MODULAR SEATBELT RETRACTOR

Abstract

A belt retractor (40) having a belt reel (14), a seat belt (12) which can be wound thereon to form a belt reel, and at least one first assembly, the first assembly being arranged coaxially with the axis of rotation of the belt reel (14) and in series with the belt reel (14). The belt retractor is especially adapted for mounting inside the frame member of a motor vehicle seat.

Claims

1. A belt retractor comprising, a belt reel, a seat belt which can be wound up into the belt reel, a first assembly; and the first assembly is disposed coaxially with the axis of rotation of the belt reel and in series with the belt reel.

2. A belt retractor according to claim 1, further comprising, the first assembly has smaller or identical outer dimension in the direction perpendicular to the axis of rotation of the belt reel than the maximum outer diameter of the belt reel when the seat belt is fully wound on the belt reel.

3. A belt retractor according to claim 1 further comprising, the belt retractor is mounted on a first web arranged between the belt reel and the first assembly.

4. A belt retractor according to claim 1 further comprising, a second web is provided for mounting the belt retractor, which second web is spaced apart from the first web in the axial direction of the belt retractor.

5. A belt retractor according to claim 1 further comprising, a second assembly is provided which is coaxial and arranged in series with the belt reel and with the first assembly.

6. A belt retractor according to claim 4 further comprising in that the second web is arranged between the first assembly and a second assembly which is coaxial and arranged in series with the belt reel and with the first assembly.

7. A belt retractor according to claim 5 further comprising, the first or the second assembly is a pyrotechnic belt tensioner having a tensioner drive tube with a pyrotechnically drivable drive device provided therein, and the drive device drives a drive movement of the belt reel is transmitted by a drive wheel, wherein the tensioner drive tube has a linear section and a curved section disposed at an end of the linear section, and the tensioner drive tube is arranged such that the linear section runs parallel to the axis of rotation of the belt reel and is directed with the curved section tangentially in the circumferential direction toward the drive wheel.

8. A belt retractor according to claim 7 further comprising, the tensioner drive tube is arranged such that the linear section and the curved section are arranged in a plane parallel to the axis of rotation of the belt reel.

9. A belt retractor according to claim 5 further comprising, the first assembly or the second assembly is formed by a force limiting device having a first torsion bar disposed coaxially with the belt reel.

10. A belt retractor according to claim 9 wherein, the force limiting device comprises a second torsion bar arranged in series with the first torsion bar.

11. A belt retractor according to claim 9 further comprising, a tubular extension, which is arranged coaxially with the axis of rotation of the belt reel and into which the first or the second torsion bar projects, is provided on an end face of the belt reel.

12. A belt retractor according to claim 11 further comprising, the belt retractor with the tubular extension is mounted on the first or a second web.

13. A belt retractor according to claim 5 further comprising, the first assembly or the second assembly or a third assembly is formed by a reversible belt tensioner having an electric motor, wherein the electric motor is arranged with a drive shaft guided out coaxially with the axis of rotation of the belt reel.

14. A belt retractor according to claim 6 further comprising, the first web and the second web are coupled to a vehicle housing member for reacting to torsional forces acting on the first or the second assembly.

15. A belt retractor according to claim 1 further comprising, the belt retractor is contained within a housing member of a motor vehicle seat structure.

16. A belt retractor according to claim 15 further comprising, wherein the housing member forms an upper generally horizontal member connecting with and positioned between a pair of vertical struts.

17. A belt retractor according to claim 1 further comprising, the housing member is an elongated member defining an elongated interior cavity with the belt reel and the first assembly contained within the interior cavity.

18. A belt retractor according to claim 17 further comprising, the housing member is generally U-shaped in cross-section.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The invention is explained in the following with reference to the enclosed figures and the preferred forms of execution.

[0025] FIGS. 1a and b show two longitudinal struts of a vehicle seat with a load-bearing structural part and a belt retractor arranged therein in accordance with the invention; and

[0026] FIG. 2 shows the load-bearing structural part having a cavity and the inventive belt retractor located therein as a single part; and

[0027] FIG. 3 is a sectional view of the load-bearing structural part with the cavity and the invention belt retractor arranged therein; and

[0028] FIG. 4 shows a belt retractor according to the invention with a two-part housing.

