Method for mounting a tubular component of a motor vehicle on a further component, component connection between a tubular component and a further component, and vehicle seat comprising such a component connection

Abstract

In order to form a component connection (2) between a tubular component (4), which extends in a longitudinal direction (L) and forms part of a motor vehicle, in particular a vehicle seat, and a further component (6) which has an opening (10) into which the tubular component (4) is inserted, an end region (12) of the tubular component (4) is radially expanded with the aid of a shaping mandrel (14) in order to achieve an axial interlocking fastening to the further component (6), this radial expansion being achieved by screwing the shaping mandrel into the tubular component (4), in particular into the end region (12). This minimises the axial loading on the tubular component (4).

Description

[0001] Description

[0002] Method for assembling a tubular component of a motor vehicle to another component and component connection between a tubular component and another component and vehicle seat with such a

[0003] Component connection

[0004] The invention relates to a method for assembling a tubular component of a motor vehicle, in particular a vehicle seat, extending in a longitudinal direction to another component, which has an opening into which the tubular component is inserted, wherein at least one end region is radially expanded for axial, positive-locking fastening to the other component. The invention further relates to a component connection between the tubular component and the other component, as well as to a vehicle seat with such a component connection.

[0005] In motor vehicles, especially in vehicle seats, a tubular component, also referred to as a support tube and designed, for example, as a cross strut or shaft, is often connected, for example rotatably, to another component. The tubular component and the other component are in particular parts of a vehicle seat assembly. An end region of the tubular component is inserted into an opening in the other component. To form an axial, positive-locking connection with the other component and thus to form a component connection between the tubular component and the other component, the end region of the tubular component is radially expanded. This positive-locking connection also serves, in particular, as crash protection.

[0006] Alternatively or additionally, retaining rings and / or screws are provided for axially securing the additional component to the tubular component. During forming, an expanding forming tool is generally pressed longitudinally into the tubular component, so that the force acting in the longitudinal direction increases the diameter of the end region of the tubular component to create the axial locking.

[0007] In conventional forming using a conical forming tool pressed in longitudinally, high axial forming forces are introduced in the axial direction. A disadvantage is that these axial forming forces must be supported by a counterbearing. This is often difficult for more complex assemblies, such as a vehicle seat assembly. This frequently leads to problems, particularly with thinner and / or longer components, such as a recliner shaft in a vehicle seat, because the high axial forming forces must be dissipated via the tubular component and supported by an additional counterbearing attached during assembly. This poses the risk of the tubular component being damaged, for example by buckling. Furthermore, providing a sufficiently dimensioned counterbearing during assembly is often difficult.Such a recliner shaft is usually used to synchronize opposing fittings that are attached for a rotatable connection between a seat frame and a backrest part.

[0008] Based on this, the invention is based on the object of enabling an expansion of an end region of the tubular component with at most low axial forming forces.

[0009] The object is achieved according to the invention by a method for assembling a tubular component of a motor vehicle, in particular a vehicle seat, extending in a longitudinal direction to another component, which has an opening into which the component is inserted. For axially positively securing the tubular component to the other component, an end region of the tubular component is radially expanded by screwing a forming mandrel into the tubular component, thereby expanding the end region.

[0010] In this case, the end region is understood to mean the end section of the tubular component which has been formed and widened in its final state.

[0011] Preferably, in the initial state before screwing in an end section, the tubular component has a cross-sectional contour that is constant in the longitudinal direction, for example circular or non-circular.

[0012] Preferably, the forming mandrel is screwed directly into this end section of the tubular component, which then forms the expanded end region in the final state.

[0013] Alternatively, the forming mandrel is preferably screwed exclusively into a further inner section of the tubular component and thus subsequently to the end region (which is widened in the final state).

[0014] In both cases, such a longitudinal section of the tubular component adjoining the end region and not (significantly) formed has an internal thread at least at the end of the forming process.

