Belt retractors for motor vehicles

Abstract

The invention relates to a belt retractor (10) for motor vehicles, comprising a housing frame (12) having two opposing side cheeks (14, 16), each with a cheek opening (18, 20), a belt spool (22) which is rotatable about a spool axis (A) and extends in the axial direction from a sensor-side spool end (24) through the cheek openings (18, 20) of the housing frame (12) to an opposite, spring-side spool end (26), and a housing cover (28) which is firmly connected to the housing frame (12), wherein the housing cover (28) forms a radially elastic pivot bearing (30) for the spring-side spool end (26), and wherein the spring-side spool end (26) of the belt spool (22) is fixed to the housing cover (28) in a guide-free manner in the radial direction.

Description

[0001] The invention relates to a belt retractor for motor vehicles, comprising a housing frame having two opposite side cheeks, each with a cheek opening, a belt spool which is rotatable about a spool axis and extends in the axial direction from a sensor-side spool end through the cheek openings of the housing frame to an opposite, spring-side spool end, and a housing cover which is firmly connected to the housing frame.

[0002] Such belt retractors are generally known from the state of the art and are widely used in the technical field of vehicle occupant restraint systems for motor vehicles.

[0003] In conventional belt retractors, for example, the belt spool is mounted radially within the housing frame, allowing it to move between a release position, in which it can rotate freely, and a locked position, in which it is fixed to the housing frame so it cannot rotate. Typically, in a restraint situation, the belt spool is first pivoted on the sensor side and then moved radially into its locked position. If the belt webbing pull-out force exceeds a predetermined value, the belt spool is deflected via a radial guide and against the spring force of a tensioning device, and moved radially into its locked position.

[0004] If the belt reel is in its locked position on both the sensor side and the spring side, the reel axis extends parallel to the reel axis again in the release position of the belt reel.

[0005] This design of the belt retractor is complex in terms of manufacturing technology and, in the locked position of the belt reel, also leads to a very different moment load on the belt reel on the sensor side and the spring side, which in extreme cases can lead to an excessive load on the sensor side of the belt reel.

[0006] From the generic EP 2 828 129 B1, a belt retractor for motor vehicles is known, comprising a housing frame having two opposing side cheeks, each with a cheek opening, and a belt spool that is rotatable about a spool axis and extends in the axial direction from a sensor-side spool end through the cheek openings of the housing frame to an opposite, spring-side spool end, and comprising a housing cover that is firmly connected to the housing frame, wherein the housing cover forms a radially elastic pivot bearing for the spring-side spool end. The spring-side spool end of the belt spool is fixed to the housing cover without any guide in the radial direction. Radially adjacent to the opening edges of the two cheek openings, the belt spool has a circumferentially running, spool-side locking toothing.

[0007] From DE 28 32 160 A1, a belt retractor is known whose belt reel is mounted in elastically flexible bearing points with little play and low friction in relation to the high tensile forces occurring in the event of a crash and is simultaneously centered in stable load bearings of the base frame with radial bearing play on all sides.

[0008] DE 34 21 960 A1 describes a belt retractor with a radially resiliently mounted belt reel, in whose locking teeth a pre-locking pawl can engage from the outside to the inside.

[0009] The object of the invention is therefore to create a structurally simplified belt retractor for motor vehicles in which the sensor side and the spring side are stressed more evenly in the restraint case.

[0010] In a belt retractor of the type mentioned above, the housing cover forms a radially elastic pivot bearing for the spring-side spool end, with the spring-side spool end of the belt spool being fixed to the housing cover without any radial guidance. In other words, the housing cover does not have a radial guide that determines a radially guided movement of the pivot bearing, and thus of the spring-side spool end, between a release position and a lock position of the belt spool. Instead, the pivot bearing is designed to be radially elastic and therefore allows free radial movement in the direction of force when a predetermined belt webbing pull-out force is exceeded.

[0011] Preferably, the radially elastic pivot bearing is formed integrally with the housing cover. This leads to a significant structural simplification of the belt retractor, since no radially guided pivot bearing or tensioning device for radially loading the pivot bearing is required in the housing cover.

[0012] The housing cover of the belt retractor can, in particular, be elastically deformable. The radial elasticity of the pivot bearing can thus be achieved with minimal effort by deforming the housing cover and can be influenced as desired by the material and thickness of the housing cover.

