FR2783476A1 - Spooling reel for vehicle seat belt comprises numerical recorder driven through hypocycloidal reducer that determines length of seat belt that is unrolled - Google Patents

Abstract

The spooling reel has a support armature (2) inside which a bobbin (3) is arranged that carries the seat belt (4). A numerical positional recorder is used to determine the length of seat belt that is unrolled from the bobbin. A moving section (10) passes through a hypocycloidal reducer that comprises of a pinion (6) in a fixed toothed crown wheel (7). An arrangement is provided to turn the pinion a single turn for a number of turns of the bobbin that corresponds to the complete unreeling of the seat belt. The pinion includes a coupling to the moving section of the positional recorder.

Description

'0 2783476

  The present invention relates to a belt strap winder

  motor vehicle security.

  More particularly, the invention relates to a reel of this type which comprises a support frame in which is disposed a reel for receiving the strap, associated with safety locking means and with

  means for returning the latter to the position for winding the strap.

  Such seat belt strap retractors participate in the

  safety of the occupants of a vehicle in the same way as for example

  the airbag or retractable steering columns, etc ...

  However, and generally speaking, all of these security systems are

  designed to provide optimal protection for a user with mor-

so-called standard phology.

  However, all the potential users of a vehicle do not have this standard morphology and it is understandable that this can have a certain number of drawbacks because the operation of the safety means is then not adapted to these users, which may have adverse safety effects

on board the vehicle.

  Systems have therefore been developed in the state of the art which make it possible to adapt the operation of the on-board security means to the

morphology of each user.

  Such systems then include, for example, user weight sensors or means making it possible to locate the user's head.

in the passenger compartment of the vehicle.

  The length of the unwound seat belt strap is also

  a parameter allowing to define the presence and the morphology of a user.

  However, measuring this unwound length is relatively difficult.

  The object of the invention is therefore to solve these problems.

  To this end, the subject of the invention is a belt strap winder

  for a motor vehicle, of the type comprising a support frame

  port in which is disposed a coil for receiving the strap, associated with safety blocking means and with elastic means for returning the latter to the strap winding position, characterized in that it comprises means determining the length of the unwound strap, comprising a

  digital absolute position sensor on one turn of the coil, fitted with a

  fixed position and a movable portion associated with this coil through hypocycloidal reduction means, comprising a pinion disposed in a fixed toothed crown and biased into engagement with a portion thereof by support means associated with the coil to move along this ring gear during the rotation of the coil, and having a reduction ratio

  determined to bring this pinion, when moving along the cou-

  toothed ronne, to turn on itself by one turn for a number of turns of the

  reel corresponding to the complete unwinding of the strap and in that the pi-

  gnon comprises means for coupling in rotation to the mobile portion of the sensor.

  The invention will be better understood with the aid of the description which follows.

  vre, given only by way of example and made with reference to the drawings an-

attached, on which:

  - Fig.1 shows a block diagram illustrating the general structure

  line of a strap winder according to the invention;

  - Fig.2 shows a sectional view of a portion of such a winding-

  their; and - Fig.3 shows a side view of such a reel, illustrating the

  structure of the means of reduction entering into the constitution of this one.

  There is shown in Figure 1, a belt strap winder

  motor vehicle safety, designated by the general reference 1.

  This strap winder generally comprises a support frame designated by the general reference 2, in which a

  reel for receiving the strap, the reel being designated by the reference ge-

  3 and the strap with the general reference 4.

  Conventionally, this coil is associated with blocking means

  safety cage and elastic return means thereof in position

strap winding.

  These means being well known in the state of the art, they are not

  will not describe in more detail later.

  According to the invention, this reel also comprises means for

  determination of the length of the unwound strap, designated by the reference ge-

  neral 5 in this figure, comprising a digital absolute position sensor on a revolution, of the coil, provided with a fixed portion and an associated movable portion

  to this coil through hypocycloidal reduction means.

  In fact, and as shown in FIGS. 2 and 3, these reduction means comprise a pinion designated by the general reference 6, placed in a fixed toothed crown 7 and biased into engagement with a portion thereof by means support associated with the coil and designated by the general reference 8 to move along this ring gear 7 during

of the coil rotation.

  These reduction means also have a reduction ratio.

  tion determined to bring this pinion 6 during its movement along the ring gear 7, to turn on itself by one turn for a number of turns of

  the reel 3 corresponding to the complete unwinding of the strap.

