JP2008105560A - Head rest device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a head rest device capable of protecting the neck part of an occupant when the head part is moved by the acceleration caused by the steering of the own vehicle. <P>SOLUTION: The head rest device is characterized in that it has a distance sensor 4 for detecting the distance between the head part of the occupant seated on a seat 3 and the head rest 1, a head rest drive mechanism 2 for moving the head rest in the longitudinal direction based on the distance detected by the distance sensor 4, and a control part 5 for operating the head rest drive mechanism 2 based on the acceleration of the own vehicle caused by the steering of the own vehicle. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a headrest device that can move a headrest of a vehicle seat in the front-rear direction, and more particularly to a headrest device that moves the headrest back and forth based on the acceleration of the host vehicle.

  It is known that when the host vehicle collides with an obstacle, a rapid acceleration is applied to the occupant, and the head moves rearward of the vehicle and places a burden on the neck. Therefore, a headrest control device that detects or predicts a collision and drives the headrest to move forward of the vehicle and stop immediately before the head, thereby receiving the moved head and reducing the burden on the occupant's neck. Has been proposed (see, for example, Patent Document 1).

In addition, there has been proposed an airbag device that deploys an airbag from a seat back toward an occupant's head when a vehicle collides (see, for example, Patent Document 2). The airbag device described in Patent Document 2 deploys an airbag after a predetermined time has elapsed since a sudden deceleration due to a collision with an obstacle in front is detected. The deployment timing is controlled so as to be interposed between the head of the passenger and the headrest in the inflated state.
JP 2006-160152 A JP-A-6-127331

  However, since the headrest control device described in Patent Document 1 or the airbag device described in Patent Document 2 does not operate unless a collision with another vehicle or the like is detected or predicted, for example, sudden start, sudden brake, etc. When the head moves due to maneuvering, there is a problem that the neck cannot be properly protected.

  In view of the above problems, an object of the present invention is to provide a headrest device that can protect the neck of an occupant when the head moves due to acceleration caused by the operation of the host vehicle.

  In order to solve the above problems, the present invention provides a distance sensor that detects the distance between the head of the passenger seated on the seat and the headrest, a headrest drive mechanism that moves the headrest in the front-rear direction based on the distance detected by the distance sensor, There is provided a headrest device comprising: a control unit that operates a headrest drive mechanism based on an acceleration of the host vehicle caused by operation of the host vehicle.

  According to the present invention, since the headrest drive mechanism is activated by detecting the acceleration of the host vehicle caused by the steering of the host vehicle, the head of the occupant moving during sudden deceleration or sudden start is received and the neck is protected. be able to.

  In one embodiment of the present invention, the control unit maintains the position of the headrest after movement when the acceleration is equal to or greater than the predetermined value A or less than the predetermined value B after operating the headrest driving mechanism, and the acceleration is equal to the predetermined value. If it is B or more and less than a predetermined value A, the headrest is stored in its original position after a predetermined time has elapsed.

  According to the present invention, since it is determined whether or not the headrest is to be stored based on the acceleration rather than the time when the headrest is driven forward, the neck can be appropriately protected.

  In one embodiment of the present invention, the maneuver that causes acceleration is at least one of a driver's accelerator operation and a brake operation.

  ADVANTAGE OF THE INVENTION According to this invention, when a head moves due to a driver | operator's operation, a passenger | crew's neck can be protected.

  Further, in one aspect of the present invention, when the maneuver that generated the acceleration is an acceleration maneuver, the headrest drive mechanism moves the headrest in the direction faster than the maneuver that caused the acceleration is a decelerating maneuver. It is characterized by that.

  According to the present invention, the speed at which the headrest is driven by the acceleration caused by the acceleration maneuver is faster than the speed at which the headrest is driven by the acceleration caused by the deceleration maneuvering. The occupant's neck can be protected.

  It is possible to provide a headrest device capable of protecting the occupant's neck when the head moves due to acceleration caused by the operation of the host vehicle.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the accompanying drawings.

