Belt tightener

Abstract

A belt retractor (10) of a seatbelt system comprises a belt tensioner (11) which is adapted to rotate a belt reel (14) of the belt retractor (10) accommodated in a belt retractor frame (12), wherein the belt retractor frame (12) is closed by a cover (16) on the tensioner side in the area of the spindle of the belt reel (14) and in the cover (16) a bearing for the belt reel (14) is provided. The cover (16) includes a first pot-shaped cover part (16a) which is mounted directly on the belt retractor frame (12) and has a side wall (24) merging into a flat portion (26). In the flat portion (26) an opening (32) is spared and a second cover part (16b) is provided which engages in the opening (32) in the first cover part (16a) and on which a bearing (40) is formed in which an end (42) of the spindle of the belt reel (14) is supported.

Claims

1. A belt retractor (10) of a seatbelt system, comprising a belt tensioner (11) which is adapted to rotate a belt reel (14) of the belt retractor (10) accommodated in a belt retractor frame (12), wherein the belt retractor frame (12) is closed by a cover (16) on the tensioner side in the area of the belt reel (14), wherein the cover (16) includes a first pot-shaped cover part (16a) which is mounted directly on the belt retractor frame (12) and which has a side wall (24) merging into a flat portion (26), and wherein an opening (32) is spared in the flat portion (26) and a second cover part (16b) which engages in the opening (32) in the first cover part (16a) and at which a bearing (40) is formed in which an end (42) of the spindle of the belt reel (14) is supported.

2. The belt retractor according to claim 1, wherein the second cover part (16b) is configured to be resilient.

3. The belt retractor according to claim 1, wherein the second cover part (16b) has a positioning structure (34) by means of which a radial position of the second cover part (16b) relative to the first cover part (16a) is defined.

4. The belt retractor according to claim 3, wherein the positioning structure (34) has at least one projection (35) which abuts on the inner edge of the opening (32) in the first cover part (16a).

5. The belt retractor according to claim 4, wherein the projection (34) is formed to be circumferential.

6. The belt retractor according to claim 1, wherein the first cover part (16a) is made from metal and the second cover part (16b) is made from plastic.

7. The belt retractor according to claim 6, wherein the first cover part (16a) is made from steel.

8. The belt retractor according to claim 1, wherein the bearing (40) is formed centrally relative to the positioning structure (34) on the second cover part (16b).

9. The belt retractor according to claim 1, wherein portions of the second cover part (16b) extend in the radial direction in parallel to the flat portion (26) of the first cover part (16a).

10. The belt retractor according to claim 1, wherein the first cover part (16a) is welded to the belt retractor frame (12).

11. The belt retractor according to claim 1, wherein a drive wheel (15) of the belt tensioner (11) arranged concentrically to the spindle of the belt reel (14) is accommodated beneath the cover (16).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Hereinafter, the invention will be described in detail by way of an example embodiment with reference to the enclosed drawings, wherein:

(2) FIG. 1 shows a schematic perspective view of a belt retractor according to the invention;

(3) FIG. 2 shows a schematic perspective view of the belt retractor from FIG. 1 when viewed from the tensioner side;

(4) FIG. 3 shows a schematic sectional view of the belt retractor according to the invention; and

(5) FIG. 4 shows an enlarged cutout from FIG. 3.

DESCRIPTION

(6) The figures illustrate the essential parts of a belt retractor 10 comprising an integrated pyrotechnically driven belt tensioner 11. In a belt retractor frame 12 of the belt retractor 10 a belt reel 14 onto which webbing can be wound and, resp., from which webbing can be unwound (not shown here) is rotatably supported. On one side of the belt reel 14, on the left side in FIG. 1, a drive wheel 15 is provided (indicated by broken lines in FIG. 1) which is arranged concentrically to the spindle of the belt reel 14 and which is covered by a cover 16 of the belt tensioner 14 in FIG. 1. The drive wheel 15 includes an external toothing and serves for rotating the belt reel 14 via the belt tensioner 11.

(7) The belt tensioner 11 includes a gas generator 18 arranged at one end of the tensioner tube 20 so that compressed gas generated may flow into the tensioner tube 20. In the tensioner tube 20 a force transmitting element 22 is movably arranged (cf. FIG. 1).

