WO2014131824A1

WO2014131824A1 - Belt retractor for a seatbelt device of a motor vehicle with a rotatory tensioner and a force-limiting device

Info

Publication number: WO2014131824A1
Application number: PCT/EP2014/053808
Authority: WO
Inventors: Klaus-Peter Singer; Ronald Jabusch
Original assignee: Autoliv Development Ab
Priority date: 2013-02-27
Filing date: 2014-02-27
Publication date: 2014-09-04
Also published as: DE102013203286A1; DE102013203286B4

Abstract

The present invention relates to a belt retractor for a seatbelt device of a motor vehicle with a rotatory tensioner (2) and a first force-limiting device (1) having - a U-shaped frame (3) which is fastenable in a manner mounted on the vehicle and has two parallel limbs, - a two-part belt shaft which is mounted rotatably in the limbs of the U-shaped frame (3) and has a belt shaft body (4), on which a seatbelt (5) can be wound up, and a profile head (7) which is lockable in relation to the frame (3) in a manner mounted on the vehicle, wherein - the first force-limiting device (1) connects the profile head (7) to the belt shaft body (4), wherein - the tensioner (2) and the profile head (7) are arranged on different sides of the belt shaft body (4), and - a transmission device (6) is provided, by means of which the tensioning movement of the tensioner (2) can be transmitted through the belt shaft body (4) to the profile head (7).

Description

Belt retractor for a safety belt device of a motor vehicle with a rotary tensioning device and a

Load limiting device

The invention relates to a belt retractor for a safety belt device of a motor vehicle with a rotary strapping device and a force limiting device having the features of the preamble of claim 1.

Belt retractors with tensioning devices and force limiting devices have basically been known for a long time in the prior art.

The purpose of the tensioning devices is to extract slacklings that are present in an early phase of an accident from the seat belt of the safety belt device, which is realized in a belt retractor by driving the belt shaft in the lifting direction. On the other hand, the force limiting devices serve to enable a force-limited belt extension movement when the belt shaft is locked, in order to reduce the occupant load while making use of the available forward displacement path. For this purpose, the force limiting device is arranged in the power flow between the belt shaft body and a vehicle-locking profile head, so that the Gurtwellenkörper can perform a force-limited rotational movement in Gurtauszugszugsrichtung with the webbing wound on activation of the force limiting device relative to the blocked profile head. Since the activation of the tensioning device and of the force limiting device takes place temporally on one another, there is the risk of a short-term gene increase the belt pull-out force at the beginning of the activation of the force limiting device when the tensioning device still acts on the belt shaft. Therefore, there is a general desire to deactivate the tensioning device as soon as possible at the end of the tightening process, in order to avoid the so-called force limitation failure.

In order to avoid the force limiting fault, it is also known from DE 102 13 906 A1 to arrange the tensioning device on the profile head which can be locked in the vehicle and to drive the belt shaft via the force limiting device provided between the belt shaft and the profile head. As a result, the tensioning device is decoupled from the force transmission path during a subsequent activation of the force limiting device, which is triggered by the blocking of the profile head and the exceeding of a predetermined belt pull-out force, and the force limitation fault is avoided. The drive of the tensioning device is formed here on the profile head, so that it is determined by the blocking of the profile head.

For a good tightening movement, the drive wheel should be arranged as close as possible to the housing of the belt retractor. Furthermore, the attachment point of the belt retractor should be arranged as centrally as possible. Since the tensioning device at the o.g. Solution is arranged with the drive wheel on the profile head of the belt retractor, both criteria are difficult to meet with this solution.

The object of the invention is therefore to provide a belt retractor with a tensioning device and a force limiting device, in which the above-described force limiting - disturbance is avoided, and which simultaneously the storage and mounting can be improved.

To solve the problem, a belt retractor with the features of claim 1 is proposed. Further preferred developments of the invention can be found in the subclaims.

According to the basic idea of the invention, it is proposed that the puncture device and the profile head are arranged on different sides of the belt body, and a transmission device is provided by means of which the tensioning movement of the tensioning device can be transmitted through the belt shaft body to the profile head.