  Fig.1 (a) shows the side view of the headrest 1 provided with the movable part 1a which can move ahead. The headrest 1 is provided on a seat 3 on which an occupant sits, and includes a front movable portion 1a and a rear fixed portion 1b, and includes a drive mechanism 2 for the movable portion 1a. When the drive mechanism 2 is driven, the movable portion 1a is reciprocated in the vehicle front-rear direction with respect to the fixed portion 1b, and the distance between the head of the occupant and the headrest 1 is controlled.

  The headrest device 10 of this embodiment reduces the distance between the head of the occupant and the headrest 1 by driving the movable part 1a forward of the vehicle when an acceleration of a predetermined level or more is detected, and the head generated during acceleration. Relieve the burden on the occupant's neck by moving the vehicle.

  A flexible thin plate-like capacitance sensor 4 is provided inside the skin of the headrest 1, and the capacitance sensor 4 detects the relative position (distance) with the head of the occupant in a non-contact state. To do. For example, when it is detected that another vehicle is approaching abnormally from behind, the drive mechanism 2 drives the movable part 1a forward of the vehicle while measuring the distance from the occupant's head by the electrostatic capacity sensor 4, and the head The movable part 1a is driven so as to stop immediately before the part. As a result, it is possible to reduce the burden on the occupant's neck during a rear collision. Hereinafter, driving the movable portion 1a is simply referred to as driving the headrest 1.

  FIG. 1B shows an example of a structure diagram of the drive mechanism 2. A pair of front and rear bases 21 and 22 are connected by a pair of left and right X-shaped links 24. One base 21 is coupled to the movable part 1a of the headrest 1 on the front side, and the other base 22 is coupled to the fixed part 1b on the back side. The pair of links 24 includes two link members 24 a and 24 b, respectively, and substantially central portions of the link members 24 a and 24 b are rotatably connected by pins 29. Both end portions of the link members 324a and 24b are connected to side portions 21a and 22a provided integrally on both sides of the bases 31 and 32, respectively.

  The link 24a has a front end portion rotatably connected to the side portion 21a of the base 21 by a pin 25a, and a rear end portion of the link 24a is rotatably connected to the side portion 22a of the base 22 by a pin 25b. On the other hand, the pair of link members 24b are coupled to each other at the front end portion by the shaft 26a and at the rear end portion by the shaft 26b. Both ends of one shaft 26 a are slidably connected to a vertically long guide hole 21 b formed in the side portion 21 a of the base 21, and both ends of the other shaft 26 b are formed in the side portion 22 a of the base 22. It is slidably connected to the vertically long guide hole 22b.

  The back side base 22 includes an electric unit 28 that is a drive source of the drive mechanism 2. The motor 28 a of the electric unit 28 is attached to the inside of the base 22. The drive shaft of the motor 28a is connected to the shaft 26b of the link 24 via the ball screw portion 28b. By the function of the ball screw portion 28b, the forward / reverse rotation of the motor 28a is converted into the lifting / lowering operation of the shaft 26b. Therefore, based on the drive control of the electric unit 28, both X-shaped links 24 operate like a pantograph, and the base 21 moves relative to the base 22.

  FIG. 2 shows an example of a block diagram of the headrest device 10. The headrest device 10 is controlled by a PCS (Pre-Crash Safety) headrest control ECU (Electronic Control Unit) 5. The PCS headrest control ECU 5 includes a drive mechanism 2 for the headrest 1, a G sensor 6 that detects acceleration in the longitudinal direction of the vehicle, and a rear radar sensor 7 that detects a three-dimensional object approaching from the rear of the vehicle via an in-vehicle LAN such as CAN. It is connected.

  The PCS headrest control ECU 5 includes a CPU that executes a program, a RAM that serves as a work area for program execution or temporarily stores data, an EEPROM (Electronically Erasable and Programmable Read Only Memory) that retains data even when the ignition is turned off, An input / output interface that serves as an interface with other ECUs for inputting data, a communication controller that communicates with other ECUs, a ROM that stores programs, and the like are configured by a microcomputer connected by a bus. A head position estimating means 5a for estimating the head position of the occupant by the CPU executing the program; a drive determining means 5b for determining whether to drive the headrest 1 based on the estimated head position and acceleration; Storage determination means 5c for determining whether or not to store the headrest 1 after driving is realized. Further, for example, the EEPROM stores a determination threshold value 11 for determining whether or not to drive the headrest 1.