DETAILED DESCRIPTION

[0029] FIGS. 1a and b show a part of a seat structure of a vehicle seat for a motor vehicle which forms the backrest of the vehicle's seat. The seat structure forms the dimensionally stable core of the vehicle seat and is additionally equipped with springs and/or upholstery to improve seating comfort. In addition, other functional components not shown on the seat structure, such as seat adjustment mechanisms, a headrest, electronic devices such as displays, or even heating devices, are provided.

[0030] The seat structure formed of a composite of several load-bearing structural parts 2, two of which are formed by parallel longitudinal struts 1. The upper ends of the longitudinal struts 1 are connected by a load-bearing structural part 2 to form a dimensionally stable upper side of the backrest. For the connection of the longitudinal struts 1, there are fixing holes 4 on these upright brackets, and fixing holes are also provided on structural part 2, through which the parts are connected either by screws or rivets.

[0031] In FIG. 2, the load-bearing structural part 2 can be seen in an enlarged representation as a single part. The load-bearing structural part 2 includes as a basic component a housing in the form of a U-shaped profile rail 7 with a base surface 10 and two opposite, parallel, well-shaped legs 8 and 9 which stand up from the base surface 10. The profile rail 7 has an opening 28 formed between the edge sides of the legs 8 and 9, which is closed by an insert 6 to be seen in FIG. 1, but which was omitted in FIG. 2 for better recognition of the structural part 2. The insert 6 is formed by a plate with a shape adapted to the shape of the opening 28 and has a slot 13 through which a seat belt 12, described in more detail below, is guided from a cavity 21 between the legs 8 and 9 to the outside towards a restrained occupant on the vehicle seat. The insert 6 closes or reduces the opening 28 to the provided slot 13 so that the cavity 21 is closed to the outside, and a belt retractor 40 provided in it is protected against mechanical influences. The ends of the profile rail 7 are each closed by a web 15 and 20.

[0032] In the cavity 21 of the load-bearing structural part 2, the belt retractor 40 is arranged with a belt reel (or spindle) 14 and the seat belt 12 that can be wound on it, which can be seen in sectional view in FIG. 3. In addition to the belt reel 14, the belt retractor 40 has a further assembly or also the first assembly in the form of a force limiting device 25 with several torsion bars 26, 36 and 37, a second assembly in the form of a pyrotechnic irreversible belt tensioner 24 and a third assembly in the form of a reversible electromotive belt tensioner 23 in a coaxial arrangement with the axis of rotation of the belt reel 14. In addition, the assemblies are arranged in series, one behind the other, with the belt spool 14. The outer dimensions of the belt reel 14 with the maximum length of seat belt 12 wound on it, as well as the outer dimensions of the force limiting device 25, the pyrotechnic belt tensioner 24 and the electromotive belt tensioner 23 are selected in the cross-sectional area perpendicular to the axis of rotation of the belt reel 14 in such a way that they are not larger than the outer dimensions of the belt reel on the belt reel 14 with the maximum length of seat belt 12 wound on it or otherwise fit within the dimensions of cavity 24. Furthermore, the external dimensions are not larger than the dimensions of the cavity 21 perpendicular to the longitudinal extension of the profile rail 7, so that the belt retractor 40 with the assemblies can be arranged in the cavity 21 of the profile rail 7.

[0033] In the profile rail 7, several webs 15,16,17,18,19 and 20 are provided in the form of wall sections aligned perpendicularly to the longitudinal extension of the profile rail 7, which extend from one of the legs 8 or 9 to the respective other leg 8 or 9 of the profile rail 7 and are connected to them. Furthermore, the webs 15, 16, 17, 18, 19 and 20 can extend up to the base surface 10 of the profile rail 7 and thus fill the entire cross-sectional area of the profile rail 7. The webs 15, 16, 17, 18, 19 and 20 each have one or more openings or projections in which the belt retractor 40 or parts thereof such as the belt reel 14 are stored, fastened and/or passed through. In addition, one of the webs 15, 16, 17, 18, 19 and 20, for example, may also have a toothing or other blocking configuration in which the reel 14 or other parts of the retractor can be blocked. In addition, the webs 15, 16, 17, 18, 19 and 20 may also have additional cavities to accommodate other components of the belt retractor such as pyrotechnic gas sources for the pyrotechnic belt tensioner 24, electronic components such as sensors, electronic control units or storage units. If the webs 15, 16, 17, 18, 19 and 20 extend from one of the legs 8 or 9 to the other leg 8 or 9, the webs 15, 16, 17, 18, 19 and 20 can also be used to stiffen the profile rail 7, which in turn is advantageous for the load-bearing capacity and dimensional stability of the profile rail 7 in the case of restraint loads exerted by the occupant.

