JPH08187139A - On-board headrest device - Google Patents

Abstract

PURPOSE: To always hold head part support attitude of a pillow at the optimum attitude so as to prevent a whiplash caused by a collision accident. CONSTITUTION: A contact pressure sensor 9 for detecting head part contact pressure is attached on a pillow 3 and a pillow attitude control mechanism 4 always holds the pillow attitude in its optimum one so that contact pressure of a head part of a seated occupant to the pillow 3 is held stable. Or when an impact sensor 14 senses impact caused by collision, a stepping motor 8 is forcedly shifted to a holding mode to fix a pillow attitude so that whiplash accident caused by mismatching between the pillow 3 and the head part is superiorly prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-vehicle headrest device which is capable of suppressing the impact on the neck of an occupant and preventing whiplash when a rear-end collision occurs.

[0002]

2. Description of the Related Art Safety devices such as an airbag and a pretensioner have been put to practical use as an occupant restraint for protecting an occupant from a vehicle collision accident. It is designed to activate the pretensioner. The airbag is inflated or the pretensioner is tensioned, so that the occupant is instantly restrained by the backrest of the seat, and can avoid an injury or a fatal accident due to a pain hitting the interior wall of the vehicle. However,
An occupant restraint such as an airbag or a pretensioner protects an occupant from an impact due to a collision accident that occurs in the front or side, that is, an impact accompanied by deceleration.
The actual situation is that it is not as effective as a backrest of a seat or a pillow of a headrest device against an impact in the acceleration direction from the rear of the vehicle such as a rear-end collision.

As is well known, in order to prevent whiplash which damages the neck when the vehicle is hit by a rear vehicle, the occupant's head should not be left behind due to the impact of the rear impact. It has long been legal to equip a vehicle with a pillow that supports weight as a headrest device. This type of headrest device has a pillow fixed to the upper part of the back of the seat, the height of the pillow can be changed by adjusting the length of the pillar that supports the pillow, and the front of the pillow. In fact, various types have been put into practical use, including those with adjustable tilt angles.

[0004]

In the conventional vehicle-mounted headrest device, the more steps the height of the pillow and the swing angle can be adjusted, the finer the adjustment can be made according to the occupant's body shape, and therefore the higher the safety. It is generally believed that the wider the adjustable range, the more difficult it is to support the head of the occupant comfortably if it is used incorrectly, and the more it tends to be of no use in preventing whiplash in a collision.

For example, like a private car that is often used by a family, a person with a driver's license is seated in the driver's seat, and a person with a bright road geography is seated in the passenger seat. When the seats to be seated on the seats are fixed in the middle, there is no problem in fixing the pillow position of the headrest device provided for each seat to the normal position most suitable for the seated occupant. However, in the case of a vehicle seat in which people of various body types may sit unspecified regardless of age or sex, there is no problem if the person seated in the seat adjusts the pillow posture each time, but rather Since it is rare for people to adjust the pillow posture, even if you are wearing a seat belt in a car equipped with an airbag and if you happen to be riding a car with a seat belt, if you happen to be hit by a succeeding car inadvertently ahead while waiting for a signal, etc. , There is a gap between the head and the pillow, and the head is not properly supported by the pillow, so there is a very high risk of a whipping accident. That is, even if a headrest device with abundant adjustment functions is used, if it is used incorrectly, the original function cannot be exerted, and there is a problem that it may be counterproductive to the prevention of whiplash.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a pillow provided on a seat of a vehicle for supporting the head of a seated occupant and a pillow posture for controlling the posture of the pillow. A control mechanism, provided on the pillow, a contact pressure sensor for detecting head contact pressure of a seated occupant, and provided on the vehicle,
An impact sensor that senses an impact at the time of a rear-end collision with the vehicle;
The pillow posture control mechanism is feedback-controlled so that the output of the contact pressure sensor matches a preset contact pressure reference value, and when the output of the impact sensor exceeds a preset rear impact collision reference value, A controller for fixing the pillow posture controlled by the pillow posture control mechanism is provided.

Further, the present invention provides a pillow posture control mechanism comprising: a pillar for supporting the pillow; a swing shaft for supporting and swinging the pillar; and a stepping motor driven by a command from a controller. And a reduction gear mechanism that is provided between the motor shaft of the stepping motor and the swing shaft and that reduces the rotation of the motor shaft and transmits the reduced rotation to the swing shaft. is there.

