CN215805886U - One-way clutch and seat belt retractor - Google Patents

Abstract

The present invention relates to a one-way clutch and a seatbelt retractor, the one-way clutch including: a driving element, a driven element, a pawl, a stop ring and a friction ring. The drive member is rotatable relative to the friction ring between a first rotational position in which the pawl is in a first pivotal position relative to the drive member and the pawl is disengaged from the driven member, and a second rotational position in which the pawl is in a second pivotal position radially inward from the first pivotal position relative to the drive member and the pawl is engaged with the driven member. The friction ring has a resilient member which, in a first pivot position of the pawl relative to the drive element, presses the pawl and resists the pawl from leaving the first pivot position in a radially inward pivot direction. This makes it possible to at least reduce vibrations of the one-way clutch during operation of the vehicle and the component impact noise caused thereby.

Description

One-way clutch and seat belt retractor

Technical Field

The present invention relates to the field of vehicle safety technology, and more particularly to a one-way clutch and a seatbelt retractor including such a one-way clutch.

Background

In vehicles, especially passenger cars, the safety belt can be an effective and reliable passive safety device, and becomes a mandatory configuration in the whole vehicle safety system. Under the trend of electric and intelligent vehicle development, the requirements of safety belts on safety protection and wearing comfort of passengers are continuously increasing.

Some safety belts known in practice comprise an irreversible pretensioning device comprising a pyrotechnic gas generator, a coil and a steel ball, a flexible rack or the like housed in the coil. When an emergency situation of the vehicle is about to occur, for example, when a vehicle collision is about to occur, the vehicle control unit can send out a control command, so that the pyrotechnic gas generator is activated, the gunpowder is ignited, the steel ball, the flexible rack or the like moves out of the coil pipe under the action of the explosive force, the belt winding drum of the safety belt retractor is driven in the webbing winding direction, so that the webbing is wound, and therefore a gap inside the safety belt retractor and a gap between the webbing and the body of a passenger are eliminated, therefore, the passenger can be better restrained on the vehicle seat, and the passenger can be well protected by the safety belt in the emergency situation of the vehicle.

In addition, some safety belts known in practice may comprise, in addition to an irreversible pretensioning device, a reversible active pretensioning device. The active pretensioning device may typically comprise a reversible electric motor, an electronic control unit for controlling the operation of the motor, a transmission and a one-way clutch. In the operation of the vehicle, in certain dangerous situations or when a passenger needs to be reminded, the reversible motor can be activated according to a preset control logic, so that the reversible motor drives the belt drum of the safety belt retractor in the belt retracting direction through the transmission device and the engaged one-way clutch, and the belt is actively pre-tensioned to a suitable degree. The reversible motor is then reversed, for example after the hazardous condition has cleared or after a predetermined period of time has elapsed, to release the active pretensioning of the webbing. The electronic control unit may, for example, obtain control instructions from the vehicle control unit. When the active pretensioning device is triggered, the one-way clutch in the transmission path between the reversible motor and the belt drum is used as a force bearing part and also plays a role in outputting the torque from the reversible motor. When the active pretensioning function is released, the one-way clutch is preferably completely decoupled from the other various functions of a conventional safety belt retractor, at least substantially, in particular completely, without interfering with the other functions of the safety belt retractor. For example, in the event of an unavoidable imminent collision, in which the powder of a pyrotechnic gas generator is ignited, the irreversible prestressing device is activated, wherein the activated active prestressing device preferably does not interfere with this irreversible prestressing function.

SUMMERY OF THE UTILITY MODEL

The object of the utility model is to provide a one-way clutch and a belt retractor comprising such a one-way clutch, wherein the one-way clutch can have good acoustic properties during operation.

A first aspect of the utility model relates to a one-way clutch including:

a drive element rotatable in a first direction and a second direction opposite the first direction;

a driven member having a common axis of rotation with the drive member;

a pawl pivotably mounted to a drive element;

a snap ring;

a friction ring frictionally coupled with the stopper ring;

wherein the drive element is rotatable relative to the friction ring between a first rotational position in which the pawl is in a first pivot position relative to the drive element in which the pawl is disengaged from the driven element and a second rotational position downstream of the first rotational position in the first direction in which the pawl is in a second pivot position relative to the drive element pivoted radially inward from the first pivot position in which the pawl is engaged with the driven element;

wherein the friction ring has a resilient member, in a first pivot position of the pawl relative to the drive element, the resilient member of the friction ring presses the pawl and resists the pawl from leaving the first pivot position in a radially inward pivot direction.

In the one-way clutch according to the utility model, the elastic component of the friction ring can dampen the vibrations of the pawl, for example during vehicle operation, and can therefore at least reduce or even completely eliminate the noise of the one-way clutch caused by the parts colliding with one another. This may be beneficial to the NVH performance of the vehicle.

In some embodiments, the pawl can have a sliding surface, the friction ring has guide means for guiding the sliding surface, in particular on both sides of the sliding surface, and the pawl can be pivoted relative to the drive element between the first and the second pivoted position by the interaction of the guide means with the sliding surface when the drive element is rotated relative to the friction ring between the first and the second rotated position. By means of the one-way clutch, the active pretensioning function for the belt retractor can be incorporated into the belt retractor and can then be released again.