The advantage of the proposed solution is the fact that a balanced package of the belt retractor can be achieved with the advantages described above by the arrangement of the criminal fVorrichtung and the profile head on different sides of the belt shaft body. Since the tensioning movement is connected by the connection of the tensioning device via the transmission device with the profile head, the tensioning force is still transmitted via the profile head on the belt shaft body, so that the tensioning device by the blocking of the profile head already at the beginning of the activation of the first force limiting device of this and the Belt shaft body is decoupled. Thus, the adverse force limiting disturbance is avoided. In particular, the proposed solution provides the advantage that the tensioning device can be arranged with the drive wheel particularly close to the housing so that the rotatable parts and in particular the drive wheel of the tensioning device can be stored particularly well. Furthermore, there is a cheaper Weight distribution, and the profile head can be made easier, since the drive wheel of the tensioning device is no longer arranged on the profile head.

It is also proposed that in the power transmission path from the tensioning device to the belt shaft body, a second force limiting device is provided, which transmits the tension of the tensioning device on the belt shaft body

Tightening force at the beginning of the tightening movement limited during a predetermined rotation angle. By the second force limiting device, the very high tensioning force can be reduced at the beginning of the tightening movement, so that the first power limiting device is charged less. The first force limiting device thus transmits the entire penalty force only when the second force limiting device is no longer active after passing through the predetermined rotation angle.

Furthermore, it is proposed that the belt shaft body is hollow, and the transmission device is formed by a belt shaft penetrating the transfer rod, which is non-rotatably connected to a first end with the tensioning device and a second end rotatably connected to the profile head. By using the transfer rod guided through the hollow belt shaft body as a transfer device, a particularly compact construction can be realized, wherein in particular a previously used hollow standard belt shaft body can be used.

In this case, the second force-limiting device can be formed by a metal band suspended in the transfer rod, which extends radially outwards from the transfer rod, is deflected in at least one deflection point and is supported with a free end in the winding direction on the belt shaft body. Due to the proposed solution, the metal strip runs around during the tensioning movement in the deflection energy-consuming and is wound up on the transfer rod or on an extension of the profile head. The metal band is supported during an initial phase of the tensioning movement directly between the transfer rod and the Gurtwellenkörper and thereby transmits the tensioning movement of the transfer rod on the belt shaft body until the metal strip is completely wound by the circulation of the deflection point on the transfer rod and the connection is canceled. In parallel, the first force limiting device is loaded simultaneously, which only then transmits the full tensioning force when the metal strip is completely wound by the circulation of the deflection point, and the connection is canceled via the second force limiting device.

In this case, the metal strip can extend through a slot in the transfer rod and be supported point symmetrically with two free ends on the belt shaft body. The proposed solution, a point-symmetrical force introduction into the belt shaft body can be achieved so that the radial forces between the transfer rod or the profile head and the belt shaft body act as uniformly as possible and the maximum radial force is lower. Furthermore, the metal strip must be inserted only in the slot and not separately fastened, since the tensile forces act from both ends on the metal strip and compensate in the ideal case.

It is further proposed that the force limiting device is arranged between the legs of the U-shaped frame. Due to the proposed arrangement of the force limiting device, both the profile head and the belt Lenkorper be rotatably mounted in the legs of the frame and that in each case so that the force introduced by the Kraftbegrenzungsein- direction force is introduced into the two parts between the bearings, so that can be achieved overall favorable lever arm ratios. The two-piece belt Elle can be stored in one leg on the belt shaft body and in the other leg on the profile head, resulting in a simple structural design with a good storage of the belt shaft.

