DE102008052953A1 - Crash-active headrest positioning method for seat of motor vehicle, involves moving headrest to stand-by position that is temporally upstream of crash position, between comfort position and crash position - Google Patents

Abstract

The method involves determining a time period until a rear end sided collision, using a calculating unit. A crash-active headrest (14) is moved from a comfort position (P1) to a crash position (P3), when the determined time period falls below a threshold value. The headrest is moved to a stand-by position (P2) that is temporally upstream of the crash position, between the comfort position and the crash position. The headrest is moved to the stand-by position, when the time period falls below another threshold value.

Description

The The invention relates to a method for positioning a crash-active Headrest according to the preamble of claim 1 as well as a crash-active headrest with a safety system for anticipatory recognition of a rear impact according to the preamble of claim 11.

In Today's vehicles are often set up security systems, the protection of the occupants in case of a collision are directed. In addition to the widespread airbag systems have Recently, more systems entering the vehicles so, too, some who are in the run-up to an approaching crash risk to be activated.

So Security systems are known, the crash-active headrests have, for example, by a spring mechanism or a pyrotechnic device from a normal position in one Crash position to be brought before a predicted crash accident. The triggering can be done by a crash detection by radar, Ultrasonic, video or other distance sensors in the pre-crash case. This type of headrest systems is irreversible or only partially reversible. That means that these headrests exchanged after a possibly misleading use or have to be reactivated by a workshop, which Time and cost means.

One Another approach is electromechanically movable headrests to use, the z. B. by means of electric motors or electromagnets can be adjusted as often as desired in different positions. These actuators can normally allow the driver to a suitable position for the headrest adjust. In addition, this form can be The actuators also use in a pre-crash case to an inmate better to protect. The approach of the crash position can although compared to the normal setting with a higher speed but is generally much slower than the first mentioned spring or pyrotechnically operated headrests. The also means that a precrash trip earlier must be made before the possible accident, which, however, to false tripping can lead. The headrest then moves forward, although in fact no accident happened and thereby causes a nuisance to the occupant.

The Activation of the movement of the headrest usually takes place by the determination of a so-called time-to-collision (TTC), d. H. a period of time until the collision. There are There are different calculation methods used to determine the time becomes, with which it possibly comes to a crash. falls below the calculated TTC a predetermined or predeterminable threshold, so an action is executed. If z. B. the headrest 1 s needed to move from the rearmost to the foremost position For example, the time threshold for the TTC should be set to t1 = 1 s to guarantee that the headrest in the event of a rear impact actually in time in their forward position located. This provides a speed-dependent design in the simplest case, by determination and evaluation the distance to the following vehicle and for example the Airspeed of the vehicle already a useful increase in safety is reachable.

In the activated front crash position touches the headrest already the neck of the occupant or is at a small distance from him, so if a rear-side impact by a colliding Vehicle is made, the head of the occupant due to inertia only cover a very short or no way until he is caught by the headrest. hereby also the rebound of the head of the occupant as a result of suspension the headrest is lower and the movement of the head generally less violent. In extreme situations, this technique prevents Damage to the cervical spine, despite a conventional headrest can occur.

DE 20 2006 005 357 U1 discloses a crash-activated headrest which is driven by a spring or pneumatically or otherwise, which is triggered by mechanical destruction of a tether. The mechanically destroyed part must be replaced if, as so often a false triggering has taken place, whereby a time and cost arises.

DE 10 2005 051 423 B3 discloses a crash-activated headrest that is powered by an electromagnet.

DE 10 2004 035 582 B3 discloses a crash-active headrest, which is driven by a spring mechanism and a plurality of so-called comfort positions or normal settings and a plurality of crash positions of the headrest, which are occupied by Einrastsperren. DE 10 2005 033 344 B3 describes a crash-active headrest, which is a blocking of the in DE 10 2004 035 582 B3 revealed several head rest positions effected.

The The object of the invention is a crash-active headrest on the one hand, the number of false trips are reduced and on the other hand the annoyance of the occupants by the activated headrest are minimized.

The The object is solved by the features of claim 1 or 11 Preferred embodiments of the invention are in the subclaims disclosed.

