The invention concerns an assembly for connecting chassis components, in particular screw connections, between a structure of a fiber-plastic-composite (FPC) and a metallic load-introducing element, in particular designed as a traction member. The invention concerns also a wheel carrier for motor vehicle with an at least double-walled structure made from fiber-plastic-composite.
The term fiber-plastic-composite, abbreviated FPC, is meant to be plastic material which comprises a textile with long or endless fibers, for instance of glass or carbon, and on the other hand a matrix component which combines the fibers, for instance a resin. Instead of the term fiber-plastic-composite, the technical literature also uses the term fiber-composite- plastic, abbreviated as FOP. Such plastic material is characterized by a relatively low weight at a high strength and is increasingly applied in the construction of motor vehicles. Hereby, the problem occurs to connect the FPC structure with other parts, for instance load-introducing devices metallic based materials, in a way that the different material characteristics of plastic and metal are sufficiently considered.
Through the publication DE 10 2007 053 120 A1, a wheel carrier for a motor vehicle is known, where its structure comprises a fiber composite material and which has several load-introducing elements. Herein, the load-introducing elements can be understood as being the support of a spring strut or the mounting of a joint bearing for a steering arm. The basic structure of the known wheel carrier is designed in a tub shape and comprises of a single deformed plastic wall. For the mounting of load-introducing elements, for instance steering arms, preferably recesses are provided in the plastic wall.
It is an object of the present invention to reliably connect plastic structures, in particular made of fiber-plastic-composite, material appropriately with a load-introducing element which is in particular made of metal.
Furthermore, it is an object of the invention to connect a fiber-plastic-composite structured wheel carrier with a metallic load-introducing element.
The objectives of the invention are solved through the characteristics of the independent claims. Advantageous embodiments result from the independent claims.
In accordance with the invention, an assembly is created to connect chassis components between a structure of fiber-plastic-composite (FPC) and a metallic, in particular designed as traction element, load-introducing element, whereby the structure is designed as multi-walled, in particular double-walled, and which has a first wall whereby the first and the additional wall each have coaxially positioned recesses. The configuration further comprises that, between the first and the additional wall, a spacer with a through hole is positioned, whereby the load-introducing element extends at least into a recess and the through hole of the spacer. Hereby, the through hole can be manufactured through cutting, or erosion, or as a highly accurate fitting. The load-introducing element has an assigned holding element, whereby the load-introducing element and the holding element are connected with each other through a connecting segment, in particular as form-fit, friction -fit, and/or material fit, and whereby the connecting segment and/or the holding element are essentially passing through the first and/or the at least additional, second wall. The connecting segment can be designed as a threaded segment. In that case, the load-introducing element and the holding element have inner or outer threads, respectively, so that these parts can be screwed together with each other.
Thus and in a first aspect of the invention, an assembly is hereby provided for the connection of chassis components with a load-introducing element and a holding element, whereby the load-introducing element and the holding element are connected with each other through a connecting section which is essentially positioned within the outer contours of the at least double-walled structure. On one hand, a construction space advantage is achieved, not only that the elements of the connecting assembly, in particular the holding element, do not essentially extend beyond the outer contour, but they are positioned within the multi-walled structure. Thus, the neighboring construction space at the outer contour of the structure can be used for other parts. Due to the multi-walled structure, comprising of a first and at least an additional, second wall positioned in a distance, the advantage is created that introduced torques and/or tension or compression forces, respectively, through the load-introducing element are accommodated by a force coupling, whereby in one wall mainly tensile forces occur and in an additional or other wall mainly compression forces occur. Bending stress, which it is especially damaging to a plastic structure, is therefore avoided. The load-introducing element is preferably designed as a tension member. In the structure which is made of fiber-plastic-composite, through holes are also provided to extend the holding element or the load-introducing element. These can be machined in. It is also possible that the through holes for the intended chassis component are created during production of the fiber-plastic composite by widening or spiking of the fiber material. It means that the fiber fabric, at the required locations for the through holes and prior to adding the plastic (for instance resin), is widened by a conical part, for instance a pin or a cone. it is hereby avoided that the fiber is cut in the area of the through hole, as it occurs in a machined through hole.
