WO2011057749A1

WO2011057749A1 - Belt tensioner with an overload clutch

Info

Publication number: WO2011057749A1
Application number: PCT/EP2010/006794
Authority: WO
Inventors: Klaus-Peter Singer; Ronald Jabusch
Original assignee: Autoliv Development Ab
Priority date: 2009-11-14
Filing date: 2010-11-08
Publication date: 2011-05-19

Abstract

A self-locking belt retractor with a blocking device which can be activated by means of a control system operating in a belt-strap-sensitive and/or vehicle-sensitive manner, for the belt shaft, and with a reversibly operating tensioning device which can be coupled up to the belt shaft and can be coupled to the belt shaft via a clutch which is activated in the event of tensioning, wherein the clutch consists of a clutch bell, which can be connected to the belt shaft and has an internal toothing arrangement, and of a clutch part which interacts with said clutch bell in the event of tensioning and is controlled by the tensioning drive, is characterized in that the clutch bell (13) is arranged in a freely rotatable manner in relation to the belt shaft (10) and is connected to the belt shaft (10) via an interconnected overload washer (15) which is connected on one side to the belt shaft (10) in a form-fitting manner and is provided on the other side, on the outer circumference thereof, with elastic spring arms (20) which are resiliently engaged with an assigned mating toothing arrangement arranged on the clutch bell (13), and the spring rigidity of said spring arms is set in such a manner that, when torque is exerted on the overload washer (15) by the clutch bell (13) in the event of tensioning, the spring arms (20) remain in engagement with the mating toothing arrangement of the clutch bell (13) and, if a predetermined torque exerted in the event of danger by the belt shaft (10) on the overload washer (15), which is secured by the clutch bell (13), is exceeded, the spring arms (20) are resiliently forced out of engagement with the mating toothing arrangement by the mating toothing arrangement of the clutch bell (13).

Description

Belt tensioner with overload clutch

Description

The invention relates to a self-locking belt retractor with a controllable by means of a belt-sensitive and / or vehicle-sensitive control system blocking device for the belt shaft and a can be coupled to the spool reversible working tensioning device, which is coupled via a driven in the event of a stall clutch with the belt shaft, the clutch from one connectable to the belt shaft, one

Internal toothing having clutch bell and from a co-acting in the penalty case and controlled by the tensioner coupling part consists.

A belt retractor with the intended features i st described in DE 100 59 227 C l. In such a belt retractor, the requirement is made that the belt retractor must withstand a slight accident, a so-called low-speed crash, without damage, so that all

Functions of the belt retractor remain maintained even after such a crash. In the belt retractor described in the generic DE 1 00 59 227 C 1, the clutch consists of a clutch bell fixedly connected to the belt shaft, arranged in the internal toothing one arranged in a plane of the clutch bell and example of an electric motor as a tensioner driven rotary body mounted clutch pawl is radially deflectable.

With the known Gurtaufrol ler the disadvantage is associated that at a subsequent to an initially triggered pre-tightening the seat belt entering light accident due to a belted

Vehicle occupants on the belt shaft in Gurtauszugsrichtung exerted load and then transmitted from the spool to the first coupling part torque such forces on the tensioner drive, such as an electric motor, exercised that it comes to a deterioration of the function of the tensioner drive and thus Following a low-speed crash, the entire belt retractor must be replaced with tensioner drive.

The invention is therefore based on the object, a belt retractor with the aforementioned generic features in such a way that the belt retractor after a low-speed crash unchanged

is functional.

The solution to this problem arises including advantageous

Embodiments and developments of the invention from the content of the claims, which are nachgestellt this description.

The invention provides in its basic idea that the clutch bell is freely rotatable relative to the belt shaft and connected to the belt shaft via an intermediate overload disk, which is on the one hand positively connected to the belt shaft and on the other hand on its outer periphery with an associated, on the clutch bell arranged counter-toothing is provided resiliently engaging elastic spring arms whose spring stiffness is adjusted so that in the event of a punishment of the clutch bell on the overload disk

applied torque, the spring arms in engagement with the counter toothing the clutch bell remain and when exceeding a predetermined in case of danger of the belt shaft on the clutch bell

held overload disk exerted torque, the spring arms of the counter teeth of the clutch bell are resiliently disengaged from the counter teeth.