According to the Characteristic part of claim 1, the headrest upon detection of a dangerous situation in one, between the comfort position and the crash position in the standby position, which is ahead of the crash position. In this way Can the headrest already in advance of dangerous situations be moved to the standby position, causing the vehicle occupants an additional sense of security potentially dangerous situations. In the standby position The headrest can be at a short distance to its crash position be prepositioned. Due to the reduced adjustment path to The crash position can only be done immediately before the crash the headrest is adjusted to the crash position, which reduces false triggering of the headrest are.

For monitoring A dangerous situation can be the time course of a collision warning parameter be recorded. Such a collision warning parameter is common the time to a rear-end collision, the can be determined by means of a calculation unit. Alternatively, you can the collision warning parameter of the distance following vehicle or be the speed difference to the following vehicle.

Usually is determined as a collision warning parameter, the time course of the determined Duration determined until the rear impact. Unless the time period determined falls below a first threshold, the headrest adjusted from a comfort position to the crash position. According to the invention a second threshold is provided, the larger as the first threshold for triggering the crash position. According to the invention, the headrest in the standby position are moved when the determined period of time until the rear impact falls below the second threshold and is still above the first threshold.

at the following description of the developments of the invention For the sake of simplicity, the collision warning parameter is the determined time duration used until the rear impact. Instead, you can with appropriate system design also the distance or the speed difference to the following vehicle used as Kollisionswarnparameter become.

According to one preferred embodiment of the method according to the present invention a pusher detection can be performed, where the frequency with which the determined time period is determined until impact, the second threshold within a predetermined Drainage time lapse. The frequency is compared with a predetermined or predefinable number threshold. The jammer recognition can also be carried out in this way will even be recognized, whether they are of "the same Vehicle is caused, as below a certain Time span and given driving speeds it physically impossible is that the multiple underruns of predetermined thresholds triggered by different vehicles can be. This can be determined with certainty because vehicles have a considerable mass and thus have inertia which is too fast Replacement of the tugboat vehicle excludes.

If a grommet is detected, the headrest can preferably moved to the ready position and while in it be maintained until the plumbing detection no drainage recognizes more, with a minimum holding time of the headrest in the standby position of the system is present and / or predetermined becomes. The driver can therefore with the automatic operation the headrest perceive a drain.

at a further preferred embodiment of the invention Procedure is the movement of the headrest from the comfort position to Standby position at an intrinsic speed of the vehicle up to 10 km / h, more preferably 16 km / h, or disabled up to 20 km / h. At speeds below 10 km / h, more preferably 16 km / h, or more preferably up to 20 km / h is an activation of the ready position unnecessary, since even a conventional system sufficient Security granted.

The Movement of the headrest from the comfort position to the ready position is further preferably at an intrinsic speed of the vehicle deactivated from 80 ± 5 km / h. At such speeds moves the adjusting movement of the headrest into the Background due to problems in driving stability after a collision.

The headrest according to another preferred embodiment of the present invention from the comfort position to the standby position with a reduced positioning speed, from the standby position to the crash position with a maximum positioning speed, and / or detection of a particularly critical pre-crash situation from the normal position moved directly to the crash position at maximum speed. Thus, less annoyance of the occupant arises when the standby position is approached slower. On the other hand, the crash position at high speed and over achieved a shortened distance, so that the adjustment time of the headrest shortened and safety is increased.

It is also advantageous if the headrest after a Positioning in the crash position and after a predetermined or predetermined holding time, preferably about 3 Seconds is moved to the ready position if no collision registered has been.

In preferred embodiments of the invention For example, the method becomes the first crash period to approximately 0.5 second and the second pre-crash time to about 1.5 seconds dialed. This will cause false alarms with the consequence of the positioning of the headrest in the Crash position reduced as this is due to the center-mounted standby position be intercepted.

in the Sense of an optimal adaptation of the invention Procedure to different vehicles or applications may be the standby position between the comfort position and the crash position in one of the center position deviating position range of ± 30%.

The Safety system of the crash-active headrest has a Calculation unit for determining the time course of a Kollisionswarnparameters on, in particular the period up to a possible rear impact. The temporal course of this Time duration is in a comparison unit with a first and second Threshold compared. Falls below / exceeds the Collision parameter the first threshold, so adjusted the security system the headrest in the crash position. Is the time course between the second and the first threshold, The safety system adjusts the headrest to the ready position.