  In addition, the pinion 6 comprises means for coupling in rotation.

to the movable portion of the sensor.

  In these figures, these coupling means are designated by the

  general reference 9, the movable portion of the sensor being designated by the reference

General reference 10.

  This mobile sensor portion comprises for example support means designated by the general reference 11, of a coded track designated by the general reference 12 movable opposite a fixed sensor portion (not shown). As an example of this digital absolute position sensor on a lathe, reference may be made to document FR-A-2 722 352 in the name

of the Applicant.

  In the embodiment shown in these figures, the support means 8 associated with the coil 3 may for example include a suitable pin

  to cooperate with an internal contact track of the pinion 6, this contact track

  tact being designated by the general reference 13.

  The pin 8 can for example be fixed in one way or another or come from molding with a support and drive part, such as the part 14 associated with the coil in one way or another. to shoot with

  this, during the winding / unwinding of the strap.

  During the rotation of the coil, the pin 8 then moves along the toothed ring 7, to cause the pinion 6 disposed in this toothed ring eccentrically, to move along this toothed ring in

meshing with it.

  The reduction ratio used between the pinion and the ring gear

  then allows as has been indicated previously, to rotate on itself-

  even the pinion 6, one turn, for a number of turns of the corresponding coil

  due to a complete unwinding of the strap.

  This number of turns of the reel corresponding to the unwinding

  strap full may for example be twelve.

  During this movement, the pinion 6 and more particularly the

  coupling means 9 interposed between it and the movable portion of the cap

  tor, drives it in rotation.

  These coupling means 9 may for example comprise a pin integral with the pinion 6, this pin being designated by the general reference 15 and being adapted to cooperate with a displacement groove 16

  thereof, provided in the movable portion 10 of the sensor.

  Advantageously, this groove is curved as can be seen on

Figure 3.

  The whole of this sensor can then be arranged for example in

  a housing designated by the general reference 17 in these figures, this housing

  carrying for example an integrated connector designated by the general reference 18

in figure 1.

  For example, the toothed crown 7 can have 36 teeth and the

pinion 6, 33 teeth.

  The angular pitch of the ring gear 7 is then 10 (360: 36).

  The rotational difference for one turn of the pinion 6 in the ring gear 7 is then 3 teeth (36 - 33), which represents a differential angular difference of 300 (3 x). Thus, the coil 3 must perform 12 turns (360: 30) to obtain a complete revolution of the pinion 6 on itself and therefore of the movable portion in rotation of the

sensor.

  This sensor being a digital absolute position sensor on a revolution of the coil, it is understood that whatever the conditions of use thereof, it delivers information relating to the rotation of the coil and therefore to

  the length of the strap unwound, without the need for reinitialization or the like.

  It goes without saying of course that still other embodiments

  of such a reel can be considered.

Claims (5)

  1. Seat belt strap retractor for motor vehicle   bile, of the type comprising a support frame (2) in which is disposed a coil (3) for receiving the strap (4), associated with safety locking means and with elastic return means of the latter in winding position   Lement of the strap, characterized in that it comprises means of determina-   tion of the length of the strap unwound, comprising a digital absolute position sensor on one revolution, of the spool (3), provided with a fixed portion and with a movable portion (10) associated with this spool by means of hypocycloid reduction, comprising a pinion (6) arranged in a fixed toothed crown (7) and biased into engagement with a portion thereof by support means (8) associated with the coil to move along this crown   toothed (7) during the rotation of the coil (3), and having a reduction ratio   tion determined to bring this pinion (6), during its movement along the ring gear (7), to rotate on itself by one turn for a number of turns of the coil (3) corresponding to the complete course of the strap and in that   that the pinion (6) comprises means for rotationally coupling (9) to the door mobile sensor (10).   2. System according to claim 1, characterized in that the support means associated with the coil comprise a pin (8) adapted to cooperate with   an internal contact track (13) of the pinion (6).   3. System according to claim 1 or 2, characterized in that the means for rotating coupling (9) of the pinion (6) and the movable portion (10) of the sensor comprise on the one hand, a pin (15) and on the other hand, a groove (16) displacement of it.   4. System according to claim 3, characterized in that the groove is curved.   5. System according to claim 3 or 4, characterized in that the pin (15) is associated with the pinion (6), while the groove (16) is formed in the movable portion (10) of the sensor.