According to the invention, the overload disk for connection between the clutch bell and the belt shaft is designed so that in one of the

Strafferantrieb in the event of punishment caused rotation of the clutch bell in Gurtaufwickelrichtung thereby exerted on the overload disk drive torque arranged on the overload disk spring arms due to their spring stiffness in each case remain in engagement with the counter teeth of the clutch bell, so that the clutch bell takes in their rotary motion, the overload disk, the rotation of the

Overload due to their positive connection with the

Belt shaft in a corresponding rotation of the belt shaft in

Gurtaufwickelrichtung is implemented.

If, following the tightening process, a dangerous situation causing the belt-sensitive or vehicle-sensitive control system to be initiated, in which the belt shaft is blocked, the belt shaft must be able to rotate by a small angle of rotation in the belt pull-out direction, so that the relative rotation between the belt shaft and the belt Control system, the Einsteuerung the blocking pawl in the housing-fixed teeth is enabled. Because of the coupling connection between the tensioner and the clutch bell a reverse rotation of

Clutch bell together with the reverse rotation of the belt shaft

is excluded or with damage to the

Strafferantriebes would be connected, the load torque is now so large that the thus acting between counter teeth and spring arms force overcomes the spring stiffness of the spring arms, so that in the direction of rotation of the overload disk in Gurtauszugsrichtung the spring arms on the teeth Slide counter teeth of the fixed clutch bell and thereby resiliently disengaged from the clutch bell. Thus, starting from a predetermined torque, a free rotation of the Gurtwel le against the coupled to the tensioner clutch bell

guaranteed. This state is maintained even if subsequently occurs when blocking the Gurtwel le by the gurtaufrollerseitige blocking device, a so-called low-speed crash, in which the in the

Belt retractor arranged force limiting system responds, for example in the form of a torsion bar, so that the belt shaft in

Belt extension direction continues to rotate by a certain angle of rotation. This rotation of the belt shaft is due to the on the counter teeth of the

Clutch bell sliding spring arms of the clutch bell

decoupled, so that the tensioner is protected from overload.

Thus, with the invention has the advantage that the force required in a crash power absorbed completely made by the blocking device of the belt retractor and the tensioner is taken out of the relevant power flow and thus protected.

According to one exemplary embodiment of the invention, the spring arms distributed over the outer circumference of a disk body of the overload disk are arranged in the circumferential direction at a distance from each other and aligned in the circumferential direction such that the outer end of the spring arms each have a radial distance from the disk body, so that a spring for radial compression of the spring arms is formed out of engagement with the counter teeth of the clutch bell.

As far as the clutch bell is freely rotatable relative to the belt shaft, it is provided according to an embodiment of the invention that the clutch bell has a central center recess and the

Disc body of the overload disk extends axially over the plane of the

Spring arms projecting arms in the middle recess of the Clutch bell centered and radially fixed therein. Thus, the clutch bell has no connection with the belt shaft and is fixed on the connected by means of positive locking design with the belt shaft disc body of the overload disk. In this case, the clutch bell is supported axially against the end face of the belt shaft.

To form the positive connection of the overload disk with the belt shaft is provided according to an embodiment of the invention that the disk body of the overload disk with a central center opening engages over an extension of the belt shaft and from the center opening bounding edge of the disk body radially into the center opening

protruding and engaging projections formed in the extension of the belt shaft grooves are provided.

As far as doing so for an axial fixation of the overload disk on the

Belt shaft or its extension is to ensure is after one

Embodiment of the invention provides that the overload disk consists of a spring steel and the engaging in the arranged on the belt shaft grooves projections dig into the softer material used for the production of the belt shaft and so provide an axial fixation of the overload disk on the shaft extension.

To improve the alignment of the disc body to the

Gurtwellenfortsatz and prevention of the interaction of

Spring arms interfering with the counter-toothing of the clutch bell

Tilting movements of the overload disk is provided according to an embodiment of the invention that the formed on the disk body

Projections spaced apart from each other over the circumference of the central opening are arranged and the disc body each having between two projections a projecting from the plane, axially aligned to the belt shaft and has on the outside of the extension of the belt shaft at its peripheral portions located between the grooves rag. To improve the engagement of the spring arms in the counter-toothing of the clutch bell and thus to adjust the spring stiffness of

Spring arms is provided according to an embodiment of the invention, that in the radial distance formed between the individual spring arms and the disc body in each case an intermediate piece of a

is arranged compressible material. By between the

Disk body and the spring arms arranged intermediate pieces, the spring arms are held in engagement with the counter-toothing of the clutch bell or it is exercised a corresponding pressing force. At the same time give the intermediate pieces in a reverse rotation of the belt shaft relative to the clutch bell caused by the counter teeth displacement of the spring arms after. To form such a

Embodiment is according to an embodiment of the invention

provided that the individual intermediate pieces are arranged on a separate ring which between disc body and the bottom of the

cup-shaped clutch bell is arranged and fixed to the clutch bell.

