BELT REEL AND ALSO BELT RETRACTOR HAVING A BELT REEL

Abstract

A belt reel (14) for a belt retractor (10) has a rotational axis (R) and a reel body (16) that is provided as a reel for a webbing (24) and has a first axial circumferential circle (34). The reel body (16) further includes a radial constriction (32) having a second axial circumferential circle (36), wherein the constriction (32) is arranged centrally on the reel body (16) in the axial direction (A) and wherein the circumference of the second axial circumferential circle (36) amounts to a maximum of 95% of the circumference of the first axial circumferential circle (34). Moreover, a belt retractor (10) comprising such belt reel (14) is described.

Claims

1-10. (canceled)

11. A belt reel (14) for a belt retractor (10), comprising a rotational axis (R) and a reel body (16) which is provided as a reel for a webbing (24) and has a first axial circumferential circle (34), wherein the reel body (16) includes a radial constriction (32) having a second axial circumferential circle (36), wherein the constriction (32) is arranged centrally on the reel body (16) in the axial direction (A), and wherein the circumference of the second axial circumferential circle (36) amounts to a maximum of 95% of the circumference of the first axial circumferential circle (34).

12. The belt reel according to claim 11, wherein the second axial circumferential circle (36) is arranged centrally on the reel body (16) in the axial direction (A).

13. The belt reel according to claim 11, wherein the circumference of the second axial circumferential circle (36) amounts to 80% to 95%, preferably 85% to 90%, of the circumference of the first axial circumferential circle (34).

14. The belt reel according to claim 11, wherein the constriction (32) has a depth (t) between 1 mm and 3 mm.

15. The belt reel according to claim 11, wherein the second axial circumferential circle (36) is arranged concentrically to the rotational axis (R), and/or the constriction (32) is formed to be rotationally symmetrical to the rotational axis (R).

16. The belt reel according to claim 11, wherein in the axial direction (A) the constriction (32) has a width (b) of from 10% to 100%, preferably from 20% to 40%, of the axial length (L) of the reel body (16).

17. The belt reel according to claim 11, wherein the constriction (32) has a concave profile.

18. The belt reel according to claim 11, wherein the constriction (32) is designed to be symmetrical to a plane (40), in particular to the axial central plane (40) of the reel body (16).

19. The belt reel according to claim 11, wherein, between the constriction (32) and adjacent axial portions (26, 28, 30), the reel body (16) includes respective axial transition portions (42, 43) in which the axial circumferential circle steadily changes in the axial direction (A) from the first axial circumferential circle (34) to the second axial circumferential circle (36), in particular wherein the axial transition portions (42, 43) are free of edges.

20. A belt retractor (10) comprising a belt reel (14) according to claim 11.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Further advantages and features will be evident from the following description and from the attached drawings, wherein:

[0020] FIG. 1 shows a schematic representation of a belt retractor according to the invention comprising a belt reel according to the invention,

[0021] FIG. 2 shows the belt reel of FIG. 1 in a lateral view,

[0022] FIG. 3 shows the belt reel of FIG. 1 in a sectional view across the plane A, and

[0023] FIG. 4 shows the belt reel of FIG. 1 in a sectional view across the plane B.

DESCRIPTION

[0024] FIG. 1 illustrates a belt retractor 10 comprising a frame 12 and a belt reel 14 which is rotatably supported about the rotational axis R within the frame 12.

[0025] The belt retractor 10 is part of a seatbelt system, in particular in a vehicle.

[0026] The belt reel 14 includes a reel body 16 as well as axial lateral portions 18, 19 disposed opposed to each other in the axial direction A which delimit the reel body 16 in the axial direction A.

[0027] In an alternative embodiment, the belt reel 14 may or may not have an axial lateral portion 18, 19.

[0028] The reel body 16 has a circular-cylindrical basic shape and a winding area 20 which is formed by the radial outer face 22 of the reel body 16 and on which a webbing 24 of a seatbelt can be wound and unwound.

[0029] In the axial direction A, the reel body 16 includes a first axial portion 26, a second axial portion 28 and a third axial portion 30.

[0030] The second axial portion 28 that is disposed in the axial direction A between the first axial portion 26 and the third axial portion 30 includes a radial constriction 32.

[0031] The radial constriction 32 is a radial recess extending in the circumferential direction U on the radial outer face 22 of the reel body 16 which forms the winding area 20.

[0032] Accordingly, the radial constriction 32 is rotationally symmetrical to the rotational axis R.

[0033] Basically, in an alternative embodiment the constriction 32 may be designed substantially at will. In particular, the reel body 16 may have radial recesses and/or radial extensions in the axial portion of the constriction 32.

[0034] The first axial portion 26 has a first axial circumferential circle 34 (see FIG. 3) with a radius r1 and the constriction 32 has a second axial circumferential circle 36 with a radius r2 that is smaller than the radius r1.

[0035] Each of the centers of the first circumferential circle 34 and of the second circumferential circle 36 is located on the rotational axis R, thus causing the first circumferential circle 34 and the second circumferential circle 36 to be arranged concentrically to each other.

[0036] The third axial portion 30 has a third axial circumferential circle 38 which is designed analogously to the first circumferential circle 34. I.e., the third circumferential circle has a radius r1 and a center that is located on the rotational axis R.

[0037] Each of the first and third circumferential circles 34, 38 is the circumferential circle having the largest circumference of the first and, resp., third axial portions 26, 30.

