DE102008004127A1 - Seat belt retractor, has overload clutch formed such that clutch is uncoupled during overload, in particular during exceeding of preset belt extraction force acting in belt band extraction direction, and arranged between belt coil and gear - Google Patents

Abstract

The retractor (10) has a belt coil (20) for winding and unwinding a seat belt and a gear (80) connected with the belt coil. A drive is connected with the gear and drives the belt coil for winding the seat belt. A positively operating overload clutch (50) is provided between the drive and the belt coil and is formed such that the clutch is uncoupled during overload, in particular during exceeding of a preset belt extraction force acting in a belt band extraction direction based upon a coupled condition in a form closure. The overload clutch is arranged between the belt coil and the gear.

Description

The The invention relates to a belt retractor with the features according to the preamble of claim 1.

Such a belt retractor is from the German patent application DE 10 2004 045 452 known. This prior art belt retractor comprises a belt spool for winding and unwinding a seat belt, a transmission associated with the belt spool and a drive connected to the transmission which can drive the belt spool to wind up the seat belt. At the interface between the transmission and the belt spindle, the transmission has a pawl coupling with which the transmission can be coupled with the belt spindle for the purpose of transmitting power. The pawl clutch comprises two pawls, which engage in the engaged state in a toothing of the belt spindle and are otherwise separated from this. Such a coupling for establishing a connection between the gear and the belt spindle or for separating such a connection is hereinafter referred to as "operating clutch". In addition, the transmission of the previously known belt retractor on a form-fitting based overload clutch; This overload clutch separates transmission parts from each other and interrupts the transmission of power within the transmission when excessive forces act in Gurtabwickelrichtung, for example, if in the event of an accident, the vehicle occupant due mass inertia immersed in the seat belt. The overload clutch is arranged in the transmission - as viewed from the power flow - between the operating clutch and the drive.

outgoing from the described prior art, the invention is the Task is to provide a belt retractor, which is an even better Adjustability of the belt force level in the event of a vehicle accident, a critical driving maneuver or an emergency braking situation allows and at the same time even more cost-effective as previous belt retractor can be produced.

These Task is starting from a belt retractor of the type described above Type according to the invention by the characterizing Characteristics of claim 1 solved. Advantageous embodiments the belt retractor according to the invention are in subclaims specified.

After that is inventively provided that the form-fitting working overload clutch between the belt spindle and the transmission is arranged.

One significant advantage of the belt retractor according to the invention is to be seen in that in this the overload clutch outside the gearbox and directly on the belt spindle is arranged, whereby it is achieved that in the event of an overload situation none of the parts of the transmission must be load bearing. As soon as an overload situation occurs, the overload clutch disengage and disconnect the belt spindle from the gearbox so that damage are excluded on the transmission in any case. It is thus at the belt retractor according to the invention - im Difference for example to the belt retractor described above - not required the operating clutch, the connection in the engaged state between belt reel and drive provides "load-bearing" for an overload situation perform. The transmission of the invention Belt retractor can thus be made kos tengünstiger and also may be lighter than previously known transmission Belt retractor, because - as already explained - none the components of the transmission survive an overload situation must be able to.

One Another significant advantage of the invention Belt retractor is the fact that in this the Gurtrückhaltekraft solely by means of belt force limiting means provided for this purpose, such as B. by a torsion bar, is determined and a Kraftniveauverfälschung by a partly mitdrehendes transmission, such as a co-rotating Operating clutch, is prevented, because all gear parts, in particular an operating clutch, provided by the inventively provided Arrangement of the overload clutch in case of overload be decoupled reliably.

Preferably is in the belt retractor additionally an operating clutch - such as this in the previously described prior art belt retractor Fall is present, which at a commissioning of the Actuator engages and thereby a power transmission between the drive and the belt reel manufactures. Such an operating clutch For example, it can be integrated in the transmission or between the overload clutch and the transmission to be arranged.

Prefers If the overload clutch is "reversible", so she can engage and disengage as often as she likes.

In a particularly preferred embodiment of the belt retractor is provided that the overload clutch has an inner ring and an outer ring, wherein the inner ring is rotatably supported coaxially in the outer ring and has positive locking elements which cooperate positively with recesses in an inner contour of the outer ring and a positive connection between the Produce outer ring and the inner ring, wherein the positive locking elements so elastic fe dernd are that they slip out of the recesses upon reaching a predetermined belt pull-out force, whereby the overload clutch disengages.