[0015] It is worth emphasizing that the forming process uses a screwing process, so the required forming forces for expanding the end area are applied via the screwing process. Unlike conventional conical expanding processes, in which a forming element is pressed in axially while exerting an axial pressing force (axial forming force), such an axial pressing force is not required, so the overall load on the component assembly is low.

[0016] In a preferred development, it is also provided that the forming mandrel is screwed into the component without the influence of an axial forming force that is dissipated via the tubular component. This means that no axial pressing force is exerted to press the forming mandrel into the tubular component via a corresponding screwing tool used to screw in the forming mandrel, as is the case with conventional forming tools, which are dissipated via the tubular component and absorbed by a counterbearing.

[0017] A certain contact pressure can be applied when screwing in the forming mandrel, for example to bring the forming mandrel into engagement with the tubular component for the desired screwing process. However, no axial force is exerted that exceeds the contact pressure applied to the forming mandrel from the outside and which would be required for expansion. The forces required for expansion are applied exclusively through the alternating support of the thread flanks during the screwing process. This alternating support of the thread flanks therefore replaces the previously required counterbearing. Since the support is already provided directly in the area of ​​the forming mandrel, there is no longer any need for axial forces to be diverted via the tubular component, thus reliably preventing damage to the tubular component.

[0018] The forming mandrel preferably has a conical and thus conical expansion section, which conically expands the end region when screwed in. The geometry of the conical expansion section determines the geometry of the expanded end region in the final state. The outer surface of the expansion section is preferably smooth.

[0019] The conical expansion section preferably has a cone angle that is, for example, in the range between 30 and 75°, and in particular in the range between 40 and 60°, and preferably between 35° and 40°. In this case, the cone angle is understood to be the angle that—viewed in a vertical section perpendicular to the longitudinal direction—subtends the conical surface to a central axis of the cone. In a useful further development, the forming mandrel has a threaded section with which it is screwed into the component. The forming mandrel is therefore a special screwing tool with an external thread, which is suitable for screwing into the component and expanding the component.

[0020] In a practical design, the threaded section and the conical expansion section are formed by longitudinally separated sections of the forming mandrel. Specifically, the threaded section is positioned in front of the expansion section. This measure therefore spatially separates the two functional areas from each other. Preferably, they are directly adjacent to each other.

[0021] In a practical embodiment, the threaded section is formed on a cylindrical envelope curve. This means that the individual thread turns are located on the same (thread) diameter. Only the beginning of the threaded section can have a chamfer or a so-called thread cut, which facilitates the insertion of the threaded section. The thread diameter is adapted to the inner diameter of the tubular component in its initial state. "Adapted" here means that the outer diameter is selected such that the threaded section engages the component for the screwing process.

[0022] According to a first embodiment, the individual thread turns are formed to extend completely around the thread. According to an alternative embodiment, threaded sections are formed that extend only partially over a certain angular range, viewed in the circumferential direction, and are spaced apart from one another in the circumferential direction. In this case, the threaded section is therefore segmented in the circumferential direction and, viewed in cross-section, has an overall non-circular shape. In particular, indentations or longitudinal grooves are formed between the partially circumferential threaded sections.

[0023] The tubular component is, for example, a cylindrical

[0024] Pipe or alternatively a partially cylindrical pipe which has discrete indentations or bulges on the outer circumference for a circumferentially positive and thus rotationally fixed connection with the other component.

[0025] For a cylindrical tube, a forming mandrel with a segmented thread is preferably used, and for a partially cylindrical tube, a forming mandrel with a continuous thread is preferably used.

[0026] According to an alternative design variant, the threaded section forms the conical expansion section at least partially or even completely. This means that the threaded section also widens conically, either completely or at least over a portion. In this design variant, the threads are also formed, for example, completely circumferentially or only partially circumferentially.

[0027] In a preferred embodiment, the threaded section has a self-forming thread, which forms the previously described internal thread when screwed into the component. In this embodiment, the tubular component is designed without an internal thread before expansion.

[0028] According to a first variant, this is a self-tapping thread, which essentially cuts into the inner wall of the tubular component through machining. Alternatively, the thread is simply formed by material displacement, without any machining.