(8) The force transmitting element 22 is accelerated by the gas generated by the gas generator 18, leaves the tensioner tube 20 through an open outlet end of the tensioner tube 20 and in an engaging area interacts with the drive wheel 15 so that the drive wheel 15 is rotated by squeezing past the force transmitting element 22 (not shown). The engaging area is provided directly at the one outlet end of the tensioner tube 20 so that the force transmitting element 22 impacts the drive wheel 15 with as high kinetic energy as possible.

(9) The force transmitting element 22 in this case is an elongate component completely made from plastic material which is so flexible that it can follow the curvature of the tensioner tube 20 and is preferably plastically deformable to such extent that the drive wheel 15 can impress itself into the force transmitting element 22 and, in this way, can provide a working structure which contributes to establishing proper force transmission between the force transmitting element 22 and the drive wheel 15, while the force transmitting element 22 is moved past the drive wheel 15.

(10) The belt tensioner 11 further includes a force limiter not shown here in detail which permits to repeatedly extend belt webbing after the belt has been tensioned.

(11) The direction of movement of the force transmitting element 22 is defined initially by the shape of the tensioner tube 20 and then by a guiding within the cover 16 of the belt tensioner 11 not shown in detail. The tensioner tube 20 is partially strongly curved in plural spatial directions so that the direction of movement of the force transmitting element 22 is not straight.

(12) The cover 16 is structured in two parts. A first pot-shaped cover part 16a in portions has a cylindrical side wall 24 which merges into a flat portion 26. The exact shape of the side wall depends on the concrete shape of the belt retractor frame 12 and of the belt tensioner 11. The side wall 24 ends at the end opposed to the flat portion 26 in a bent flat edge 28. The cover 16 is tightly connected to the belt retractor frame 12 via the flat edge 28, in this case by superimposed portions of the flat edge 28 and of a flat edge 30 of the belt retractor frame 12 being welded to each other.

(13) In the flat portion 26 of the first cover part 16a a circular opening 32 is spared.

(14) A second cover part 16b which is substantially disk-shaped and which covers the opening 32 from the inner face of the first cover part 16a engages in the opening 32.

(15) On the outer face of the second cover part 16b a positioning structure 34 defining the radial position of the second cover part 16b relative to the first cover part 16a is formed. The positioning structure 34 in this example is a circular projection 35 which precisely abuts on the inner circumferential edge of the opening 32.

(16) The second cover part 16b extends radially further outwardly beyond the projection 35 into a contact portion 36 (cf. FIGS. 3 and 4) which is fully adjacent to the inner face of the flat portion 26 of the first cover part 16a until it ends in a bent edge 38. In the area of the opening 32, however, the cover 16 is formed by the second cover part 16b only which in this area of the belt retractor 10 seals against the environment.

(17) The bent edge 38 is spaced apart from the side wall 24 of the first cover part 16a so that the second cover part 16b and the first cover part 16a are in contact with each other only via the projection 35 and the portion 36.

(18) The projection 35 and the opening 32 are configured so that the second cover part 16b abuts on the first cover part 16a free from play.

(19) The outer periphery of the second cover part 16b need not be circular, its shape may be chosen depending on the shape of the belt retractor 10. However, the projection 35 preferably describes a circle, just as the opening 32.

(20) In the center of the circle formed by the projection 35 a bearing 40 for an end 42 of the spindle of the belt reel 14 is formed. In this example, the bearing 40 takes the shape of a peripheral annular projection in which the pin-shaped end 42 of the spindle of the belt reel 14 is inserted. The end 42 of the spindle of the belt reel 14 in this case further includes projections located radially outside the pin which improve the hold of the end 42 within the bearing 40.

(21) The first cover part 16a in this example is made from steel, whereas the second cover part 16b is made from appropriate plastic. Due to its material properties and due to its flat disk-type shape, the second cover part 16b has a certain flexibility along the axial direction of the belt reel 14.

(22) Therefore, the bearing 40 can hold the end 42 of the spindle of the belt reel at sufficient bias so that tolerances can be compensated without obstructing smooth rotatability of the belt reel 14.

(23) The second cover part 16b may be held at the first cover part 16a exclusively by the plug connection of the projection 35 in the opening 32 as well as the bias exerted by the spindle of the belt reel 14, but it is also possible to glue or weld the radially projecting portion 36 to the inner face of the flat portion 26 of the first cover part 16a.