CN114655157B

CN114655157B - Seatbelt retractor and stopper for seatbelt retractor

Info

Publication number: CN114655157B
Application number: CN202011542437.XA
Authority: CN
Inventors: 刘崇庆
Original assignee: Yanfeng Automotive Safety Systems Co Ltd
Current assignee: Yanfeng Automotive Safety Systems Co Ltd
Priority date: 2020-12-23
Filing date: 2020-12-23
Publication date: 2024-04-12
Anticipated expiration: 2040-12-23
Also published as: CN114655157A

Abstract

The present invention relates to a stop device for a seatbelt retractor and a seatbelt retractor having such a stop device. The stop device includes: a ratchet wheel, which is configured for a driven wheel drive connection, preferably a torsion-resistant connection, with a pretensioner of a seatbelt retractor; a movably supported pawl (64); a spring element (63) biasing the pawl towards the ratchet; and a movable part (62) which in an initial position disengages the pawl from the ratchet against the biasing force of the spring element, the movable part being configured for movement of the drive member of the activated pretensioning device away from the initial position such that the pawl engages the ratchet and thereby unidirectionally locks the ratchet in the webbing pull-out direction. By means of the stop device, a good pretensioning function of the seatbelt retractor and a restraint function for the occupant can be ensured.

Description

Seatbelt retractor and stopper for seatbelt retractor

Technical Field

The present invention relates to a seatbelt retractor. The seatbelt retractor can be used, for example, in vehicles in general, such as motor vehicles, in particular in passenger cars. The invention also relates to a stop device for a seatbelt retractor.

Background

Currently, a number of seatbelt retractors are known in the vehicle art, which have a pretensioning function and a force limiting function. For the pretensioning function of these seat belt retractors, a gas generator is typically employed which can generate a high pressure gas after a burst, and the driven wheel is driven by a ball or other driving medium so that it rotates the webbing drum in the webbing retracting direction, pretensioning the webbing. After the pretensioning function is activated, when the occupant pulls the webbing due to inertia such that the spool of the seatbelt retractor rotates in the webbing pull-out direction opposite to the webbing take-up direction, the force limiting device acts to provide the occupant with a stable restraining force to avoid or reduce injury to the occupant.

In the prior art, the rotational direction of the spool changes from the pretensioning function to the force limiting function, in which the sum of various resistances of the inside of the seatbelt retractor needs to be overcome. These resistances are mainly the remaining reverse thrust generated by the gas generator, the friction of the meshing transmission, the torsion of the torsion bar. After the tension of the webbing overcomes the remaining reverse thrust and friction force and rotates the take-up drum in the webbing-pulling-out direction, a relatively stable torsion force of the torsion bar is output to the take-up drum, thereby realizing the force limiting function. Before the force limiting device is activated, i.e. before the take-up drum is rotated in the webbing-pull-out direction, the sum of the various resistances needs to be overcome, which causes the restraining force of the webbing against the occupant to peak. The magnitude of this peak is related to a number of factors and will be continuously applied to the web spool and ultimately conducted to the webbing. The problem associated therewith may be referred to as a pretension overload problem, wherein the situation of the pretension overload may also be unstable and thus result in a low robustness of the protection performance of the restraint system.

In order to reduce the preload overload, it is considered to reduce the residual reverse thrust generated by the gas generator. However, this may mean that a low operating pressure of the gas generator needs to be selected, but this also reduces the pretension performance; or the gas is vented after the gas generator fires, but this is also at the expense of pretension performance and may produce smoke, even an open flame, as the gas is vented.

Disclosure of Invention

The object of the present invention is to provide a locking device for a seatbelt retractor, by means of which the driven wheel of the pretensioner can be locked in one way reliably when the pretensioner is activated, and thus the pretensioner function of the seatbelt retractor and the restraint function for the occupant are ensured.