[0029] In a preferred embodiment, the forming mandrel has a stop that rests against the end region during screwing, in particular against an end face of the component. The (axial) stop limits and defines the screw-in depth and, in particular, the length of the expanded end region. This ensures a defined and, in particular, precisely positioned expansion of the end region. The stop is generally formed downstream of the expansion section and, in particular, is directly adjacent to it.

[0030] In principle, the formation of the expansion by means of the screwing process already achieves a defined expansion of the end area and thus a defined formation of an axial lock with functionally appropriate and, in particular, defined tolerance deviations. The stop further improves the tolerance accuracy and enables process reliability. Depending on the application, for example, a defined axial play is set between the expansion and the other component, allowing axial displacement of the tubular component within a desired axial play. Alternatively, the expansion can be specifically designed to create a play-free axial lock.

[0031] The object is further achieved according to the invention by a component connection between a tubular component and a further component, in particular of a vehicle seat, wherein the further component has an opening into which the tubular component is inserted, wherein an end region of the tubular component is radially widened for an axial positive locking on the further component, and the tubular component has an internal thread.

[0032] The internal thread is merely the result of the special process described here for expanding the end section. It therefore does not serve as any other screw fastening, and in particular, it does not serve to axially secure the tubular component to the other component. Overall, therefore, a screwless axial securing of the tubular component to the other component is formed. Furthermore, preferably no other axial securing element is arranged or formed besides the expansion.

[0033] In the assembled state, therefore, no screw element is preferably screwed into the formed internal thread. The tubular component is preferably open in the area of ​​the internal thread or, for example, simply closed by a cover cap.

[0034] Preferably, the internal thread has a cylindrical internal thread section that adjoins the widened end region. This internal thread section directly adjoins the widened end region. It preferably extends only over a portion of the tubular component. In particular, its length corresponds to the length of the cylindrical thread section of the forming mandrel.

[0035] In a preferred embodiment, the internal thread, in particular in addition to the cylindrical internal thread section, has a conical internal thread section formed in the widened end region. Depending on the design variant, the thread and the thread turns are completely circumferential (particularly in the case of an originally cylindrical tubular component) or are interrupted in the circumferential direction and have spaced-apart thread sections, so that a circumferentially segmented internal thread is formed.

[0036] According to a preferred embodiment, thread flanks in this conical internal thread section are deformed.

[0037] Alternatively, according to a preferred development, the inner wall is smooth in the conically widened end region.

[0038] Such a design—either with a deformed conical internal thread section or even with a smooth inner wall in the end region—is formed in particular with the previously described method, in which the forming mandrel is screwed in with a (cylindrical) thread section, followed by the conical and smooth expansion section. During the screwing process, an internal thread is therefore first formed in the end section of the component or is already present there, which is subsequently at least deformed or completely smoothed by the expansion process. An initially existing internal thread section in the end region is thus reshaped by the expansion section.

[0039] The component connection is in particular part of a motor vehicle and specifically part of a vehicle seat of such a motor vehicle.

[0040] Furthermore, the tubular component is preferably designed as a rotary shaft which is rotatably mounted on the further component or on another component.

[0041] Preferably, the component is a so-called recliner shaft of a vehicle seat. This connects two opposite side parts of the vehicle seat and is designed in particular to synchronize the rotational position of fittings by means of which a backrest part is rotatably mounted relative to a seat frame.

[0042] According to a first variant, the component is preferably connected to the further component in a rotationally fixed manner. For this purpose, in a preferred embodiment, it is non-circular at the ends, and in particular also in the end region, and has, for example, radial protrusions or indentations. Correspondingly, the opening in the further component is also non-circular and has corresponding radial indentations or indentations, so that these two components engage with each other in a form-fitting manner in the circumferential direction for the rotationally fixed connection.

[0043] According to an alternative, second variant, the tubular component is rotatably mounted on the further component. For this purpose, the tubular component and the opening are preferably round and / or rotatably mounted to one another via a bearing element. In this variant, the opening forms a bearing opening. The bearing element is, in particular, a bearing bush and is arranged between the tubular component and an inner wall of the opening of the further component.

