Patent Application
20160059878
The invention relates to a device for connecting a steering column to a crossmember positioned between two A-pillars of a vehicle, which device comprises a front connecting region, a crossmember-accommodating region, and a rear connecting region.
The endeavor to attempt to reduce emissions values leads automobile manufacturers to design their vehicles lighter and lighter. At the same time, however, there is an obligation to fulfill ever-increasing legal safety requirements. This is sometimes a great challenge for many components or assemblies, especially against the background that these components or assemblies generally must have particularly high strength in order to meet the legal requirements.
It can be observed that many automobile manufacturers are switching over to modularly constructing as many assemblies of a vehicle as possible so that these assemblies are versatile in application and are easy to assemble. Because of the modular construction, it is also possible to fulfill the requirement that many modules of a component or of an assembly are produced in different locations, and therefore the logistical complexity can be minimized for already assembled assemblies.
To produce the devices for connecting a steering column that are known from the prior art, steel sheet shells, die-cast components, or plastic-metal hybrid structures injection-molded directly on the crossmember are predominantly used. These usually consist of many individual components having associated high joining costs and high investment costs for the progressive tools required therefore. Although topology analyses during a design process are known and also common, the traditional devices for connecting a steering column are only conditionally designable in a load-path-oriented manner in the case of the sheet-metal shell design, and therefore overdimensioning necessary results. Therefore, these devices are heavy and/or, while also involving complex assembly, cannot be used modularly.
As an example, it is clear from DE 10 2004 025 245 A1 that two metal inserts are used therein to connect a steering column, wherein bores are provided in these metal inserts for this purpose. In addition to the structure of the metal inserts illustrated in
This prior art has the disadvantage that the design of the corresponding device for connecting a steering column is not optimized with regard to the load path, resulting in higher weight. In addition, this type of design results in less flexibility. The cause of this is especially that additional logistical expense is connected therewith, provided that the crossmember must be shipped again for further final assembly, because the crossmember has significantly more unwieldy dimensions because of the overmolding. Increased tool expenditure is also necessary in order to achieve accurate positioning of the device, and therefore a tolerance compensation can be realized only at great expense. In addition, modular usability is precluded, because specific tools always must be used to realize a connection.
Furthermore, a structure of a steering column support for increasing the stiffness of the steering column support and of a dashboard cross element is known from DE 10 2007 002 431 B4. The steering column support is formed pairwise from a combination of a fork plate or stop plate and an accommodating main body and thus is formed as a pair of right and left mounting segments. The fork plate and the accommodating main body are composed of metal, wherein the fork plate and the accommodating main body are joined by welding.
A disadvantage of this steering column support structure is that the design thereof likewise is not optimized in a load-path-oriented manner. Rather, the fork plate or stop plate serves as a closing plate for the accommodating main body in order to be able to realize a required stiffness. Because a support unit thus formed has to be designed as a pair and in the manner of a shell, a higher weight, more complex production methods, and assembly difficulties result. In addition, design freedom with regard to a connection of clips, retainers, etc. can be implemented only by means of increased complexity.
In DE 10 2004 051 182 B4, a further steering-column holding structure is shown. A column-holding support is attached to a firewall support and a column-holding extension by means of pedals pivotably fastened to a dashboard by means of a pedal support. The column-holding support is designed in a shell shape as a closed profile having a column-holding extension, which furthermore is to be attached as an additional component, and thus the column-holding support is not optimally designed in a weight-oriented or load-path-oriented manner.
Therefore, the aim of the invention is that of providing a device for connecting a steering column to a crossmember, a so-called cross car beam, that eliminates or at least reduces the problems discussed at the beginning with respect to the prior art.
This aim is achieved by means of a device of the type in question, as mentioned at the beginning, wherein the device comprises at least one metal structure, which is designed as a bow or has at least one such bow and extends from the front connecting region to the rear connecting region, and a base body that supports the metal structure, wherein the metal structure is the main load path for introducing force into the crossmember and wherein the base body is connected to the metal structure in the direction of the main load path at least in the front connecting region and in the rear connecting region.
