DE102022101080A1 - belt retractor - Google Patents

Abstract

Belt retractor with a belt shaft (5) which is rotatably mounted in a frame (1) and on which a seat belt can be wound, and a force-limiting unit (61) which, when activated, enables a rotary movement of the belt shaft (5) in the pull-out direction of the seat belt, the force-limiting unit (61) has an electric motor (4) and a first blocking device, and the first blocking device is set up to, controlled by activation of the electric motor (4), cause a rotary movement of the belt shaft (5) in the pull-out direction in one to be released and blocked again in a repetitive sequence, the first blocking device and/or a blocking contour (68), on which the first blocking device comes to rest in the blocking position, being resiliently mounted in or counter to the blocking direction of the first blocking device in each case via at least one spring.

Description

The present invention relates to a belt retractor having the features of the preamble of claim 1.

Belt retractors have as basic components a load-bearing frame and a belt spool which is rotatably mounted in the frame and on which a safety belt can be wound. In addition to storing the belt reel, the frame also serves to fasten the belt retractor to a seat structure or to a vehicle structure and is made from a suitably thick sheet of steel, which is bent into a U-shaped frame.

Vehicle seats with integrated safety belt devices are known, e.g. for use as front seats in convertibles, in which at least the belt retractors of the safety belt devices are fastened in the backrests of the vehicle seats. In this case, due to the lack of a load-bearing B-pillar and for reasons of access to the rear seats or for reasons of distance from the rear vehicle structure, the belt retractors are preferably integrated into the backrests of the vehicle seats, which are therefore also designed to absorb the tensile forces acting in the event of restraint Need to become. The retractors themselves have all the basic components of a standard retractor and are only fitted with various ancillary assemblies specifically designed for installation in the seat back, such as a self-aligning inertial sensor.

In its basic design, the vehicle seat has a seat structure made up of a number of load-bearing structural parts which are used to fasten the vehicle seat to the vehicle structure. The seat structure is provided with springs and padding to improve seating comfort and is also used to attach other components such as various seat adjustment mechanisms, including the associated electric motors and other components such as heaters, sensors, displays, headrests and the like.

In modern vehicles with autonomous driving systems, increased adjustability of the vehicle seats in different orientations and positions in the passenger compartment is increasingly required, so that the vehicle occupants can use the freedom gained through autonomous driving, e.g. for in-depth communication with other occupants, for longer and more intensive rest phases or also can use it for work and align the vehicle seat accordingly. As a result, the seat belt device and in particular the belt retractor no longer has to be attached to the vehicle structure as before, but instead has to be attached to the vehicle seat with all its components, i.e. belt retractor and belt buckle, as is already the case with the front seats of convertibles, for example.

Furthermore, belt retractors in modern safety belt devices are provided with electric motors which, when activated, drive the belt shaft in the winding direction, for example for reversible belt tightening. The electric motor is also fastened to the frame and is arranged to the side of the spool with a drive shaft aligned parallel to the axis of rotation of the spool. Furthermore, it is known to provide a transmission between the spool and the electric motor, through which the speed of the electric motor is translated into a predetermined speed of the spool. The use of the gear also makes it possible to use an electric motor that is as small as possible and has a high rotational speed, while nevertheless exerting a comparatively high torque on the belt shaft. Overall, this results in a belt retractor with an increased installation space requirement despite the use of the small electric motor made possible by the transmission. Such a belt retractor is, for example, from the publication WO 03/0 99 619 A2 known.

If the belt shaft is to be driven at different speeds and torques, further gear stages must be provided, which further increase the space requirement. Such a belt retractor is, for example, from the publication DE 199 27 731 C2 known.

Furthermore, it is known to provide force-limiting units in the seat belt retractors, which enable the occupant to be displaced forward with limited force in order to reduce the occupant load before it is absorbed by the airbags. Torsion bars made of steel have proven particularly effective as force-limiting units, which are connected at one end in a rotationally fixed manner to a part that can be locked in place on the vehicle and at the other end to the belt shaft. During their activation, these torsion bars are plastically twisted around their longitudinal axis and thereby consciously destroy energy. The force limitation level or the force limitation characteristic is determined by the plastic deformation resistance of the torsion bar, which in turn depends on the material and the diameter of the torsion bar. The torsion bar provides a constant level of force limitation and is only activated when its plastic deformation limit is exceeded.

If the tensile force in the belt is not great enough, e.g. when restraining small children, and the plastic deformation resistance is not exceeded, the occupant, i.e. in this case the child, does not experience any force-limited forward displacement. In this case, the occupant does not utilize the forward displacement path available for restraint in the passenger compartment and is instead restrained with a higher occupant load than would actually be possible if the forward displacement path available was fully utilized.

From the patent DE 10 2005 016 822 B3 a frequency-controlled force-limiting unit is also known, which enables a force-limited belt webbing extension by means of a mass system to be set in motion. The advantage of this force-limiting unit is that the force-limited webbing extension is activated independently of the tensile forces acting in the webbing, and that the forward displacement path used to reduce the occupant load is also independent of the severity of the accident. Thus, in the ideal case, the maximum forward displacement path is always utilized for the occupant and the occupant load is reduced to the maximum. The force-limiting characteristic of this force-limiting unit is defined by the design of the mass system to be set in motion.

Both the force-limiting unit with the torsion bar and the frequency-controlled force-limiting unit are activated by the tensile force acting in the belt and have unchangeable force-limiting characteristics that are defined solely by their design.

In the applicant's not yet published application DE 10 2020 207 535.2 it is proposed that the force-limiting unit in the belt retractor should have an electric motor and a first blocking device, and the first blocking device be set up to release and block again a rotary movement of the belt shaft in the pull-out direction in a repeating sequence by activating the electric motor. The first blocking device is formed here by a plurality of blocking elements which block and unblock again in order to implement the force-limited belt extension in a repetitive sequence by contacting a ramp-shaped blocking contour and thereby performing a radial movement made possible by a control contour.

The advantage of the proposed solution can be seen in the fact that the force-limiting unit of the belt retractor has a controllable electric motor, and that the first blocking device is deliberately set up to enable a force-limited belt webbing extraction movement, triggered by the activation of the electric motor, by preventing the rotational movement of the belt shaft in the extraction direction releases and blocks again in a repeating sequence. In this way, the start and end of the belt webbing extraction movement can be controlled independently of the tensile forces acting in the belt. The rotational movement of the belt shaft is blocked before the activation of the electric motor by the blocking device arranged in the blocking position and is only made possible by the activation of the electric motor. The electric motor can also be regarded as the trigger for the force-limited belt webbing extraction movement. As a result of the brief release of the first blocking device, the belt webbing is pulled out for a very short period of time under the tensile forces exerted by the occupant during restraint in the accident until the next blocking of the first blocking device, and the occupant moves forward with a reduced occupant load as a result, before the forward displacement is stopped again by the blockage and the process is repeated. The first blocking device is designed in such a way that the time intervals between unlocking and the subsequent blocking are between 0.1-2ms, so that the webbing is pulled out step by step in very short, repetitive pull-out movements, which for the occupant due to the very short periods of time are imperceptible.