The object is achieved by a stop device for a seat belt retractor, comprising:

a ratchet wheel, which is configured for a driven wheel drive connection, preferably a torsion-resistant connection, with a pretensioner of a seatbelt retractor;

a movably supported pawl;

a spring element biasing the pawl toward the ratchet; and

a movable part which in an initial position, against the biasing force of the spring element, disengages the pawl from the ratchet wheel, the movable part being configured for movement of the drive member of the activated pretensioning device out of the initial position such that the pawl engages with the ratchet wheel and thus unidirectionally locks the ratchet wheel in the webbing pull-out direction.

In the locking device according to the invention, the ratchet has unidirectional teeth, so that, when the ratchet engages with the pawl, the ratchet can only be rotated in the webbing take-up direction or in the pretensioning direction, but is locked in the opposite direction or in the webbing pull-out direction. The driven wheel of the pretensioner can thus be reliably locked in one direction in the event of activation of the pretensioner, and thus the pretensioner function of the seatbelt retractor and the restraint function for the occupant are ensured.

The object is also achieved by a seat belt retractor comprising a rotatably supported belt drum configured for winding a webbing, and a pretensioner configured for driving the belt drum in a webbing winding direction when it is activated, such that the webbing is pretensioned, the pretensioner having a driving member and a driven wheel which is connected in torsion-resistant manner to the belt drum, wherein the seat belt retractor comprises a stop device for a seat belt retractor according to the invention.

In some embodiments, the seatbelt retractor may further include a force limiting device configured to limit a pulling force of the webbing as the webbing is pulled out from the webbing spool.

In some embodiments, the torsion-resistant connection of the driven wheel to the drum can be released when a predetermined torque threshold of the drum relative to the driven wheel in the webbing-pull-out direction is exceeded.

When the pretensioner is activated during operation of the seatbelt retractor, for example as a result of a vehicle crash, after the pretensioning process has ended, before the force limiting process or at the beginning of the force limiting process, the torsion-resistant connection of the driven wheel to the seatbelt drum can be released by means of the webbing tension, so that the pretensioning overload is no longer conducted onto the webbing in a superimposed manner with the load generated by the force limiting device, so that the pretensioning overload problem is eliminated and a robust webbing restraint force is achieved.

In some embodiments, the drive member may be a set of spheres, in particular steel balls, and thus the driven wheel may be a ball gear.

In some embodiments, the drive member may be a flexible element, such as a flexible gear or flexible bar, that is capable of engaging the driven wheel. The flexible strip may be visually referred to as a "snake" in that it may be advanced like a snake in a tortuous guide tube under the urging of gas generated by a gas generator.

In some embodiments, the driven wheel and the tape spool may be connected in torsion by means of at least one pin element.

In some embodiments, the torsion-resistant connection may be achieved by a set of pin elements, wherein the tape cartridge may have a set of circumferentially distributed, preferably axially extending, first grooves, and the driven wheel may have a set of circumferentially distributed, preferably axially extending, second grooves, each pin element being insertable into one of the first grooves and one of the second grooves.

In some embodiments, the seatbelt retractor may include an integral fixing member, which may have a ring from which the set of pin elements axially protrude. The fixing member may be made of plastic material, for example, by injection molding.

In some embodiments, at least one pin element of the set of pin elements may have a rated breaking point.

In some embodiments, all of the pin elements may be identically constructed.

In some embodiments, the tape cartridge may have a journal axially protruding on a first end side thereof, the driven wheel may be fitted over the journal, the journal may have the set of first grooves, and the driven wheel may have the set of second grooves on an inner peripheral surface thereof.

In some embodiments, the ratchet may be a separate component and torsionally connected with the driven wheel, or may be integrally formed with the driven wheel. Instead of a direct drive connection, the ratchet wheel can also be connected to the driven wheel by a drive mechanism, which can be, for example, a planetary gear mechanism or a spur gear mechanism.

In some embodiments, the stop device may include a base.