In the case of the device according to the invention for connecting a steering column to a crossmember, the steel shell components predominantly used in the prior art are replaced by a construction of a modularly produced connecting device, namely by a load-path-optimized metal structure having at least one bow and having a base body. According to a preferred embodiment, the base body is a plastic body, particularly having a polymeric matrix, in which fibers are contained for reinforcement. The base body serves as a supporting structure in order to hold individual segments of the metal structure in their intended spatial position in relation to each other when force is introduced into the crossmember via the main load path. These segments of the metal structure are partial bow segments that project away from the crossmember. For this reason, the metal structure is connected accordingly to the base body in the front connecting region and in the rear connection region. If the base body is a plastic part, it is advantageous for these parts of the bow segments to be at least partially accommodated and/or enclosed in the plastic base body. In the case of such an embodiment, the bow-like metal structure is preferably accommodated in or surrounded by the plastic base body in the front connecting region and rear connecting region of the metal structure in such a way that the accommodation and/or surrounding is not only positively locking in the direction of the main load path but also is positively locking in at least one direction transverse thereto. Especially preferred is an embodiment in which the metal structure is connected in the stated regions to the base body in such a way that evasion of the partial bow segments is prevented when force is applied as intended. This can be achieved, for example, by means of a bonded joint. If the connecting device is a hybrid component, it is advantageous for the corresponding parts of the partial bow segments to be connected to the base body in a positively locking manner, i.e., in such a way that the base body at least partially accommodates and/or surrounds the corresponding segments of the partial bow segments.
The base body is generally designed in such a way that the aforementioned supporting function of the metal structure is ensured for a specified introduction of force. By means of the support of the at least one bow of the metal structure, the at least one bow of the metal structure retains its form within the limits of the supporting force that can be absorbed by the base body, so that an introduction of force into the crossmember via the main load path provided by the at least one metal bow is ensured when the device is used as intended. If this force is exceeded, which can be possible in the event of a crash, the supporting function of the base body can be exceeded, so that in such a case, despite a possible failure of the base body, the connected components (e.g., steering column) still remain connected to the crossmember by means of the metal structure.
According to a further development, the metal structure substantially represents the base structure of the device and the base body is optionally connected to a firewall designed for the engine compartment in order to form a further load path.
In a preferred embodiment, the metal structure consists of a first and two second bent metal bows, which each correspond to a load path typically investigated in a topology analysis. If the base body is a base body composed of a polymeric material, the first metal bow is at least partially surrounded by and/or embedded in the polymeric matrix of the base body, and the two second metal bows are designed as closing bows and can be inserted into and/or through the base body. The base body itself is preferably designed at least partially in a shell form with corresponding closing-bow-accommodating devices.
The thus-formed base body of the device for connecting a steering column can be attached to any points of the crossmember by means of a crossmember-accommodating region and can be fastened by means of the closing bows. The metal bows, which accordingly lie against the crossmember at least in partial regions, preferably can additionally be connected to these points by means of a thermal joining method. In this case, it becomes clear that the device for connecting to a steering column can be used modularly both for so-called left-hand drive vehicles and for right-hand drive vehicles. In addition, tolerances can be compensated more easily.
With regard to the first metal bow substantially representing the base structure of the base body of the device, in a preferred embodiment, the first metal bow is V-shaped or U-shaped and bent in a load-path-optimized manner in such a way that, in order to better absorb force, the first metal bow points upward and forward in a front region and, in a further partial region, lies against the crossmember contour at least in partial regions, and the corresponding two ends of the metal bow point upward and inward in order to contact the closing bows on the inside thereof.
When the terms “upward,” “forward,” “downward,” or “inward” are used in the context of these embodiments, these terms describe the standardized directions in a vehicle, wherein “forward” and “rearward” are directions in the x axis, “upward” and “downward” are directions in the z axis, and “inward” refers to directions in the y axis.
Because higher loads are sometimes introduced into the device by means of the closing bows during normal operation, the closing bows are designed thicker than the preferably V- or U-shaped metal bow in a further preferred embodiment.
In a further preferred embodiment, several closing-bow guides for accommodating the closing bows are introduced in the base body. In addition, any number of stiffening elements, retainers, and/or cable guides can be attached to, introduced into, injection-molded onto, and/or integrated in the base body.