Depending on activation of the electric motor, the first blocking device can be moved from a position blocking the spool to a position releasing the spool, and the first blocking device is automatically blocked again by the enabled rotary movement of the spool in the extension direction after a predetermined angle of rotation of the spool. Accordingly, the electric motor is used to trigger the unlocking process of the first blocking device and thus to enable the intended belt webbing extraction movement by means of a belt shaft released as a result. The subsequent pull-out movement can, for example, be brought about by the pulling force exerted by the occupant on the belt webbing; the electric motor does not have to be involved here. However, it cannot be ruled out that the electric gate is also actively used to influence the extension movement. Since the first blocking device is also set up to automatically block again after a predetermined angle of rotation of the spool, the rotary movement of the spool in the pull-out direction is then automatically stopped again before it is released and blocked again in a repetitive process.

It has been found that the blocking device or the blocking elements are exposed to very high accelerations and the resulting impulse forces in the circumferential direction during the blocking process, which require a corresponding dimensioning or dimensioning of the blocking elements and the blocking contour.

Against this background, the invention is based on the object of providing a belt retractor with a force-limiting unit with an electric motor and a first blocking device, which is set up to release and block again a rotary movement of the belt shaft in the extension direction in a repetitive sequence by activating the electric motor , which should enable an improved, controlled webbing extraction with a reduced load on the blocking device and the blocking contour.

According to the invention, a belt retractor having the features of claim 1 is proposed to solve the problem. Further preferred further developments can be found in the dependent claims, the figures and the associated description.

According to the basic idea of the invention, it is proposed that the first blocking device and/or a blocking contour, on which the first blocking device comes to rest in the blocking position, is or are resiliently mounted in or against the blocking direction of the first blocking device via at least one spring.

The resilient mounting of the blocking contour and/or the first blocking device deliberately introduces a resilience into the force transmission path, through which the acting impulse forces and the associated loads on the parts involved in the blocking movement can be reduced.

The blocking movement is particularly effectively damped in that the spring(s) is/are arranged in the circumferential direction of the rotary movement of the belt shaft. This targeted alignment of the spring(s) deliberately dampens the rotational movement in a preferred direction in the direction of its circumference, while radial movements are undamped, so that the bearing of the parts involved in the rotational movement is not adversely affected.

It is further proposed that the spring(s) is or are formed by one or more helical springs. Helical springs are particularly compact springs and can cause very high damping with high spring forces in a small space due to the large number of deforming coils. Furthermore, helical springs can be aligned in a particularly simple manner by a corresponding curvature in the circumferential direction of the rotational movement.

It is further proposed that at least two springs acting in parallel be provided. The spring force and the associated damping can be further increased by the springs acting in parallel. Furthermore, this can further reduce the probability of failure of the force-limiting unit, since in the event of damage to one of the springs, damping is still effected by the second spring acting in parallel.

It is further proposed that the blocking contour is formed by a blocking ring with a plurality of cams arranged evenly distributed over the circumference. The proposed design of the blocking contour allows a particularly compact design of the belt retractor to be implemented with a corresponding force-limiting unit.

The triggering of the unlocking process of the first blocking device can be implemented particularly easily and in a compact design by providing an unlocking ring driven by the electric motor, which has a control contour, and the first blocking device is formed by at least one blocking element lying against the control contour. Due to the movement triggered by the drive via the electric motor, the unlocking ring controls the triggering and the course of the movement or the possibility of movement of the blocking element lying against it due to the shape of its control contour. The control contour is designed in such a way that its shape forces the blocking element into the blocking position over certain sections during the movement and deliberately releases it again in certain sections, so that the blocking element moves out of the blocking position into a release position and into a release position during the movement relative to the unlocking ring can move vice versa or is forced to move by the shape of the control contour.

Such a shaping of the control contour can be realized, for example, by being formed by a ramp structure with a number of ramps corresponding to the number of blocking elements and depressions arranged between the ramps, against which the blocking element rests alternately in the blocking position and the releasing position. The blocking element is unlocked and blocked by a relative movement of the blocking element or elements elements to the control contour, which in turn can be triggered by the drive of the unlocking ring via the electric motor relative to the blocking element(s) and subsequently formed by a combination of the movement of the unlocking ring and the blocking element(s).

It is further proposed that a direction of rotation reversing gear is provided, which is in a rotary connection with the sling shaft via a first part, and the first blocking device between the first part of the direction of rotation reversing gear and a second part driven by the direction of rotation reversing gear to a direction of rotation opposite to the direction of rotation of the sling shaft of the direction of rotation reversing gear is arranged. The proposed further development can in any case ensure that the parts which are blocked to one another via the first blocking device always perform a relative movement to one another, which in turn is used for the automatic blocking of the first blocking device. Furthermore, this relative movement is additionally increased by the direction of rotation reversing gear and the resulting different directions of rotation of the parts to be blocked in relation to one another. Due to this increased relative movement, the angle of rotation of the first part and thus also the angle of rotation of the belt shaft, after which the first blocking device blocks again, can be reduced in reverse.

In this case, the direction of rotation reversing gear can preferably be designed in such a way that the second part, compared to the first part, carries out a rotational movement which is translated into a higher speed by the direction of rotation reversing gear. As a result, the relative rotary movement available for blocking the first blocking device can be further increased and the angle of rotation of the belt shaft after it is blocked again can be shortened, since the second part then performs an increased movement compared to the movement of the first part and thus the larger part of the relative movement executes Furthermore, the direction of rotation reversing gear can be designed so that it can be designed in its actual functional direction to tighten the belt as the speed of the electric motor in a lower speed of the belt shaft reducing gear. Furthermore, an advantage can be obtained through the translation of the rotational movement in that the first blocking device can be realized with comparatively small motor torques.

A particularly compact design of the belt retractor can be achieved in that the direction of rotation reversing gear is formed by a planetary gear, and the reversal of the direction of rotation in the direction of rotation reversing gear is realized by a planet carrier of the planetary gear that is blocked by a second blocking device relative to the frame of the belt retractor. The advantage of this solution can be seen in the fact that planetary gears basically have a very compact structure and allow high transmission ratios. Furthermore, the planetary gear can be constructed in a very simple manner as a direction of rotation reversing gear by blocking a planet carrier with respect to the frame of the belt retractor. This means that the planetary gear can basically be used without blocking the planet carrier, e.g. to implement another function such as reversible pre-tightening without reversing the direction of rotation of the rotary movement to translate the rotary drive movement.

It is also proposed that the first part or the second part of the direction of rotation reversing gear have a blocking contour against which the first blocking device rests in the blocking position. The blocking contour here forms a form-fitting connection with respect to the direction of rotation of the two parts relative to one another and prevents further rotational movement of the second part relative to the first part. The blocking contour is arranged in such a way that the first blocking device automatically comes into contact with it during the rotary movement of the first part or also the belt shaft in the pull-out direction of the belt webbing and blocks further rotary movement.

It is further proposed that the first part is formed by a tubular, axial extension which is non-rotatably connected to the belt shaft and which forms the housing of the direction of rotation reversing gear. The first part practically forms a tubular extension of the spool in the axial direction, which forms a lug for blocking the spool and at the same time serves as a housing for the direction of rotation reversing gear due to its shape.