[0013] In one embodiment of the belt retractor, a sensor device is provided that forms a radially pivotable pivot bearing for the sensor-side spool end. This sensor device is mounted on the side panel of the housing frame and can move the belt spool from the release position to the lock position in a known manner, either vehicle-sensitive or belt-strap-sensitive.

[0014] According to a further embodiment of the belt retractor, each of the two cheek openings has a frame-side locking toothing at its opening edge, wherein the frame-side locking toothings are geometrically identical.

[0015] Radially adjacent to the opening edges of the two cheek openings, the belt reel has a circumferentially encircling reel-side locking toothing.

[0016] According to the invention, the object is achieved by the features of the main claim. In particular, the solution results from the locking teeth on the spring-side spool end lagging the locking teeth on the sensor-side spool end in the belt webbing extension direction. This lag is preferably 4° to 10°. Due to the radially unguided bearing of the belt spool on the spring side, this so-called "lag angle" is particularly large. However, due to this radially unguided bearing on the spring side, the belt spool is no longer forced into a locked position in which the spool axis extends parallel to the spool axis in the release position of the belt spool, so that the moment load in the locked position is distributed much more evenly between the sensor side and the spring side despite the comparatively large lag angle.

[0017] Further features and advantages of the invention will become apparent from the following description of preferred embodiments with reference to the drawings, in which: - Fig. 1 is a partially sectioned, perspective view of a belt retractor according to the invention; - Fig. 2 an axial longitudinal section of the belt retractor according to Fig. 1; - Fig. 3 a cross-section III-III of the belt retractor according to Fig. 2; - Fig. 4 a schematic, spring-side view of the belt retractor according to the Fig. 1 to 3 in one load case; - Fig. 5 is a further schematic, spring-side view of the belt retractor according to the Fig. 1 to 3 in another load case; - Fig. 6 a schematic, sensor-side view of the belt retractor according to the Fig. 1 to 3 with indicated radial deflection of the belt reel; - Fig. 7 a schematic, spring-side view of the belt retractor according to the Fig. 1 to 3 with indicated radial deflection of the belt reel; - Fig. 8 an axial projection of the radial deflections of the belt reel according to the Fig. 6 and Fig. 7 to determine a lag; - Fig. 9 a side view and a top view of a belt retractor according to the invention in a release position of the belt reel; - Fig. 10 a side view and a top view of the belt retractor according to Fig. 9 with the belt reel deflected into the locking position on the sensor side; and - Fig. 11 a side view and a top view of the belt retractor according to Fig. 9 in a locking position of the belt reel.

[0018] The Fig. 1 to 3 show a belt retractor 10 for motor vehicles, with a housing frame 12 which has two opposite side cheeks 14, 16, each with a cheek opening 18, 20, a belt spool 22 which is rotatable about a spool axis A and extends in the axial direction 23 from a sensor-side spool end 24 through the cheek openings 18, 20 of the housing frame 12 to an axially opposite, spring-side spool end 26, and a housing cover 28 which is firmly connected to the housing frame 12 and forms a radially elastic pivot bearing 30 for the spring-side spool end 26, wherein the spring-side spool end 26 of the belt spool 22 is fixed to the housing cover 28 in the radial direction 31 without any guides.

[0019] The housing frame 12 is essentially U-shaped and has a back plate 32 and the two opposing side walls 14, 16 projecting from the back plate 32. When installed in the motor vehicle, the housing frame 12 is firmly mounted to a vehicle body (not shown), in particular screwed to the vehicle body. According to the Fig. 1 and Fig. 2, a fastening opening 34 is provided in the back plate 32 of the housing frame 12 for this purpose.

[0020] The belt reel 22 comprises a reel body 36 in the axial center for receiving a belt strap (not shown) as well as reel flanges 38, 40 axially adjacent to the reel body 36 on both sides, which extend axially in the region of the cheek openings 18, 20.

[0021] The spool flanges 38, 40 of the belt spool 22 each have, radially adjacent to the opening edges of the two cheek openings 18, 20, a spool-side locking toothing 42, 44 running in the circumferential direction 41, wherein the spool-side locking toothings 42, 44 are geometrically identical but are rotated relative to one another in the circumferential direction 41 by a fraction of a tooth pitch angle of the locking toothings 42, 44.