[0044] The additional component is arranged and supported directly adjacent to the widened portion, resulting in a compact design. The radial widened portion can serve to axially secure the additional component to the tubular component. In particular, the radial widened portion can be designed such that no radial clamping forces act on the additional component. Due to the high tolerance accuracy of the axial securing means formed by the widened portion, the additional component can be arranged close to this axial securing means and—in a rotatable arrangement—supported without the risk of stiffness.

[0045] The forming mandrel used for radial forming is preferably removed from the end region after the radial deformation has been completed, so that the end region of the tubular component, in its finished form, does not have a forming mandrel. The forming mandrel is therefore not a part of the component connection but a forming tool.

[0046] According to one embodiment, the radial expansion of the end region of the tubular component can prevent any radial clamping force from acting on the additional component. This prevents stiffness. This also has the advantage that an external axial locking device for the additional component can be formed on the tubular component, for example, without requiring additional locking elements to form the external axial locking device.

[0047] The additional component is - depending on the design variant - a side part, for example, of the seat frame, or the backrest of a vehicle seat. The side parts are usually formed sheet metal parts. Additionally or alternatively, the additional component is a fitting element attached to such a side part, for example, which is designed as a rotary fitting or locking fitting. Furthermore, the additional component can be a lever of a kinematic system, in particular a kinematic system that enables height or tilt adjustment of a seat part.

[0048] The tubular component is typically axially secured in both directions: on one side by the flared end section and on the other side by an additional positive axial securing device. This can be formed, for example, by an abutment attached to the tubular component, by a flange, or by a circumferential fold or bulge of the tubular component itself.

[0049] An embodiment of the invention is explained in more detail below with reference to the figures, which show in simplified representations:

[0050] FIG 1 is a view of a backrest part of a vehicle seat of a motor vehicle with a recliner shaft attached thereto and forming a tubular component,

[0051] FIG 2 shows an end region of the recliner shaft, which is guided through an opening of a further component designed as a fitting element, together with a forming mandrel according to a first variant,

[0052] FIG 3 a perspective view of a forming mandrel according to a second variant,

[0053] FIG 4 a simplified sectional view through the tubular component and through the further component before the forming of the end region and

[0054] FIG 5 the sectional view according to FIG 4 after the widening of the end area.

[0055] FIG 1 shows a perspective partial view of a vehicle seat 1 of a motor vehicle, specifically of a component group which has a rotatable component connection 2 between a backrest part 3 and a seat frame, wherein only one fitting 5 is shown in FIG 1.

[0056] In the exemplary embodiment, the component connection 2 is formed between a tubular component 4 and a further component 6 designed as a fitting element. The fitting element is designed, in particular, in the manner of a disc.

[0057] The tubular component 4 extends in a longitudinal direction L. The tubular component 4 is designed, in particular, as a transverse tube forming a shaft (recliner shaft). It connects two opposite side parts of the vehicle seat 1 to one another. The tubular component 4 forms a rotary shaft. In the design as a recliner shaft, it serves, in particular, to synchronize the opposing fittings. In alternative variants, the tubular component 4 simultaneously forms, for example, a rotation axis about which two seat parts of the vehicle seat can be rotated relative to one another.

[0058] The further component 6 has an opening 10 through which the tubular component 4 is passed with an end region 12, so that the end region 12 projects beyond the further component 6.

[0059] The tubular component 4 generally extends from an end face of the end region 12 in the longitudinal direction L. In the initial state, the tubular component 4 has, for example, a constant outer diameter along its length and is designed as a hollow tube, in particular a round tube, wherein—as in the present embodiment—an end section of the round tube can be formed into a non-circular circumferential contour. Alternatively, the non-circular circumferential contour can also be formed over the entire length.

[0060] This non-circular circumferential contour (see especially FIG. 2) is formed by several radial bulges, three in the exemplary embodiment, in the originally round tube. Correspondingly, the opening 10 also has a non-circular cross-section, in particular with corresponding bulges.