[0034] The components of the belt retractor 40 are deliberately arranged coaxially and one behind the other, so that the assemblies do not increase the outer dimensions of the belt retractor radially outwards, and the belt retractor 40 can also be arranged in a narrow, elongated cavity 21 of the profile rail 7. This allows the profile rail 7 and the load-bearing structural part to be correspondingly narrow and elongated which is particularly advantageous when using the load-bearing structural part in a seat structure of the vehicle seat. Webs 15, 16, 17, 18, 19 and 20 may be affixed to profile rail 7 in a manner to restrain torsional forces imparted by the first, second or third assemblies. Accordingly, the structure of belt retractor does not bear all such loads, which are instead, distributed along rail 7.

[0035] FIG. 3 shows the load-bearing structural part in section through the profile rail 7 and the belt retractor. The profile rail 7, which is U-shaped in cross-section, has the legs 8 and 9 facing the observer in this illustration and a base surface 10. Between the legs 8 and 9, there is a cavity 21 in which the belt retractor 40 is arranged. The cavity 21 is divided in accordance with this embodiment by six webs 15, 16, 17, 18, 19 and 20 in the longitudinal direction of the profile rail 7, whereby the two outer webs 15 and 20 close the cavity 21 to the outside at the two ends of the profile rail 7. A spring cassette with a driving spring 27 is held on the right web 15, which in turn is connected to the belt reel 14 and thereby pretensions the belt reel 14 in the winding direction of the seat belt 12 wounds on it. The belt reel 14 is provided at its end projecting into the profile rail 7 with force limiting device 25, which is formed by a tubular extension 38 of the belt reel 14 arranged coaxially to the belt reel 14, three torsion bar 26, 36 and 37 arranged in series and a blocking part 41 which can be locked against rotation relative to the profile rail 7. In the present design, three torsion bar 26, 36 and 37 are provided, which are each connected or connectable with one end to the belt reel 14 or to the tubular extension 38 in a rotationally fixed manner and with the other end in each case by a switching device provided in a web 16 or 17 in a rotationally fixed manner relative to the profile rail 7 blockable or detachable from the latter. The torsion bar 26, 36 and 37 can thus be activated individually or in combination, whereby the restraining forces can be realized at different force limitation levels or a step-shaped force limitation process.

[0036] The locking part 41 may be lockable in the pull-out direction of the seat belt 12 by a locking device which can be controlled in a vehicle-sensitive and/or webbing sensitively manner, whereby the force limiting device 25 is locked, so that it is subsequently automatically activated when the force limiting level defined by the force limiting device 25 itself is exceeded. In addition, a pyrotechnic, irreversible belt tensioner 24 with a drive wheel 35 arranged coaxially to the belt reel 14 is provided, which drives the belt reel 14 in the winding direction when activated via an intermediate clutch and tightens the seat belt 12. In addition, a reversible belt tensioner 23 with an electric motor 22 is provided which, when activated via a second or even the same coupling as the pyrotechnic belt tensioner 24, drives the belt reel 14 in the winding direction and thereby tightens the seat belt 12. The electric motor 22 is also arranged coaxially to the belt reel 14 and thus also to the force limiting device 25 and to the pyrotechnical belt tensioner 24. Furthermore, an electronic control unit 29 is provided in the profile rail 7 of the load-bearing structural part 2, which can be used to control the belt retractor 40 and/or other components.

[0037] Load-bearing structural part 2 is a basic component of the seat structure by connecting other parts of the seat structure, such as the longitudinal struts 1 shown in FIG. 1. The structural part 2 has thus the task to form the seat structure and serves by the provided cavity 21 additionally for the admission of the belt retractor 40 according to the invention. The load-bearing structural part 2 can be pre-assembled as an assembly with the belt retractor 40 and then be finally assembled with the manufacturing of the seat structure and/or the vehicle seat as an assembly unit.

[0038] The profile rail 7 forms the basic component of the load-bearing structural part 2 and is shaped and dimensioned according to the connection of the other structural parts to be realized in the seat structure. The profile rail 7 can replace the previously required frame of the belt retractor 40 by serving both to support the belt retractor 40 and to fasten the belt retractor 40 to the vehicle seat and to block the belt reel 14.