[0022] The two cheek openings 18, 20 have a corresponding frame-side locking toothing 46, 48 on their opening edge, wherein the frame-side locking toothings 46, 48 are geometrically non-dentical and are located one behind the other in the axial direction 23 essentially congruent.

[0023] As in Fig. As indicated in Figure 2, a pivot lever with a sensor device 50 is provided on the sensor-side coil end 24, which is attached to the housing frame 12 and forms a radially pivotable pivot bearing 52 for the sensor-side coil end 24. This sensor device 50 can be activated in a known manner in a vehicle-sensitive or belt-webbing-sensitive manner, wherein the sensor-side coil end 24 is radially deflected upon belt webbing withdrawal after such activation.

[0024] The belt reel 22 moves from its release position, in which the belt reel 22 is freely rotatable in the housing frame 12 about the reel axis A, on the sensor side into its locking position, in which the reel-side locking toothing 42 engages in the frame-side locking toothing 48 and fixes the sensor-side reel end 24 essentially in a rotationally fixed manner to the housing frame 12.

[0025] The sensor device 50 is accommodated in a pivoting lever which is mounted on the housing frame 12, specifically on the side wall 16 of the housing frame 12.

[0026] At the spring-side coil end 26 of the belt reel 22, a drive spring 56 is provided, which acts on the belt reel 22 in the belt webbing winding direction 58. In order to clearly recognize the spring-side mounting of the belt reel 22 on the housing cover 28, which is essential to the invention, the drive spring 56, which is usually designed as a spiral spring, is in Fig. 2 is only indicated schematically.

[0027] The drive spring 56 for the belt reel 22 is accommodated in the housing cover 28, which is firmly connected to the housing frame 12, in particular the side cheek 14 of the housing frame 12.

[0028] The housing cover 28 forms the radially elastic pivot bearing 30 for the spring-side coil end 26, wherein this elastic pivot bearing 30 is arranged according to the Fig. 1 and Fig. 2 is formed in one piece with the housing cover 28. The housing cover 28 is elastically deformable in this embodiment, so that the pivot bearing 30, when the spring-side coil end 26 is subjected to a radial load, deforms the housing cover 28 and, under certain circumstances, additionally deforms the housing frame 12 in the direction of a belt pull-out force F (see Fig. 4 to 6) can move radially.

[0029] Since the spring-side coil end 26 is fixed in the radial direction 31 without any guide on the housing cover 28, the spring-side coil end 26 moves together with the radially elastic pivot bearing 30, deforming the housing cover 28 in the direction of the acting belt pull-out force F.

[0030] A radial deflection of the spring-side coil end 26 is limited by a guide of the coil flange 40 in the cheek opening 20. To illustrate this, Fig. 4 shows a load case in which the belt pull-out force F acting on the belt reel 22 has a lateral force component to the left and / or in which a deceleration a of the belt retractor 10, specifically of the housing frame 12 of the belt retractor 10, occurs to the right. In contrast, in Fig. 5 shows a load case in which the belt pull-out force F acting on the belt reel 22 has a force component to the right and / or in which a deceleration a of the belt retractor 10, specifically of the housing frame 12 of the belt retractor 10, occurs to the left.

[0031] The direction of the belt pull-out force F varies, for example, depending on the thickness of the belt wrap on the spool body 36 in the restraint case.

[0032] The Fig. 6 illustrates a sensor-side deflection of the belt reel 22, wherein the reel axis A at the sensor-side reel end 24 is pivoted from a position A (in the release position of the belt reel 22) about a defined pivot point P on the housing frame 12 and assumes a position A' (in the blocking position of the belt reel 22).

[0033] In contrast, the Fig. 7 a spring-side deflection of the belt reel 22, wherein the reel axis A at the spring-side reel end 26 is displaced radially from a position A (in the release position of the belt reel 22) in the direction of the acting load (in Fig. 7, for example, by a belt pull-out force F vertically upwards) and takes a position A'' (in the locking position of the belt reel 22).

[0034] These in the Fig. 6 and Fig. The different deflections of the spool axis A on the sensor side and the spring side, as shown in Figure 7, result in the spool axis A in the (sensor-side and spring-side) locking position of the belt spool 22 no longer running parallel to the spool axis A in the release position, and the spool-side locking teeth 44, 46 are rotated relative to one another in the circumferential direction 41 by a fraction of a tooth pitch angle. The angle by which the locking teeth 42 on the spring-side spool end 26 lag behind the locking teeth 44 on the sensor-side spool end 24 results from the different deflections of the spool axis A on the sensor side and the spring side, wherein this deflection difference in Fig. 8 is shown as lag e. In this way, a more homogeneous distribution of the locking torques between the sensor side and the spring side is achieved in the locked position of the belt reel 22. In other words, the lagging angle on the spring side is closed even with a comparatively low moment load on the locking side, and the moment load is subsequently distributed between the sensor side and the spring side.