  The G sensor 6 is a sensor that detects the amount of displacement generated in the detection body due to acceleration by a change in electric resistance or capacitance, and detects acceleration in each of the three axes in the vehicle front-rear, vertical, and left-right directions. Note that this embodiment particularly uses acceleration in the longitudinal direction of the vehicle, and the acceleration (deceleration) during deceleration and acceleration during acceleration are both referred to as acceleration.

  The rear radar sensor 7 is, for example, a millimeter wave radar sensor, and receives the radar that is transmitted from the radar and reflected by the three-dimensional object. The rear radar sensor 7 is arranged around the trunk of the own vehicle, and detects the distance and relative speed with the other vehicle approaching from behind, based on the time until the transmitted radar is received, the frequency change of the radar, etc. To do. The detection signal of the rear radar sensor 7 is sent to, for example, a collision determination ECU that predicts / determines a collision, and the collision determination ECU determines the possibility of a collision of a rear vehicle and determines that the possibility of a collision is high. A headrest drive signal is sent to the PCS headrest control ECU 5 several seconds before the collision.

  Next, a description will be given of the head position of an occupant that may occur due to the operation of the vehicle. FIG. 3 is a diagram illustrating an example of a head position that moves according to the acceleration of the vehicle. FIG. 3 shows the temporal change of velocity and acceleration, and the estimated head position. The head position is indicated by the distance from the front surface of the headrest 1 in a state where it is not driven. The head position in a stopped state or at a constant speed is at a position away from the headrest 1 by a predetermined distance (hereinafter referred to as an initial value), and the head position moves according to the acceleration of the vehicle.

  For example, at the time of starting, since the acceleration increases rapidly, the head position moves backward (becomes smaller) than the initial position. In the maneuvering area that accelerates from deceleration, the head moves forward (increases) when the vehicle decelerates from constant speed travel, and the head position moves forward (becomes larger). The head position rapidly decreases under the influence of acceleration.

  Such a change in the head position for a short time places a burden on the neck. The headrest device 10 of the present embodiment estimates the head position from the acceleration value, and when the estimated head position and acceleration have a predetermined relationship, the headrest 1 is driven forward of the vehicle to occupant's neck. Protect parts.

  The acceleration or deceleration is not limited to the case where the driver operates, but also occurs in automatic steering such as auto cruise control. In the present embodiment, the description will focus on the operation of the driver, but the same applies to the acceleration generated by the automatic steering.

The head position estimation will be described. FIG. 4A is a diagram for explaining the head position. The head position x indicates the distance from the front surface of the headrest 1 that is not driven. The stationary head position x is set to an initial value C, and the estimated position of the head that has moved due to acceleration (deceleration) is set to D, as in a stationary state or a constant speed state. The head position D is estimated by the following equation, for example.
D = C−∫∫F (x) dtdt (1)
Where F (x) = a−g (x)
Here, a is the acceleration, and g (x) is a predetermined function for determining the suppression acceleration that works to suppress the movement of the head according to the estimated head position D. FIG. 4B is a diagram illustrating an example of g (x). When the head position is at the initial value C, the suppression acceleration is also zero, so g (x) is zero at x = initial value C. In addition, since the head movement is suppressed as the head position moves forward, g (x) increases as the head position D increases (moves forward). Similarly, since the movement of the head is suppressed when the head position D is behind the initial value C, g (x) is a function that decreases as the head position D decreases (moves backward).

The head position estimating means 5a calculates the head position D according to the formula (1) every predetermined cycle time, determines the suppression acceleration based on the calculated head position D, and further uses the suppression acceleration to The calculation for estimating the part position D is repeated. For example, when the acceleration a is detected when the head position D is at the initial value C, g (x) is zero, so Equation (1) is as follows.
D1 = C−∫∫a dtdt
When decelerating, acceleration a is a negative value and D1 is greater than C, and during acceleration, acceleration a is a positive value and D1 is smaller than C.