In some embodiments, the drive element may be a gear, a friction wheel or a pulley, in particular a cylindrical gear.

In some embodiments, the driven element may be a gear, in particular a ratchet.

In some embodiments, the pawl may have a single pawl portion configured for interacting with the driven element.

In some embodiments, the pawl may have a free end remote from the pivot axis, in particular a pivot axis parallel to the rotation axis, which is configured for interacting with the driven element.

In some embodiments, the sliding surface may project axially from the body of the pawl with reference to the pivot axis.

In some embodiments, the body of the pawl may have a flat outer side surface, and the sliding surface may be coplanar with the outer side surface.

In some embodiments, the one-way clutch may include two pawls.

In some embodiments, the pivot axes of the two pawls lie on a diameter line with reference to the axis of rotation, in other words, the two pawls or the two pivot axes can have an angular separation of 180 °. It will be appreciated that the angular spacing of the two pawls may be other than 180 °, for example the angular spacing may be 90 °, 120 ° or 150 °.

In some embodiments, the one-way clutch may include three pawls. Preferably, with reference to the axis of rotation, the pivot axes of the three pawls may have an angular spacing of 120 ° from each other.

In principle, the number of pawls may be arbitrary, for example, a single pawl is also possible.

In some embodiments, the friction ring can have a single guide member for each sliding surface, which guide member can have a radially inner contact portion and a radially outer contact portion, between which the sliding surface is guided.

In some embodiments, the friction ring may have a pair of guide members for guiding the sliding surface on both sides of the sliding surface, the pair of guide members having contact portions opposed to each other, the sliding surface being guided between the contact portions.

In some embodiments, any one of the contact portions may be configured for single-point, multi-point, linear, or planar contact with the sliding surface.

In some embodiments, the contact portion may have a cylindrical surface. The cylindrical surface may be in linear contact with the sliding surface. The cylindrical surface may be a cylindrical surface or an elliptic cylindrical surface, or may be a part of a cylindrical surface or an elliptic cylindrical surface.

In some embodiments, a first guide member of the pair of guide members may include a first portion protruding inward from the ring body of the friction ring, a second portion bent with respect to the first portion at a radially inner end of the first portion, and a third portion protruding axially from the second portion. Preferably, the second part can be plate-shaped, further preferably, the second part extends in a radial plane perpendicular to the axis of rotation. Preferably, the third part can be designed as a cylinder with a cylindrical surface as the contact section.

In some embodiments, a second guide member of the pair of guide members may include an arm projecting inwardly from the ring body of the friction ring. Preferably, the free end of the arm may have a cylindrical surface as the contact portion. Preferably, the arms may be curved arms. Further preferably, with reference to the axis of rotation, the curved arm may comprise a first section extending substantially in a circumferential direction and a second section extending substantially in a radial direction.

In some embodiments, the third portion may be radially inward of the free end of the arm, with reference to the axis of rotation.

In some embodiments, with reference to the axis of rotation, the third portion and the free end of the arm may have substantially the same angular position in the circumferential direction or have an angular spacing, for example may have an angular spacing of 1 ° to 3 °.

In some embodiments, the friction ring may be installed radially inward of the stopper ring, wherein an outer circumferential surface of the friction ring and an inner circumferential surface of the stopper ring may be frictionally coupled.

It will be appreciated that as an equivalent to "frictional coupling", the friction ring may be magnetically coupled to the stop ring. For this purpose, at least one of the friction ring and the snap ring may have a permanent magnet. The friction ring can be rotated relative to the stop ring against the magnetic force.

In some embodiments, the drive element and the friction ring may each have a first cam, which is configured to define a first rotational position of the drive element and the friction ring relative to each other.

In some embodiments, the drive element and the friction ring may each have a second cam, which is configured to define a second rotational position of the drive element and the friction ring relative to each other.

Alternatively, one of the drive element and the friction ring may have one projection and the other of the drive element and the friction ring may have two projections, the one projection being movable between the two projections. By means of the interaction of the one cam and the two cams, a first rotational position and a second rotational position of the drive element and the friction ring relative to one another can be defined.

In some embodiments, the contact surface of the drive element and the first projection of the friction ring may deviate from a radial plane with reference to the axis of rotation. Thus, when the mating first projections are brought into contact, the force perpendicular to the contact surface deviates from the tangential direction.

In some embodiments, the stop ring may be a stator. This means that the stator is an at least substantially stationary part. Due to manufacturing tolerances or due to assembly requirements, the snap ring can be moved slightly after installation, and the movement play of the snap ring can be, for example, not more than 3 °.

In some embodiments, the stop ring is capable of limited rotation, for example the stop ring is capable of limited rotation in an angular range of less than 30 °, for example 20 ° to 30 °, or less than 10 °.

In some embodiments, to limit the movement of the stop ring, the housing part of the transmission may have a pin that can be inserted into a recess of the stop ring.