In some embodiments, the movable member is guided in translational movement.

In some embodiments, the base may have a guide rail, and the movable member is guided by the guide rail.

In some embodiments, the pawl is pivotally supported on the base, such as on a pivot of the base. Alternatively, the pawl is supported in a translationally movable manner, for example on a base body.

In some embodiments, the spring element may be mounted on a base. The spring element may be, for example, a sheet metal profile spring, a wire spring, a coil spring, a helical torsion spring or other spring. The movable part may be held in an initial position by a spring element.

In some embodiments, the guide rail may be formed by a sliding hole in the base body.

In some embodiments, the sliding aperture and the body of the movable member may have complementary non-circular cross-sections. For example, the sliding hole may have a cross-sectional shape of a key hole.

In some embodiments, the movable member may have a stop extending laterally from its body.

In some embodiments, in the initial position, the stop may bear against a free end of the pawl.

In some embodiments, the movable part may have a ramp for co-acting with the drive member.

In some embodiments, the movable member is guided linearly in a tangential direction of the ratchet.

In some embodiments, in the initial position, the ramp extends into the path of movement of the drive member such that the movable component can be pushed by the drive member out of the initial position.

In some embodiments, the pretensioning device may comprise a guide tube and a gas generator arranged on the end of the guide tube remote from the driven wheel, in which guide tube a plurality of balls are accommodated as drive members, which balls can be guided by the guide tube towards the driven wheel when the gas generator is implosion, the driven wheel being configured as a ball gear with a ball socket between adjacent teeth for receiving the balls.

In some embodiments, the guide tube may have a completely enclosed gas chamber for containing gas generated by the gas generator. A "completely closed gas chamber" is understood to mean that no leakage path is provided for the gas chamber for venting the gas. Typically, the gas chamber may have gas leakage that is small due to unintentional gaps that may exist between the components forming the gas chamber. Typically, the gas chamber may be closed on one side by a gas generator and on the other side by a piston. In contrast, in some prior art there may be a specially designed leakage path in the piston or between the piston and the wall of the guide tube, thereby solving the problem of pretensioning overload. The solution according to the invention with a completely closed gas chamber eliminates the problems associated with gas venting, while at the same time there is no problem of pre-load overload. In addition, since a completely closed gas chamber is employed, a lower design pressure gas generator may be employed than in the case of a gas chamber having a leakage path, which may have smaller size and lower cost, as well as improved safety. In alternative embodiments, the plenum may also have a leakage path for venting gas. For example, the leakage path may be designed smaller than in the prior art.

In some embodiments, the force limiting device may be coupled with the tape cartridge with a gap such that the tape cartridge is rotatable through a lost motion angle relative to the force limiting device. By means of the connection with play, the superposition of the preload and the torque of the force limiter can be at least reduced.

In some embodiments, the free-running angle may be greater than or equal to a maximum value of the running angle, wherein, when the pretensioning device is activated, the web drum is pulled by the web in the web-pulling direction, such that the torsion-resistant connection of the driven wheel to the web drum is released, the web drum rotates by the running angle in the web-pulling direction. By means of this technical measure, a superposition of a pretensioning overload and the torque force of the force limiter can be avoided, so that the effect of the pretensioning overload on the web drum is relieved before the force limiter acts, and after the force limiter acts, the web is only subjected to the torsional load of the force limiter.

The technical features mentioned above and the technical features to be mentioned below and technical features which can be derived from the drawings can be combined with each other arbitrarily, as long as the individual technical features combined with each other are not contradictory.

Drawings

Exemplary embodiments of the present invention are described below with reference to the schematic drawings in which like components or functionally identical components are designated by like reference symbols.

Fig. 1 is an exploded view of a seatbelt retractor according to an embodiment of the present invention.

Fig. 2 is a perspective view of the seatbelt retractor of fig. 1 in an assembled state.

Fig. 3 is a front view of the seatbelt retractor of fig. 1 in an assembled state.

