U.S. patent application number 16/173166 was filed with the patent office on 2020-02-13 for modular seatbelt retractor.
This patent application is currently assigned to AUTOLIV DEVELOPMENT AB. The applicant listed for this patent is AUTOLIV DEVELOPMENT AB. Invention is credited to GUNTER CLUTE, RONALD JABUSCH.
Application Number | 20200047711 16/173166 |
Document ID | / |
Family ID | 67667820 |
Filed Date | 2020-02-13 |
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United States Patent
Application |
20200047711 |
Kind Code |
A1 |
JABUSCH; RONALD ; et
al. |
February 13, 2020 |
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.
Inventors: |
JABUSCH; RONALD; (ELMSHORN,
DE) ; CLUTE; GUNTER; (ELMSHORN, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AUTOLIV DEVELOPMENT AB |
VARGARDA |
|
DE |
|
|
Assignee: |
AUTOLIV DEVELOPMENT AB
VARGARDA
DE
|
Family ID: |
67667820 |
Appl. No.: |
16/173166 |
Filed: |
October 29, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60R 2022/3402 20130101;
B60R 22/4628 20130101; B60R 2022/4473 20130101; B60R 2022/4642
20130101; B60R 22/3413 20130101; B60R 22/46 20130101; B60R
2022/4666 20130101; B60R 2022/287 20130101; B60R 22/44
20130101 |
International
Class: |
B60R 22/46 20060101
B60R022/46 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 8, 2018 |
DE |
10 2018 213 282.8 |
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
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of priority under 35
U.S.C. .sctn. 119 to German Patent Application No. 10 2018 213
282.8, filed Aug. 8, 2018, the contents of which are incorporated
herein by reference in their entirety.
FIELD OF THE INVENTION
[0002] The present invention concerns a seat belt retractor for a
motor vehicle.
BACKGROUND
[0003] The basic components of seat belt retractors are a
load-bearing frame and a rotatable belt reel mounted in the frame,
on which a seat belt can be wound up.
[0004] In addition to supporting the belt reel, the frame is also
used to attach the retractor to a seat structure or a vehicle
structure and is typically made of a correspondingly thick steel
sheet which is bent into a U-shaped frame.
[0005] Vehicle seats with seat belt devices are, for example, known
for use as front seats in cabriolet style vehicles in which at
least the belt retractors of the seat belt devices are fastened to
the backrests of the vehicle seats. In this case, the belt
retractors are preferably integrated into the backrests of the
vehicle seats for lack of a load-bearing B-pillar and reasons of
access to the rear seats or for reasons of distance to the rear
vehicle structure, which must also be designed to absorb the
tensile forces applied to the seatbelt webbing in the case of
restraint. The belt retractors themselves have all the basic
components of a standard belt retractor and are only fitted with
various additional components specially designed for installation
in the backrest, such as a self-aligning inertia sensor.
[0006] In its basic structure, the vehicle seat has a seat
structure consisting of several load-bearing structural parts which
serve to fasten the vehicle seat to the vehicle structure. The seat
structure is equipped with springs and upholstery to improve
seating comfort and also serves to attach other components such as
various seat adjustment mechanisms, including the associated
electric motors and other components such as heating devices,
sensors, displays, headrests and the likes.
[0007] In modern vehicles with autonomous driving systems, there is
an increasing demand for greater adjustability of the vehicle seats
in different orientations and positions, so that the vehicle
occupant can use the freedoms gained by autonomous driving, e.g.
for deeper communication with the other occupants, for extended and
more intensive rest periods or work and can align the vehicle seat
accordingly. As a result, the seat belt device and in particular
the belt retractor no longer has to be attached to the vehicle
structure as before, but instead to the vehicle seat, as was the
case with the front seats of convertibles, for example.