The arrangement of spacers made of a different material and with a different hardness makes it possible, in each case the same design of the clutch bell with internal teeth and the

Overload disk with spring arms different spring stiffnesses of the spring arms and thus different transmission torques

set, so that according to an embodiment of the invention, it is provided that the ring is interchangeably arranged with the intermediate pieces held thereon.

In the drawing, an embodiment of the invention is reproduced, which is described below. Show it: 1 is a self-locking belt retractor with drive wheel al s part of the tensioner drive in a perspective view,

2 shows the subject matter of FIG. 1 in a sectional view,

Fig. 3, the clutch bell in an end view when removed

Drive wheel,

4 shows the overload disk in a single representation,

Fig. 5 shows the assembly of clutch bell and guided it

Overload disc

Fig. 6, the belt shaft with superposed overload disk and

Clutch bell in a perspective front view,

Fig. 7, the clutch bell and overload disk with at the

Overload disk arranged intermediate pieces in a perspective front view,

Fig. 8 overload disk with an associated, the intermediate pieces

wearing ring in a perspective view,

Fig. 9, the clutch bell arranged thereon overload disk and

Ring in a perspective view.

In Figure 1, the belt shaft 1 0 is shown a self-locking belt retractor, which is mounted on both sides in the housing legs of a U-shaped housing, not shown. On the left in the illustration of Figure 1 side of the belt shaft is to the belt shaft 10 a

Blocking device connected to an associated belt-sensitive and vehicle-sensitive control system. Training and function of a corresponding blocking device are known and described in the prior art, for example according to DE GM 74 25 23 1, where it does not matter for understanding the invention thereto. On the right in the illustration of Figure 1 side of the belt shaft 10, a drive wheel 1 1 is arranged with an external toothing 12, wherein the

Drive wheel 1 1 of a tensioner, not shown, for example, an electric motor, is set in the penalty case in rotation. Such a tensioner drive with a worm toothing engaging with the external teeth 12 of the drive wheel 11 is described, for example, in DE 10 2005 047 21 2 B4.

As is further apparent from Figure 2, the drive wheel 1 1 is a

associated internally toothed clutch bell 1 3, which according to the invention with respect to the belt shaft 1 0 rotatably mounted and connected to the belt shaft 1 0 by means of a cup-shaped inside the bell cup 1 3 arranged and a shaft extension 14 encompassing overload disk 1 5, as follows in detail yet will be to describe. To connect drive wheel 1 1 and clutch bell 1 3 two clutch pawls 16 are slidably disposed on the drive wheel 1 1, which are moved upon rotation of the drive wheel 1 1 in the penalty case radially outward to engage in the internal teeth 1 7 of the clutch bell and so the drive wheel 1 1 to the clutch bell 1 3 couple, so that the rotation of the drive wheel 1 1 in a rectified rotation of the

Clutch bell 1 3 is implemented. The arrangement of the coupling pawls 16 is shown in Figure 3, wherein this coupling principle in a

Belt tensioner is described in DE 100 59 227 C2. Also on this

Clutch principle is not important for the understanding of the invention, as long as an effective in the event of an emergency coupling between the

Drive wheel 1 1 and the clutch bell 1 3 is realized.

From Figure 3, in addition, parts of the between the clutch bell 1 3 and the shaft extension 1 4 of the belt shaft 1 0 connected overload disk 1 5 can be seen, the structure and design of which is now described with reference to FIG 4. The overload disk has a disk body 1 8 with a central opening 1 9 arranged therein, with which the overload disk 1 5 on the shaft extension 14 of the belt shaft 1 0 can be pushed. The overload disk 1 5 has from the center opening 1 9 bounding edge of the disk body 1 8 radially into the central opening 1 9 protruding projections 2 1.

In addition, 9 axially projecting from the plane of its axial flaps 22 are arranged on the disc body 1, which at the shaft extension 14th

slid over overload disk on the outer circumference of the shaft extension 14 abut. On the opposite side, the clutch bell also still on the plane of the disc body axially projecting bearing arms 23. Distributed over the outer circumference of the disk body 1 8 are further circumferentially spaced spring arms 20 are provided which are aligned in the circumferential direction to each other so that the outer end of the spring arms 20 in each case has a radial distance 24 to the disk body or the adjacent Federarmansatz, so that a spring for radial compression of the spring arms 20 in the direction of the disc body 1 8 is formed.