Fig. 4 is a sectional view taken along section line B-B in fig. 3.

Fig. 5 is a side view of the seatbelt retractor of fig. 1 in an assembled state.

Fig. 6 is a sectional view taken along section line C-C in fig. 5.

Fig. 7 is a plan view of a fixing member of the seatbelt retractor of fig. 1.

Fig. 8 is a cross-sectional view of a single pin element.

Fig. 9 is a perspective view of an assembly of the seatbelt retractor of fig. 1.

Fig. 10 is an enlarged front view of a portion of the assembly of fig. 9.

Fig. 11 is a cross-sectional view of the assembly of fig. 9 taken along the midplane of the driven wheel.

Fig. 12 is a view corresponding to fig. 10 in another state.

Fig. 13 is an exploded view of the stop device.

Fig. 14 is a cross-sectional view of the tape cartridge in a section engaged with the plum blossom head of the torsion bar.

Detailed Description

The general overview of a seatbelt retractor according to one embodiment of the present invention is shown in fig. 1 to 6, in which the mounting frame, mechanical side cover and coil spring side cover of the seatbelt retractor, as well as other components not critical in the present invention, are omitted. For example, the seatbelt retractor may include a vehicle sensing assembly and a belt sensing assembly, which are not shown. The guide tube 7 of the pretensioning device is also omitted in fig. 1 for the sake of simplicity.

The seatbelt retractor may include a seatbelt drum 3 rotatably supported in a mounting frame. The webbing, not shown, may be wound onto the take-up drum 3 in the webbing take-up direction, and may be pulled out from the take-up drum 3 in the webbing pull-out direction opposite to the webbing take-up direction. The winding drum 3 is configured as a hollow drum and has a journal 32 projecting axially on its first end side. On the circumference of the journal 32 there is a set of circumferentially distributed axially extending first grooves 31. The hollow chamber of the tape cartridge 3 is open on the second end side of the tape cartridge. The driven wheel 2, which will be described below, can be fitted in a rotationally fixed manner over the axle journal 32, and the axle head 52 can be inserted with its projection rotatably on the second end side into the hollow space of the winding drum 3.

The seat belt retractor may comprise a pretensioning device 10 configured to drive the spool 3 in the webbing take-up direction when it is activated, so that the webbing is pretensioned, fulfilling a pretensioning function. The pretensioning device 10 may have a gas generator 9, a guide tube 7, a drive member 8 (see fig. 6) and a driven wheel 2. The gas generator 9 may be arranged on the end of the guide tube 7 remote from the driven wheel 2 and may define a gas chamber with a piston, not shown, movable in the guide tube 7, which gas chamber may be a completely closed gas chamber, for example. A plurality of spheres may be accommodated as drive members 8 in the guide tube 7. When the gas generator 9 is ignited, the plurality of balls can be driven by the piston and guided by the guide tube 7 toward the driven wheel 2 and thus drive the driven wheel 2 to rotate in the webbing take-up direction. The driven wheel 2 may be configured as a ball gear with a socket between adjacent teeth for receiving a ball.

The driven wheel 2 is connected to the belt drum 3 in a rotationally fixed manner, wherein the rotationally fixed connection of the driven wheel 2 to the belt drum 3 can be released when a predetermined torque threshold of the belt drum 3 relative to the driven wheel 2 in the webbing-pull-out direction is exceeded. For this purpose, the seatbelt retractor may comprise an integral fixing member 1, which may have a ring 12, from which ring 12 a set of pin elements 11 may axially project, and the driven wheel 2 may have on its inner circumferential surface a set of circumferentially distributed axially extending second grooves 21. Each pin element 11 can be inserted into one of the first recesses 31 and one of the second recesses 21, so that the driven wheel 2 is connected to the belt drum 3 in a rotationally fixed manner by means of the pin elements 11 in a form-locking manner. The pin element 11 may be made of plastic and/or metal. Preferably, the entire fixing member 1 is made entirely of plastic.