[0008] One problem however, is that the belt retractor with its
other components requires a comparatively large amount of
installation space due to its external dimensions so that
installation in the vehicle seat can be problematic. This is due in
particular to the fact that the seat belt must have a certain
minimum thickness for the tractive forces to be absorbed at a
specified width of e.g. 46 mm and a certain minimum length of e.g.
2,500 mm for the restraint of the occupant so that the belt reel on
the reel of a fully wound seat belt has a correspondingly large
outer diameter due to the volume of the seat belt to be wound up.
This large belt reel is further enlarged towards the outside by a
correspondingly large frame of the belt retractor and other
components such as a drive device for an irreversible belt
tensioner, an electric motor for a reversible belt tensioner, a
force limiting device, sensor devices or the like, which further
increases the installation space required.
[0009] Against this background, the invention is based on the task
of providing a belt retractor which can also be arranged in a
limited installation space of a vehicle seat.
[0010] To solve the problem, a belt retractor with the features as
described herein is proposed.
SUMMARY AND INTRODUCTORY DESCRIPTION OF THE INVENTION
[0011] According to an embodiment of the invention, a belt
retractor is described with a belt reel, a seat belt which can be
wound onto it to form a belt reel (or spindle) and at least one
first assembly in which the other assembly is arranged coaxially
and in series with the belt reel. With the proposed solution, the
belt retractor can be arranged in a space-saving design in a
narrow, elongated space on the vehicle seat. The assembly is
deliberately arranged in coaxial alignment in series with the belt
reel so that an elongated geometry of the belt retractor can be
achieved. Since the further assembly is arranged in series with the
belt reel, i.e. in relation to the longitudinal direction of the
axis of rotation of the belt reel, behind or in front of the belt
reel, the assembly can be arranged so that it protrudes only
slightly, if at all, beyond the belt reel to the outside. Since
vehicle seats generally have cavities, but these are often oblong
and narrow, the proposed solution allows the belt retractor to be
much better adapted to and arranged in these existing installation
spaces. The assembly can include for example, a reversible belt
tensioner, an irreversible belt tensioner, a force limiting device,
a sensor device or a control device. If further assemblies are
planned, these assemblies are preferably arranged in series with
respect to the axis of rotation of the belt reel, i.e. one behind
the other, whereby the elongated design of the belt retractor is
continued and further extended.
[0012] It is further proposed that the other assembly,
perpendicular to the axis of rotation of the reel, has external
dimensions smaller than or identical to the maximum external
diameter of the reel when the seatbelt is fully wound on the reel.
Since the belt reel has a circular cross-section and, in the design
embodiments described is arranged in each case in a cavity with a
quadrangular cross-section, the cavities for receiving the belt
retractor have a quadrangular cross-section with side lengths
corresponding at least to the diameter of the maximum belt reel.
This results in approximately triangular, elongated free spaces in
the corners, which can of course also be used. In the sense of the
present invention, such a protrusion into these free spaces should
also be understood as within the external dimensions specified by
the maximum diameter of the belt reel.
[0013] The completely wound up belt reel thus determines the
maximum outer dimensions of the belt retractor with a maximum outer
diameter, which cannot be reduced for the reasons mentioned above.
This allows the belt retractor to be as narrow as possible so that
it can also be arranged in elongated narrow installation spaces of
the vehicle seat or other vehicle structures. If the belt retractor
is mounted in a cavity of a load-bearing structural part of the
vehicle or vehicle seat, it may also replace the previously
required frame of the belt retractor by holding and supporting the
belt reel of the belt retractor directly on the load-bearing
structural part. Furthermore, in this case, the tensile forces
acting on the seatbelt webbing in the case of restraint can be
introduced directly into the structural part, whereby the
load-bearing structural part can be specifically designed to absorb
the restraining forces by shaping the cavity. If the load-bearing
structural part is a structural part of the seat structure, it is
already designed to absorb seat forces and other forces acting on
the vehicle seat and thus would typically have sufficient strength
to be used by the proposed solution to absorb the restraining
forces exerted by the seat belt. Furthermore, the load-bearing
structural part has a particularly high torsional and bending
stiffness due to the intended hollow space and the resulting
three-dimensional design, which in turn is advantageous for load
absorption and restraint of the occupant in an accident.