In this case, the blocking contour can preferably be formed by ramps which are directed in the circumferential direction and are arranged on the inside of the annular extension and on which the blocking elements bear in the blocking position. The proposed shape has the advantage that the ramps enable the first part to be carried along in a form-fitting manner when the first blocking device is in the blocking position. On the other hand, due to their inclines, the ramps allow the blocking device to be automatically displaced from the blocking position into the releasing position when the first blocking device is driven by the control contour of the Ent locking ring is no longer pushed in the direction of the blocking position. The blocking contour is used not only to block the first blocking device, but also to trigger the unblocking movement when the first blocking device is released.

It is also proposed that the unlocking ring be spring-loaded by a spring in relation to the belt shaft. The proposed solution keeps the unlocking ring in a spring-elastic connection to the spool and thus rotates with the spool so that it is held by the spring in a position relative to the spool in which it urges the blocking device into the blocking position.

It is also proposed that the belt shaft be spring-loaded by a drive spring that is fixed to the frame in the winding direction of the safety belt, and that the spring force of the drive spring is smaller than the spring force of the spring loading the unlocking ring. With the proposed further development, the electric motor can also be used to implement a comfort function, in that it also acts on the belt shaft parallel to the drive spring while the seat belt is being fastened, thereby either increasing the retraction force acting on the belt shaft, e.g. for sporty driving, or also to a reduction in the retraction force acting on the seat belt, so that the occupant is less aware of the seat belt. Furthermore, this also allows the seat belt to be wound up into the parking position after it has been unbuckled.

• 1 einen in der DE 10 2020 207 535.2 beschriebenen Gurtaufroller in zwei Darstellungen mit einem montierten und einem teilweise demontierten Rahmen, und
• 2 einen in der DE 10 2020 207 535.2 beschriebenen Gurtaufroller mit den einzelnen Baugruppen in einem demontierten Zustand, und
• 3 einen in der DE 10 2020 207 535.2 beschriebenen Gurtaufroller ohne Rahmen in einer Explosionsdarstellung, und
• 4 eine Baugruppe aus einem Planetengetriebe, einer Kraftbegrenzungseinheit und einem Elektromotor eines erfindungsgemäßen Gurtaufrollers in einer Explosionsdarstellung in einer ersten Perspektive, und
• 5 eine Baugruppe aus einem Planetengetriebe, einer Kraftbegrenzungseinheit und einem Elektromotor eines erfindungsgemäßen Gurtaufrollers in einer Explosionsdarstellung in einer zweiten Perspektive, und
• 6 das Planetengetriebe mit der Kraftbegrenzungseinheit als Baugruppe ohne ein Gehäuse, und
• 7 das Planetengetriebe mit der Kraftbegrenzungseinheit in Explosionsdarstellung in einer ersten Perspektive
• 8 das Planetengetriebe mit der Kraftbegrenzungseinheit in Explosionsdarstellung in einer zweiten Perspektive
• 9 eine vergrößerte Schnittdarstellung des Planetengetriebes mit der Kraftbegrenzungseinheit, und
• 10 die Kraftbegrenzungseinheit in Schnittdarstellung im Ausgangszustand und bei hoher einwirkender Last, und
• 11 die Kraftbegrenzungseinheit in Schnittdarstellung im Ausgangszustand und bei Gurtbandausgabe nach einer reversiblen Gurtstraffung; und
• 12 die Kraftbegrenzungseinheit in Schnittdarstellung bei geringer einwirkender Last während der Gurtbandausgabe, und
• 13 die Kraftbegrenzungseinheit in Schnittdarstellung bei hoher einwirkender Last während der Gurtbandausgabe, und
• 14 das Blockierelement als Einzelteil, und
• 15 das Blockierelement in der radial äußeren Anschlagstellung, und
• 16 das Blockierelement in der radial inneren Anschlagstellung.

The invention is explained below on the basis of preferred embodiments with reference to the accompanying figures. while showing

• 1 one in the DE 10 2020 207 535.2 described belt retractor in two representations with an assembled and a partially disassembled frame, and
• 2 one in the DE 10 2020 207 535.2 described belt retractor with the individual assemblies in a disassembled state, and
• 3 one in the DE 10 2020 207 535.2 described belt retractor without frame in an exploded view, and
• 4 an assembly of a planetary gear, a force limiting unit and an electric motor of a belt retractor according to the invention in an exploded view in a first perspective, and
• 5 an assembly of a planetary gear, a force limiting unit and an electric motor of a belt retractor according to the invention in an exploded view in a second perspective, and
• 6 the planetary gear with the force limiting unit as an assembly without a housing, and
• 7 the planetary gear with the force limiting unit in an exploded view in a first perspective
• 8th the planetary gear with the force limiting unit in an exploded view from a second perspective
• 9 an enlarged sectional view of the planetary gear with the force limiting unit, and
• 10 the force limiting unit in a sectional view in the initial state and with a high applied load, and
• 11 the force-limiting unit in a sectional view in the initial state and when the belt webbing is released after reversible belt tightening; and
• 12 the force limiting unit in sectional view with a low load applied during webbing payout, and
• 13 the force limiting unit in sectional view with high applied load during webbing payout, and
• 14 the blocking element as a single part, and
• 15 the blocking element in the radially outer stop position, and
• 16 the blocking element in the radially inner stop position.

The belt retractor according to the invention corresponds in its basic structure to the 1 until 3 shown and in the DE 10 2020 207 535.2 described belt retractor, which has an elongate, in cross section, apart from curves and some slopes, rectangular in the basic structure, tubular frame 1 of two housing shells 3. The frame 1 has a slot 2 from which an unillustrated seat belt is led out to an occupant restrained by the seat belt in a vehicle. So that the assemblies of the belt retractor are easier to recognize, the illustration below 1 and in the 2 one of the housing shells 3 omitted. The belt retractor is specially designed in its elongated shape for an arrangement in a vehicle seat, the belt retractor having the smallest possible height and width by a coaxial arrangement of the assemblies described below in cross section, so that it can also be used in narrow cavities men of the vehicle seat can be arranged. The frame 1 is divided by a plurality of webs 7 and closed at its ends, the webs 7 on the one hand stiffening the frame 1 and on the other hand serving to store or hold the assemblies.

The belt retractor has a belt shaft 5, on which the safety belt, not shown, can be wound up. Furthermore, a spring cassette 9 is fastened to the outside of the right-hand web 7 in the illustration, which, as will be explained in more detail below, is connected to the right-hand side of the belt shaft 5 in the illustration. The belt shaft 5 is also connected on its left side to a gear 6 and is mounted on another web 7 above it. Furthermore, a locking unit 8 and an electric motor 4 are provided in a coaxial arrangement with the belt shaft 5 and the gear mechanism 6 . The assembly of the spool 5 and the gear 6 form in normal operation of the belt retractor so during the buckling process, wearing and unbuckling the seat belt when the electric motor 4 is not activated, a subassembly which by in the 3 recognizable mainspring 91 of the spring cassette 9 is prestressed in the winding direction. Furthermore, the subassembly consisting of the belt shaft 5 and the gear 6 can be blocked in the extension direction via the locking unit 8 if predetermined limit values of the belt webbing extraction acceleration and/or vehicle deceleration are exceeded.