The position estimating means 5a substitutes the calculated D1 for g (x) to calculate a new suppression acceleration, and estimates a new head position D2 by the equation (1).
D2 = D1-∫∫F (D1) dtdt
= D1-∫∫ (ag (D1)) dtdt
The head position estimating means 5a repeats such estimation of the head position D until the acceleration a becomes, for example, zero (constant speed running).

  Next, determination of whether or not to drive the headrest 1 will be described. As described in g (x), as the head decelerates and the head moves forward, a restraining force to return to the original position is applied, so the head moves backward at high speed only with a small acceleration. To do. On the other hand, when the head is near the initial value C, only the acceleration or deceleration acceleration acts and the head moves. Therefore, the head does not move greatly unless a relatively large acceleration is applied. That is, when the head position D is greatly moved forward even if the acceleration a is small, neck protection is necessary. When the acceleration a is large, the neck protection is required even if the head position D is not so forward. is required.

  Therefore, a determination threshold 11 for determining whether to drive the headrest 1 based on the estimated head position D and acceleration a is set in advance. FIG. 5 shows an example of the determination threshold 11. The determination threshold 11 is a smaller acceleration a as the estimated head position D is larger, and a larger acceleration a as the estimated head position D is smaller. That is, the lane region in FIG. 5B is a region where the headrest 1 is driven. The drive determination means 5b determines whether or not to drive the headrest 1 based on the determination threshold 11 as shown in FIG.

  By determining whether or not to drive the headrest 1 in this manner, the headrest device 10 can appropriately protect the neck portion against head movement due to acceleration after deceleration or sudden start. Further, when the estimated head position D is small and the detected acceleration a is small, the drive determination unit 5b does not determine that the headrest 1 is driven, and thus unnecessary driving can be prevented.

  Next, storage control after driving the headrest 1 will be described. The movable part 1a stopped immediately before the head of the occupant is housed in an initial position before driving after a predetermined time in principle. However, when the vehicle is accelerating or decelerating even after a certain time has elapsed after driving, it is preferable to keep the movable portion 1a at the driven position because the head may move.

  When the acceleration a after a predetermined time has passed the predetermined value A or more (when accelerating), it is assumed that the head of the occupant is in contact with the movable part 1a driven forward or moves backward. When the movable part 1a is stored in a state where the acceleration a is large, the head may move backward together with the movable part 1a.

  Further, when the acceleration a after a certain time has elapsed is less than the predetermined value B (when decelerating), the estimated head position D is large, and it is estimated that there is a high possibility of satisfying the determination threshold 11 again. For this reason, when the movable part 1a is housed in a state where the acceleration a is less than the predetermined value B, it is driven immediately after the movable part 1a is housed, and there is a risk of frequent operation.

  Accordingly, the storage determining means 5c determines that the movable portion 1a is stored when the acceleration a after a fixed time has elapsed after driving is greater than or equal to the predetermined value B and less than the predetermined value A (hereinafter simply referred to as storage conditions). . The absolute values of A and B may be the same.

  FIG. 6 is a flowchart of a processing procedure in which the headrest device 10 controls driving and storing of the headrest 1. The processing procedure in FIG. 6 starts, for example, when the ignition is turned on.

  Since the G sensor 6 detects the acceleration a every predetermined cycle time and sends it to the PCS headrest control ECU 5 (S1), the head position estimation means 5a estimates the head position D by the equation (1) using the acceleration a. (S2).

  The drive determination unit 5b refers to the determination threshold 11 in FIG. 5 based on the estimated head position D and acceleration a, and determines whether or not the determination threshold 11 is satisfied (S3). When the determination threshold 11 is not satisfied (No in S3), the PCS headrest control ECU 5 ends the process as it is without driving the headrest 1, and repeats from step S1.

  When the determination threshold value 11 is satisfied (Yes in S3), the PCS headrest control ECU 5 sends a drive signal to the drive mechanism 2 to drive the movable part 1a of the headrest 1 until just before the head (S4).

  After driving, the storage determination unit 5c waits until a predetermined time elapses (S5), and when the predetermined time elapses (Yes in S5), it determines whether the storage condition is satisfied (S6). If the storage condition is not satisfied (No in S6), the storage determination unit 5c repeats the determination in step S6 until the storage condition is satisfied.