Fig. 7 is a plan view of the fixing member 1, and fig. 8 is a cross-sectional view of the single pin element 11. As can be seen from fig. 7, the fixing member 1 has 11 pin elements 11 uniformly distributed in the circumferential direction. Each pin element has a circumferential extension angle α. The extension angle α is about 10 ° in the embodiment shown. In order to facilitate an exact release of the torsion-resistant connection under a predetermined load, a part of the pin elements 11 or all of the pin elements 11 may have a nominal breaking point 13 in order to shear the pin elements 11 by rotating the winding drum 3 relative to the driven wheel 2. By suitable design of the number of pin elements 11, the effective length, the cross-sectional area, the desired breaking point, etc., the predetermined load for releasing the torsion-resistant connection can be determined.

The seat belt retractor may comprise a force limiting device 20 configured to limit the tension of the webbing as the webbing is pulled out of the spool 3. The force limiting device 20 may comprise a torsion bar 4, which torsion bar 4 is connected with a first end to the winding drum 3 and with a second end to the stub shaft 5. Specifically, the first and second ends of the torsion bar 4 may have respective plum blossom heads 41, 42. The winding drum 3 may have a plum blossom recess 33 which cooperates with, in particular is a clearance fit with, the plum blossom head 41 of the first end of the torsion bar 4, see fig. 14, in which the direction of rotation of the winding drum 3 relative to the torsion bar 4 in the webbing-pull-out direction is indicated by the dashed arrow. The stub shaft 5 may have a plum blossom recess 51 cooperating with the plum blossom head 42 of the second end of the torsion bar 4, in particular, an interference fit. The torsion bar 4 may be twisted off when a predetermined torsion threshold is exceeded and thus limit the maximum restraining force of the webbing. Furthermore, the axle head 5 can cooperate with a main locking device, for example, for locking the axle head 5 and thus the tape cartridge 3 by means of a locking claw engaging with a toothed ring of the mounting frame guided in the recess 52 of the axle head 5 when the vehicle-or tape-sensing device is activated.

Advantageously, the force limiting device 20 can be connected with play to the tape reel 3 such that the tape reel 3 can be rotated relative to the force limiting device 20 by a free-running angle β (see fig. 14), which can be, for example, approximately 15 °. It is further advantageous if the free travel angle β is equal to or greater than the maximum value of the travel angle, wherein, when the pretensioning device 20 is activated, the web drum 3 is pulled by the web in the web pullout direction, so that the torsion-resistant connection of the driven wheel 2 to the web drum 3 is released, the web drum 3 rotates in the web pullout direction by the travel angle. In particular, in the embodiment shown, the torsion-resistant connection of the plum blossom head 41 of the first end of the torsion bar 4 to the plum blossom depression 33 of the winding drum 3 is provided with play, so that the winding drum 3 can be rotated with respect to the torsion bar 4 by a play angle β which is greater than or equal to the sum of an angle α of rotation and an indexing angle γ of the teeth 22 of the ratchet wheel 23 (which will be described further below in connection with fig. 9, which may be approximately 5 °, for example), wherein a rotation of the winding drum 3 with respect to the driven wheel 2 in the webbing-extraction direction by the angle α can cause the pin element 11 to be sheared and thus the torsion-resistant connection of the winding drum 3 to the driven wheel 2 to be released. In this preferred embodiment, since β is greater than or equal to α+γ, the torsion-resistant connection of the belt drum 3 to the driven wheel 2 is released after the pretensioning process has ended and before the force limiting process has begun, so that the problem of overload of the pretensioning is completely avoided. In suboptimal solutions, reduced backlash angles, such as alpha+gamma > beta ∈ (alpha+gamma)/2, or even no backlash angle, may also be employed. Preferably, β.ltoreq.2 (α+γ), for example β.ltoreq.1.5 (α+γ).