In the 3 the belt retractor can be seen without the frame 1 with its individual parts in an exploded view. The spring cassette 9 comprises a housing 90 in which the mainspring 91 is arranged and is fastened with its outer end. The open side of the housing 90 is closed by a housing cover 92 so that the spring cassette 9 can be prefabricated as an assembly and attached to the outside of the right and first web 7 via the housing 90 . The spool 5 has a two-part structure with a spool body 50 and a radial flange 52 on the end face, which are connected to one another via a torsion bar 51 . The torsion bar 51 is designed here with a very high force limitation level of, for example, 7 or 9 kN or more and only serves as overload protection here, ie it is not activated either during normal use or in accident scenarios. If the overload protection is to be dispensed with, the torsion bar 51 can also be omitted; in any case, it is irrelevant for functions made possible by the electric motor 4 . Furthermore, the belt shaft body 50 protrudes with an extension into the spring cassette 9 and is connected there to the mainspring 91 via a spring core.

The gear 6 is arranged on the left side of the spool 5 and is non-rotatably connected to the radial flange 52 of the spool 5 by a gear housing 60 via a bayonet connection. The bayonet connection is here by correspondingly shaped fingers 521 on the radial flange 52 and in the 4 to be recognized, form-corresponding recesses 603 realized on the gear housing 60. The gear 6 comprises a planetary gear 62, a force limiting unit 61, which will be explained in more detail below, and a drive wheel 63 which is non-rotatably connected to the drive shaft 41 of the electric motor 4.

The assembly of the gear 6 and the spool 5 is mounted on its left side on a second web 7 and extends through an internally toothed opening of the second web 7 therethrough. Furthermore, a further third web 7 is provided, forming an intermediate space, on which the electric motor 4 is held. The locking unit 8 is arranged in the space between the second and third web 7 . The locking unit 8 includes an electrically controllable actuator 82 which is held on the same web 7 to which the electric motor 4 is also attached. Furthermore, the locking unit 8 comprises an externally toothed control disk 80 mounted rotatably on an extension of the gear mechanism 6 and a WS blocking pawl 81 that can be controlled by a belt webbing acceleration sensor. The control disk 80 has a control contour in which a second blocking pawl 6211 engages with a control pin, a first planetary carrier 621a, explained in more detail below. The second blocking pawl 6211 here forms the second blocking device, the function of which will be explained in more detail below.

If the locking unit 8 is activated, the actuator 82 is energized and a lever of the actuator 82 is thereby deflected. The lever of actuator 82 thus engages the toothing of control disk 80, which is then stopped relative to belt shaft 5 against a further rotational movement in the pull-out direction of the seat belt and forces second blocking pawl 6211 to move, during which it moves belt shaft 5 in one direction Extension direction blocking engagement in an internal toothing 71 of the web 7 passes. The locking unit 8 also includes the WS blocking pawl 81, which, when a predetermined acceleration of the belt webbing pull-out is exceeded, engages a tooth system and thereby blocks the control disk 8 against a further rotational movement in the belt webbing pull-out direction, thereby forcing the second blocking pawl 6211 to perform the modulation movement in the same way. Finally, on the left side of the retractor is a fourth and last Ter web 7 is provided, which closes and stiffens the frame 1 on its left side. However, the fourth web 7 can also be used for additional storage of the electric motor 4 .

In the 4 and 5 the transmission 6 can be seen in an enlarged exploded view in different perspectives. The planetary gear 62 includes a first planetary carrier 621a with a plurality of first planetary gears 622a rotatably mounted thereon and the blocking pawl 6211 pivotally mounted thereon, which forms the second blocking device. The planetary gear 62 further includes a second planetary carrier 621b, which has a sun gear meshing radially inward with the first planetary gears 622a of the first planetary carrier 621a on one side and a plurality of rotatably mounted second planetary gears 622b on the other side. Furthermore, an internally toothed ring gear 623 is provided, which has a sun gear on one side, which meshes radially on the inside with the second planetary gears 622b of the second planetary carrier 621b. A set of further third planetary gears 622c engage in the internal toothing of the ring gear 623, which in turn are each rotatably mounted on pins 618 protruding axially from a carrier part 612 of the force-limiting unit 61.

The first planetary gears 622a of the first planetary carrier 621a mesh in an internal toothing 601 of the housing 60 and thereby connect the belt shaft 5 to the planetary gear 62 . The planetary gear 62 further comprises a gear shaft 624 which is rotatably mounted on a drive shaft 41 of the electric motor 4 and which at its first end with a first toothing 625 engages radially on the inside in the toothing of the third planet gears 622c of the right-hand planetary stage of the planetary gear 62 in the illustration. The transmission shaft 624 also has a central second helical gear 627 on a larger diameter, a ring portion 628 arranged next to the second gear 627 with a smooth surface and at the second end a third also helical gear 626 .

The force limiting unit 61 comprises a three-part unlocking ring 611, which is composed of a middle ring part 611a with two outer ring parts 611b and 611c enclosing it. An axially protruding annular flange is provided on one side of the central ring part 611a, on which a radially outwardly directed control contour 616 is provided on one side and a protruding annular flange with radially directed internal teeth 617 is provided on the other side. The ring part 611b on the left in the illustration and the ring part 611c on the right are each pushed onto axially directed webs 605 of the housing 60 via outer recesses 6111, with the recesses 6111 being dimensioned such that the ring parts 611b and 611c can perform slight rotational movements relative to the housing 60 or are also rotatably connected to the housing 60. Furthermore, the ring spring 615 is supported with one end on one of the ring parts 611b or 611c and with the other end on the middle ring part 611a.

The force-limiting unit 61 also includes the ring-shaped carrier part 612 with axially projecting pins 618, on which the third planet gears 622c of the last planetary stage of the planetary gear 62 in the illustration are rotatably mounted. The carrier part 612 is constructed in two parts with a base body 612a and an insert part 612b. The axially protruding pins 618 protrude from the base body 612a, which has recesses on its rear wall, into which the insert part 612b engages with projections of the appropriate shape, forming a non-rotatable, compact unit. In the projections of the insert part 612b, radially directed recesses 614 are provided, in which blocking elements 613 are guided in a radially displaceable manner.

The gear shaft 624 protrudes with the first end and the first toothing 625 arranged thereon in the axial direction from the carrier part 612 and engages with this first toothing 625 between the third planet gears 622c of the right and third planetary stage of the planetary gear 62. The second toothing 627 is in the Diameter, the width and the arrangement on the gear shaft 624 designed so that it is arranged in the mounted position of the gear shaft 624 in an opening of the support part 612. Furthermore, two spring-loaded pawls 629 are pivotally mounted in the opening of the carrier part 612, the pawls 629 being urged by the spring loading in the direction of engagement into the second oblique toothing 627.