[0008]

According to the present invention, the pillow is provided with the contact pressure sensor for detecting the head contact pressure, and the pillow posture control mechanism keeps the pillow in the optimum posture so that the contact pressure of the head of the seated occupant with the pillow becomes constant. By keeping the pillow posture when the impact sensor senses the impact associated with the rear-end collision, the whiplash accident associated with the rear-end collision is reliably prevented.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 is a schematic side view showing an embodiment of an in-vehicle headrest device of the present invention, and FIG.
3 is a schematic front view of the in-vehicle headrest device shown in FIG.
A block configuration diagram of the vehicle-mounted headrest device shown in FIG. 1,
FIG. 4 is a flow chart for explaining the operation of the CPU shown in FIG.

In-vehicle headrest device 1 shown in FIGS.
Is provided on a bucket seat such as a driver's seat or a passenger seat of an automobile, and automatically adjusts the pillow posture according to the sitting posture of a person sitting on the seat 2 and adjusts the pillow posture when a rear-end collision accident occurs. It has the function of instant fixing. Pillow 3
The surface of the core material 3a is covered with a cushion material 3b such as urethane foam, and two pillars 5 of the pillow posture control mechanism 4 are provided.
Supports the core material 3a from below. The pillow posture control mechanism 4
The lower end of the column 5 is fixed to a swing shaft 6 whose both ends are rotatably supported by bearings 6a, and a driven gear 7a fixed to the swing shaft 6 is directly connected to a motor shaft 8a of a stepping motor 8. A value obtained by multiplying the resolution (rotation angle per one step pulse) of the stepping motor 8 by the reduction ratio of the reduction gear mechanism 7 including the drive gear 7b and the driven gear 7a. Is the minimum angle of adjustable pillow position. In the case of the embodiment, the number of teeth of the driven gear 7a is larger than that of the drive gear 7b, so that the rotation of the motor shaft 8a of the stepping motor 8 is decelerated by the reduction gear mechanism 7 and transmitted to the swing shaft 6.

Regarding the connection of the stepping motor 8, in addition to the gear connection method described above, for example, a coupling connection method in which the stepping motor 8 is directly connected to the swing shaft 6, or the motor shaft 8a and the swing shaft 6 are connected via a timing belt. A belt connecting method for connecting, and a clutch-equipped brake connecting method for connecting the swing shaft 6 via a brake mechanism having a built-in clutch are also possible. Further, the stepping motor 8 is, as is well known,
Compared to other motors, etc., it has a very large holding torque when stationary (including when not energized) and does not require a holding mechanism such as an electromagnetic brake. It is particularly convenient. However, since the holding torque obtained by energization is also limited, the maximum static torque, which is the limit value, is greater than the torque exerted on the motor shaft 8a by the inertial force applied to the occupant's head during a rear-end collision via the swing shaft 6. Attention should be paid to the selection of the stepping motor 8 so that it also becomes large. Further, in the embodiment, a four-phase type is used as the stepping motor 8 and is driven by a two-phase excitation method in which two phases are always energized to enhance the braking effect during operation. It is also possible to drive by another excitation method such as 1-2 phase excitation.

A contact pressure sensor 9 is embedded in the front surface of the pillow 3, that is, the head contact surface, and the head contact pressure of the occupant detected by the contact pressure sensor 9 is supplied to the controller 10. As shown in FIG. 3, the controller 10 A / D-converts the head contact pressure supplied from the contact pressure sensor 9 with the AD converter 11, and converts the converted digital data to the CPU.
Send to 12. The CPU 12 compares the input head contact pressure with a contact pressure reference value preset according to a predetermined operation program, and feedback-controls the pillow posture so that the head contact pressure matches this contact pressure reference value. CPU12
The control output of is applied to the stepping motor 8 as a required number of step pulses from the motor drive circuit 13, and the pillow posture is controlled to tilt forward or backward so that the head contact pressure matches the contact pressure reference value.

By the way, an impact sensor 14 for detecting the acceleration generated when the vehicle undergoes a rear-end collision is arranged in the passenger compartment near the seat 2, and the output of the impact sensor 14 is also AD.
It is supplied to the CPU 12 in the controller 10 via the converter 11. The CPU 12 compares the magnitude of the impact sent from the impact sensor 14 with a preset rear impact impact reference value, and when the impact exceeding the rear impact impact reference value occurs, the stepping motor 8 is forced to the holding mode. To do.
The stepping motor 8 forced into the holding mode keeps the pillow 3 in the angular posture immediately before the rear-end collision by fixing the excitation phase, which causes whiplash when the occupant is strongly pulled backward with the rear-end collision. The danger of reaching is eliminated.