In some embodiments, the drive element may have a cavity with a bottom at one axial end side of the drive element and open at the other axial end side of the drive element, in which the stop ring, the friction ring and the pawl may be accommodated. Preferably, an axial stop disk connected to the drive element can be attached to the open other axial end face. The driven element is accessible into the chamber through an opening in the bottom. The axial stop disk can also have an opening through which the driven element passes if the driven element is to look through the entire one-way clutch. Preferably, the opening of the axial stop disk can be formed identically to the opening of the bottom of the drive element.

In some embodiments, with reference to the axis of rotation, in the first and/or second pivot position, the component parts of the pawl from the pivot axis to the free end occupy an angular region of not more than 90 °, in particular not more than 60 °, for example not more than 45 °, particularly preferably not more than 30 ° or not more than 20 °. Therefore, the pawls occupy a small space in the one-way clutch, so that the entire one-way clutch can be compact.

In some embodiments, the pawl can have a locking member which is configured to lock with the drive element in a crossing position in which the pawl crosses the first pivot position in the radial outward pivot direction when the pawl crosses the first pivot position in the radial outward pivot direction.

In some embodiments, the locking component may be a snap-fit element that can snap into a mating snap-fit receptacle.

In some embodiments, the locking member may be a spring catch that may lock in the override position.

In some embodiments, the locking member may be a hook member, in particular a resilient hook member.

In some embodiments, the locking member may be a resilient member, in the first pivot position the pawl abuts the drive element with the locking member, the locking member resisting movement of the pawl in a radially outward pivot direction out of the first pivot position. Thus, the locking member may be added to the elastic member of the friction ring, which may further contribute to the resistance against vibration of the pawl and the resulting noise caused by part impact.

In some embodiments, the locking component may have a hook configured to be hooked by the drive element when the pawl passes the first pivot position in the radially outward pivot direction such that the pawl is held in the pass-over position.

In some embodiments, the locking member may be injection molded onto the body of the pawl.

In some embodiments, the locking member protrudes from the body of the pawl in a direction away from the free end of the pawl.

In some embodiments, the drive element may have a projection having a mating hook, in the first pivot position the pawl abuts with the hook on a surface of the projection adjacent to the mating hook, and the hook may slide over the projection as the pawl pivots relative to the drive element from the first pivot position toward the over position such that the hook catches the mating hook.

In some embodiments, the protrusion may be injection molded onto the drive element. In particular, the projection may be injection molded on the bottom of the cavity of the drive element.

In some embodiments, the friction ring may have a resilient member that, in a first pivot position of the pawl relative to the drive element, presses the pawl and resists the pawl from moving out of the first pivot position in a radially inward pivot direction. Therefore, in the first pivot position of the pawl, the elastic member can suppress vibration of the pawl, avoid rattling of the pawl, collision with other components of the one-way clutch, and noise caused thereby.

In some embodiments, the resilient member of the friction ring may be out of contact with the pawl upon a predetermined travel of the pawl from the first pivot position in the radially inward pivot direction. The elastic component of the friction ring can then substantially not affect the active pretensioning function of the one-way clutch at all.

In some embodiments, the resilient component of the friction ring may be a finger that is injection molded onto the ring body of the friction ring.

A second aspect of the utility model relates to a seatbelt retractor comprising a spool, a drive device and a one-way clutch, the drive device being in driving connection with a drive element of the one-way clutch, the spool being in driving connection with a driven element of the one-way clutch.

The seatbelt retractor may have the aforementioned advantageous technical effects associated with the one-way clutch.

In some embodiments, the drive device is a reversible motor.

In some embodiments, the drive device is in driving connection with the drive element of the one-way clutch via a transmission. Preferably, the drive element can be an output gear of the transmission, in particular a spur gear.

In some embodiments, the transmission may be a gear transmission including a housing and a gear set housed in the housing. Alternatively, a belt drive or a wire rope drive are also possible.

In some embodiments, the take-up spool and the driven element of the one-way clutch may be in direct drive connection. Preferably, the driven element can be an integral component of the winding reel.

The features already mentioned above, those to be mentioned below and those shown in the drawings can be combined with one another as desired, provided that the combined features are not mutually inconsistent. All possible combinations of features are the technical content contained in the present application.

Drawings

Exemplary embodiments will now be described with reference to the accompanying drawings. Wherein:

fig. 1 is a perspective view of a spool and a one-way clutch of a seatbelt retractor according to an embodiment of the present invention.

Fig. 2 shows a structural unit of an active pretensioning device of a seatbelt retractor according to an embodiment of the present invention.

Fig. 3 is an exploded view of a one-way clutch for a seatbelt retractor according to an embodiment of the present invention.

Fig. 4 and 5 are front views of the one-way clutch of fig. 3 in a first state and in a second state.

FIG. 6 is a front view of a pawl of the one-way clutch of FIG. 3.

FIG. 7 is a perspective view of a friction ring of the one-way clutch of FIG. 3.

Fig. 8A is a partial view of the friction ring.

FIG. 8B is a partial view of the friction ring and drive element of the one-way clutch.

FIG. 9 is a front view of the drive element of the one-way clutch of FIG. 3.