The middle ring part 611a of the unlocking ring 611 has, on the side facing the carrier part 612, the ring flange with the control contour 616 arranged thereon, which is formed by alternately arranged ramps 6161 and depressions 6162. The spring 615 is designed as an annular spring and is designed to have a much stronger spring force than the mainspring 91 in the spring cassette 9 . Furthermore, the spring 615 is dimensioned such that it fixes the middle ring part 611a in the unloaded state, i.e. in the assembled state before the activation of the electric motor 4, in a position in which the blocking elements 613 are radially inward from the ramps 6161 of the control contour 616 of the unlocking ring 611 get supported.

Furthermore, a three-part blocking part 66 is provided, which has two ring-shaped frame parts 661 and 662 which are non-rotatably fixed relative to the housing 60 . The frame parts 661 and 662 are of identical design and are each formed with four axially projecting fingers which are arranged at angles of 90 degrees to one another and which each have a groove on their outer sides for creating the non-rotatable connection with the housing 60 . The frame parts 661 and 662 are arranged mirror-symmetrically so that they abut one another with the end faces of the fingers and each enclose four closed windows, as in FIG 6 can be seen. Furthermore, the blocking part 66 has, as a third part, a blocking ring 663 with a blocking contour 68 arranged radially on the inside in the form of four cams that project radially inward and are directed in the axial direction. The blocking ring 663 is further provided with four radially outwardly directed webs 69 which are arranged at angles of 90 degrees to one another and which protrude into the windows formed between the frame parts 661 and 662 in the assembled position of the three-part blocking part 66 . Furthermore, four pairs of two mutually parallel and circumferentially aligned coil springs 67 are provided, which are arranged in the windows and are supported with first ends on the frame parts 661 and 662 and with second ends on the webs of the blocking ring 663. The blocking ring 663 is thus spring-loaded in the circumferential direction via the coil springs 67 in relation to the frame parts 661 and 662 which are supported on the housing 60 . In the 7 and 8th the carrier part 612 and the blocking part 66 can be seen in an exploded view from different perspectives.

The drive wheel 63 has a central axial opening with internal teeth 631, in which the electric motor 4 with its in the 4 shown drive shaft 41 is rotatably connected via a toothed end 42. The drive wheel 63 and the drive shaft 41 thus form a non-rotatable connection. Provided on the drive wheel 63 is an annular flange 635 which protrudes axially in the direction of the unlocking ring 611 and is the carrier of two diametrically arranged, radially inwardly protruding, pivotably mounted first pawls 632 . The first pawls 632 are spring-loaded by two spring plates held in the annular flange 635 . The radially inner first pawls 632 are thereby urged into the third outer teeth 626 of the transmission shaft 624 . The first pawls 632 and the third toothing 626 are aligned in such a way that a rotational movement of the drive wheel 63 is transmitted to the gear shaft 624 in the direction in which the seat belt is wound up. This rotational movement of the transmission shaft 624 is then transmitted via the first toothing 625 to the third planet gears 622c in the representation of FIG 9 transferred to the right planetary level.

In the 9 the transmission 6 can be seen in an enlarged sectional view. The drive shaft 41 of the electric motor 4 extends through the gearbox 6 and drives the gearbox 6 via the drive wheel 63 . The rotational movement of the drive shaft 41 is then transmitted from the drive wheel 63 via the force limiting unit 61, the planetary gear 62 and finally the housing 60 to the belt shaft 5 in various functions, which are explained in more detail below.

The input shaft 41 extends through the first planetary carrier 621a, the first planetary carrier 621a being free to rotate with respect to the input shaft 41. Furthermore, the first planetary carrier 621a is connected to the housing 60 of the transmission 6 in the direction of rotation A counterclockwise in the direction in which the seat belt is wound up, e.g. via a latching connection. The planetary gear 62 is simultaneously connected to the belt shaft 5 via the rotary connection of the planetary gear 62 to the housing 60 created in this way. When the electric motor 4 is activated, this rotary connection allows the belt shaft 5 to rotate with a drive rotary movement of the drive shaft 41 via the drive wheel 63, the gear shaft 624, the planetary gear 62 and finally via the housing 60 of the gear 6 in the winding direction to roll up the seat belt after unbuckling be rolled up into the parking position. For this purpose, the rotary drive movement of the drive shaft 41 of the electric motor is transmitted via the drive wheel 63 to the gear shaft 624 via the first pawls 632 mounted on the drive wheel 63 and engaging in the third toothing 626 . The first pawls 632 and the oblique third toothing 626 are aligned in such a way that the rotational movement is transmitted in this direction of rotation, but not in the other direction of rotation.

In this function, the electric motor 4 acts as a winding aid for the seat belt. The force limiting unit 61 is driven by the drive wheel 63 together with the planetary gear 62 and the housing 60 as an assembly in a transmission ratio of the rotational movement of the drive shaft 41 of 1:1. Since the planetary gear 62 inherently has a predetermined sluggishness, this rotational movement of the gear shaft 624 is transmitted 1:1 to the housing 60 during the winding movement of the seat belt into the parking position without activating the planetary gear 62 . The drive shaft 41, the drive wheel 63, the gear shaft 624, the housing 60 and finally the spool 5 rotate in this Fall with an identical speed in the winding direction of the seat belt.

Furthermore, the belt retractor enables reversible belt tightening with a higher retraction force in the seat belt for pulling out possible belt slack in a pre- or early-accident phase. For this purpose, the electric motor 4 drives the spool 5 initially in an identical rotary drive motion via the drive wheel 63, in the same power transmission path as in the function as a winding aid in the winding direction, but at a much higher speed. The slack in the belt is suddenly pulled out until the belt force to be overcome in the safety belt has increased to such an extent that it is greater than the self-locking in the planetary gear 62. This increase in the belt force means that the housing 60 of the gear 6 can no longer rotate and the internal gear 601 becomes a fixed gear. In this phase, the planetary gear 62 briefly becomes a reversing gear and the first planetary carrier 621a is driven by the first planetary gears 622a rolling on the fixed internal toothing 601 to rotate in the direction of the seat belt extension. At the same time, in addition to the abrupt increase in the speed of the electric motor 4 to activate the reversible belt tightening, the locking unit 8 is also activated and the lever of the actuator 82 engages in the toothing of the control disk 80, so that the control disk 80 is blocked against rotation in the direction of the seat belt extension . The second blocking pawl 6211 mounted on the first planetary carrier 621a engages with a pin in a bean-shaped control contour of the control disk 80 and is coupled to it via this. As a result, the second blocking pawl 6211 is forced, due to the rotational movement of the first planetary carrier 621a relative to the blocked control disk 80, to perform a pivoting movement defined by the shape of the control bean in the control disk 80, during which it engages with the internal toothing 71 of the web 7, through which the first planetary carrier 621a extends. This engagement of the second blocking pawl 6211 then blocks the first planetary carrier 621a in the pull-out direction of the safety belt and the rotational movement of the first planetary carrier 621a, which reverses the direction of rotation, is ended.