  When the storage condition is satisfied (Yes in S6), the PCS headrest control ECU 5 sends a storage signal to the drive mechanism 2 and stores the movable portion 1a of the headrest 1 in the initial position (S7).

  According to the present embodiment, the occupant's neck can be protected even if the head moves due to acceleration or deceleration caused by the occupant's steering or automatic steering.

  In this embodiment, a headrest device 10 that determines whether to drive the headrest 1 at an early stage by predicting the acceleration generated in the vehicle from the accelerator opening in addition to the acceleration a actually generated in the vehicle will be described.

  FIG. 7 shows an example of a block diagram of the headrest device 10. In FIG. 7, the same components as those in FIG. 2 are denoted by the same reference numerals, and the description thereof is omitted. The headrest device 10 of FIG. 7 differs in that an accelerator pedal stroke sensor 8 is connected to the PCS headrest control ECU 5. The accelerator pedal stroke sensor 8 detects the accelerator opening in accordance with the driver's accelerator pedal operation amount.

  Further, the PCS headrest control ECU 5 has an acceleration predicting means 5d, and the acceleration predicting means 5c predicts an acceleration generated in the vehicle after a predetermined time has elapsed based on the accelerator opening. The prediction of acceleration may be simply calculated based on a map in which the PCS headrest control ECU 5 has an accelerator opening, an engine driving state, a gear ratio, and the like, and acceleration received from the engine ECU. May be. In auto-cruise control, acceleration is predicted from a signal that requests the throttle opening of the engine ECU instead of the driver's accelerator pedal operation amount.

  Vehicle acceleration is determined by engine torque, gear ratio, vehicle speed, and the like. The engine ECU refers to an engine torque calculation map determined in association with the throttle opening, the intake amount, and the engine speed controlled according to the accelerator opening, and determines the engine torque. The engine speed may be predicted according to the accelerator opening, or the actual engine speed after a predetermined time from when the accelerator opening is detected may be detected. The engine ECU predicts the acceleration after a predetermined time from the gear ratio and the current vehicle speed in addition to the engine torque. Note that the predicted acceleration may be corrected by detecting the gradient of the road surface.

  The head position estimation means 5a estimates the head position D based on the predicted acceleration as in the first embodiment. That is, the head position D is estimated by substituting the acceleration predicted from the accelerator opening into the acceleration a in the equation (1).

  In this way, by estimating the acceleration based on the accelerator opening and estimating the head position D before the acceleration actually occurs in the vehicle, it is possible to determine early whether or not the headrest 1 should be driven. Can securely protect the neck. For example, when the host vehicle suddenly starts, the distance between the head and the headrest 1 is small, but by determining at an early stage whether or not the head should be driven, the headrest 1 is driven before the head moves backward, and the occupant Can securely protect the neck.

  The determination methods of the drive determination unit 5b and the storage determination unit 5c are the same as those in the first embodiment. The drive determination means 5b refers to the determination threshold 11 based on the estimated head position D and the predicted acceleration, and determines whether or not to drive the headrest 1.

  The storage determination unit 5c stores the movable part 1a when the acceleration predicted after a certain period of time has elapsed after driving is within a predetermined range (deceleration is not higher than a predetermined value and acceleration is not higher than a predetermined range; hereinafter simply referred to as a storage condition). Judge that. For the storage determination, the acceleration detected by the G sensor 6 may be used.

  FIG. 8 is a flowchart of a processing procedure in which the headrest device 10 controls driving and storing of the headrest 1. The processing procedure in FIG. 6 starts, for example, when the ignition is turned on.

  Since the accelerator pedal stroke sensor 8 detects the accelerator opening every predetermined cycle time and sends it to the PCS headrest control ECU 5 (S10), the acceleration predicting means 5d predicts the acceleration after the predetermined time (S20).

  The subsequent steps are the same as in FIG. The head position estimating means 5a estimates the head position D by the formula (1) using the predicted acceleration (S2).