Preferably the inner ring has helical form-locking elements Thighs pointing towards an inner area of the inner ring (Inner ring area) along a predetermined spiral rotation direction converge inwardly, the spiral direction of rotation being the direction of rotation, which has the outer ring when the seat belt of the belt reel is unrolled, is opposite. So can the spiral direction For example, the belt extension direction (Gurtabrollrichtung) of Belt reel be opposite.

Preferably is the inner ring by a disc, in particular one in radial Direction resilient or "radially resilient" plane disc (hereafter briefly called flat spring washer), with spiral Thighs formed.

The Positive locking elements are preferably uniform distributed on the circumference of the spring washer to a uniform To achieve power transmission.

Of the Inner ring or the spring washer, for example, rotatably with be connected to the transmission or the operating clutch, in this Trap, the outer ring is preferably rotatably with the belt reel connected.

alternative can also the inner ring or the spring washer against rotation with the belt reel get connected; In this alternative embodiment, the Outer ring preferably rotatably with the transmission or the Operating clutch connected.

Preferably paint over the spiral legs each have a circular sector of Inner ring or the spring washer, wherein the circular sector angle at least 30 degrees. Particularly preferred is the circular sector angle between 30 and 225 degrees, and has, for example, a value of 90 Degree, or of at least approximately 90 degrees (e.g. between 70 and 110 degrees).

Also it is considered advantageous if the spiral Leg from the inner region of the inner ring or from the inner pane at least approximately radially or vertically outwards emerge and then against the Spiralrehrichtung are bent over. Preferably, the spiral Leg by bending against the Spiralrehrichtung a predetermined rotational angle between the inner ring area or the Disc interior end facing away from the leg end and the radially out the inner region of the inner ring or from the inner pane area exiting leg attachment end, wherein the angle of rotation is between 90 and 225 degrees and, for example, a value of 180 degrees or at least approximately 180 degrees (e.g. between 150 and 210 degrees).

Preferably the predetermined belt pull-out force is such that the overload clutch disengages, if in the case of a vehicle accident, a critical Driving maneuvers or an emergency braking situation, a through the Seat belt of protected vehicle occupant due to inertia in the safety belt dips and a given maximum force exerts in Gurtauszugsrichtung.

Prefers the leg width is constant in leg longitudinal direction and / or the distance between the spiral legs in leg longitudinal direction at least partially constant or equidistant.

Preferably, the recesses are formed asymmetrically in the inner contour of the outer ring. The term "asymmetrically shaped" is to be understood, for example, as meaning that one edge of the recesses has a different shape than the respective other edge of the respective recess An advantage of this embodiment is the fact that, in the case of asymmetrically shaped recesses, after a disengagement due to overload, a more low-vibration Thus, an overload situation and thus overload-related disengagement occurs in most cases in Gurtauszugsrichtung when mass inertia due to a forward displacing vehicle occupant dips into the seat belt and exercises too high a belt pull-out force on the seat belt Thus, the coupling will be loaded mainly in a single power transmission direction, so that the force-transmitting edge of the recess in the belt extension direction with respect to the desired or required Kr aftübertragungseigenschaften the coupling will be designed; in the other power transmission direction, however, the clutch must be able to transmit less force. Asymmetric recesses now provide the possibility of adapting the shape of the recess in the less stressed edge region of the recess or in the less stressed direction of transmission such that the slippage of the positive locking elements after a disengagement is less vibration and the mechanical stress of the positive locking elements is reduced by a swing. Thus, the fact that the mechanical load of the overload clutch in a belt retractor is dependent on the direction of rotation and that this is for vibration reduction and Re Production of the mechanical load of the form-locking elements can be exploited.

One particularly good slipping behavior of the positive-locking elements and a good Wiederinkinkuppverhalten can be according to a continue to achieve preferred embodiment, when the recesses at least one steep and at least one shallower Flank. Seen in relative direction of rotation of the inner ring, which has the inner ring relative to the outer ring when the Seat belt is unrolled from the belt reel and the positive locking elements slipping on the inner contour of the outer ring is the Flank where the interlocking elements slide into the recess, preferably flatter than the flank on which the interlocking elements slip out of the recess. Or in other words, the Flank where the interlocking elements slide into the recess, when the clutch is disengaged and the interlocking elements on slipping through the inner contour of the outer ring is preferably flatter than the flank on which the interlocking elements from the recess slip out.