In this case, it is further proposed that the force limiting device is formed annular disc-shaped, and the transmission device protrudes centrally through the Kraftbegrenzungs- device. The force limiting device practically encompasses the two-part belt shaft and connects the belt shaft body and the profile head to a radially outer section. Due to the annular disk-shaped design of the force limiting device, a free section is provided centrally through which the transmission device, a section of the belt shaft body and a section of the profile head can protrude, whereby a simple connection of the transfer rod to the profile head through the force limiting device is possible. Furthermore, the components may overlap centrally in the opening of the force limiting device in the axial direction, so that the belt shaft body can be supported on the profile head during the activation of the force limiting device and is thus practically supported. In this case, the components may overlap so far that there is a plane in which protrude the first and second force limiting device, a portion of the profile head and a portion of the belt shaft body and an end of the transfer rod. It is further proposed that the force limiting device is speed-controlled. Velocity-controlled force limiting devices can, for example, on the basis of an oscillating mass system or on the basis of liquid damping, enable a force-limited belt webbing pull-out, wherein the belt pull-out force is dependent on the speed of the mutually moving parts of the force limiting device. Since the tensioning device causes a very high acceleration of the transfer rod and the profile head at the beginning of the activation, the rotational speed of the driven components increases very quickly in the initial phase of the tightening movement. Since the first force limiting device is also speed-controlled, the tensioning force transferable via the first force limiting device likewise increases, so that the first force limiting device practically adapts to the tensioning force to be transmitted. In particular, the use of the proposed second force limiting device in conjunction with the speed-controlled first force limiting device makes sense, since the speed-controlled first force limiting device only requires a certain relative speed of the moving components to build up their effect. In this initial phase, the first force limiting device is practically relieved by the second force limiting device by a part of the tensioning force is transmitted from the second force limiting device.

It is further proposed that the tensioning device comprises a driven drive wheel which is connected to the profile head in a tensile-resistant manner via the transmission device in the axial direction. The drive wheel is axially secured by the tensile connection with the profile head, so that it is held in a position in which it optimally with a can interact drive device. Since the profile head is also connected via the second force limiting device with the belt shaft body, the drive wheel is thereby fixed relative to the belt shaft body in the axial direction, without being directly connected to this. The belt shaft body and the drive wheel are thereby axially fixed to each other and can still rotate to each other, which in turn is important for the force-limited Gurtbandauszugsbewegung during Kraftbegrenzungsphase.

The invention will be explained below with reference to preferred embodiments with reference to the accompanying figures. Showing:

Fig. 1: a belt retractor according to the invention with a

StraffVorrichtung and a force limiting device;

Fig. 2: a sectional view of the belt retractor from the

Fig. 1 in the cutting direction C-C; and

Fig. 3: a sectional view of the belt retractor along the cutting direction A-A from FIG. Second

In the Fig. 1 shows a belt retractor according to the invention with a first force limiting device 1 and a tensioning device 2, which has a two-part belt shaft mounted rotatably in a vehicle-fixed U-shaped frame 3. The two-part belt shaft comprises a belt shaft body 4, on which a safety belt 5 can be wound up. The belt shaft is spring-biased by means of a winding spring in the elevator direction and by means of a vehicle-sensitive and web-belt-sensitive controllable blocking device. blockable in the extension direction. The tensioning device 2 and the first force limiting device 1 are arranged on different sides of the belt shaft body 4, the first force limiting device 1 being arranged between the legs of the frame 3 and the tensioning device 2 on the outside of the left leg of the frame 3.

In the sectional views of FIG. 2 and FIG. 3, the construction of the belt retractor can be seen in detail. The belt shaft is formed in two parts from the belt shaft body 4 and a profile head 7 and rotatably mounted on the belt shaft body 4 in the left leg and on the profile head 7 in the right leg of the frame 3. The belt shaft body 4 and the profile head 7 are connected to each other via the first ring-shaped force limiting device 1 in a radially outer portion. The tensioning device 2 comprises a drive wheel 17, which is non-rotatably connected to a first end 12 of a transmission device 6. The transmission device 6 is formed by a transfer rod which extends through the hollow belt shaft body 4 and is connected to a second end 11 in a tension-proof and rotationally fixed manner to the profile head 7. As a result, the drive wheel 17 and the profile head 7 form a non-rotatable composite, and the drive wheel 17 is also connected in the axial direction of the belt shaft tensile strength with the profile head 7. Since the profile head 7 is also connected to the belt shaft body 4 via the first force limiting device 1, the drive wheel 17 is thus also fixed relative to the belt shaft body 4 in the axial direction. The second end 11 of the transfer rod is contoured in cross-section such that the profile head 7 is connected in a form-fitting manner with the second end 11 of the transfer rod in the circumferential direction by two axial fingers 8 resting against the second end 11. Furthermore, between the profile head 7 and the second end 11 of the transfer rod, a second force limiting device 10 is provided in the form of a metal strip which is inserted into a transverse slot in the second end 11 and in the circumferential direction between the axial fingers 8 of the profile head 7 and the second End 11 of the transfer rod is trapped. The metal strip extends point-symmetrically from the transfer rod radially outward through two opposite deflection points and lies with the free ends in the winding direction in a form-fitting manner against the second end 11 of the transfer rod axially overlapping annular flange 9 of the belt shaft body 4. The second force limiting device 10 is thus arranged parallel to the first force limiting device 1 between the profile head 7 and the belt shaft body 4.