The seat belt retractor may comprise a stop means 6. Fig. 9 to 13 show an embodiment of the locking device 6. The locking device 6 can be switched by the drive member 8 from a deactivated state (see fig. 9 and 10) to an activated state (see fig. 12) when the pretensioning device 20 is activated, in which the locking device 6 can unidirectionally lock the driven wheel 2 in the webbing pull-out direction.

In the embodiment shown, the stop device 6 may comprise a ratchet wheel 22 assigned to the driven wheel 2, the teeth 23 of which ratchet wheel are unidirectional teeth, so that the ratchet wheel 22 and thus the driven wheel 2 can be locked in the webbing pull-out direction and cannot be locked in the webbing take-up direction. Advantageously, the ratchet 22 may be integrally formed with the driven wheel 2.

The stop means 6 may comprise a pivotably supported pawl 64 and a spring element 63 and a movable part 62, the spring element 63 biasing the pawl 64 towards the ratchet wheel 22, the movable part 62 in an initial position disengaging the pawl 64 from the teeth 23 of the ratchet wheel 22 against the biasing force of the spring element 63, the movable part 62 being movable by the drive member 8 out of the initial position upon activation of the pretensioning device 20 such that the pawl 64 engages the teeth 23 of the ratchet wheel 22 and thereby unidirectionally locks the ratchet wheel 22 in the webbing pull-out direction. The direction of rotation of the pawl 64 from the inactive state to the active state is indicated by the arrow in fig. 12.

Advantageously, the stop means 6 may comprise a base body 61, the pawl 64 and the spring element 63 and the movable part 62 may all be mounted on the base body 61. The base body 61 may be fixedly mounted, for example, on a mounting frame of the seatbelt retractor. In the embodiment shown, the base body 61 can have a guide rail 66 in the form of a sliding bore having a keyhole cross section. The movable member 62 is guided, preferably translatably, by a guide rail 66. The pawl 64 is pivotally supported on a pivot 65 of the base body and the spring element 63 encloses the pawl 64. The movable part 62 may have a stop 67 projecting transversely from its body, in the initial position the stop 67 bearing against a free end 69 of the pawl 64, as shown in fig. 9 and 10. The movable part 62 may also have a ramp 68 for co-acting with the drive member 8. As shown in fig. 11, when the pretensioning device 20 is activated, the drive member 8, which is formed by a set of spheres, is pushed out towards the driven wheel 2. The direction of movement of these spheres is shown by the solid arrows in fig. 11. When the foremost ball encounters the movable part 62 in the initial position, the ball loads the inclined surface 68 of the movable part 62, so that the movable part 62 moves away from the initial position, the direction of movement of the movable part 62 being indicated by the dashed arrow in fig. 11. Advantageously, the movable part 62 can move in the tangential direction of the ratchet, in other words the guide rail 66 can be a guide rail that extends linearly along the tangential direction of the ratchet. After the movable part 62 has moved away from the initial position, the stop 67 has moved away from the free end 69 of the pawl 64, the pawl 64 engages the ratchet 22 under the spring force of the spring 63, embedding in the tooth space between two adjacent teeth 23 of the ratchet 22 (see fig. 12). After the pawl 64 is engaged with the ratchet 22, the ratchet 22 is only rotatable in the webbing take-up direction and is not rotatable in the webbing pull-out direction. When the pawl 64 is engaged with the ratchet 22, the ratchet may have a backlash angle in the reversal from the webbing take-up direction to the webbing take-out direction, which may be randomly between 0 and the indexing angle γ (see fig. 9) of the teeth of the ratchet.

In the embodiment shown, the driven wheel 2 and the winding drum 3 are connected to each other by pin elements 11, which pin elements 11 can transmit torque between the driven wheel 2 and the winding drum 3 within set shear limits. When the torque to be transmitted is greater than the shearing limit, the pin element 11 is sheared, during which the take-up drum 3 is rotated by an angle α in the webbing-pull-out direction relative to the driven wheel 2.