FIG. 10 is a partial front view of the one-way clutch of FIG. 3 in a third state.

Detailed Description

Fig. 1 is a perspective view of a spool 1 and a one-way clutch 10 of a seatbelt retractor according to an embodiment of the present invention. Fig. 2 shows a structural unit of an active pretensioning device of a belt retractor, which includes a one-way clutch 10 and also a drive 4 and a transmission 5, which are designed as reversible motors. The assembly shown in fig. 2 can be mounted on the winding reel 1 shown in fig. 1, wherein a gear wheel, in particular a ratchet wheel, which is formed integrally with the winding reel 1 or is connected in a rotationally fixed manner coaxially, can be passed through a central opening of the one-way clutch 10 as the driven element 12 of the one-way clutch 10. The driven element 12 and the winding reel 1 can have a common axis of rotation 3. The reversible electric motor as the drive means 4 can be driven bidirectionally. The structural unit shown in fig. 2 can form the active pretensioning device of a seatbelt retractor.

Typically, the belt retractor can comprise a not shown frame in which the belt drum 1 is rotatably supported, to which the housing part 8 of the gear mechanism 5 can be fixedly connected. As shown in fig. 2, the gear 5 can be designed as a gear wheel transmission, which has a housing. To show the gear set housed inside the housing, another housing component of the housing is removed to expose the various gears of the gear set. The two housing parts of the housing of the transmission 5 can be plastic parts or metal parts. The drive 4 can be fixed to the housing part 8 of the transmission, for example by screws. Advantageously, when the housing part 8 is produced by injection molding, the housing part 8 can have a substantially cylindrical receptacle for receiving a substantially cylindrical electric motor. A pinion 6, which is fixedly connected to the output shaft or motor shaft of the drive 4 or is formed in one piece, meshes with a transmission gear 7, and an intermediate gear 9, which rotates coaxially with the transmission gear 7, meshes with an output gear, which at the same time forms a drive element 11 of the one-way clutch. The one-way clutch 10, with the exception of the driven element 12, can be accommodated as a module in the housing of the transmission 5. In principle, the drive 4 and the gear 5 can be implemented by other devices known per se, such as hydraulic drives, belt drives, cable drives, friction wheel drives, etc. A unidirectional drive 4 is also possible if the transmission 5 has a reversing mechanism.

In fig. 1, a gear wheel 2 (which is shown in fig. 1 as a ball gear) can also be seen, which gear wheel 2 is assigned to a non-illustrated irreversible prestressing device which can comprise a gas generator, a coil and a steel ball, a flexible toothed rack or the like. For example, when a vehicle is about to collide, the powder of the gas generator is ignited, the gas generated by the gas generator drives a steel ball, a flexible rack or the like accommodated in a coil, and the steel ball, the flexible rack or the like ejected from the coil impacts a gear 2, so that the take-up drum 1 is pre-tensioned in the webbing take-up direction, so that an occupant can be better restrained on a vehicle seat during the vehicle collision, and thus the injury to the occupant caused by the vehicle collision can be reduced or even completely avoided.

Fig. 3 is an exploded view of a one-way clutch 10 for a seatbelt retractor according to an embodiment of the present invention, which may be an integral part of the seatbelt retractor including the assembly shown in fig. 1 and 2.

The one-way clutch 10 may include a drive element 11. Due to the bidirectional drive of the drive means 4, the drive element 11 can be rotated in a first direction D and a second direction R opposite to the first direction (see fig. 4 and 5). The first direction D may correspond to a webbing take-up direction of the take-up reel 1. The second direction R may correspond to the webbing unwinding direction of the spool 1. The drive element 11 may be an output gear of the transmission 4. As shown in fig. 1 to 3 and 9, the drive element 11 can have a chamber which has a base on one axial end side of the drive element 11 and is open on the other axial end side of the drive element 11, on which an axial stop disk 18 connected to the drive element 11 can be mounted. The axial stop disc 18 may be a pressure plate which may be crimped onto two pins 111 projecting from the bottom of the cavity of the drive element.

The one-way clutch 10 may include a snap ring 15, a friction ring 14, and two pawls 13, which are pivotally mounted on a pin 111. The pin 111 provides the pivot axis of the pawl. The axial stop disk 18 makes it possible to axially position the stop ring 15, the friction ring 14 and the pawl 13, preventing any of them from being disengaged from the cavity of the drive element 11. The two pins 111 may lie on a diameter line, in other words, may have an angular spacing of 180 °.

The one-way clutch 10 may include a driven member 12, and the driven member 12 may have a common axis of rotation 3 (see fig. 1) with the driving member 11. The driven element 12 may be received in the chamber. The driven element 12 can enter the chamber of the drive element 11 through an opening 116 in the bottom of the drive element 11. If the axial length of the driven element 12 is long, the driven element 12 may protrude from the axial stop disk 18 through the opening 19 of the axial stop disk 18, as shown in FIG. 1.