Furthermore, in a further preferred embodiment, the base body is designed in the manner of a skeleton or as a solid body.
The present device for connecting a steering column is extremely variable with regard to the design possibilities and additionally provides the advantage that the flexibility required by automobile manufacturers with regard to packaging space designs, e.g., with regard to size and geometry, can be achieved. Also, because of the load-path-oriented optimization, overdimensioning of the device is at least reduced in comparison with the prior art by using metal bows, resulting in weight savings.
A further advantage of the invention is that, in such an embodiment, steel sheet shells, die-cast components, and plastic-metal hybrid structures injection-molded directly onto the crossmember can be dispensed with, whereby the number of required work steps is reduced and thus the production of the device according to the invention can be realized relatively economically.
Furthermore, a further advantage of the invention is that the present device is not injection-molded onto a crossmember, but rather is produced initially detached from the crossmember. Because of this, these elements can also be flexibly produced at a different location than the crossmember and thus also can be sent logistically more effectively than a crossmember having a device for connecting a steering column that is injection-molded onto the crossmember. In addition, such devices can be also be flexibly modularly used for left-hand and right-hand drive vehicles, can contribute to the compensation of tolerances, and additionally can be produced in an optimized manner with orientation toward the load path even in the case of the most complicated geometries.
The statements made above clearly show that, by means of a load-path-optimized device preferably designed in such a way, the problems discussed at the beginning with respect to the prior art have been eliminated or at least reduced, in that, with corresponding weight savings because of the optimal use of various materials, both easier and more economical manufacturability has been achieved while at the same time the required legal provisions regarding the various crash requirements are complied with. In addition, the device is extremely flexible with regard to packaging space designs and prevents overdimensioning of the device, resulting in weight savings. In this regard, it is advantageous in particular that the device, although it is a so-called hybrid part, is not injection-molded onto a crossmember but rather is simply produced initially detached from the crossmember. This is against the background, above all, that the systems necessary therefor and the associated know-how particularly for joining by means of thermal methods are available or known in the industry. Thus, logistical challenges also can be more easily overcome by applying known methods.
All possibilities obvious to a person skilled in the art can be used in the assembly and the design implementation of the present optimized load-path-oriented device for connecting a steering column.
Below, the invention is described on the basis of embodiment examples with reference to the attached drawings, wherein further advantages and preferred embodiments of the present invention will become clear to a person skilled in the art.
In
As can be seen in the figures, the metal structure 8 extends largely in the x direction, while the crossmember 2 extends in the y direction. The metal structure 8 is produced in accordance with the results of a performed topology analysis. Such topology analyses and such topology analysis tools are well known. Therefore, this analysis and these analysis methods and tools are not discussed here. In other words, the metal structure 8 is designed as a main load path for the predominant introduction of force into the crossmember 2. This does not mean that force cannot also be introduced into the crossmember 2 by means of other components during use as intended. However, an introduction of force by means of these other components occurs only to a subordinate extent. Without overdimensioning of the metal structure 8 associated therewith, it is thus possible to produce an optimized device in that the base body 6 at least partially accommodates and/or encloses the metal structure 8 in the polymeric matrix of the base body 6, wherein the metal structure 8 substantially represents the base structure of the device 1. This occurs in a separate overmolding process, so that the component—the device 1—does not have to be injection-molded onto the crossmember 2. The base structure of the device is likewise based on the topology optimization, wherein any reinforcing ribs are preferably arranged in a loading direction.
The base body 6 is preferably designed as a thermoset or thermoplastic, particularly as polyoxymethylene. However, other materials, such as polyamide, polypropylene, fiber composite plastics, or glass fiber mat thermoplastics, are also conceivable.
In the illustrated embodiment, the front connecting region 3 of the polymeric base body 6 is designed in a shell shape and is open upward. In addition, the front connecting region 3 is reinforced by the formation of stiffening ribs 20 extending transversely to the longitudinal extent of the base body 6. Furthermore, the illustrated reinforcing ribs 20 are arranged between two side walls 19, 19.1, which extend along the bow segments 11, 11.1 of the first metal bow 8. Further embodiments of the reinforcing ribs not shown can of course be represented in all geometric shapes, particularly of course diagonal, y-shaped, cross-shaped, etc.