In a preferred embodiment, the holding element is designed as a threaded sleeve which supports itself, directly or indirectly, in reference to the first wall and which extends with its threaded section into the space between the first and the second wall. Thus, a relatively flat outer contour of the first wall is created. The connection section is preferably form-fit designed as a threaded/screwed connection. Alternatively, a material-fit connection in form of a glued connection or welded connection can be selected.
In an additional, preferred embodiment, the holding element is designed as an embedded nut, meaning that the nut, in reference to the outer contour of the first wall, is buried in the space between the first and the at least second wall. The countersunk nut supports itself hereby in reference to the first wall.
In an additional, preferred embodiment, the holding element is designed as a cylinder head screw, preferably with an Allen or hexagonal socket, with the cylinder head screw indirectly supported relative to the first wall. Hereby, a flat outer contour is also created.
In an additional, preferred embodiment, the load-introducing element is designed as a ball stud, whereby the ball head is positioned at the outside of the outer contour of the second wall and where it is part of an articulatable ball joint through which transverse forces can be introduced into the at least double-walled structure.
In an additional, preferred embodiment, the ball stud has a substantially conical shaft or a cylindrical shaft. Thus, there is a possibility for a free of play, force or friction fit, respectively, accommodation in a respective tapered sleeve.
In an additional, preferred embodiment, in particular the conical shaft (outer cone) of the ball stud is positioned in the recess, in particular the inner cone of a cone sleeve, where it is friction-fit supported under tensile loading. Radial and axial forces which act on the ball stud from the outside are therefore introduced free of play through the cone sleeve in the at least double-walled structure.
In an additional preferred embodiment the holding element, in particular the threaded sleeve or the countersunk nut, has an inner thread while the bail stud has an outer thread at its end. The inner and the outer threads create, positioned inside of the double-walled structure, the connection segment, in particular the threaded segment. Hereby, space is gained in reference to the tension direction.
In an additional, preferred embodiment, a blind hole with a polygonal cross-section is positioned in the load-introducing element, in particular the traction part, preferably in the ball stud and either in the end of the ball stud or the end of the thread. Preferably the blind hole has an inner hexagon or a hexagonal cross section so that, by means of a suitable installation tool, torque can be created at the traction member part for the purpose of a screw connection with the holding element. A construction space gain is hereby achieved in the tension direction, meaning in the longitudinal direction of the ball stud.
In an additional, preferred embodiment, the holding element and in particular the threaded sleeve, has a collar which is supported directly or indirectly in reference to the first wall. The tension force which results from the ball stud is hereby transferred through the collar of the threaded sleeve to the outer surface of the first wall.
In an additional, preferred embodiment, the countersunk nut is indirectly supported in reference to the first wall through a collar sleeve, meaning that the countersunk nut supports itself on the collar sleeve and the hollow sleeve supports itself in reference to the first wall, which also creates a flat construction method. The countersunk nut can be tightened or loosened by means of a socket wrench.
In an additional, preferred embodiment, the cylinder head screw which is designed as the holding element, has an outer thread and the ball stud which is designed as the traction member has an inner thread which creates with the outer thread of the cylinder head screw, the threaded section which is positioned within the double-walled structure. The head of the cylinder head screw is almost completely countersunk in reference to the outer contour of the first wall.
In an additional, preferred embodiment, a first disc with a micro-toothed surface is positioned between the collar of the threaded sleeve, which is designed as the holding element, and the first wall and which presses into the first wall which has a softer surface. Hereby the advantage of an increase of the friction coefficient between metal and plastic is achieved. Micro toothed surfaces are already known, for instance from “Konstruktion 2013”, page 62-65 (H.Schürmann, H.Elter: Beitrag zur Gestaltung von Schraubverbindungen bei Laminaten aus Faser-Kunststoff-Verbunden), In the case of the preferred screw connection, the increase of the friction coefficient creates an increase of the friction (parallel to the wall surface) so that, during the same preload force of the traction member, a larger force couple is available for accommodating the load torque which is initiated from the outside.