The steep flank and its flank height determines the for a disengagement in Gurtstrazugsrichtung required force; the flatter one Flank prevents disengagement and slipping of the positive-locking elements, that each too abruptly in the next one Recess occur and the inner ring and its positive locking elements start swinging. By the described shape design leaves thus achieve that the outer ring in case of overload can be pulled past the interlocking elements, without these too large mechanical vibration loads get abandoned.

The For example, flanks can be rectilinear or also be completely or partially curved. In case of a crooked Flanks is the radius of curvature - in relative direction of rotation the inner ring seen, the inner ring relative to the outer ring when the seat belt is unrolled from the belt reel and the positive locking elements on the inner contour of the outer ring slip through - preferably first in the recess big, a small slope and a gentle re-coupling and preferably out of the recess smaller, to prevent accidental slipping of the positive locking elements prevent and the required power transmission in To provide strap extension direction. For example, the Recesses on a sawtooth shape.

When independent invention is also a belt retractor for a safety belt viewed with a belt reel for winding and unwinding the seat belt and a drive, the the belt reel can drive to wind up the seat belt, wherein between the drive and the belt spindle a form-fitting working overload clutch is present, which designed in such a way is that it is based on a positive engagement in the engaged state and in case of overload, especially if it is exceeded a predetermined Gurtauszugskraft acting in Gurtbandauszugsrichtung, disengages by the positive connection is canceled. In this belt retractor is provided that the overload clutch an inner ring, in particular a radially resilient disc having an inner ring area, are integrally formed on the leg, with an outer ring the overload clutch cooperate.

For example the legs are aligned radially outwards. Alternatively it can be provided that the legs spiral are and in the direction of inner ring area along a predetermined Spiralrehrichtung converge inwardly, the spiral direction of rotation being the direction of rotation, having an associated outer ring when the seat belt is unrolled from the belt reel, is opposite.

embodiments The invention will be explained below with reference to figures; thereby show exemplarily:

1 an exploded view of an embodiment of a belt retractor according to the invention,

2 according to the belt retractor 1 in the assembled state,

3 an inner ring and an outer ring of the belt retractor according to 1 in the plan view,

4 according to the inner ring 3 in another representation with circular sectors,

5 according to the inner ring 3 in another turn,

6 another embodiment of an inner ring,

7 Yet another embodiment of an inner ring and

8th an embodiment in which the inner ring is rotatably connected to the belt reel.

In The figures are for the sake of clarity identical or similar components always use the same reference numerals.

In the 1 recognizes components of an embodiment of a belt retractor 10 with a belt reel 20 , With the belt reel 20 rotatably connected is an outer ring 30 , This outer ring 30 may be a separate component that with the belt reel 20 is connected, or even a part of the belt reel 20 form. In the latter case would be the outer ring 30 and the belt reel 20 thus executed in one piece.

In the 1 can be seen that the outer ring 30 an inner contour 40 having in the form of an internal toothing. The outer ring 30 forms part of a form-fitting overload clutch 50 to which an inner ring 60 belongs. The inner ring 60 is formed for example by a radially resilient flat disc (hereinafter referred to as spring washer) and rotatably with a transmission output 70 a transmission not shown 80 of the belt retractor 10 connected. Inside the transmission 80 is an operating coupling also not shown, with which a non-illustrated drive of the belt retractor 10 with the belt reel 20 can be coupled, for example, to tighten a seat belt.

The inner ring 60 is in the outer ring 30 Coaxially rotatable on a bolt 100 held. The inner ring 60 So it can be in the outer ring 30 and thus relative to the outer ring 30 rotate.

In the 1 In addition, it can be seen that the inner ring 60 Form-fitting elements 110 which are formed by spiral legs. The leg ends 120 grab in recesses 130 the inner contour 40 so that during normal operation of the belt retractor 10 the inner ring 60 and the outer ring 30 rotatably coupled with each other and the outer ring 30 rotates when the inner ring 60 is rotated, and vice versa, the inner ring 60 rotates when the outer ring 30 is turned. However, if an overload situation is reached in which, for example, the belt reel has too great a force on the inner ring 60 exercise, so the recesses 130 from the ends of the legs 120 pulled away, so that the outer ring 30 relative to the inner ring 60 will turn. Described descriptively slips in this case, each leg end 120 from its respective recess 130 out and slips into the nearest recess 130 into it. This slip continues as long as the overload situation continues; only after the end of the overload situation are the leg ends 120 again in a nearest recess 130 snap, thereby forming a positive connection, a coupling restored and the overload clutch 50 is engaged again.