As far as according to Figure 2, the bottom of the cup-shaped clutch bell 1 3 axially against the front of the belt shaft 10 is supported and in its interior, the overload disk 1 5 is arranged, which clamps the clutch bell 1 3 between the belt shaft 10 and itself and thereby axially fixed, grab arranged on the overload disk 1 5 axial bearing arms 23 in a formed on the clutch bell 1 3 center recess 25, so that the

Clutch bell radially fixed by the axial bearing arms 23 of the overload disk 1 5 and at the same time a relative rotation between the

Clutch bell 13 and the overload disk 1 5 is made possible by the axial bearing arms 23 act as a pivot bearing in such a relative rotation. As is apparent from Figure 6, the internal teeth 1 7 of the clutch bell 1 3 is not configured over its full width with a same tooth depth, but the internal teeth in the deepest of

Clutch bell 1 3 formed in her in the plane of the arranged in the clutch bell 1 3 overload disk 1 5 as flatter counter-toothing, with which the spring arms 20 are due to their radially outward spring action in engagement. Upon rotation of the clutch bell 1 3 counterclockwise according to arrow 35 are thus the

Tooth flanks of the counter-toothing endeavors to urge spring arms 20 inwardly out of engagement with the counter-toothing. The penalty of the clutch bell 1 3 on the initially stationary belt shaft 1 0 and thus also resting overload disk 1 5 exerted torque now generates no force acting on the tooth flanks of the counter teeth sufficient to overcome the spring stiffness of the spring arms 20 and the spring arms 20th thus pushing outward into engagement with the counter-toothing. Thus, upon rotation of the clutch bell 1 3 the

Overload disk 1 5 offset in a rectified rotational movement. For the positive connection of the overload disk 1 5 with the belt shaft 1 0 extending grooves 26 are formed on the shaft extension 14 in the axial direction, in which the radially into the shaft extension 1 4 receiving center opening 19 protruding projections 2 1 engage and thus for a

Ensure positive connection. In this case, which are arranged between the radial projections 21 axial tabs 22 are on the existing between the grooves 26 peripheral portions 27 of the shaft extension 1 4 and provide so far for a support of the overload disk 1 fifth

If, subsequent to the tightening process, a dangerous situation which brings about the response of the belt-sensitive or vehicle-sensitive control system is intended, the blockage of the belt shaft 10 should first be brought about by means of the blocking device assigned to it.

For this purpose, it is necessary that the belt shaft 10 rotates by a small angle of rotation in Gurtauszugsrichtung, so by this anfängl iche Rotary movement of the blocking pawl is controlled in the associated housing-fixed toothing, as described in the prior art. This rotation of the belt shaft 10 in Gurtauszugsrichtung is by a

corresponding load of the wound on the belt shaft 1 0

Seat belt brought about by the belted person and thus is on the belt shaft 1 0 an increasing torque effect, which on the positive connection between the belt shaft 1 0 and

Overload disk 1 5 also acts on the overload disk 1 5. As far as the overload disk 1 5 to rotate relative to the detained by the tensioner 1 1 clutch bell 1 3, which is on the tooth flanks of the

Gegenverzahnung the clutch bell 1 3 due to the rising, exerted by the belt shaft 1 0 torque resulting force so large that the spring arms 20 of the overload disk 1 5 are urged against its spring stiffness inside and out of engagement with the counter teeth of the clutch bell 1 3 so that the belt shaft 1 0 can rotate relative to the fixed clutch bell 1 3, without excessive forces on the clutch bell 1 3 and the associated tensioner drive 1 1 are exercised.

Finally, FIGS. 7 to 9 also show the manner in which the spring stiffness of the spring arms 20 of the overload disk 1 5 can be adjusted, so that different transmission torques can be set with a constant configuration of the clutch bell and the overload disk. For this purpose, 29 intermediate pieces 28 made of a compressible material, preferably a suitable elastomer are arranged on a ring, which have such a shape that they can be inserted into the provided between the spring arms 20 and the disk body 1 8 of the overload disk 1 5 distance 24. In this case, the intermediate pieces 28 are arranged on one side of the ring 29, while on the other side of the ring 29 distributed over the circumference holding naps 30 are arranged in an arrangement of the ring 29 between the overload disk 1 5 and the bottom of the cup-shaped clutch bell. 1 3 in the bottom of the clutch bell 1 3 trained recordings 3 1 engage, so that the ring 29 is replaceably mounted on the clutch bell 1 3. The lying in the intervals 24 spacers 28 while still exert a pressing force of the spring arms 20 against the tooth flanks of the counter-toothing of the clutch bell 1 3, whereby the transmission torque is increased accordingly. At the same time but give the intermediate pieces 28 at a correspondingly high torque of the spring arms 20 inwardly pressing force component.