[0061] For axial securing of the tubular component 4, its end region 12 is conically widened, as shown in particular in FIG 5.

[0062] To widen the end region 12, a forming mandrel 14 is used, as shown by way of example in FIG 2 and FIG 3.

[0063] The forming mandrel 14 has a threaded section 16 provided with a thread, which is adjoined—counter to the longitudinal direction L—by a conical and thus conical expansion section 18 with a preferably circular cross-sectional area. In the exemplary embodiment, the threaded section 16 has completely circumferential threads. Alternatively, the threaded section 16 is segmented in the circumferential direction and has individual threaded areas spaced apart from one another in the circumferential direction.

[0064] Following the widening section 18, an end section 20 is preferably formed, which is in particular cylindrical.

[0065] In the embodiment according to FIG. 3, a stop 22 is directly adjacent to the expansion section 18. In the embodiment, this is designed as an annular surface oriented perpendicular to the longitudinal direction L.

[0066] Preferably, the forming mandrel 14 has a conical insertion section 24 leading up to the threaded section 16 and a tool engagement section 26 at the opposite end, in the exemplary embodiment a polygonal bolt, via which the forming mandrel can be inserted into a screwdriver, for example.

[0067] To expand the end region 12, the forming mandrel 14 is screwed into the end region 12. Preferably, the end region 12 and in particular the entire tubular component 4 do not have an internal thread in the initial state.

[0068] The thread of the threaded section 16 is preferably a self-tapping thread. The forming mandrel 14 is therefore preferably designed as a special thread cutter.

[0069] When the threaded section 16 is screwed into the initially unexpanded and threadless end region 12, an internal thread 28 is formed in its inner wall. The forming mandrel 14 is screwed further into the end region 12 in the longitudinal direction L. The expanding section 18 thereby conically expands the end region 12.

[0070] In the variant shown in FIG. 3, the forming mandrel 14 is screwed in up to the stop 22. The expanding and screwing-in processes are preferably carried out mechanically, and in particular, automatically. The stop 22 ensures a reliable, defined expansion of the end region 12.

[0071] Subsequently, the forming mandrel 14 is unscrewed again and the situation shown in FIG 5 is obtained with the widened end region 12, in which the internal thread 28 is now formed.

[0072] As a result of the special screwing-in process using the forming mandrel 14 with the leading, in particular cylindrical threaded section 16 and the trailing widening section 18, a cylindrical internal thread section 28A is formed in this final state in the cylindrical portion of the tubular component 4 adjoining the end region 12. In the exemplary embodiment, this is segmented in the circumferential direction with several threaded sections spaced apart from one another in the circumferential direction due to the non-circular, non-cylindrical design of the tubular component 4 in the initial state. In the expanded end region, this is followed by a conical, likewise segmented internal thread section 28B. However, due to the forces occurring during expansion, this is typically deformed, so that only deformed thread turns remain, as shown by the dotted lines in FIG 5.Depending on the application, it is also possible for the internal thread section 28B initially formed in the end region 12 to subsequently be completely flattened again by the expanding section 18, so that a smooth inner surface is present in the expanded end region 12.

[0073] The particular advantage of the axial securing arrangement described here, which involves expanding the end region 12 by screwing in the forming mandrel 14, is that no axial forming forces are exerted on the tubular component 4 and / or the forming mandrel 14, which would otherwise have to be absorbed and dissipated by the component assembly. The expansion of the end region 12 therefore occurs, in particular, without axial force support on a counterbearing.