[0035] The Fig. 9 to 11 show a side view and a top view of the belt retractor 10 during a locking operation of the belt reel 22.

[0036] According to Fig. 9, the belt reel 22 is in its release position, in which it is mounted in the housing frame 12 so as to be freely rotatable about the reel axis A. Starting from this release position, upon activation of the sensor device 50, the belt reel 22 is initially guided into its locked position only on the sensor side. On the spring side, the belt reel 22 has an articulated seat in its pivot bearing 30, which is designed as a pointed bearing.

[0037] The Fig. 10 shows a state of the belt retractor 10 in which the spool-side locking teeth 42 engage with the frame-side locking teeth 46, and the sensor-side spool end 24 is essentially fixed in a rotationally fixed manner to the housing frame 12. As the belt webbing pull-out force F continues to increase, the belt spool 22 is also deflected on the spring side due to deformation of the housing cover 28. The direction of the spring-side deflection occurs without radial guidance and is strongly dependent on the direction of the belt webbing pull-out force F. Therefore, the angle by which the locking teeth 44 on the spring-side spool end 26 lags behind the locking teeth 42 on the sensor-side spool end 24 must be quite large, amounting to 4° to 10°.

[0038] According to Fig. 11, the spool-side locking teeth 44 also engage with the frame-side locking teeth 48, so that the belt spool 22 has reached its locking position on both the sensor side and the spring side. In the top view of the belt retractor 10 ( Fig. 11, below) it is clear that the coil axis A in the locking position according to Fig. 11 relative to the coil axis A in the release position according to Fig. 9 is inclined by an angle α. This angle of inclination α determines the lag e (see Fig. 8) is compensated. Accordingly, in the restraint case, a more balanced moment load results on the sensor side and the spring side than in belt retractors 10, in which the belt spool 22 is forced into a locking position parallel to the release position by a spring-side radial guide.

Claims

[1] Belt retractors for motor vehicles, with a housing frame (12) having two opposite side cheeks (16) each with a cheek opening (18, 20), a belt reel (22) which is rotatable about a reel axis (A) and extends in the axial direction from a sensor-side reel end (24) through the cheek openings (18, 20) of the housing frame (12) to an opposite, spring-side reel end (26), and a housing cover (28) which is firmly connected to the housing frame (12), wherein the housing cover (28) forms a radially elastic pivot bearing (30) for the spring-side coil end (26), wherein the spring-side coil end (26) of the belt reel (22) is fixed in the radial direction without any guide to the housing cover (28), and wherein the belt reel (22) has, radially adjacent to the opening edges of the two cheek openings (18, 20), a reel-side locking toothing (42, 44) running circumferentially in the direction of the reel, characterized by that the coil-side locking teeth (42, 44) are geometrically identical but are rotated relative to each other in the circumferential direction by a fraction of a tooth pitch angle, and that the locking toothing (44) on the spring-side coil end (26) lags behind the locking toothing (42) on the sensor-side coil end (24) in the belt webbing extension direction. [2] Belt retractor according to claim 1, characterized by that the radially elastic rotary bearing (30) is formed integrally with the housing cover (28). [3] Belt retractor according to claim 1 or 2, characterized by that the housing cover (28) is elastically deformable. [4] Belt retractor according to one of the preceding claims, characterized bythat a sensor device (50) is provided which forms a radially pivotable rotary bearing (52) for the sensor-side coil end (24). [5] Belt retractor according to one of the preceding claims, characterized by that each of the two cheek openings (18, 20) has a frame-side locking toothing (46, 48) on its opening edge, wherein the frame-side locking toothings (46, 48) are geometrically identical and lie essentially congruently one behind the other in the axial direction. [6] Belt retractor according to any preceding claim, characterized by that the locking toothing (44) on the spring-side coil end (26) lags behind the locking toothing (42) on the sensor-side coil end (24) by an angle of at least 4° to 10° in the belt pull-out direction.

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