[0014] It is also proposed that the belt retractor is mounted in
one or more webs between an assembly and the reel or between two
assemblies. In addition to supporting the belt retractor, the web
can also be used to accommodate other functional units such as
sensors, gas generators, control units or the like. The web can
also be used to reinforce the load-bearing structural part. In
particular, the web allows the belt retractor to have an elongated
shape with assemblies arranged in series.
[0015] It is also suggested that at least one-second web be
provided, spaced from the first web. The second web allows the belt
retractor's bearing arrangement to be further improved and further
assemblies and functional units, e.g. for the further assemblies of
the belt, retractor can be provided.
[0016] It is also proposed that a second assembly is provided which
is coaxial and arranged in series with the belt reel and the first
assembly. The second assembly allows the belt retractor to be
provided with further functions, whereby the belt reel and the
first assembly are taken over unchanged at least in their basic
structure. The belt retractor can therefore have a modular design,
which can be equipped with various functions according to customer
and application requirements thanks to its modular design.
[0017] The second web can preferably be arranged between the first
assembly and the second assembly so that it serves as a bearing
location for two assemblies simultaneously.
[0018] It is further suggested that the first or second assembly is
a pyrotechnic belt tensioner including a tensioner drive tube
having a pyrotechnically drivable drive provided therein and a
drive wheel transmitting the drive movement of the drive to the
belt reel, the tensioner drive tube having a linear section and a
curved section disposed at the end of the linear section, and the
tensioner drive tube being disposed such that the linear section is
parallel to the axis of rotation of the belt reel and with the
curved section tangentially circumferentially directed toward the
drive wheel. The advantage of the proposed design of the
pyrotechnic belt tensioner is that it can be made particularly
compact with the proposed design and arrangement of the tensioner
drive tube, whereby the tensioner drive tube can preferably be
arranged in a linear clearance at the edge of the belt retractor
through the linear section and the parallel arrangement to the axis
of rotation, whereby the outer dimensions of the belt retractor are
increased only slightly, if at all.
[0019] It is also proposed that a force limiting device forms the
first or second assembly with a first torsion bar coaxial with the
belt reel. The proposed solution allows the belt retractor to be
realized in the narrowest possible compact design with a
particularly simple design.
[0020] If the force limiting device is to be realized with a
step-shaped force limitation curve, it may have at least one-second
torsion bar arranged in series with the first torsion bar. With the
second torsion bar, the force limitation level can be achieved with
different force limiting levels depending on the dimensioning of
the two torsion bars, whereby the coaxial arrangement, in turn
allows a compact, slim structure of the belt retractor to be
achieved.
[0021] It is also proposed that a tubular extension, coaxial with
the axis of rotation of the belt reel and into which the first
and/or second torsion bar projects, be provided at one end of the
belt reel. The extension extends the belt reel axially and creates
a bearing shoulder for a blocking part which can be blocked by a
blocking device and to which the first and/or second torsion bar is
connected or can be connected via a coupling. The torsion bar is in
turn connected either directly to the belt reel or via the
extension to the latter in a rotationally fixed manner so that when
the blocking part is blocked and a defined belt pull-out force is
exceeded, it begins to deform plastically about its own
longitudinal axis and thus destroy the energy.
[0022] It is also proposed that the belt retractor with the tubular
extension be mounted on the first and/or second web. This is
particularly advantageous during plastic deformation of the torsion
bar(s), as the forces to be absorbed can be absorbed as close as
possible to their point of origin by the bearing, and the resulting
torques in the bearing can be kept low.
[0023] It is further proposed that the first or second or third
assembly is formed by a reversible belt tensioner with an electric
motor, the electric motor with its extended drive shaft being
coaxial with the axis of rotation of the belt reel.
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.
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