Therefore, the metal structure 8 can be described as bow-shaped, because the metal structure 8 lies against the contour of the crossmember 2 or lies around the contour of the crossmember 2 by means of a segment and the partial bow segments that can be described as legs protrude from the crossmember 2 in other directions.
At the end of the front connecting region 3 directed toward the engine compartment and thus forward, an additional connecting device 7 is formed, which is provided as a firewall connection in the embodiment example shown. Such a coupling can optimize the natural frequency of a steering column.
In order to accommodate the second metal bows 9, 9.1, which are provided for fastening the base body 6 and the first metal bow 8 at least partially embedded and/or enclosed in the base body 6, an accommodating pocket 14, 14.1 is formed on each of the side walls 19, 19.1. In order that the assembly is made easier and the second metal bows 9, 9.1 are securely retained the base body 6 and the first metal bow 8 is securely retained on the crossmember 2, two guide groove segments 15, 15.1 and accordingly 15.2 and 15.3 are formed in each accommodating pocket 14, 14.1, as is shown for the accommodating pocket 14 in
In a further embodiment (not shown), either several guide groove segments or merely one continuous guide groove can be formed, wherein the guide groove optionally can be integrated in the corresponding side wall 19, 19.1.
In addition, in the preferred embodiment, an accommodating opening 17, 17.1 for accommodating the corresponding second metal bow 9, 9.1 is formed in the accommodating pocket 14, 14.1.
It becomes apparent to a person skilled in the art that it is also possible to form the front connecting region 3 as a solid body, in the manner of skeleton, or from a combination of the variants mentioned herein (not shown). Of course, the same applies analogously to the entire design of the base body 6. In particular, it becomes apparent to a person skilled in the art that of course further reinforcing structures and/or retainers and/or cable guides can be attached to and/or integrated on the entire base body 6 (not shown). Therefore, the embodiment examples just mentioned are not described further.
The crossmember-accommodating region 4 of the base body 6 is designed in such a way that the crossmember-accommodating region 4 of the base body 6 extends around the crossmember 2 substantially in a contacting manner, as shown in
In other words, the bottom region of the crossmember-accommodating region 4 is designed in such a way that the bottom region of the crossmember-accommodating region 4 has two holes in the region of the bow segments 11, 11.1 lying against the crossmember 2. The holes are designed in such a way that the bow segments 11, 11.1 are still surrounded by the polymeric matrix of the base body 6 in the transition regions from the front connecting region 3 to the crossmember-accommodating region 4 and from the crossmember-accommodating region 4 to the rear connecting region 5 for reasons of guidance and stability. In these transition regions, the bow segments 11, 11.1 are fully enclosed by the plastic in the illustrated preferred embodiment. However, it is also conceivable that these transition regions are designed as guide groove segment(s) or a guide groove (not shown).
The integration of the bow segments 11, 11.1 of the bow-shaped metal structure 8 into the base body 6 makes it possible for the base body 6 to assume a supporting function against buckling of the bow segments 11, 11.1 in the relevant directions. Thus, when the connecting device 1 is loaded as intended, the base body 6 serves to retain the metal structure 8 in the shape of the metal structure 8 shown in the figures. This ensures that the force to be introduced into the crossmember 2 is introduced into the crossmember 2 by means of the metal structure 8, in any case predominantly, and therefore the metal structure 8 is the main load path.
The segment located between the holes in the central bottom region has a tongue-like shape and is provided with a Y-shaped reinforcing rib on the bottom side of said segment, as
It still must be stated that it is obvious to a person skilled in the art that the Y-shaped reinforcing rib described in more detail above has the described shape as an example and this example shape is representative for a multitude of possible rib geometries. The rib geometries can be designed in all geometric versions, such as X-shaped, I-shaped, or as a bead, and therefore are not described in more detail below.
Furthermore, the transition region to the rear connecting region 5 is preferably not designed as a continuous bounding or supporting wall but rather as a rib that extends substantially in the region of the tongue-shaped segment transversely to the base body 6 and that simultaneously fulfills the function of reinforcing the base body 6. In addition, guide grooves 16 for accommodating one each of the second metal bows 9, 9.1 protrude into the crossmember-accommodating region 4, said guide grooves 16 being formed in the rear connecting region 5. However, it is obvious here that this is not mandatory and, in an embodiment according to the invention, the transition region just described in more detail can also be designed as an at least partially continuous bounding or supporting wall (not shown).