The stop ring 15 may be a stator, which is at least substantially a stationary part. In an alternative embodiment, the stop ring 15 can be rotated to a limited extent, for example within an angular range of less than 30 °, for example between 20 ° and 30 °, or less than 10 °. For this purpose, the housing part not shown in fig. 2 can have at least one, for example three, pins which are inserted into recesses 20 (see fig. 3) in the outer circumference of the locking ring 15 during assembly, which pins can render the locking ring 15 substantially non-rotatable or can render the locking ring 15 only limitedly rotatable.

The friction ring 14 may be frictionally coupled with the stop ring 15. For this purpose, the friction ring 14 may be mounted radially inside the snap ring 15, wherein the outer circumferential surface of the friction ring 14 is frictionally coupled with the inner circumferential surface of the snap ring 15. The friction ring 14 may have two ends opposite to each other, between which a compression spring 16 is mounted, so that the friction ring 14 may be permanently stably held in frictional coupling with the snap ring 15. In operation of the one-way clutch 10, the friction ring 14 and the snap ring 15 remain stationary until the frictional force between the friction ring 14 and the snap ring 15 is overcome; after this friction force is overcome, the friction ring 14 can be rotated relative to the stop ring 15.

Fig. 4 is a front view of the one-way clutch 10 of fig. 3 in a first state, and fig. 5 is a front view of the one-way clutch 10 in a second state, wherein, to show internal structure, the axial discs 18 of the one-way clutch 10 are removed to reveal the structure of the one-way clutch 10 hidden by the axial discs 18 in the cavity of the drive element 11.

In the first state of the one-way clutch 10, as shown in fig. 4, the drive element 11 is in a first rotational position relative to the friction ring 14, which can be defined by one first cam 114, 144 on each of the drive element 11 and the friction ring 14. As shown in fig. 8B, the first cam 114 of the drive element 11 abuts against the first cam 144 of the friction ring 14, thereby defining a first rotational position of the drive element 11 and the friction ring 14 relative to each other, in which the second cam 115 of the drive element 11 is disengaged from the second cam 145 of the friction ring 14. Starting from the first state, when the drive element 11 is rotated in the second direction R, the friction ring 14 rotates together with the drive element 11 in the second direction R, wherein the first rotational position of the drive element 11 and the friction ring 14 relative to one another can be kept constant.

In the second state of the one-way clutch 10, as shown in fig. 5, the drive element 11 is in a second rotational position relative to the friction ring 14, which can be defined by one second cam 115, 145 on each of the drive element 11 and the friction ring 14. As can be seen from fig. 8B, the second cam 115 of the drive element 11 can rest against the second cam 145 of the friction ring 14, so that a second rotational position of the drive element 11 and the friction ring 14 relative to one another can be defined, in which case the first cam 114 of the drive element 11 and the first cam 144 of the friction ring 14 are separated from one another. Starting from the second state, when the drive element 11 is rotated in the first direction D, the friction ring 14 rotates together with the drive element 11 in the first direction D, wherein a second rotational position of the drive element 11 and the friction ring 14 relative to one another can be maintained.

As shown in fig. 8A, the first cam 144 and the second cam 145 of the friction ring 14 can advantageously be arranged in the region of the free ends of the friction ring which are opposite one another and project axially from the ring body 140 (see fig. 7) of the friction ring. It will be appreciated that the two projections of the friction ring may be provided in any suitable location. With reference to the rotation axis 3, when the first cam 114 of the drive element 11 abuts against the first cam 144 of the friction ring 14, the force of the first cam 114 of the drive element 11 on the first cam 144 of the friction ring 14 deviates from the tangential direction. With regard to the course of the contact surface of the first cam 114 of the drive element 11, reference can be made to fig. 9, which deviates from the radial direction.

The friction ring 14 may have a guide structure that cooperates with the pawl 13. The guide structure may be configured to: as shown in fig. 4, in a first rotational position of the driving element 11 relative to the friction ring 14, the pawl 13 is brought into a first pivot position relative to the driving element 11, in which the pawl 13 is disengaged from the driven element 12; and as shown in fig. 5, in a second rotational position of the driving element 11 relative to the friction ring 14, the pawl 13 is brought into a second pivotal position relative to the driving element 11, in which second pivotal position the pawl 13 is engaged with the driven element 12.

The active pretensioning process of the active pretensioning device comprising the one-way clutch 10 can be carried out as follows:

starting from the first state as shown in fig. 4, the drive device 4 drives the drive element 11 of the one-way clutch 10 in the first direction D in accordance with a control command. At this time, the friction ring 14 is held stationary with the snap ring 15 by a frictional coupling. The drive elements 11 are rotated relative to the friction ring 14 from a first rotational position relative to one another until a second rotational position relative to one another is reached, as shown in fig. 5, while the pawls 13 are pivoted relative to the drive elements 11 from the first pivotal position shown in fig. 4 to the second pivotal position shown in fig. 5. Then, as the mating second cams 115, 145 meet, the frictional force of the friction ring 14 and the snap ring 15 is overcome by the driving force of the driving element 11, and the friction ring 14 rotates together with the driving element 11 in the first rotational direction D. Since the pawl 13 is engaged with the driven element 12, the driving force is transmitted from the driving element 11 to the spool 1 via the pawl 13 and the driven element 12, so that the spool 1 pretensions the webbing in the webbing take-up direction. The rotational travel of the drive element 11 in the first rotational direction D can be predetermined. The achievement of said rotational travel may for example be related to at least one of the following conditions: a predetermined pre-tightening degree is achieved on the mesh belt; the drive element 11 is rotated by a set angle in a first direction of rotation D; the motor runs for a preset time; the current of the motor reaches a predetermined threshold value.