  The drive determination unit 5b refers to the determination threshold value 11 in FIG. 5 based on the estimated head position D and acceleration, and determines whether or not the determination threshold value 11 is satisfied (S3). When the determination threshold 11 is not satisfied (No in S3), the PCS headrest control ECU 5 ends the process as it is without driving the headrest 1, and repeats from step S1.

  When the determination threshold value 11 is satisfied (Yes in S3), the PCS headrest control ECU 5 sends a drive signal to the drive mechanism 2 to drive the movable part 1a of the headrest 1 until just before the head (S4).

  After driving, the storage determination unit 5c waits until a predetermined time elapses (S5), and when the predetermined time elapses (Yes in S5), it determines whether the storage condition is satisfied (S6). If the storage condition is not satisfied (No in S6), the storage determination unit 5c repeats the determination in step S6 until the storage condition is satisfied.

  When the storage condition is satisfied (Yes in S6), the PCS headrest control ECU 5 sends a storage signal to the drive mechanism 2 and stores the movable portion 1a of the headrest 1 in the initial position (S7).

  According to the present embodiment, since it can be determined at an early stage whether or not the headrest 1 should be driven, the occupant's neck can be reliably protected.

  In the present embodiment, the headrest device 10 is described in which the moving speed during driving of the movable portion 1a is variable depending on whether or not the maneuver that generated the acceleration a is acceleration. The operation of the present embodiment includes not only the operation by the driver but also automatic operation such as auto cruise control. Hereinafter, the headrest device 10 that detects the accelerator operation or the brake operation by the operation of the driver will be described.

  FIG. 9 shows an example of a block diagram of the headrest device 10. In FIG. 9, the same components as those in FIG. The headrest device 10 of FIG. 9 is different in that an accelerator pedal stroke sensor 8 and a stop lamp switch 9 are connected to the PCS headrest control ECU 5. The accelerator pedal stroke sensor 8 detects the accelerator opening in accordance with the driver's accelerator pedal operation amount. The stop lamp switch 9 detects the operation of the brake pedal. The detected accelerator opening and brake pedal operation signal are sent to the PCS headrest control ECU 5.

  When the acceleration a detected by the head position D and the G sensor 6 satisfies the determination threshold 11, the drive determination unit 5b determines whether or not an operation signal of the brake pedal is detected, and the brake pedal is operated. If not, the PCS headrest control ECU 5 sends a drive signal for driving the movable portion 1a to the drive mechanism 2 at a faster speed than when the brake pedal is operated. Therefore, when only the accelerator operation is detected, the movable portion 1a reaches immediately before the head earlier than when the brake operation is detected.

  FIG. 10 is a flowchart of a processing procedure in which the headrest device 10 controls the driving and storage of the headrest 1. The processing procedure in FIG. 6 starts, for example, when the ignition is turned on.

  Since the G sensor 6 detects the acceleration a every predetermined cycle time and sends it to the PCS headrest control ECU 5 (S1), the head position estimation means 5a estimates the head position D by the equation (1) using the acceleration a. (S2).

  The drive determination unit 5b refers to the determination threshold 11 in FIG. 5 based on the estimated head position D and acceleration a, and determines whether or not the determination threshold 11 is satisfied (S3). When the determination threshold 11 is not satisfied (No in S3), the PCS headrest control ECU 5 ends the process as it is without driving the headrest 1, and repeats from step S1.

  When the determination threshold value 11 is satisfied (Yes in S3), the drive determination unit 5b determines whether only the accelerator operation is detected (S40). The determination in step S40 is to determine whether a brake operation has been detected immediately before the accelerator operation or within a predetermined time.

  When only the accelerator operation is detected (Yes in S40), the PCS headrest control ECU 5 requests the drive mechanism 2 to drive the movable portion 1a of the headrest 1 at a faster speed than when the brake operation is detected (S50). .

  When the determination threshold value 11 is satisfied without brake operation, the head does not move forward due to inertia during deceleration, and the head approaches the headrest 1 by acceleration, so that the movable part 1a of the headrest 1 is moved at a high speed. By driving, the occupant's neck can be reliably protected.