To the described engagement and disengagement of the leg ends 120 to enable are the spiral legs 120 formed resiliently, so that the engagement and disengagement described can be "reversible", in other words, the overload clutch 50 not be damaged when disengaging, but remains operational for subsequent engagement and Auskupuppelvorgänge.

In the 2 is the belt retractor 10 shown in the assembled state. You can see the spring washer 60 in the outer ring 30 is used. The leg ends 120 each engage in an associated recess 130 in the outer ring 30 one. In addition, you can see the connection of the spring washer 60 to the transmission output of the transmission 80 ,

In the 3 are the spring washer 60 and the outer ring 30 according to the 1 and 2 shown in a plan view. You can see the spiral legs 110 with the leg ends 120 , which are evenly distributed on the circumference of the spring washer. In addition, it can be seen that the spiral legs converge inwardly along a predetermined spiral rotation direction D1, wherein the spiral rotation direction D1 of the spiral legs of the belt unrolling direction D2 of the belt reel 20 is opposite.

The direction of rotation D2 thus corresponds to the direction of rotation of the outer ring 30 when the seat belt is unrolled from the belt reel. The spiral rotation direction D1 corresponds to the relative direction of rotation of the spring washer, which is the spring washer relative to the outer ring 30 when the seat belt is unrolled from the belt spool and the spiral legs 110 on the inner contour 40 slip through the outer ring.

If, in the case of an overload situation, the outer ring 30 the belt reel 20 turns faster than the spring washer 60 be able to turn, the leg ends become 120 from the recesses 130 slip out. The spiral direction ensures that the clutch works "on train" and not "on pressure"; This configuration ensures that the overload clutch 50 reversible coupling and uncoupling without damage.

As reflected in the 3 You can also see the recesses 130 - seen in the direction of rotation - asymmetrically shaped; For example, have the recesses 130 a sawtooth shape. The design of the recesses 130 is preferably set such that each recess in Gurtrückollrichtung D2 of the belt reel seen first a steep flank F1 (with a steep slope angle) and then a flat flank F2 (with a shallow drop angle) has. This shape design ensures in a particularly simple manner that the outer ring 30 in case of overload on the spiral legs 120 can be "passed along" without the leg ends 120 to damage or break off. In addition, vibrations in the spring washer are kept low.

In the 4 is shown that the spiral legs 110 a circular sector 200 around the center M of the spring washer 60 - Starting from the leg beginning 220 on the disk inside 300 - paint over. The circular sector angle α is slightly more than 90 degrees in this embodiment. The spiral legs are preferred 110 configured such that the circular sector angle α is between 30 and 225 degrees.

In the 5 is the spring washer 60 shown again, wherein in this illustration, the course of the spiral legs is highlighted. It can be seen that each spiral leg 110 at its leg attachment end 220 - hereinafter called short leg beginning - from the disc interior 300 initially approximately perpendicularly or radially outward emerges (see arrow direction P1) and is then bent against the direction of spiral rotation D1. By bending against the spiral rotation direction D1 is a rotation angle ω between the leg beginning 220 and the leg end 120 (see arrow direction P3) caused; this angle of rotation ω is in the embodiment according to the 5 at about 180 degrees, because in the middle of the leg 310 (see arrow direction P2) an angle of rotation of approximately 90 degrees has already been reached.

Preferably, the angle of rotation ω is in a range between 90 ° and 225 ° and, for example, has a value of approximately 180 °, as shown in the 5 is shown by way of example.

The given belt pullout force at which the overload clutch 50 is to be decoupled, is preferably dimensioned such that the overload clutch disengages, if in the case of a vehicle accident, a critical maneuver or an emergency braking situation protected by the seat belt occupant drowned inertia in the seat belt and exerts a predetermined maximum force in Gurtauszugsrichtung. The decoupling prevents the belt pull-out force in the transmission 80 or the drive of the belt retractor 10 is initiated and damage the gearbox 80 or the drive occurs.

As reflected in the 5 In addition, it can be seen, the leg width in the leg longitudinal direction is at least approximately constant. Also, the distance between the spiral legs 120 in leg longitudinal direction at least partially constant or equidistant.