The process of releasing the active pretensioning function of the active pretensioning device can be essentially reversed:

starting from the second state shown in fig. 5, the drive device 4 drives the drive element 11 of the one-way clutch 10 in the second direction R in accordance with the control command. At this time, the friction ring 14 is held stationary with the snap ring 15 by a frictional coupling. The driving element 11 is rotated relative to the friction ring 14 from the second rotational position relative to each other until the first rotational position relative to each other, as shown in fig. 4, is reached, while at the same time the pawl 13 is pivoted relative to the driving element 11 from the second pivotal position, as shown in fig. 5, to the first pivotal position, as shown in fig. 4, the pawl 13 being disengaged from the driven element 12. Then, since the mating first cams 114, 144 meet, the frictional force of the friction ring 14 and the snap ring 15 is overcome by the driving force of the driving element 11, and the friction ring 14 rotates together with the driving element 11 in the second rotational direction R, returning collectively to the initial position. Since the pawl 13 is disengaged from the output element 12, the winding reel 1 can be operated independently of the active pretensioning device.

Fig. 6 is a front view of one of the pawls 13 of the one-way clutch 10. The two pawls 13 of the one-way clutch 10 may be identically or similarly constructed. The pawl 13 may have a body 31, for example made by casting or powder metallurgy. The body 31 may have a shaft hole 34. The pawl 13 may be pivotally mounted on the pin 111 of the drive element 11 through the shaft hole 34. The shaft hole 34 or the pin 111 may define a pivot axis of the pawl 13, which may be parallel to the rotation axis 3. The pawl 13 can have a free end 32 remote from the pivot axis, which free end 32 is designed for interacting with the driven element 12, which is designed as a gear, in particular as a ratchet.

The pawl 13 may have a flat outer surface with which the sliding surface 33 may be coplanar. Said sliding surface 33 may axially project from the body 31 of the pawl 13. The sliding surface 33 can interact with a guide structure of the friction ring 14, so that the pawl 13 can be pivoted between a first pivot position and a second pivot position relative to the drive element 11 in each case when the drive element 11 is rotated relative to the friction ring 14 between the first and the second rotational position. Each pawl 13 can occupy a small angular area over the entire circumference of the drive element 11. For example, with reference to the axis of rotation 3, in the first and/or second pivot position, the angular region occupied by the components of each pawl 13 from the pivot axis to the free end 32 may be no more than 60 °, for example no more than 45 °, in particular no more than 30 °, in particular no more than 20 °.

An exemplary embodiment of the guide structure of the friction ring 14 is described in detail below with reference to fig. 7. For each pawl 13, the friction ring 14 may have a pair of guide members 141, 142 for guiding the sliding surface 33 of the pawl 13 on both sides of the sliding surface 33. The pair of guide members 141, 142 have contact portions opposed to each other, and the sliding surface 33 is guided between the contact portions.

A first guide member 141 of the two guide members may include a first portion 41 protruding inward from the ring body 140 of the friction ring 14, a second portion 42 bent with respect to the first portion 41 at a radially inner end of the first portion 41, and a third portion 43 protruding in an axial direction from the second portion 42. The first portion 41 may have a width that decreases from a radially outer portion to a radially inner portion. The second portion 42 may be plate-shaped, wherein the plate-shaped body may extend substantially in a radial plane perpendicular to the axis of rotation of the friction ring (which may coincide with the axis of rotation 3 of the winding reel 1 or of the output element 12). The third portion 43 may be configured as a cylinder having a cylindrical surface as a contact portion. The sliding surface 33 may linearly contact the cylindrical surface of the third portion 43. The second guide member 142 of the two guide members may comprise an arm projecting inwardly from the ring body of the friction ring 14, the free end 44 of which may have a cylindrical surface as a contact portion. The arms may be curved arms. For example, with reference to the axis of rotation 3, the curved arm may comprise a first section extending substantially in a circumferential direction and a second section extending substantially in a radial direction. With reference to the axis of rotation 3, the third portion 43 may be radially internal to the free end of the arm. With reference to the axis of rotation 3, the third portion 43 can have substantially the same angular position in the circumferential direction as the free end 44 of the arm or be spaced apart from one another (in other words, have an angular spacing).

As shown in fig. 3 to 6, the pawl 13 may have a locking member 35. The locking member 35 may be an elastic member. The locking member 35 may have a hook 36. The locking part 35 may be injection moulded onto the body 31 of the pawl 13. Advantageously, said locking member 35 can project from the body 31 of the pawl 13 in a direction away from the free end 32 of the pawl 13.