Subsequently, the blocked first planetary carrier 621a forms a vehicle-fixed abutment and the housing 60 or the spool 5 are now driven by the electric motor 4 with activation of the planetary gear 62 at a speed translated into a lower speed with a higher torque in the winding direction. As a result, the seat belt is subsequently tightened with an increased tension force of e.g. 1000 N, and more slack is pulled out of the seat belt. The planetary gear 62 is driven via the gear shaft 624 without the unlocking ring 611 or the carrier part 612 being moved as a result of the locking pawls 629 of the carrier part 612 ratcheting over the second toothing 627 of the gear shaft 624 . Furthermore, due to the reduction of the planetary gear 62, the gear shaft 624 rotates faster than the belt shaft 5 and thus faster than the housing 60, which is made possible by the fact that the gear shaft 624 can rotate freely in relation to the unlocking ring 611 and at the same time by the ratcheting of the pawls 629 in relation to the Support part 612 can rotate. Since the carrier part 612 is blocked by the blocking elements 613 in relation to the housing 60, the carrier part 612 rotates together with the housing 60 at the same speed and can simultaneously perform a rotary movement in relation to the gear shaft 624 by the ratcheting of the pawls 629.

In a further function, the belt retractor works with the cooperation of the electric motor 4 as a controlled force limiter, which allows a force-limited extension of the seat belt to reduce the occupant load in a forward displacement phase of the occupant in the accident following the reversible tightening. For this purpose, the belt retractor has the force-limiting unit 61, the functioning of which is explained in more detail below. In the illustration on the left 10 the position of the interacting parts of the force limiting unit 61 before the activation of the controlled force limiter can also be seen, for example, during reversible belt tightening, winding into the parking position (winding aid) or also during the seat belt warning function explained below. The unlocking ring 611 is in a rotational angle position in which it radially supports the blocking elements 613 through the ramps 6161 of the control contour 616, in particular through flat sections or sections in the shape of circular rings in the end sections of the ramps 6161, thereby urging it into a radially extended blocking position.

The blocking ring 663 has on its inside a blocking contour 68 in the form of four cams directed in the axial direction, each with ramps 602 and 604 rising laterally opposite to the centers of the cams. The unlocking ring 611 is arranged to enclose the ridges 605 of the housing 60 with the cutouts 6111, the cutouts 6111 being sized slightly larger in the circumferential direction than the ridges 605, so that the unlocking ring 611 can rotate slightly relative to the housing 60 with respect can run to the axis of rotation of the belt retractor or the belt shaft 5. Furthermore, the Blocking elements 613 on the ramps 6161 of the control contour 616 on the axially projecting annular flange of the middle ring part 611a of the unlocking ring 611 are supported radially on the inside. The blocking elements 613 are thus in the circumferential direction on the ramps 604 of the blocking contour 68 formed by the cams of the blocking ring 663 fixed to the housing and thus connect the carrier part 612 counterclockwise to the housing 60. The carrier part 612 is thus via the blocking elements 613, which are on the Ramps 604 abut laterally, blocked counterclockwise via the blocking ring 663 relative to the housing 60 . The blocking ring 663 with the blocking contour 68 is resiliently mounted in relation to the frame parts 661 and 662 via the springs 67 so that the blocking ring 663 can yield slightly in relation to the blocking elements 613 . As a result, the accelerations of the blocking elements 613 during blocking and unblocking and the impulse forces acting on the blocking elements 613 and on the blocking contour 68 or the blocking ring 663 can be reduced.

Starting from this initial position, the locking unit 8 is activated before the beginning of the controlled, force-limited belt webbing extraction, and the lever of the actuator 82 then engages in the toothing of the control disk 80, and the control disk 80 is blocked in the belt extraction direction. The electric motor 4 is then controlled in such a way that it drives the drive wheel 63 in the direction in which the webbing is pulled out. As a result, the control disc 80 is also driven in the pull-out direction and the second blocking pawl 6211 is forced to perform a modulation movement in the housing-fixed internal toothing 71 of the web 7, whereby the first planetary carrier 621a is blocked in the pull-out direction of the seat belt. Furthermore, the unlocking ring 611 is also driven in the pull-out direction via the pawls 632 mounted on the drive wheel 63 . As a result, the unlocking ring 611 is rotated in relation to the carrier part 612 to such an extent that the blocking elements 613 lose their support radially on the inside via the ramps 6161 of the control contour 616 . At the same time, in this early phase of the forward displacement or after a reversible or irreversible belt tightening, there are already considerable tensile forces in the seat belt, which in a first step lead to the belt shaft 5 rotating together with the gear 6 in a very short angle of rotation in the extension direction , whereby the second blocking pawl 6211 on the first planetary carrier 621a is forced into the toothing 71 due to the blocked control disk 80 in addition to the modulation movement and blocks the first planetary carrier 621a with respect to the frame 1 of the belt retractor if the blocking due to the previous drive of the control disk 80 is over the electric motor 4 is not yet fully completed. The belt shaft 5 rotates until the second blocking pawl 6211 is locked, without the unlocking ring 611 rotating relative to the gear housing 60 . After the first planet carrier 621a is blocked, the tensile force exerted by the seat belt leads to a force being introduced into the planetary gear 62.

Due to the first planetary carrier 621a being blocked by the second blocking pawl 6211, the first stage of the planetary gear 62 becomes a direction of rotation reversing gear, and the belt shaft 5 can only continue to rotate together with the housing 60 of the gear 6 under the action of the tensile force in the direction of the seat belt extraction, in that the first Planet gears 622a no longer revolve but only rotate about their axes of rotation and transmit the rotary motion to the other planetary stages in the opposite direction of rotation. If a reversible belt tensioning movement has taken place, which is to be assumed in the event of an accident, the first planetary carrier 621a is already blocked due to the preceding tensioning movement described above, and the blocking process described for activating the force-limited belt extraction movement is omitted, or the first planetary carrier 621a is already at the beginning the activation of the electric motor 4 for the controlled force-limited webbing extension blocked. By blocking the first planetary carrier 621a, the speed of the belt shaft 5 and the housing 60 is translated into a faster rotational movement by the transmission and finally transmitted to the carrier part 612, on which the third planetary gears 622c of the last planetary stage are mounted and the blocking elements 613 are movably guided . A reaction torque, which is caused by the tension in the belt webbing and acts on the carrier part 612, is thus produced in the planetary gear 62 and acts on the blocking elements 613 in the circumferential direction. Since the blocking elements 613 are no longer supported radially on the inside by the control contour 616 , they slide off the ramps 604 of the blocking ring 663 and thereby perform a forced radially inward movement, during which they dip into the depressions 6162 of the control contour 616 . Depending on the forces that have to be overcome, the blocking ring 663 with the blocking contour 68 can yield slightly due to its resilient mounting. This removes the blocking of the carrier part 612 relative to the housing 60 in the circumferential direction and the carrier part 612 can rotate by a short angle of rotation, in this case exactly 90 degrees to the housing 60 with four blocking elements 613 arranged at 90 degrees to one another. At the same time, the housing 60 can rotate the spool 5 by a small angle of rotation in the extension direction. This rotational movement is stopped again after the rotation angle of 90 degrees by the blocking elements 613 on the ramps 6161 of Control contour 616 run up again, and are then supported radially inward by the ramps 6161 and thus pushed outwards until they finally come to rest again in the circumferential direction on the ramps 604 of the blocking contour 68 and block the further rotary movement of the carrier part 612 to the housing 60, This blocking movement is in turn dampened by the resilient mounting of the blocking ring 663.