The setting of the belt pullout force at which the overload clutch is to disengage can be determined, for example, by the hardness of the spring washer 60 , the leg width and the thickness of the spring washer 60 and thus the thigh thickness, the shape of the leg ends 120 as well as the shape of the recesses 130 influence. In addition, by a suitable choice of material of the spring washer 60 or the material of the leg ends 120 as well as the material of the recesses 130 an additional friction component can be added so that the coupling behavior of the overload clutch 50 not only by positive locking, but also by frictional control.

As mentioned earlier, after a drop in the overload clutch 50 applied torque below the predetermined for disengaging overload torque of the positive connection between the spring washer 60 and the outer ring 30 restored, so that the overload clutch 50 will dock again. The coupling process and the decoupling process are completely reversible, so that the overload clutch is largely wear-resistant.

In the embodiment according to the 1 to 5 is the outer ring 30 rotatably with the belt reel 20 connected. Alternatively, with the belt reel 20 also the spring washer 60 be rotatably connected; In this case, the outer ring would 30 with the transmission output 70 of the transmission 80 rotatably connected. In the latter embodiment, the spring washer 60 with the belt reel 20 for example, be integrally connected or form a single component with this.

In the 6 is another embodiment of an inner ring 60 shown. In this embodiment, the spiral form-locking elements or legs 110 starting from the leg attachment end 220 (Leg start) tapers in the leg longitudinal direction. Thus, the deformation behavior is optimized and optimized the stress distribution in the form-locking elements.

In the 7 is yet another embodiment of an inner ring 60 shown. In this embodiment, the form-locking elements or legs 110 from the interior 470 aligned radially outwards. An outlet area 460 is bent inwardly away from the flat flank F1 to ensure a distance d to the flat flank F1.

In the 8th an embodiment is shown in which the inner ring or the disc 60 via a connecting element 500 rotatably with the belt reel 20 connected is. The outer ring 30 is rotatable with a in the 8th not shown further th gear or with one in the 8th also not shown further operating coupling connected.

10

retractor

20

belt reel

30

outer ring

40

inner contour

50

Overload clutch

60

Inner ring, spring washer

70

transmission output

80

transmission

100

bolt

110

Interlocking elements, leg

120

leg ends

130

recesses

200

circular sector

220

leg early

300

Slice indoors

310

the leg center

460

discharge area

470

interior

500

connecting element

D1

Spiral direction of rotation

D2

belt extracting

F1

steep flank

F2

area flank

M

Bull's-eye

α

Circle sector angle

ω

angle of rotation

P1

alignment on exit from the disk interior

P2

alignment in thigh center

P3

alignment at the end of the leg

d

distance

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 102004045452 [0002]

Claims (23)