In a first pivot position of the drive element 11 relative to the friction ring 14, the pawl 13 can rest with the locking part 35 on the drive element 11. More specifically, the drive element 11 can have a projection 112, and the locking member 35 can rest with the hook 36 on the projection 112 in the first pivot position of the pawl 13. The projection 112 may be injection molded on the bottom of the cavity of the drive element 11. The projection 112 may have a mating hook 117 that cooperates with a hook of the locking member 35. Advantageously, the drive element 11 can be a plastic gear, in particular can be produced by injection molding, and the projection 112 can be an integrally formed component of the injection molded drive element. It is also possible that the drive element 11 may have a metallic body and that the projection 112 is injection-molded onto the metallic body.

When the pawl 13 is pivoted relative to the drive element 11 from the first pivot position in a radially inward pivoting direction, the locking member 35 is lifted from the projection 112. The protrusion 112 does not interfere with the active pretensioning function.

If the irreversible pretensioning device is activated immediately after the activation of the active pretensioning device, the powder of the pyrotechnic gas generator of the irreversible pretensioning device is ignited, the belt drum 1 is driven by the irreversible pretensioning device in the direction of the webbing take-up with a significantly increased rotational speed, as a result of which the driven element 12 rotating at high speed impacts the pawl 13 with high energy, so that the pawl 13 bounces from the second pivot position in the radially outward pivot direction towards the first pivot position and passes beyond the first pivot position. The locking part 35 of the pawl 13 is then locked with the drive element 11 in the override position. Specifically, the hook 36 of the locking member 35 can slide over the projection 112 of the drive element 11 until the hook 36 of the locking member 35 catches the mating hook 117 of the projection 112, so that the pawl 13 can no longer pivot about the pivot axis, remaining disengaged from the driven element 12, as shown in fig. 9. The active pretensioning device therefore does not interfere with the irreversible pretensioning function and possibly the force limiting function of the belt retractor, which can improve the operational safety of the safety belt.

As shown in fig. 3 to 5, the one-way clutch 10 may include a return spring 17. For this purpose, the drive element 11 can have a pin 113, and the friction ring 14 can have a pin 143, and the return spring 17 can be hooked with its two ends on the pins 113, 143. In the unloaded state, the return spring 17 can hold the friction ring 14 together with the locking ring 15 in the initial position relative to the drive element 11.

As shown in fig. 3 to 5 and 7, the friction ring 14 can have a spring element 146, wherein in a first pivot position of the pawl 13 relative to the drive element 11, the spring element 146 presses the pawl 13 and counteracts the pawl 13 from the first pivot position in a radially inward pivot direction. When the pawl 13 leaves the first pivot position by a predetermined distance in the radially inward pivoting direction, the spring element 146 is out of contact with the pawl 13 and therefore does not interfere with the active pretensioning function. The resilient member 146 may be a finger molded onto the body 140 of the friction ring. In the first pivot position, the rotation direction of the finger element may be opposite to the rotation direction of the free end of the pawl, with reference to the pivot axis of the pawl 13. As shown in fig. 4, the direction of extension of the finger is right-handed and the direction of rotation of the free end 32 is left-handed, with reference to the pivot axis of the pawl 13. In the initial position of the pawls 13, the locking member 35 of the pawls 13, which is configured as an elastic member, can resist the pivotal movement of the pawls 13 in the radially outward pivotal direction, and the elastic member 146 of the friction ring 14 can resist the pivotal movement of the pawls 13 in the radially inward direction, so that the vibrations of the pawls 13 about the pivotal axis in the initial position can be suppressed, and rattling of the pawls 13, collision with other components of the one-way clutch 10, and noise generated thereby can be avoided.

It is noted that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be understood that the terms "comprises" and "comprising," and other similar terms, when used in this specification, specify the presence of stated operations, elements, and/or components, but do not preclude the presence or addition of one or more other operations, elements, components, and/or groups thereof. The term "and/or" as used herein includes all arbitrary combinations of one or more of the associated listed items. In the description of the drawings, like reference numerals refer to like elements throughout.

The thickness of elements in the figures may be exaggerated for clarity. It will be further understood that if an element is referred to as being "on," "coupled to" or "connected to" another element, it can be directly on, coupled or connected to the other element or intervening elements may be present. Conversely, if the expressions "directly on … …", "directly coupled with … …", and "directly connected with … …" are used herein, then there are no intervening elements present. Other words used to describe the relationship between elements, such as "between … …" and "directly between … …", "attached" and "directly attached", "adjacent" and "directly adjacent", etc., should be similarly interpreted.

Terms such as "top," "bottom," "above," "below," "over," "under," and the like, may be used herein to describe one element, layer or region's relationship to another element, layer or region as illustrated in the figures. It will be understood that these terms are intended to encompass other orientations of the device in addition to the orientation depicted in the figures.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Thus, a first element could be termed a second element without departing from the teachings of the present inventive concept.

Finally, it is pointed out that the above-described embodiments are only intended to be understood as an example of the utility model and do not limit the scope of protection of the utility model. It will be apparent to those skilled in the art that modifications may be made in the foregoing embodiments without departing from the scope of the utility model.