The blocking elements 613 form the first blocking device here, which enables the force-limited extension of the seat belt through their movement in a repetitive process of releasing and blocking the extension movement of the seat belt. When activated, the electric motor 4 is used to trigger or enable the movement of the first blocking device by driving the unlocking ring 611 with the control contour 616 provided on it, thereby causing or activating the release of the blocking elements 613 in connection with the tensile forces acting in the safety belt. allows. The shape of the radial control contour 616 with the alternately arranged ramps 6161 and depressions 6162 is of particular importance, since it forces or enables and controls the radial movement of the blocking elements 613, which is of particular importance for releasing and blocking the first blocking device. The planetary gear 62 is also of particular importance here, since the planetary gear 62 translates the extension rotary movement of the belt shaft 5 into a significantly faster rotary movement of the carrier part 612, which means that the blocking path available for blocking the first blocking device is increased. Furthermore, in addition to the resilient mounting of the blocking ring 663, the forces acting on the blocking elements 613 are thereby reduced. It is also advantageous that the gear 6 in the form of the planetary gear 62 operates in this phase as a reversing gear, so that the carrier part 612 and the housing 60, between which the planetary gear 62 is arranged, perform opposite rotary movements, and the blocking of the first Blocking device required relative movement is further increased. The housing 60 forms here with the internal teeth 601 the first part of the direction of rotation reversing gear, which is in a rotary connection with the belt shaft 5 . The carrier part 612 here forms the second part of the direction of rotation reversing gear, which is driven by the direction of rotation reversing gear to rotate in the opposite direction relative to the housing 60, i.e. the first part, with the blocking elements 613, i.e. the first blocking device, being arranged between the first and second parts.

The housing 60 of the transmission 6 with the frame parts 661 and 662 fixed to it in a rotationally fixed manner form a fixed abutment for the blocking ring 663 spring-mounted thereon, which in turn forms the blocking contour 68, formed by the ramps 604, which when the blocking elements 613 abut Block or stop further rotation of the carrier part 612 relative to the housing 60 .

The force limiting characteristic can also be influenced by driving the unlocking ring 611 at an increased speed. As a result, the unlocking ring 611 with the control contour 616 follows the gear housing 60 rotating in the pull-out direction, which in turn can reduce the number of blockages of the blocking elements 613 in relation to one revolution of the gear housing 60 . In extreme cases, it is even possible to drive the unlocking ring 611 at a speed corresponding to the speed of the gear housing 60 in the pull-out direction, and to hold the unlocking ring 611 in a rotational angle position relative to the gear housing 60 in which the ramps 6161 of the control contour 616 rotate in one Angle of rotation between two ramps 604 of the blocking ring 68, so that the blocking elements 613 when driving over the ramps 6161 of the control contour 616 do not reach the ramps 604 blocking the system and can practically rotate without blocking. The unlocking ring 611 is thereby held in an “open position” relative to the gear housing 60, and the blocking of the carrier part 612 with respect to the gear housing 60 is prevented. In this way, the belt webbing can be pulled out as quickly as possible with the lowest possible force limitation, with the force limitation being effected solely by the energy dissipation in the transmission 6 caused by friction.

The spring 615 is designed in such a way that its spring force is significantly greater than the spring force of the drive spring 91. As a result, a comfort function can also be implemented by the electric motor 4 winding the belt shaft 5 directly via the unlocking ring 611, the spring 615, the housing 60 - Drives or unwinding, thereby increasing or reducing the retraction force acting on the spool 5. In this case, the planetary gear 62 is bypassed by the power transmission via the spring 615 . This applies to the transmission of very small torques and corresponding speeds at which the inner first pawls 632 do not engage with the third toothing 626 of the transmission shaft 624, so that the transmission shaft 624 is not driven.

In the 10 and 11 is the effect of the resilient mounting of the blocking ring 663 formed by the helical springs 67, the initial position of the blocking elements 613 in the blocking position in the unloaded state being recognizable in the illustration on the left.

In the right representation of the 10 the carrier part 612 with the blocking elements 613 can be seen in the maximum loaded state. The carrier part 612 exerts a peripheral force on the blocking elements 613 so that these twist the blocking ring 663 with compression of the coil springs 67 in relation to the frame parts 661 and 662 . The blocking elements 613 are still supported by the ramps 6161 of the control contour 616 and can therefore not move inwards. This implements an overload function, which allows the carrier part 612 to rotate relative to the frame parts 661 and 662 or relative to the housing 60 . This overload function can reduce the stress and the probability of damage to all parts involved in this movement.

In the 11 another possible function can be seen, in which the electric motor 4 is also used to release the belt webbing after a reversible belt tightening has taken place. The electric motor 4 has turned the unlocking ring 611 or the central ring part 611a with the control contour 616 clockwise, so that the blocking elements 613 lose their support on the ramps 6161 radially inward, whereupon the belt outlet process described above is made possible. Only very small tensile forces act in the webbing, which result from the detaching webbing, which enable the webbing to be pulled out as described above, but the parts are moved towards one another at much lower speeds and accelerations and the resulting forces than is the case with the force-limited webbing is the case in the force limitation phase.

In the 12 and 13 shows the rotary movement of the parts under different loads with and without a spring movement of the blocking ring 663. With small tensile forces acting in the webbing, the blocking ring 663 does not spring, as in FIG 12 can be seen. The blocking ring 663 springs only with greater tensile forces, as in FIG 13 can be seen. This means that the blocking movement of the blocking elements 613 is only dampened when there are greater tensile forces in the belt webbing. In the case of smaller tensile forces, there is deliberately no damping of the blocking movement of the blocking elements 613, since it is not required in this case, which in turn enables the belt webbing to be pulled out at a maximum speed.

In the 14 the blocking element 613 can be seen as an individual part in an enlarged view. The blocking element 613 has two planar sections 6131 and 6132 with a straight cross section, which are separated from one another by a curved section 6133 and are offset laterally with respect to one another. Due to the curved section 6133, the blocking element has a stop surface 6133a directed radially outwards and a stop surface 6133b directed radially inwards. Furthermore, the blocking element 613 has a side surface 6134 inclined in accordance with the shape of the ramp 604, with which the blocking element 613 comes to rest flat against the ramp 604 of the blocking ring 663 in the blocking position.

As in the 15 and 16 As can be seen, the recesses 614 on the insert part 612b also have two parallel and laterally offset linear guide sections 614c and 614d, which overlap with their outer guide surfaces. As a result, a widened cavity is formed in the middle, which is delimited radially on the inside and outside by a stop surface 614a and 614b. The distance between the stop surfaces 614a and 614b is greater than the distance between the stop surfaces 6133a and 6133b of the blocking element 613, or the thickness of the blocking element 613 is selected so that the blocking element 613 guided in the recess 614 has the required space for the blocking and Unblocking movements required radial movements can perform in the recess 614, the radial movement of the blocking element 613 is limited in each case by the stop surfaces 614a and 614b.