The first force limiting device 1 is a speed-controlled force limiting device with two annular toothed disks 14 and 15 connected in a rotationally fixed manner to the belt shaft body 4 and a vibrating disk 16 arranged between the gear disks 14 and 15

Oscillating disk 16 is rotatably connected via an internal toothing and axially displaceable with a toothed ring 13, which in turn is rotatably connected to the profile head 7. The first force limiting device 1 is activated by the profile head 7 is blocked in a first step by an activation of the blocking device relative to the vehicle-fixed frame 3. As a result, the toothed ring 13 and the vibrating plate 16 are also blocked in the circumferential direction.

Thereafter, if the belt pull-out force further increases, the belt shaft body 4 starts to rotate in the extension direction, whereby the rotational movement is made possible by the swing disk 16 executing a periodic oscillating movement in the axial direction, while alternately engaging the gears of the splines 14 and 15. The operating principle of the first force limiting device is also described for example in DE 10 2011 101 516 AI.

Upon activation of the tensioning device 2 in the early phase of an accident, the drive wheel 17 is driven abruptly in the winding direction of the safety belt 5. This drive movement of the drive wheel 17 is transmitted via the second end 11 of the transfer bar to the profile head 7 which is not blocked at this time. In the course of the power flow, the tensioning movement is transmitted from the profile head 7 via the parallel acting first and second force limiting means 1 and 10 on the belt shaft body 4. In this case, the second force limiting device 10 transmits the

Tightening movement by in the Umf ngsrichtung on the annular flange 9 of the belt shaft body 4 supporting free ends of the metal strip. During the tensioning movement, the deflections of the metal strip run around until the metal strip is completely wound up to the diameter of the second end 11 of the transfer rod, ie until the metal strip no longer rests positively against the belt shaft body 4 with the free ends. By circulating the deflections energy is destroyed in the metal strip by the flexing done, which is the cause of the force limit of the second force limiting device 10. By the second force limiting device 10, the first force limiting device 1 is correspondingly relieved until the metal strip is no longer positively applied to the belt shaft body 4. This angle of rotation, until the metal strip is no longer present, corresponds to the angle of rotation during which the second force limiting device 10 acts. At the same time, the oscillating disc 16 is driven via the toothed ring 13 by the profile head 7 driven by the transmission device 6. Since the vibrating plate 16 is at least in the initial position in engagement with one of the toothings of the toothed discs 14 and 15, the belt shaft body 4 is driven in parallel via the first force limiting device 1. In this case, the acceleration of the vibrating disk 16 is so great that the vibrating disk 16, due to its mass and the inertial force to be overcome thereby, does not carry out the oscillating motion and transmits the rotational motion lossless to the belt shaft body 4. If the mass and the acting inertial forces are not sufficiently large, it may be that the vibrating plate 16 starts to oscillate axially and thereby performs a feed movement relative to the toothed discs 14 and 15, whereby the length of the tension can be reduced. It is, however, desirable to transfer the tensioning movement as far as possible without losses, ie the rotational movement of the profile head 7 should be transmitted as identically as possible to the belt shaft body 4.

The tightening performance of the tensioning device 2 is particularly high at the beginning of the activation. This high tensioning performance can be transmitted particularly well by the force-limiting devices 1 and 10 acting in parallel and with the least possible losses. Since the tightening force basically decreases after the tightening movement has been completed in the initial phase, the first force limiting device 1 alone is sufficient to transfer the tightening movement from a specific tightening length alone. In this case, the acting tension force in relation to the forces acting on the force limitation is so small that it is arranged in a relatively low portion of the design range of the force limiting characteristic of the first force limiting device 1, by the first Force limiting device 1 is not yet fully effective. In this range of the force limiting characteristic of the first force limiting device 1, the vibrating plate 16 does not yet start to vibrate, or the vibrating plate 16 oscillates only at a very small frequency, so that the loss of tension is thereby also minimized.