Specifically, the CPU 12 executes the posture control of the pillow 3 according to the flowchart shown in FIG. First, in step (101) shown in the figure, the output of the contact pressure sensor 9 is AD-converted, and the subsequent step (10
In 2), it is taken into the CPU 12 and compared with a preset contact pressure reference value in a judgment step (103). As a result of the comparison, when it is determined that the contact pressure exerted on the pillow 3 by the occupant exceeds the contact pressure reference value, it is because the occupant leans his head strongly backward, so that in the following step (104). , CPU 12 issues a motor reverse rotation command. The motor drive circuit 13, which receives the motor reverse command,
A step pulse for exciting the stepping motor 8 in the reverse direction is applied, whereby the stepping motor 8 is driven in reverse. On the other hand, on the contrary, the contact pressure sensor 9
If the contact pressure detected by the CPU does not reach the contact pressure reference value, it is because the occupant leans his head forward and there is a gap with the pillow 3. Therefore, in step (105), the CPU 1
2 issues a motor forward rotation command. The motor drive circuit 13, which receives the motor forward rotation command, applies a step pulse for exciting the stepping motor 8 in the forward rotation direction, whereby the stepping motor 8 is normally driven.

The forward / reverse rotation command from the CPU 12 to the stepping motor 8 is given in step (10) described later.
6) to (108) and returning to step (101) again, the feedback loop is repeatedly executed as long as it functions, and finally the output of the contact pressure sensor 9 must be settled to the optimum pillow posture that matches the contact pressure reference value. become. However,
When the contact pressure changes because the occupant changes his / her seating posture, the feedback control function that sets the contact pressure reference value as a target works again, and the pillow posture follows the optimum posture at that time.

The CPU 12, which has issued the control command to the stepping motor 8 in this way, proceeds to the next step (106).
At, the AD conversion of the output of the impact sensor 14 is commanded, and in step (107), the output of the impact sensor 14 is fetched from the AD converter 11. The output of the impact sensor 14 is
It is compared with a preset rear impact reference value in the CPU 12, and processing is performed according to the determination result in step (108). That is, when it is determined that the magnitude of the impact force detected by the impact sensor 14 is equal to or smaller than the rear impact collision reference value, it is determined that the rear impact has not been received and the pillow posture control as before is continued. The process returns from step (108) to step (101). On the other hand, the impact sensor 14
When it is determined that the magnitude of the impact force detected by the vehicle exceeds the collision impact reference value, it is clear that a collision has occurred, and therefore the CPU 12 immediately proceeds to step (109) and holds the stepping motor 8. Force into mode. As a result, the excitation phase of the stepping motor 8 is fixed, and the rotation phase immediately before the rear-end collision is fixed. At this time, the motor shaft 8a does not inadvertently rotate with respect to the impact torque equal to or less than the maximum static torque, and the pillow posture is fixed to the optimum posture immediately before the rear-end collision.

For this reason, even when an acceleration that pushes the occupant from the back acts due to an impact from the rear of the vehicle, the occupant not only makes the back adhere to the backrest but also makes the head adhere to the pillow 3. It is possible to move forward as it is, and it is possible to satisfactorily eliminate the risk that the occupant may get whiplash due to the incomplete supporting posture with a gap between the pillow and the occupant's head as in the past. be able to.

Thus, the in-vehicle headrest device 1 described above
According to the contact pressure sensor 9 for detecting head contact pressure on the pillow 3.
The pillow posture control mechanism 4 always maintains the pillow posture in the optimum posture so that the contact pressure of the head of the seated occupant on the pillow 3 becomes constant, and the pillow posture is detected when the impact sensor 14 senses the impact caused by the rear-end collision. Since it is configured to be fixed, it is possible to reliably prevent whiplash caused by the mismatch between the pillow 3 and the head when a rear-end collision occurs. Also, the stepping motor 8
Since the forward leaning posture of the pillow can be adjusted with an accuracy obtained by multiplying the resolution of 1 to the reduction ratio of the reduction gear mechanism 7, the pillow 3 can be applied to the head with the optimum contact pressure for the seated occupant, and the rear impact Since the stepping motor 8 is immediately forced into the holding mode at the time of occurrence of the impact, even if the impact torque less than the maximum static torque acts on the motor shaft 8a due to the impact at the time of the rear impact, the pillow 3 is set to the optimum posture immediately before the rear impact. It can be maintained and can reliably prevent whiplash.