The blocking element 613 is dimensioned with its stop surfaces 6133a and 6133b in conjunction with the position of the stop surfaces 614a and 614b in the recess 614 such that the blocking element 613 comes to rest radially only with the inclined side surface 6134 on the ramp 604 of the blocking ring 663. During the rotary movement of the carrier part 612 in relation to the blocking ring 663, the blocking element 613 is in the maximum radial outward deflection in a stop position in which it either rests with its stop surface 6133a on the stop surface 614a and is thereby held in a position in which between between the radially outer tip of the blocking element 613 and the radially inner wall of the blocking ring 663 there is a first gap S1 (see 15 ). The same applies to the radially inwardly pushed-in position of the blocking element 613, for example shortly after the blocking element 613 has been unblocked, in which the blocking element 613 is pushed through by the stop surfaces 614b and 6133b, forming a second gap S2 is kept at a distance from the control contour 616.

The blocking elements 613 are thus subjected to significantly less stress during blocking, unblocking and during the movement of the carrier part 612 to the blocking ring 663 . In particular, this can reduce the frictional and impulse forces acting on blocking ring 663, blocking elements 613 and control contour 616, since contact of the inner and outer end of blocking element 613 with blocking ring 663 and control contour 616 is avoided or at least is reduced to the lowest possible level.

The belt retractor according to the invention corresponds in its basic structure to that in the patent application DE 10 2020 207 535.2 described belt retractor, with only the blocking elements 613 to reduce their load, the carrier part 612 in its two-part design, the blocking contour 68 on the three-part blocking part 66 with the blocking ring 663 and the resilient mounting of the blocking ring 663 and the multi-part unlocking ring 611 with the advantages described above were changed and developed.

Reference List

1

Frame

2

slot

3

housing shells

4

electric motor

41

drive shaft

42

serrated end

5

belt shaft

50

spool body

51

torsion bar

52

radial flange

521

finger

6

transmission

60

gear case

601

internal teeth

602

ramp

603

recesses

604

ramp

605

web

61

force limiting unit

611

release ring

611a

ring part

611b

ring part

611c

ring part

6111

cutout

612

carrier part

612a

body

612b

insert part

613

blocking element

6131

straight section

6132

straight section

6133

curvature section

6133a

stop surface

6133b

stop surface

6134

side face

614

recesses

614a

stop surface

614b

stop surface

614c

guide section

614d

guide section

615

Feather

616

control contour

6161

ramp

6162

deepening

617

internal teeth

618

Pen

62

planetary gear

621a

first planet carrier

6211

second locking pawl

621b

second planet carrier

622a

first planet gears

622b

second planet gears

622c

third planet gears

623

ring gear

624

gear shaft

625

first gearing

626

third toothing

627

second toothing

628

ring section

629

pawl

63

drive wheel

631

internal teeth

632

first latch

634

spring plate

635

ring flange

636

first ring protrusion

637

second ring protrusion

638

opening

639

opening

66

blocking part

661

frame part

662

frame part

663

locking ring

67

coil springs

68

blocking contour

69

web

7

web

71

internal teeth

8th

locking unit

80

control disc

81

first blocking pawl

82

actuator

9

spring cartridge

90

Housing

91

mainspring

92

cover

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• WO 03/099619 A2 [0006]
• DE 19927731 C2 [0007]
• DE 102005016822 B3 [0010]
• DE 102020207535 [0012, 0034, 0035, 0070]

Claims (15)

Belt retractor with -a belt shaft (5) which is rotatably mounted in a frame (1) and on which a seat belt can be wound up, and -a force-limiting unit (61) which, when activated, enables a rotary movement of the belt shaft (5) in the pull-out direction of the seat belt, the force limiting unit (61) has an electric motor (4) and a first blocking device, and - the first blocking device is set up, controlled by the activation of the electric motor (4), to release a rotary movement of the belt shaft (5) in the extension direction in a repetitive sequence and to block again, characterized in that - the first blocking device and/or a blocking contour (68), on which the first blocking device comes to rest in the blocking position, is resiliently mounted in or against the blocking direction of the first blocking device in each case via at least one spring or are. seat belt retractor claim 1 , characterized in that - the spring (s) is or are arranged in the circumferential direction of the rotary movement of the belt shaft (5). seat belt retractor claim 2 , characterized in that the spring(s) is or are formed by one or more helical springs (67). Belt retractor after one of Claims 1 until 3 , characterized in that at least two springs acting in parallel are provided. Belt retractor after one of Claims 1 until 4 , characterized in that - the blocking contour (68) is formed by a blocking ring (663) with a plurality of cams distributed uniformly over the circumference. Belt retractor after one of Claims 1 until 5 , characterized in that - an unlocking ring (611) driven by the electric motor (4) is provided, which has a control contour (616), and - the first blocking device is formed by at least one blocking element (613) bearing against the control contour (616). . Belt retractor after one of Claims 1 until 6 , characterized in that - the control contour (616) is formed by a ramp structure with a number of ramps (6161) corresponding to the number of blocking elements (613) and depressions (6162) arranged between the ramps (6161) on which the blocking element ( 613) rests alternately in the blocking position and the releasing position. Belt retractor according to one of the preceding claims, characterized in that -a rotational direction reversing gear is provided, which is in a rotational connection with the belt shaft (5) via a first part, and -the first blocking device between the first part of the rotational direction reversing gear and a through the rotational direction reversing gear a second part of the direction of rotation reversing gear driven in the opposite direction of rotation to the direction of rotation of the belt shaft (5). seat belt retractor claim 8 , characterized in that - the second part carries out a rotational movement translated into a higher speed by the direction of rotation reversing gear in relation to the first part. Belt retractor after one of Claims 8 or 9 , characterized in that - the direction of rotation reversing gear is formed by a planetary gear (62), and that - the reversal of the direction of rotation in the direction of rotation reversing gear by a first planetary carrier (621) of the planetary gear ( 62) is realized. seat belt retractor claim 8 until 10 , characterized in that -the first part or the second part of the direction of rotation reversing gear have a blocking contour (68) on which the first blocking device rests in the blocking position. Belt retractor after one of Claims 8 until 11 , characterized in that the first part is formed by a tubular, axial extension which is non-rotatably connected to the belt shaft (5) and which forms the housing (60) of the direction-of-rotation reversing gear. Belt retractor after the claim 12 in feedback claim 11 , characterized in that - the blocking contour (68) is formed by ramps (604) directed in the circumferential direction and arranged on the inside of the annular extension, against which the blocking element (613) rests in the blocking position. Belt retractor after one of Claims 6 or 7 or after one of the Claims 8 until 13 in relation to one of the Claims 6 or 7 , characterized in that the unlocking ring (611) is spring-loaded via a spring (615) relative to the belt shaft (5). seat belt retractor Claim 14 , characterized in that - the belt shaft (5) is spring-loaded by a drive spring (91) fixed to the frame in the winding direction of the safety belt, and - the spring force of the drive spring (91) is smaller than the spring force of the spring ( 615).

Images