  When only the accelerator operation is not detected (No in S40), the PCS headrest control ECU 5 sends a drive signal to the drive mechanism 2 to drive the movable portion 1a of the headrest 1 to just before the head (S4).

  The subsequent processing is the same as in the first embodiment. After driving, the storage determination unit 5c waits until a predetermined time elapses (S5), and when the predetermined time elapses (Yes in S5), it determines whether the storage condition is satisfied (S6). If the storage condition is not satisfied (No in S6), the storage determination unit 5c repeats the determination in step S6 until the storage condition is satisfied.

  When the storage condition is satisfied (Yes in S6), the PCS headrest control ECU 5 sends a storage signal to the drive mechanism 2 and stores the movable portion 1a of the headrest 1 in the initial position (S7).

  According to the present embodiment, when only the accelerator operation is detected, the movable portion 1a of the headrest 1 is driven at a higher speed than when the brake operation is detected. Therefore, even if the distance between the head and the headrest 1 is short Can reliably protect the occupant's neck.

  When driving the headrest 1 during automatic piloting, it is determined from the acceleration a during a predetermined period before the determination threshold 11 is satisfied whether or not there has been a deceleration pilot before acceleration. Further, even when a driver's operation is detected, the acceleration a during a predetermined period before the determination threshold 11 is satisfied may be monitored to determine whether or not there has been a deceleration maneuver before acceleration.

  The headrest device 10 of the present embodiment can protect the occupant's neck because the headrest 1 is driven forward when the head moves due to the operation of the host vehicle. When driven forward, the driven position is maintained until the storage condition is satisfied, so that the neck can be reliably protected even when the acceleration a of the vehicle continues to be high. Further, if the acceleration is predicted based on the accelerator opening, it is possible to determine at an early stage whether or not the headrest 1 is to be driven and to reliably protect the occupant's neck. In addition, when the deceleration maneuver is not detected, the movable portion 1a is driven at a higher speed than when the deceleration maneuver is detected. Therefore, even if the distance between the head and the headrest 1 is short, the occupant's neck is reliably protected. be able to.

The side view of the headrest provided with the movable part which can move ahead is shown. An example of the block diagram of a headrest apparatus is shown. It is a figure which shows an example of the head position which moves with the acceleration of a vehicle. It is a figure for demonstrating a head position. It is a figure which shows an example of a determination threshold value. It is a flowchart figure of the process sequence in which a headrest apparatus controls the drive and accommodation of a headrest. It is an example of the block diagram of the headrest apparatus in Example 2. FIG. It is a flowchart figure of the process sequence in which a headrest apparatus controls the drive and accommodation of a headrest. It is an example of the block diagram of the headrest apparatus in Example 3. FIG. It is a flowchart figure of the process sequence in which a headrest apparatus controls the drive and accommodation of a headrest.

Explanation of symbols

1 Headrest 1a Movable part 1b Fixed part 2 Drive mechanism
3 seat 4 capacitance sensor 5 PCS headrest control ECU
6 G sensor
7 Rear radar sensor 8 Accelerator pedal stroke sensor 9 Stop lamp switch 10 Headrest device 11 Judgment threshold

Claims (4)

A distance sensor for detecting the distance between the head of the occupant seated on the seat and the headrest;
A headrest drive mechanism for moving the headrest in the front-rear direction based on the distance detected by the distance sensor;
A control unit that operates the headrest drive mechanism based on the acceleration of the host vehicle caused by the operation of the host vehicle;
A headrest device characterized by comprising: The control unit maintains the position of the headrest after movement when the acceleration is greater than or equal to a predetermined value A or less than a predetermined value B after operating the headrest drive mechanism,
If the acceleration is greater than or equal to the predetermined value B and less than the predetermined value A, the headrest is stored in the original position after a predetermined time has elapsed.
The headrest device according to claim 1.   The headrest device according to claim 1, wherein the maneuver that causes the acceleration is at least one of a driver's accelerator operation and a brake operation. When the maneuver that caused the acceleration is an acceleration maneuver, the headrest drive mechanism moves the headrest forward at a higher speed than when the maneuver that caused the acceleration is a deceleration maneuver.
The headrest device according to claim 1, wherein the headrest device is a headrest device.

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