In the above-described embodiment, the pillow posture control mechanism 4 may have a structure in which a driving means other than the stepping motor 8, for example, a piston cylinder mechanism or the like is used as a power source. Other configurations may be used. Further, in the embodiment, the angle posture of the pillow 3 is fixed by switching the stepping motor 8 to the holding mode, but in addition to this, for example, a lock pin (not shown) is incorporated in the backrest of the seat 2, When the rear-end collision occurs, the lock pin may be protruded to hold the angular posture of the pillow 3 in the immediately previous posture, and the stepping motor in the holding mode and the locking by the lock pin are combined. Is also possible.

Further, in the above embodiment, the pillow 3 is constructed so that only the swing adjustment around the swing shaft 6 is possible.
It is also possible to construct the structure so that it can be expanded and contracted in several stages, and the height of the pillow 3 can be automatically and optimally adjusted according to the height of the head of the seated occupant. Further, in the above-described embodiment, the impact sensor 14 is arranged near the seat in the vehicle interior, but the impact sensor 14 can be arranged at any place inside and outside the vehicle interior, so that the impact for the airbag and the pretensioner can be reduced. It is also possible to use the sensor for prevention of whiplash.

[0021]

As described above, according to the present invention,
The pillow is equipped with a contact pressure sensor that detects the head contact pressure, the pillow posture control mechanism keeps the pillow in an optimum posture so that the contact pressure of the head of the seated occupant against the pillow is constant, and the impact sensor accompanies the rear-end collision. Since the pillow posture is fixed when the impact is detected, the pillow posture control mechanism can always apply the pillow to the head with the optimum contact pressure for the seated occupant, which causes a rear impact. Occasionally, whiplash accidents caused by inconsistencies between the pillow and the head can be minimized, and there is a gap between the pillow and the head of the occupant or a supporting posture of the pillow as in the conventional headrest device. Since the head has a hit on the pillow due to the impact at the time of a rear-end collision, it is possible to surely eliminate the inconvenience that the neck is hurt or whiplash is caused.

Further, according to the present invention, a pillow posture control mechanism includes a pillar for supporting the pillow, a swing shaft for supporting and swinging the pillar, a stepping motor driven by a command from a controller, Since the reduction gear mechanism is provided between the motor shaft of the stepping motor and the swing shaft and configured to reduce the rotation of the motor shaft and transmit the rotation to the swing shaft, the reduction gear has the resolution of the stepping motor. The forward tilting posture of the pillow can be adjusted with the accuracy multiplied by the reduction ratio of the mechanism, so that the head can always be applied to the seat occupant with the optimum contact pressure, and the stepping motor can be used when a rear-end collision occurs. By switching to the holding mode, it is possible to maintain the pillow in the optimum posture immediately before the rear impact even if the impact torque below the maximum static torque acts on the motor shaft due to the impact during the rear impact. Disease is an effect of the like can be reliably prevented.

[Brief description of drawings]

FIG. 1 is a schematic side view showing an embodiment of an in-vehicle headrest device of the present invention.

FIG. 2 is a schematic front view of the vehicle headrest device shown in FIG.

3 is a block diagram of the vehicle headrest device shown in FIG. 1. FIG.

FIG. 4 is a flowchart for explaining the operation of the CPU shown in FIG.

[Explanation of symbols]

 1 In-vehicle headrest device 2 Seat 3 Pillow 4 Pillow posture control mechanism 5 Strut 6 Swing shaft 7 Reduction gear mechanism 8 Stepping motor 9 Contact pressure sensor 10 Controller 11 AD converter 12 CPU 13 Motor drive circuit 14 Impact sensor

Claims (2)

[Claims] 1. A pillow provided on a seat of a vehicle for supporting the head of a seated occupant, a pillow posture control mechanism for controlling the posture of the pillow, and a head contact of a seated occupant provided on the pillow. A contact pressure sensor for detecting pressure, an impact sensor provided on the vehicle for detecting an impact at the time of a rear-end collision with the vehicle, and the pillow so that the output of the contact pressure sensor matches a preset contact pressure reference value. A controller for feedback controlling the posture control mechanism and for fixing the pillow posture controlled by the pillow posture control mechanism when the output of the impact sensor exceeds a preset rear impact collision reference value. In-vehicle headrest device. 2. The pillow posture control mechanism, a pillar that supports the pillow, a swing shaft that supports and swings the pillar, a stepping motor that is driven in response to a command from a controller, and the stepping motor. The vehicle-mounted headrest according to claim 1, further comprising: a reduction gear mechanism that is provided between the motor shaft of the motor and the swing shaft and that reduces the rotation of the motor shaft and transmits the rotation to the swing shaft. apparatus.