In the preferred embodiment, the rear connecting region 5 of the base body 6 is likewise designed in the shape of a shell and open upward, wherein one accommodating opening 18, 18.1 for each of the second metal bows 9, 9.1, particularly for the leg end 13, 13.1 thereof, is arranged in a rear segment of the rear connecting region 5. In addition, a connecting device 23 is integrally injection-molded onto the rear end of the rear connecting region, which rear end of the rear connecting region is designed as a terminating wall in the preferred embodiment, wherein the connecting device 23 is formed with two reinforcing ribs. This connecting device is used, for example, to accommodate a dashboard or other devices.
It already needs to be stated here, particularly in the context of the rear connecting region 5, that a restriction of the reinforcing structures is limited neither to the number thereof nor to a certain geometric design or arrangement. Rather, all designs obvious to a person skilled in the art should be included thereunder.
A guide groove 16, 16.1 for the corresponding second metal bow 9, 9.1 is formed along each side wall of the rear connecting region 5. Each guide groove leads directly into the corresponding accommodating opening 18, 18.1.
In a further embodiment not shown, at least one guide groove segment is formed. In addition, the guide groove or the at least one guide groove segment can extend into the crossmember-accommodating region and can be part of the side wall at least in some segments.
For illustration,
In addition, the second metal bow 9, 9.1 is furthermore bent in such a way that the second metal bow 9, 9.1, over the longitudinal course thereof, corresponds to the corresponding at least one guide groove segment 15, 15.1, 15.2, 15.3, 15.4, 15.5 and the largely continuous guide groove 16, 16.1 of the front and rear connecting region 3, 5 and can be or is arranged therein.
Finally, in a preferred embodiment, the second metal bow 9, 9.1 is furthermore bent in such a way that the leg ends 13, 13.1 thereof each can be inserted through a corresponding accommodating opening 17 and 18 or 17.1 and 18.1 of the corresponding accommodating pocket 14, 14.1. It is also conceivable that the leg ends 13, 13.1 only can be inserted therein or both variants can be implemented in combination. The second metal bow 9, 9.1 also corresponds to a load path of the device 1 determined in a topology analysis and is not encased by the polymeric matrix of the base body 6 but rather is inserted into and/or through the base body 6.
In a preferred embodiment (not shown), the corresponding leg ends 13, 13.1 are provided with an external thread so that a steering column can be screwed on by means thereof. Of course, all other methods of bonded, positively locking, or force-closed connection known in the prior are also possible.
The second metal bow 9, 9.1 is preferably thicker than the first metal bow 8. A thickness of at least 6 mm, particularly 8 mm, is preferably used, and the production preferably occurs in advance in a wire-bending machine or in a pressing tool, wherein the external threads just described are preferably rolled on in advance.
Overall, it is advantageous in the assembly to first fasten the preferably two second metal bows 9, 9.1 to the crossmember by thermal joining, to place the base body 6 with the first metal bow 8 integrated therein onto the crossmember 2 and the corresponding leg ends 13, 13.1 from below in a further step, to fasten the exposed bow segments 11, 11.1 of the first metal bow 8 to the crossmember 2 by thermal joining, and finally to connect the leg ends 25, 25.1 of the first metal bow 8 to the corresponding second metal bow 9, 9.1 by thermal joining. In addition, by means of the subsequent mounting of the steering column, a further form closure of the corresponding metal bow 9, 9.1 with respect to the crossmember 2 is achieved.
The preceding statements relate to the device 1, 1.1, which has been described for connecting a steering column to a crossmember. Furthermore, such a device can also be used to connect other objects, such as an airbag retainer, to such a crossmember. Of course, this device is then a separate device.
The preceding description relates only to preferred embodiment examples and should not restrict the claims to these preferred embodiment examples.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2013 106 384.5 | Jun 2013 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2014/062339 | 6/13/2014 | WO | 00 |