In the embodiment shown, during pretensioning of the webbing, the driven wheel 2 transmits a torque less than the shear limit to the spool 3 via the pin element 11, the pin element 11 is not sheared, the spool 3 rotates in the webbing take-up direction, and the webbing is pretensioned. After the pretensioning process has ended, the webbing is pulled by the load of the occupant against the take-up drum 3. At this time, the stopper 6 has been activated, and the webbing drum 3 is locked unidirectionally by the stopper 6 and cannot rotate in the webbing-pull-out direction. When the tension of the webbing on the spool is sufficiently great, the pin element 11 is sheared after overcoming the resistance and passing through a free-running angle which may be between 0 and an angle γ in the webbing-pull-out direction, and after continuing to rotate by an angle α in the webbing-pull-out direction with respect to the driven wheel 2. Since the sum of the angle α and the angle γ is smaller than or equal to the angle β, the webbing does not have to overcome the resistance generated by the torsion bar 4 during the shearing of the pin member 11. When the pin element 11 is sheared, the spool 3 can continue to rotate in the webbing pull-out direction until the lost motion angle β is completely eliminated, and then the torsion bar 4 acts to provide a stable force limiting output, preventing injury to the occupant due to excessive webbing tension.

Although the invention is described in more detail above by means of specific embodiments with reference to the accompanying drawings, the invention is not limited thereto. The particular embodiments shown are illustrative. Various modifications may be made by those skilled in the art.

For example, instead of or in addition to a "form-locking connection of the driven wheel 2 to the winding drum 3 via the pin element 11", the driven wheel 2 can be connected to the winding drum 3 in a material-locking manner, for example by welding, which can be broken when a predetermined load threshold is exceeded, and thus the driven wheel 2 can be released from the winding drum 3. For example, instead of a positive connection by means of a pin element, the driven wheel 2 and the winding drum 3 can also be connected by means of a fine-toothed spline, which can fail when a predetermined load threshold is exceeded. In the embodiment shown, the pin element 11 is mounted in the axial direction. Alternatively, the pin elements may also be radially mounted and thus the driven wheel 2 and the take-up drum 3 may have corresponding radial holes.

For example, instead of an integral torsion bar 4, a torsion bar with two bar sections which can be plugged into one another and have a predetermined rotational play in the plug-in region and which can be connected in a rotationally fixed manner without play to the winding drum 3 and the stub shaft 5 can also be used.

For example, instead of the releasable rotationally fixed connection of the driven wheel 2 to the belt drum 3 via the pin element 11, both can also remain rotationally fixed during operation of the belt retractor when the pretensioning device is activated.

For example, the seatbelt retractor may not have a force limiting device.

It will be understood that if an element is referred to as being "on", "coupled" or "connected" to another element, it can be directly on, coupled or connected to the other element or one or more intervening elements may be present therebetween. Conversely, if the expressions "directly on … …", "directly coupled to … …" and "directly connected to … …" are used herein, it is intended that there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted similarly such as "between … …" and "directly between … …", "attached" and "directly attached", "adjacent" and "directly adjacent", and so forth.

Finally, it is pointed out that the above embodiments are only intended to understand the invention and do not limit the scope of protection thereof. Modifications to the above would be obvious to those of ordinary skill in the art, but would not bring the invention so modified beyond the scope of the present invention.

Claims

1. A stop device for a seatbelt retractor, the stop device comprising:

a ratchet wheel (22) configured for driving connection with a driven wheel (2) of a pretensioning device of a seatbelt retractor, wherein the pretensioning device comprises a guide tube (7) and a gas generator (9) arranged on an end of the guide tube remote from the driven wheel, a plurality of balls being accommodated as driving members in the guide tube, which balls can be guided by the guide tube towards the driven wheel when the gas generator is implosion, the driven wheel being configured as a ball gear with a ball socket for receiving the balls between adjacent teeth;

a movably supported pawl (64);

a spring element (63) biasing the pawl towards the ratchet; and

a movable part (62) which in an initial position disengages the pawl from the ratchet against the biasing force of the spring element, the movable part being configured for movement of the drive member (8) of the activated pretensioning device out of the initial position such that the pawl engages the ratchet and thus unidirectionally locks the ratchet in a webbing pull-out direction.