[0074] 1 vehicle seat

[0075] 2 Component connection

[0076] 3 backrest part

[0077] 4 tubular component

[0078] 5 Fitting

[0079] 6 additional component

[0080] 10 Opening

[0081] 12 End area

[0082] 14 Forming mandrel

[0083] 16 threaded section

[0084] 18 Expansion section

[0085] 20 final section

[0086] 22 stop

[0087] 24 Introductory section

[0088] 26 Tool attack

[0089] 28 internal threads

[0090] 28A cylindrical internal thread section

[0091] 28B tapered internal thread section

[0092] L longitudinal direction

Claims

Claims 1 . Method for assembling a tubular component (4) of a motor vehicle, in particular a vehicle seat, which extends in a longitudinal direction (L), to a further component (6) which has an opening (10) into which the tubular component (4) is inserted, wherein an end region (12) of the tubular component (4) is radially widened for an axially positively locking connection of the tubular component (4) to the further component (6), characterized in that for the radial widening of the end region (12), a forming mandrel (14) is screwed into the tubular component (4) and in particular into the end region (12), and the end region (12) is widened in the process.

2. Method according to the preceding claim, characterized in that the forming mandrel (14) is screwed into the tubular component (4) without the action of an axial forming force to be dissipated via the tubular component (4).

3. Method according to one of the preceding claims, characterized in that the forming mandrel (14) has a conical widening section (18) which conically widens the end region (12) when screwed in.

4. Method according to one of the preceding claims, characterized in that the forming mandrel (14) has a threaded portion (16) with which it is screwed into the tubular component (4).

5. Method according to the preceding claims, characterized in that the threaded section (16) is arranged in front of the widening section (18).

6. Method according to one of claims 4 to 5, characterized in that the threaded portion (16) is formed on a cylindrical envelope curve.

7. Method according to one of claims 4 to 6, characterized in that the threaded portion (16) has a self-forming thread, which when screwed into the tubular component (4) an internal thread (28) is formed therein.

8. Method according to one of the preceding claims, characterized in that the forming mandrel has a stop (22) which comes into contact with the end region (12) when screwed in.

9. Method according to one of the preceding claims, characterized in that the forming mandrel is removed from the end region (12) of the tubular component (4) after the end region (12) has been radially expanded.

10. Method according to one of the preceding claims, characterized in that due to the radial widening of the end region (12) of the tubular component (4), no radial clamping force acts on the further component (6).

11. Method according to one of the preceding claims, characterized in that by the radial widening of the end region (12) of the tubular component (4) an external axial securing of a bearing point of the further component (6) on the tubular component (4) is formed, preferably wherein no additional securing elements are used for the external axial securing of the further component (6) on the tubular component (4).

12. Component connection (2) between a tubular component (4) extending in a longitudinal direction (L) and a further component (6), in particular a vehicle seat, wherein the further component (6) has an opening (10) into which the tubular component (4) is inserted, wherein an end region (12) of the tubular component (4) is radially widened for an axial positive locking on the further component (6), characterized in that the tubular component (4) has an internal thread (28).

13. Component connection (2) according to the preceding claim, in which a screwless axial lock is formed between the tubular component (6) and the further component (6).

14. Component connection (2) according to one of the two preceding claims, in which the internal thread (28) has an internal thread section (28A) with a diameter that remains constant in the longitudinal direction, the internal thread section (28A) adjoining the widened end region (12).

15. Component connection (2) according to one of the preceding claims, in which the internal thread (28) has a conical internal thread section (28B) in the end region (12).

16. Component connection (2) according to one of the preceding claims, in which the tubular component (4) is a rotary shaft which is rotatably mounted on the further component (6) or on another component.

17. Component connection (2) according to one of the preceding claims, in which the tubular component is connected to the further component (6) in a rotationally fixed manner and preferably the tubular component (4) is non-circular at the end and the opening is also non-circular.

18. Component connection (2) according to one of the preceding claims, characterized in that the end region (12) of the tubular component (4) in its finished form does not have a forming mandrel.

19. Component connection (2) according to one of the preceding claims, characterized in that due to the radial widening of the end region (12) of the tubular component (4), no radial clamping force acts on the further component (6).

20. Component connection (2) according to one of the preceding claims, characterized in that an external axial securing of a bearing point of the further component (6) on the tubular component (4) is established by the radial widening of the end region (12) of the tubular component (4), preferably wherein no additional securing elements for the external axial securing of the further component (6) on the tubular component (4) are present.

21. Vehicle seat with a component connection (2) according to one of the preceding claims.

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