Claims (21)

1. A one-way clutch, comprising:

a drive element (11) rotatable in a first direction (D) and in a second direction (R) opposite to the first direction;

a driven element (12) having a common axis of rotation (3) with the drive element;

a pawl (13) pivotally mounted to the drive element;

a snap ring (15);

a friction ring (14) frictionally coupled with the stop ring;

wherein the drive element is rotatable relative to the friction ring between a first rotational position in which the pawl is in a first pivot position relative to the drive element in which the pawl is disengaged from the driven element and a second rotational position downstream of the first rotational position in the first direction in which the pawl is in a second pivot position relative to the drive element pivoted radially inward from the first pivot position in which the pawl is engaged with the driven element;

wherein the friction ring has a resilient member (146), in a first pivot position of the pawl relative to the drive element, the resilient member of the friction ring presses the pawl and resists the pawl from leaving the first pivot position in a radially inward pivot direction.

2. The one-way clutch according to claim 1, wherein the elastic member of the friction ring is out of contact with the pawl upon a predetermined stroke of the pawl from the first pivot position in the radially inward pivot direction.

3. One-way clutch according to claim 1 or 2, characterized in that the elastic component of the friction ring is a finger element injection-moulded on the ring body of the friction ring.

4. One-way clutch according to claim 1 or 2, characterized in that the pawl has a locking member (35) which is configured to lock with the drive element in an override position which overrides the first pivot position in the radial outward pivot direction when the pawl overrides the first pivot position in the radial outward pivot direction.

5. The one-way clutch according to claim 4, wherein the locking member is a resilient member, and in the first pivot position the pawl abuts the drive element with the locking member, the locking member resisting movement of the pawl in a radially outward pivot direction out of the first pivot position.

6. The one-way clutch according to claim 4, characterized in that the locking component has a hook (36) which is configured to be hooked by the drive element when the pawl passes a first pivot position in a radially outward pivot direction, so that the pawl is held in the pass-over position.

7. The one-way clutch of claim 4, wherein the locking member is injection molded onto the body of the pawl.

8. The one-way clutch according to claim 4, wherein the locking member projects from the body of the pawl in a direction away from the free end of the pawl.

9. The one-way clutch according to claim 6, characterized in that the drive element has a projection (112) with an engaging hook (117), the pawl abutting with the hook on a surface of the projection adjacent to the engaging hook in the first pivot position, the hook sliding over the projection as the pawl pivots relative to the drive element from the first pivot position towards the override position, so that the hook catches on the engaging hook.

10. One-way clutch according to claim 1 or 2, characterized in that the pawl has a sliding surface (33), the friction ring has guide members (141, 142) for guiding the sliding surface, and the pawl is pivotable relative to the drive element between the first and the second pivoted position by the cooperation of the guide members and the sliding surface when the drive element is rotated relative to the friction ring between the first and the second rotated position.

11. The one-way clutch according to claim 1 or 2, characterized in that the pawl has a free end (32) remote from the pivot axis parallel to the rotation axis, which free end is configured for co-action with a driven element.

12. One-way clutch according to claim 10, characterized in that the sliding surface projects axially from the body (31) of the pawl, with reference to the pivot axis of the pawl.

13. One-way clutch according to claim 1 or 2, characterized in that it comprises two pawls, the pivot axes of which lie on one diameter line with reference to the axis of rotation.

14. The one-way clutch according to claim 1 or 2, wherein the friction ring is mounted radially inward of the snap ring, wherein an outer peripheral surface of the friction ring is frictionally coupled with an inner peripheral surface of the snap ring.

15. The one-way clutch according to claim 1 or 2,

the drive element and the friction ring each have a first cam (114, 144) configured to define a first rotational position of the drive element and the friction ring relative to each other; and/or

The drive element and the friction ring each have a second cam (115, 145) which is designed to define a second rotational position of the drive element and the friction ring relative to each other.

16. The one-way clutch according to claim 15, wherein, with reference to the axis of rotation, the contact surfaces of the drive element and the first projection of the friction ring deviate from a radial plane.

17. The one-way clutch according to claim 1 or 2, wherein the snap ring is a stator or the snap ring is limitedly rotatable.

18. One-way clutch according to claim 1 or 2, characterized in that the drive element has a chamber with a bottom at one axial end side of the drive element and is open at the other axial end side of the drive element, in which chamber the stop ring, the friction ring and the pawl are accommodated, on which open other axial end side an axial stop disk (18) connected to the drive element is mounted, the driven element being able to enter the chamber through an opening (116) of the bottom.

19. The one-way clutch according to claim 1 or 2, characterized in that, with reference to the axis of rotation, in the first and/or second pivot position, the angular area occupied by the constituents of the pawl from the pivot axis to the free end does not exceed 60 °.

20. The one-way clutch according to claim 1 or 2, wherein the driving element and the driven element are gears.

21. A safety belt retractor comprising a spool (1), a drive (4) and a one-way clutch (10) according to any one of claims 1 to 20, the drive being in driving connection with a drive element (11) of the one-way clutch, the spool being in driving connection with a driven element (12) of the one-way clutch.

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