The Invention will be described below in embodiments explained a single drawing. Show it:

1 a schematic side view of a vehicle seat with a headrest and control sequence according to the invention;

2 temporal course of time until a rear impact, and

3 Time course of time TTC at a drainage

In the 1 illustrated schematic side view of a vehicle seat with a headrest according to the invention 14 shows a preferred embodiment of the present invention and a control flow.

The headrest 14 is on a scaffold in one of the conventional ways 13 preferably adjustable in height and / or inclination on a seat back 12 of the vehicle seat 10 arranged. The motor vehicle seat 10 also has a conventional seat 11 on.

The headrest 14 According to the invention can be arranged in the three positions P1, P2 and P3. For this purpose, preferably (not shown) electric drive is used, which is set up for example inside the headrest. It can be realized with an electric motor and a gear or by an electromagnet and makes it possible to position the headrest in each of the positions and back.

The Position P1 is the normal position and position P3 is the crash position the headrest, which also has a conventional system. According to the invention, at least one between the Normal position P1 and the crash position P3 selected and / or selectable standby position P2 set up. Preferably is this ready position P2 in the middle between P1 and P2, but may deviate from the center, for the respective application optimized position in a position range occupy, which differs from the center preferably by ± 30%.

The standby position P2 according to the invention Headrest is anticipating when detecting an earlier taken on the one hand to get along with a gentler movement, and, on the other hand, if finally aggravated by another Danger event the crash position with maximum positioning speed to be approached, also this movement faster and gentler can go on.

Above the vehicle seat 10 is a schematic embodiment of the control of the security system 15 shown. Hereby receives a calculation unit 17 for determining the time duration TTC up to a possible rear impact, a number of sensor signals 16 ,

After an occurrence of a TTC signal, the triggering event associated TTC value in the calculation unit 17 determined and to a comparison unit 19 to hand over. The comparison unit 19 preferably performs two comparisons in parallel I and II by.

Compared I is determined whether TTC between a first threshold SW1 and a second threshold SW2 within a period of time between t1 and t2. If it is not, there is no potential crash and it will therefore return to the calculation unit 17 branches, constantly constantly the emerging sensor signals 16 evaluates.

However, if the result of this comparison I positive, it means that there is a potential pre-crash case and it generates a ready signal S _B , the further to a drive 21 the headrest 14 is directed, which is then positioned in the ready position P2.

In a parallel to I ongoing comparison II a query is made as to whether the current determined TTC value is equal to or less than the first threshold value SW1 of the TTC. If this is not the case, there will be no signal output and it will be returned to the calculation unit 17 branched.

However, if the result of this comparison II positive, it means that there is a potential crash case and it will generate a crash signal S _C , the further to the drive 21 the headrest 14 is directed, which is then positioned in the crash position P3.

Should no crash event have occurred after a period of time and the calculation unit 17 return TTC values for both comparisons I and II give negative results, the respective Yes signal is withdrawn, which leads to the headrest 14 is moved from the previously taken position P2 or P3 back to the position P1 or P2.

2 shows a time course of time TTC up to a potential rear impact.

If, at the time t1, the longer threshold value SW2 has been undershot, a standby signal S _{B is} generated which causes the headrest 14 is moved to the ready position P2.

If the TTC value reaches or falls below the first threshold value SW1 at a later point in time t2 as a result of a further increasing traffic situation, a crash signal S _{C is} generated, which leads to the head restraint 14 in the crash position P2 is moved.

3 shows a time course of the time TTC at a detected slammer.

Within a predetermined and / or predefinable time interval Δtd after a first triggering of the ready signal S _B , the threshold value SW2 is exceeded several times. If the number of these exceedances reaches or exceeds a predetermined and / or predefinable number threshold Nmax, then a pusher is detected. As a response, in preferred embodiments, it may be evaluated for the length of stay of the headrest 14 is maintained in the ready position P2 for a predetermined or predetermined minimum holding time t4.

