retracted position and a fully expanded position, a driving means moving the headrest front portion, an capacitance sensor outputting a detection signal representing an capacitance, a controller moving the headrest front portion toward the fully expanded position and controlling the driving means to stop the headrest front portion, a load sensor detecting a load applied to the headrest front portion, and the controller judging a completion of a protection of the head of the occupant on the basis of the load detected by the load sensor in a condition where the headrest front portion is stopped and controlling the driving means to move the headrest front portion toward the fully retracted position when a completion of the protection of the head of the occupant is determined.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and additional features and characteristics of the present invention will become more apparent from the following detailed description considered with reference to the accompanying drawings, wherein:

FIG. 1 is a side view of a vehicle seat for explaining a headrest apparatus according to an embodiment of the present invention;

FIG. 2A is a side view of the headrest apparatus in a condition where a head of an occupant is detected;

FIG. 2B is a side view of the headrest apparatus in a condition where an impact from a backside is applied to the vehicle;

FIG. 2C is a side view of the headrest apparatus in a condition where the impact from the backside of the vehicle is eased;

FIG. 2D is a side view of the headrest apparatus in a condition where a headrest front portion is retracted;

FIG. 3 is a graph for explaining a change of a load detected by a load sensor;

FIG. 4 is a block diagram indicating an electrical structure of the headrest apparatus; and

FIG. 5 is a flow chart for explaining processes performed by an controller.

Claims

1. A headrest apparatus, comprising: a headrest rear portion supported at a seatback;a headrest front portion movable between a fully retracted position, which is close to the headrest rear portion, and a fully expanded position, which is distant from the headrest rear portion;a driving means moving the headrest front portion in a retracting or an expanding direction;an capacitance sensor provided at the headrest front portion and outputting a detection signal representing an capacitance variable in response to an approach of a head of an occupant to the headrest front portion;a controller moving the headrest front portion toward the fully expanded position on the basis of a trigger signal and controlling the driving means to stop the headrest front portion when the head of the occupant is detected on the basis of the detection signal of the capacitance sensor;a load sensor detecting a load applied to the headrest front portion in response to a contact of the head of the occupant with the headrest front portion, whereinthe controller judging a completion of a protection of the head of the occupant by the headrest front portion on the basis of the load detected by the load sensor in a condition where the headrest front portion is stopped and controlling the driving means to move the headrest front portion toward the fully retracted position when a completion of the protection of the head of the occupant is judged.

2. The headrest apparatus according to claim 1, wherein the controller determines the completion of the protection of the head of the occupant by the headrest front portion when the load applied to the headrest front portion by striking the head is becomes less than a second predetermined load, which is lower than a first predetermined load, after the load exceeds the first predetermined load.

3. The headrest apparatus according to claim 1, wherein the controlling means is inputted with information representing a vehicle rear impact from rearward and controls the driving means to move the headrest front portion in the expanding direction, and the controlling means controls the driving means to move the headrest front portion toward the fully retracted position after past a predetermined time under a condition which the vehicle rear impact is not occur after the stop of the headrest front portion.

4. The headrest apparatus according to claim 2, wherein the controller determines the completion of the protection of the head of the occupant by the headrest front portion when the headrest front portion is moved and stopped at the fully expanded position.

5. The headrest apparatus according to claim 2, wherein the controller moves the headrest front portion to the fully retracted position after the headrest front portion is moved to the fully expanded position and then a predetermined time is elapsed.

6. The headrest apparatus according to claim 3, wherein the predetermined time is determined by moving the headrest front portion from the fully retracted position to the fully expanded position.

7. The headrest apparatus according to claim 2, wherein the controller retracts the headrest front portion to the fully retracted position after the predetermined time is elapsed since the headrest front portion is stopped in a condition where the load applied to the headrest front portion is not exceed the first predetermined load.

8. The headrest apparatus according to claim 2, wherein the load sensor is provided anterior to the capacitance sensor provided at the headrest front portion and detects the load applied to the headrest front portion by striking the head of the occupant.

9. The headrest apparatus according to claim 1, wherein the trigger signal is a signal predicting the vehicle rear impact.