[0039] The belt retractor 40 is modular with the belt reel 14 and the other assemblies, namely the force limiting device 25, the pyrotechnical belt tensioner 24 and the reversible belt tensioner 23 in a coaxial row arrangement. The assemblies are deliberately designed in such a way that their radial outer dimensions do not exceed the dimensions of the belt reel on the belt reel 14 with the maximum number of wraps of seat belts wound, for example, up to 12, as can be seen in FIG. 3.

[0040] The webs 15, 16, 17, 18, 19 and 20 can be understood as functional walls in addition to their storage and structural function, or alternatively by providing corresponding receptacles and an arrangement of different functional units in or on the receptacles. To enable them to fulfill their bearing function, the webs 15, 16, 17, 18, 19 and 20 are preferably supported between the legs 8 and 9 and the base surface 10 of the profile rail 7 or between the housing parts 30 and 31 shown in FIG. 4 in a rotationally fixed manner.

[0041] FIGS. 4a and 4b show an alternative design example in which the belt retractor 40 is equipped with a two-part housing with two housing parts 30 and 31 instead of a one piece housing in the form of profile rail 7. The housing parts 30 and 31 are each U-shaped and enclose the belt reel 14 and the other assemblies including the webs 15, 16, 17, 18, 19 and 20 in the assembled position on the outside, as shown in the upper right illustration of FIG. 4b. In the assembled position, the housing parts 30 and 31 form an elongated cavity 21 with a square cross-section. Since the belt reel 14 with the seat belt 12 wound thereon and the other assemblies are of circular cross-section, an elongate free space of approximately triangular cross-section is provided in the corners between the belt reel of the belt reel 14, the assemblies and the housing, which free space is used here for the arrangement of the tensioner drive tube 32. The tensioner drive tube 32 is used to guide a drive device, such as a chain of loose-mass bodies, or an elastic drivetrain, which is accelerated when the pyrotechnic belt tensioner is activated and thus brought into drive connection with the drive wheel 35. The drive wheel 35 and the belt reel 14 are then driven to rotate in the winding direction of the seat belt 12. The tensioner drive tube 32 has a linear section 33 and a curved section 34 and is aligned and arranged to be aligned with the linear section 33 parallel to the axis of rotation of the belt reel 14 and the drive wheel 35 and to be tangentially circumferentially directed with the curved section 34 toward the outer periphery of the drive wheel 35. The curved section 34 is curved exclusively in one plane so that the curved section 34 and the linear section 33 are arranged in one plane, wherein the tensioner drive tube 32 is aligned so that the plane spanned by the linear section 33 and the curved section 34 is parallel to the axis of rotation of the belt reel 14.

[0042] The housing parts 30 and 31 in the assembled position with the belt retractor 40 arranged in the form of a dimensionally stable part which can be used as the load-bearing structural part 2 in the seat structure as seen in FIG. 1. Moreover, the various webs 15, 16, 17, 18, 19 and 20 can be structurally coupled to one or both of housing parts 30 and 31 to react against torsion forces imposed by the first, second or third assemblies.

[0043] The load-bearing structural part 2 with the housing in the form of profile rail 7 or the housing parts 30 and 31 was described in a horizontal installation geometry as shown in FIG. 1, which has advantages with regard to an horizontal alignment of the seat belt 12 in the feed to the occupants. A horizontal alignment of the seat belt 12 in the feed to the occupants is advantageous in that the seat belt 12 can be guided horizontally onto the shoulder of the occupants without being deflected again. Alternatively, the load-bearing structural part 2 can also be arranged on the seat structure in a vertical or inclined orientation. The seat belt 12 is then fed in an inclined direction or deflected to the occupant in the intended direction by a separate deflecting device. In addition, structural part 2 may also be located at a lower point or on one side of the seat structure of the backrest instead of at an upper edge of the backrest if the seat structure or the supply of the seat belt so requires and/or allows. Instead of the profile rail 7 or the housing parts 30 and 31, it would also be conceivable to provide a tubular structural part 2 with a circular or different cross-section in which the belt retractor 40 is arranged and in particular, pushed in at the end face.

[0044] While the above description constitutes the preferred embodiment of the present invention, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope and fair meaning of the accompanying claims.