The in the above description, the claims, the

Summary and the drawing disclosed features of

Subject of this document may be individually or in any

Combinations with each other for the realization of the invention in its various embodiments essential.

Claims

P at e n t a n s p r e c h e

1. Self-locking belt retractor with a controllable by means of a belt-sensitive and / or vehicle-sensitive control system blocking device for the belt shaft and with an attachable to the belt shaft reversible working tensioning device, which is coupled via a controlled in the event of a stall clutch with the belt shaft, the clutch of a with the belt shaft connectable, one

Internal toothing clutch bell and from a cooperating in the penalty case and from the tensioner drive

controlled coupling part, characterized in that the coupling bell (13) relative to the belt shaft (10) freely rotatably arranged and with the belt shaft (10) via an intermediate overload disk (15) is connected, on the one hand form-fitting manner to the belt shaft (10) and on the other hand on its outer periphery with an associated, on the clutch bell (13) arranged counter-toothing resiliently engaged

elastic spring arms (20) is provided whose spring stiffness is set so that in the penalty case of the clutch bell (13) on the overload disk (15) torque exerted by the spring arms (20) engage with the counter teeth of the clutch bell (13) and when a predetermined in case of danger by the belt shaft (10) on the clutch disc (13) held overload disk (15) torque exerted the spring arms (20) of the counter teeth of the clutch bell (13) are resiliently disengaged from engagement with the counter teeth. Self-locking belt retractor according to claim 1, characterized in that over the outer periphery of a disc body (18) of the overload disk (15) arranged distributed spring arms (20) in

Circumferentially arranged with distance from each other and in

Circumferential direction are aligned such that the outer end of the spring arms (20) each have a radial distance (24) to the disc body (18), so that a spring travel for radial compression of the

Spring arms (20) disengaged from the counter teeth of the

Clutch bell (13) is formed.

Self-locking belt retractor according to claim 1 or 2, characterized in that the clutch bell (13) is a centric

Mittenausnehmung (25) and the disc body (18) of the overload disk (15) with axially above the plane of the spring arms (20) projecting bearing arms (23) in the central recess (25) of the

Clutch bell (13) centered and radially fixed therein.

Self-locking belt retractor according to one of claims 1 to 3, characterized in that the disc body (18) of the

Overload disk (15) with a central center opening (19) engages over an extension (14) of the belt shaft (10) and for forming the positive connection with the belt shaft (10) of the

Providing projections (21) which project radially into the central opening (19) and engage in grooves (26) formed on the extension (14) of the belt shaft (10) are provided in the center opening (19) of the disk body (18).

Self-locking belt retractor according to claim 4, characterized in that the overload disc (15) consists of a spring steel and in the on the belt shaft (10) arranged grooves (26) engaging projections (21) in the for the production of the belt shaft (10) dig in the softer material used and thus ensure that the overload disk (1 5) is fixed axially on the shaft extension (1 4).

6. Self-locking belt retractor according to claim 4 or 5, characterized

in that the projections (2 1) formed on the disk body (1 8) are spaced apart from each other over the circumference of the

Between the two projections (21) projecting from the plane, axially to the belt shaft (1 0) aligned and outside of the extension (14) of the belt shaft (10) at the Having lying between the grooves (26) peripheral regions (27) abutting tabs (22).

7. A self-locking belt retractor according to any one of claims 1 to 6,

characterized in that in between the individual

Spring arms (20) and the disc body (1 8) formed radial distance (24) in each case an intermediate piece (28) is arranged made of a compressible material.

8. A self-locking belt retractor according to claim 7, characterized in that the individual intermediate pieces (28) on a separate ring (29) are arranged between the disc body (1 8) and the bottom of the cup-shaped clutch bell (1 3) and arranged on the clutch bell (1 3) is fixed.

9. Self-locking belt retractor according to claim 8, characterized in that the ring (29) is interchangeably arranged with the held thereon intermediate pieces (28).