10

Automotive seat

11

seat

12

seatback

13

scaffold

14

headrest

15

Security system

16

sensor signals

17

calculation unit for determining the time TTC until a possible rear impact

19

comparing unit

21

Drive the headrest 14

a1

minimal Distance, first distance value

a2

second distance value

n

number the underruns

nmax

Anzahlschwellwert

P1

normal position

P2

stand-by position

P3

Crash Position

S _B

ready signal

S _C

Crash signal

SW1

first threshold

SW2

second threshold

t1

(first) Crash time

t2

second Vorcrash-time

t3

hold time

t4

hold time

Δtd

Tailgaters-time

TTC

Time-to-collision, Time to a rear impact

V1

maximum Positioning velocity

V2

comfortable Positioning velocity

I

time Course of time until a rear impact, first comparison

II

time Course of the time period TTC for a spud, second comparison

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 202006005357 U1 [0007]
• DE 102005051423 B3 [0008]
• - DE 102004035582 B3 [0009, 0009]
• - DE 102005033344 B3 [0009]

Claims (11)

Method for positioning a crash-active headrest ( 14 ) of a vehicle seat ( 10 ) of a motor vehicle with a safety system for the anticipatory recognition of a rear impact, wherein a calculation unit determines a time duration (TTC) until the rear impact and the headrest ( 14 ) is moved from a comfort position (P1) to a crash position (P3) when the determined time duration (TTC) falls below a first threshold value (SW1), characterized in that the headrest ( 14 ) in at least one, the crash position (P3) temporally upstream standby position (P2) between the comfort position (P1) and the crash position (P3) is moved. Method according to claim 1, characterized in that that at least a second threshold value (SW2) is provided, the is greater than the first threshold (SW1), and the headrest is moved to the ready position (P2), if the determined time duration (TTC) the second threshold (SW2) below. A method according to claim 2, characterized in that a plumbing detection is carried out, in which the frequency (n) is determined, with which the determined time duration (TTC) within a predetermined drainer time period (td) falls below the second threshold (SW2), and the frequency (n) is compared with a driver threshold (n _max ). Method according to claim 3, characterized that when a jam is detected, the headrest as long as in the standby position (P2) is held until the Damper detection no longer recognizes drainage. Method according to one of the preceding claims, characterized in that the movement of the headrest ( 14 ) is deactivated from the comfort position (P1) to the standby position (P2) at an intrinsic vehicle speed of up to 10 km / h, more preferably up to 16 km / h, or up to 20 km / h. Method according to one of the preceding claims, characterized in that the movement of the headrest ( 14 ) is deactivated from the comfort position (P1) to the ready position (P2) at an intrinsic speed of the vehicle from 80 ± 5 km / h. Method according to one of the preceding claims, characterized in that the headrest ( 14 ) from the comfort position (P1) to the standby position (P2) at a reduced positioning speed (V2), from the standby position (P2) to the crash position (P3) at a maximum positioning speed (V1), and / or upon detection a particularly critical pre-crash situation from the normal position (P1) is moved directly to the crash position (P3) with the maximum speed (V1). Method according to one of the preceding claims, characterized in that the headrest ( 14 ) after positioning in the standby position (P2) and after a predetermined or predeterminable holding time (t3), preferably of about 3 seconds when no collision has been registered, is moved to the comfort position (P1). Method according to one of the preceding claims, characterized in that the first threshold (SW1) at approx. 0.5 seconds and / or the second threshold (SW2) is about 1.5 seconds. Method according to one of the preceding claims, characterized in that the at least one standby position (P2) between the comfort position (P1) and the crash position (P3) in a position range deviating from the center position of ± 30% lies. Crash-active headrest with a safety system by means of which the headrest is adjustable from a comfort position (P1) to a crash position (P3) in the event of an impending rear impact, which safety system has a calculation unit for determining a collision warning parameter, in particular a time duration (TTC). up to a possible rear impact, and has a comparison unit in which the collision warning parameter is comparable to a first threshold value (SW1), and when the first threshold value (SW1) is undershot, the safety system blocks the headrest (FIG. 14 ) in the crash position (P3), characterized in that the headrest ( 14 ) by means of the safety system in one of the crash position (P3) temporally upstream standby position (P2) is adjustable.