After completion of the tightening process, the profile head 7 is blocked when exceeding a predetermined vehicle deceleration or GurtbandausZugsbeschleunigung relative to the frame 3 in Gurtauszugsrichtung and the tensioning device 2 thereby decoupled from the belt shaft body 4. The GurtausZugkraft then continues to increase, the first force limiting device 1 is activated without the tensioning device 2 has an influence on the acting GurtausZugkraft. The previously occurring force limiting fault is thus excluded. It is of particular importance that at this time the connection between the profile head 7 and the second end 11 of the transfer rod and the belt shaft body 4 is already repealed, so that the force limiting characteristic is determined solely by the first force limiting device.

The advantage of the proposed solution is the fact that the tensioning device 2 can be arranged on the side of the frame 3, on which the spring cassette 18 of the belt retractor is arranged, or in other words, the tensioning device 2 and the blocking device or the first force limiting device 1 are arranged on different sides of the belt shaft body 4. This results in a very balanced package of the belt retractor with a balanced weight distribution and an approximately centered screw point of the belt retractor. In addition, the tensioning device is at a distance from the blocking device or the

System side of the belt retractor arranged so that the probability that the blocking device and the associated Sensörik is damaged by the activation of the Straffvoxrichtung 2, is much lower.

Claims

Claims :

A belt retractor for a seat belt device of a motor vehicle with a rotary tensioning device (2) and a first force limiting device (1) with a vehicle-fixed U-shaped frame (3) with two parallel legs,

-a rotatable in the legs of the U-shaped frame (3) mounted, two-piece belt shaft with a belt shaft body (4) on which a safety belt (5) can be wound, and a profile head (7), which with respect to the frame (3) fixed to the vehicle is lockable, wherein

the first force limiting device (1) connects the profile head (7) to the belt shaft body (4),

characterized in that

the tensioning device (2) and the profile head (7) are arranged on different sides of the belt shaft body (4), and

a transfer device (6) is provided, by means of which the tensioning movement of the tensioning device (2) can be transmitted through the belt shaft body (4) to the profile head (7).

2. Belt retractor according to claim 1, characterized in that

in the power transmission path from the tensioning device (2) to the belt shaft body (4) a second force limiting device (10) is provided, which the on the belt shaft body (4) transmitted tensioning force at the beginning of the tensioning movement during a predetermined rotation angle of the criminal fVorrichtung (2 ) limited .

3. Belt retractor according to claim 1 or 2, characterized in that -the belt shaft body (4) is hollow, and

the transmission device (6) is formed by a transfer rod penetrating the belt body (4), which with a first end (12) is non-rotatably connected to the puncture device (2) and with a second end (11) rotatably fixed to the profile head (7) is connected.

Belt retractor according to claim 2 and 3, characterized in that

the second force limiting device (10) is formed by a metal band suspended in the transfer rod, which extends radially outwards from the transfer rod, is deflected in at least one deflection point, and is supported on the belt shaft body (4) with a free end in the winding direction.

Belt retractor according to claim 4, characterized in that -the metal strip extends through a slot of the transfer bar and is supported point-symmetrically with two free ends on the belt shaft body (4).

Belt retractor according to one of the preceding claims, characterized in that

the force limiting device (1) is arranged between the legs of the U-shaped frame (3).

Belt retractor according to claim 6, characterized in that the force-limiting device (1) is formed annular disk-shaped, and

the transmission device (6) projects centrally through the first force limiting device (1).

8. Belt retractor according to one of the preceding claims, characterized in that

the first force limiting device (1) is speed-controlled.

s

9. Belt retractor according to one of the preceding claims, characterized in that

the tensioning device (2) comprises a driven drive wheel (17) which is connected to the profile head (7) in the axial direction by means of the transmission device (6).