[0038] The second circumferential circle 36 is the circumferential circle having the smallest circumference of the second axial portion 28 and the constriction 32.

[0039] In an alternative embodiment, each axial portion 26, 28, 30 as well as the constriction 32 may have an individual circumferential circle 34, 36, 38 which may differ from each other, particularly as to their radius and/or the position of their center relative to the rotational axis R.

[0040] In addition, or as an alternative, the circumference of the circumferential circle 34, 36, 38 may have any size in the corresponding axial portion 26, 28, 30 and in the constriction 32 relative to further circumferential circles in the corresponding axial portion 26, 28, 30 as well as in the constriction 32.

[0041] Preferably, each of the radii of the first circumferential circle 34 and of the third circumferential circle 38 is larger than the radius r2 of the second circumferential circle 36.

[0042] The circumference of the second circumferential circle 36 amounts to 90% of the circumference of the first circumferential circle 34.

[0043] In an alternative embodiment, the circumference of the second circumferential circle 36 may be from 80% to 95%, preferably from 85% to 90%, of the circumference of the first circumferential circle 34.

[0044] Basically, the circumference of the second circumferential circle 36 is allowed to amount to a maximum of 95% of the circumference of the first circumferential circle 34 so that the constriction 32 has a sufficient depth t so that the webbing 24 can appropriately constrict to the smaller diameter, as will be described later.

[0045] The depth t corresponds to the difference of the first radius r1 and the second radius r2 and, in the shown embodiment, amounts to 2 mm.

[0046] In an alternative embodiment, the depth t of the constriction 32 may be between 1 mm and 3 mm.

[0047] The constriction 32 is provided, in the axial direction A, centrally on the reel body 16, i.e., equally distanced from both axial ends of the reel body 16.

[0048] Furthermore, the second circumferential circle 36 is located in the axial central plane 40t which, in FIG. 2, at the same time forms the sectional plane A-A.

[0049] Thus, the second circumferential circle 36 is arranged, in the axial direction A, centrally on the reel body 16 as well as centrally on the winding area 20.

[0050] The constriction 32 is designed symmetrically to the axial central plane 40 and has a concave profile (see FIG. 4).

[0051] The reel body 16 further includes axial transition portions 42, 43 which extend from the second circumferential circle 36 to the first axial portion 26 and, resp., the third axial portion 30 and which are designed so that the radii of the axial circumferential circles in said axial transition portions 42, 43 steadily increase from r2 to r1 in the axial direction A between the second circumferential circle 36 and the first circumferential circle 34 or, resp., the third circumferential circle 38.

[0052] The axial transition portions 42, 43 are rounded and, thus, are free of edges so as to provide an advantageous transmission of the loads from the winding area 20 to the webbing 24 in the case of restraint.

[0053] Basically, the reel body 16 may have a profile of any course.

[0054] The constriction 32 has a width b in the axial direction A (see FIG. 4) which amounts to 30% of the axial length L of the reel body 16.

[0055] In the present embodiment, in which the belt reel 14 is provided for a webbing 24 having a width of 48 mm, the length L of the reel body 16 amounts to 50 mm and the width b of the constriction 32 amounts to 15 mm.

[0056] In an alternative embodiment, the width b of the constriction 32 may be between 10% and 100%, in particular between 20% and 40% of the axial length L of the reel body 16.

[0057] This means particularly that, according to an alternative embodiment, the constriction 32 may extend over the entire axial length L of the reel body 16.

[0058] Accordingly, the axial length L of the reel body 16 at the same time corresponds to the axial length of the winding area 20.

[0059] The reel body 16 further includes mounting pockets 44 and an axial gap 46 dividing the reel body 16 which interrupt the winding area 20.

[0060] In an alternative embodiment, the reel body 16 may have no or any number of geometrical elements such as pockets, gaps and/or projections.

[0061] In addition, or as an alternative, the reel body 16 may have any basic shape.

[0062] In particular, the reel body 16 may include, in the circumferential direction, a radial step to which one end of the webbing 24 is fastened so that, at the step, the webbing 24 merges tangentially into the second winding.

[0063] Moreover, the belt reel 14 includes a cavity 48 extending along the rotational axis R (see FIG. 4) in which a rod-shaped or tubular load-limiting element that is part of a load limiter of the belt retractor 10 can be disposed.

[0064] The belt retractor 10 can basically include any load-limiting elements. This means that the belt reel 14 is compatible with the common load limiters and can be used, jointly with the latter, in a belt retractor 10.

[0065] If the webbing 24 is loaded in the case of restraint, for example in the case of crash, the constriction 32 results in the webbing 24 being partially wound on the reel body 16 constricting at least partially to the smaller diameter of the second circumferential circle 36. Said constricting causes the acting lever to decrease, in particular to the radius r2, and consequently the acting forces of the webbing 24 being reduced to the belt reel 14.

[0066] This effect is additionally promoted by the afore-described geometrical design of the reel body 16 and the constriction 32.

[0067] In this way, a belt reel 14 is provided which results in a reduction of the forward displacement in the sled test according to ECE R16 and in a reduction of the webbing extension in the loop load test according to FMVSS 209.

[0068] The belt reel thus exhibits improved characteristics in the case of restraint, thereby improving the safety of a vehicle occupant who is protected by a safety system in such belt reel.

[0069] The invention is not limited to the shown embodiment. In particular, individual features of one embodiment can be combined at will with features of other embodiments, particularly independently of the other features of the respective embodiments.