2. A stop device for a seat belt retractor according to claim 1, wherein the ratchet is configured for a rotationally fixed connection with a driven wheel (2) of a pretensioner device of the seat belt retractor and/or the pawl is pivotably supported and/or the movable part is guided in a translationally movable manner.

3. The retaining device for a seatbelt retractor according to claim 1, characterized in that it comprises a base body (61), wherein the retaining device has at least one of the following features:

a) The base body has a guide rail (66), the movable part being guided by the guide rail;

b) The pawl is pivotally supported on a pivot (65) of the base;

c) The spring element is mounted on the base body.

4. A stop device for a seatbelt retractor according to any of claims 1-3, wherein the movable part has a stop (67) protruding laterally from its body, which stop in the initial position abuts against a free end (69) of the pawl.

5. A stopper device for a seat belt retractor according to any one of claims 1 to 3 wherein the movable part has a ramp (68) for co-acting with the drive member.

6. A stop arrangement for a seatbelt retractor according to claim 5, wherein the movable part is guided straight in a tangential direction of the ratchet wheel, and in the initial position the inclined surface protrudes into the movement path of the driving member so that the movable part can be pushed out of the initial position by the driving member.

7. A stop arrangement for a seatbelt retractor according to any of claims 1 to 3, wherein the ratchet is an integral part of the driven wheel or is in torsion connection with the driven wheel as a separate component.

8. A seat belt retractor comprising a rotatably supported belt drum (3) configured for winding a webbing, and a pretensioning device (10) configured for driving the belt drum in a webbing retraction direction when it is activated such that the webbing is pretensioned, the pretensioning device having a drive member (8) and a driven wheel (2) which is rotationally fixedly connected to the belt drum, wherein the pretensioning device comprises a guide tube (7) and a gas generator (9) arranged on an end of the guide tube remote from the driven wheel, a plurality of balls being accommodated as drive members in the guide tube, the balls being guidable by the guide tube towards the driven wheel when the gas generator is spot-exploded, the driven wheel being configured as a ball gear with a ball socket between adjacent teeth for receiving a ball, characterized in that the seat belt retractor comprises a stop device for a seat belt retractor according to any one of claims 1 to 7.

9. A safety belt retractor according to claim 8 wherein the driven wheel is in torsion-resistant connection with the belt drum by means of at least one pin element (11).

10. The seatbelt retractor according to claim 9, wherein the torsion-resistant connection is achieved by a set of pin elements, wherein the belt drum has a set of circumferentially distributed axially extending first grooves (31), the driven wheel has a set of circumferentially distributed axially extending second grooves (21), each pin element being inserted into one of the first grooves and one of the second grooves.

11. The seatbelt retractor according to claim 10, comprising one integral fixing member (1) having a ring (12) from which the set of pin elements axially protrude.

12. The seatbelt retractor according to claim 10 or 11, wherein at least one pin element of the set of pin elements has a rated breaking point (13).

13. The seatbelt retractor according to claim 10 or 11, wherein the seatbelt cartridge has a journal (32) axially protruding on a first end side thereof, the driven wheel being fitted over the journal, the journal having the set of first grooves, the driven wheel having the set of second grooves on an inner peripheral surface thereof.

14. The seatbelt retractor according to any one of claims 8 to 11, wherein the torsion-resistant connection of the driven wheel to the take-up drum is released when a predetermined torque threshold of the take-up drum relative to the driven wheel in the webbing-pull-out direction is exceeded.