Belt retractor ( 10 ) for a safety belt with - a belt reel ( 20 ) for winding and unwinding the seat belt, - a transmission connected to the belt reel ( 80 ) and - connected to the gear drive, which can drive the belt reel for winding the seat belt, - wherein between the drive and the belt spindle a positive-working overload clutch ( 50 ) is present, which is designed such that it is based on a form-fitting overload and, in particular when exceeding a predetermined, acting in Gurtbandauszugsrichtung Gurtauszugskraft disengages by the form-fitting is canceled, characterized in that the positively acting overload clutch between the belt spindle ( 20 ) and the transmission ( 80 ) is arranged. Belt retractor according to claim 1, characterized that in addition an operating clutch is present, the engages at a commissioning of the drive and thereby a Power transmission between the drive and the belt reel manufactures. Belt retractor according to claim 2, characterized that the operating clutch is integrated in the transmission. Belt retractor according to claim 2, characterized that the operating clutch between the overload clutch and the transmission is arranged. Belt retractor according to one of the preceding claims, characterized in that - the overload clutch an inner ring ( 60 ) and an outer ring ( 30 ), wherein the inner ring is held coaxially rotatable in the outer ring and positive-locking elements ( 110 ), which with recesses ( 130 ) in the inner contour ( 40 ) of the outer ring interact positively and form a positive connection between the outer ring and the inner ring, - wherein the interlocking elements are elastically resilient so that they are separated upon reaching the predetermined belt withdrawal force from the recesses, whereby the overload clutch disengages. Belt retractor according to claim 5, characterized in that the positive-locking elements ( 110 ) are formed by helical legs which are directed towards an interior area ( 300 ) of the inner ring along a predetermined spiral rotation direction inwardly converge (D1), wherein the spiral rotational direction (D1) of the rotational direction (D2), the outer ring ( 30 ), when the seat belt is unrolled from the belt spool is opposite. Belt retractor according to claim 5 or 6, characterized in that - the inner ring ( 60 ) is formed by a disc, in particular a resilient disc in the radial direction, and - the interlocking elements are distributed uniformly on the circumference of the spring washer. Belt retractor according to one of the preceding claims 1-4, characterized in that the overload clutch ( 50 ) an outer ring ( 30 ) and a cooperating inner ring ( 60 ) with spiral legs ( 110 ) facing towards an interior area ( 300 ) of the inner ring along a predetermined spiral rotation direction (D1) converge inwardly, wherein the Spiralrehrichtung the direction of rotation, which has the outer ring when the seat belt is unrolled from the belt reel, is opposite. Belt retractor according to one of the preceding claims 1-4, characterized in that the overload clutch ( 50 ) a disc, in particular a radially resilient disc ( 60 ), with spiral legs ( 110 ), which are evenly distributed on the circumference of the disc. Belt retractor according to one of the preceding claims 5-9, characterized in that - the inner ring or the disc ( 60 ) rotatably with the gear ( 80 ) or the operating clutch is connected and - that the outer ring ( 30 ) rotatably with the belt reel ( 20 ) connected is. Belt retractor according to one of the preceding claims 5-9, characterized - that the inner ring or the disc is rotatably connected to the belt reel and - that the outer ring against rotation with the gearbox or the operating clutch connected is. Belt retractor ( 10 ) for a safety belt with - a belt reel ( 20 ) for winding and unwinding the seat belt and - a drive that can drive the belt reel for winding the seat belt, - wherein between the drive and the belt spindle a form-fitting overload clutch ( 50 ) is present, which is designed such that it is based on a form-fitting in the engaged state and disengages in an overload, in particular when exceeding a predetermined, acting in Gurtbandauszugsrichtung belt pullout force by the positive connection is canceled, characterized in that the overload clutch ( 50 ) an inner ring ( 60 ), in particular a radially resilient disc, having an inner ring area ( 300 ), on the thigh ( 110 ) are formed, which with an outer ring ( 30 ) the overload clutch ( 50 ) interact. Belt retractor according to claim 12, characterized in that the legs ( 110 ) are aligned radially outward. Belt retractor according to claim 12, characterized in that the legs are helical and converge in the direction of the inner ring area along a predetermined spiral rotation direction (D1) inwards, wherein the spiral rotation direction of the rotational direction (D2), which is an associated outer ring (D2). 30 ), when the seat belt is unrolled from the belt spool is opposite. Belt retractor according to one of the preceding claims 6-14, characterized in that - the helical legs each have a circular sector ( 200 ) of the inner ring or the disk, - wherein the circular sector angle (α) is at least 30 ° degrees. Belt retractor according to claim 15, characterized in that that the circular sector angle (α) is between 30 and 225 degrees is, in particular a value of 90 degrees or at least approximately 90 degrees. Belt retractor according to one of the preceding claims 6-16, characterized in that the spiral Leg from the inner region of the inner ring or from the inner pane at least emerge approximately radially outward and then bent against the spiral rotation direction (D1) are. Belt retractor according to claim 17, characterized in that the helical legs, by bending against the direction of spiral rotation, reach a predetermined angle of rotation (ω) between the end of the leg facing away from the inner ring or the disk inner region (US Pat. 120 ) and the radially out of the inner region of the inner ring or from the disk inner region exiting leg attachment end ( 220 ), wherein the angle of rotation (ω) is between 90 and 225 degrees, in particular has a value of 180 degrees or at least approximately 180 degrees. Belt retractor according to one of the preceding claims, characterized in that the predetermined belt pull-out force in such a way is dimensioned that disengages the overload clutch when in the event of a vehicle accident, a critical driving maneuver or an emergency braking situation, a seat belt protected Vehicle occupant mass inertia in the seat belt dips and a given maximum force in Gurtauszugsrichtung exercises. Belt retractor according to one of the preceding claims, characterized in that the leg width in leg longitudinal direction is constant and / or that the distance between the spiral Legs in the leg longitudinal direction at least in sections constant or equidistant. Belt retractor according to one of the preceding claims, characterized in that the leg width of the spiral legs ( 110 ) varies in leg longitudinal direction. Belt retractor according to claim 21, characterized in that the spiral legs ( 110 ) in thigh longitudinal direction. Belt retractor according to one of the preceding claims, characterized in that the recesses in the inner contour of the outer ring are formed asymmetrically.