In an additional, preferred embodiment, the conical sleeve has a collar which is supported relative to the second wall. Thus, axial forces of the ball stud, especially resulting from the preload with the holding element, are transferred to the second wall through the collar of the cone sleeve.
In an additional, preferred embodiment, a second disc with a micro-toothed surface is positioned between the collar of the cone sleeve and the second wall. Thus, the resulting friction force also creates an increase of the friction coefficient at the outer surface of the second wall, so that a larger force couple counteracts the load torque. Altogether, the load torque which is introduced through the ball stud into the multi-walled, in particular double-walled, structure is transferred by either friction-fit or also by form-fit, whereby the form-fit functions as a quasi reserve or safety, respectively, if the friction-fit fails (changes from static friction to sliding friction).
In an additional, preferred embodiment, the countersunk cylinder head screw is supported by a collar sleeve with respect to the first wall, meaning indirectly. The cylinder head screw is supported with respect to a collar of the collar sleeve, and the collar sleeve is supported by a second collar with respect to the first wall. A low profile construction is hereby achieved, which also needs little construction space from the radial view point.
In an additional, preferred embodiment, the holding element, in particular the collar of the threaded sleeve, has surfaces or openings, where at the perimeter or in its opening or recesses, respectively, a form-fit mounting tool can be applied to, whereby the mounting tool, in particular exclusively, is used for the installation and the creation of the preload for the screw connection.
In a second aspect of the invention, load elements are attached to a wheel carrier for motor vehicles, in a fiber-plastic-composite construction, by means of the inventive configuration for a connection of chassis components, in particular a screw connection. It is hereby preferably a wheel carrier and is in accordance with an older application by the applicant with the official file number DE 10 2013 209 987.8, and the contents of which are fully incorporated by reference thereto, into the disclosure of the present application. The wheel carrier in the old the application has a first shell, designed as inner shell, and at least an additional, second outer shell, designed as a wall so that a multi-walled, in particular in double-walled structure is created, and to which by means of the configuration for the connection of chassis components, in particular screw connection, load-introducing elements, preferably metallic ball studs can be attached. A control arm and a steering rod are preferably attached to the ball stud and which introduce lateral forces or torques, respectively, into the structure of the wheel carrier. Due to the inventive connection, in particular the screw connection, the FPC structure of the wheel carrier is hereby relatively minimally stressed and minimally deformed.
Embodiment examples of the invention are presented in the drawings and described in more detail below and from which further characteristics and/or advantages can result. These show:
For the creation of a force loadable screw connection, the ball stud 4 and the rotatably positioned threaded sleeve 6 are screwed together through the threaded section 7 and tensioned, wherein the tightening torque is applied by the installation tool 11 and the holding torque by the inner hexagon 4d. The thus created biasing and tensile force in the direction of the longitudinal axis a now cause the micro-toothed surfaces 9a, 10a to press into the outer surfaces 2b, 3b. The first wall 2 is supported with respect to the second wall 3 by the spacer 5 which can be made from metal or plastic. Lateral forces, meaning substantially perpendicular to the longitudinal axis a of the FPC structure 2, 3, are here introduced by way of the ball head 4a, meaning that the structure 2, 3 is loaded with a torque. This loading torque is accommodated through a couple of forces comprising friction forces which are present in the planes of the outer surfaces 2a, 2b. Thus, there is a relatively low load for the double-walled structure 2, 3. As it can be seen from the drawing, the threaded section 7 is essentially, that is to say a large portion thereof, positioned within the outer contour 2b, meaning that only at relatively small portion of the threaded section 7 and the threaded sleeve 6 extend beyond the outer contour 2b. The fastening of the load-introducing element 4 is therefore essentially positioned within the double-walled structure 2, 3, meaning their outer contours 2b, 3b.
Number | Date | Country | Kind |
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10 2014 202 628.8 | Feb 2014 | DE | national |
This application is a National Stage completion of PCT/EP2015/050383 filed Jan. 12, 2015, which claims priority from German patent application serial no. 10 2014 202 628.8 filed Feb. 13, 2014.
Filing Document | Filing Date | Country | Kind |
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PCT/EP2015/050383 | 1/12/2015 | WO | 00 |