Force-absorbing insert element, component structure with the insert element as well as associated component connection and manufacturing process therefor

Abstract

A force-absorbing insert element (10; 110; 210) made of plastic has an axial extension and a central through-opening (12; 112; 212) extending in the axial direction through the insert element (10; 110; 210), which defines a central longitudinal axis (L) and an inner diameter (d) of the insert element (10; 110; 210). A radial outer side (14; 114; 214) of the insert element (10; 110; 210) has a contour that provides an anti-twist feature, in particular a polygonal or non-circular cross-sectional shape with respect to the central longitudinal axis (L). The insert element (10; 110; 210) consists of a plastic, in particular a fiber-reinforced or self-reinforcing plastic, with a creep resistance under tensile load and / or compressive load with cc ≥ 0.8.

Description

1. Field of the InventionThe present invention relates to a force-absorbing insert element made of plastic, a component structure having the insert element, a component connection having the component structure, and a production method of a component structure.2. BACKGROUND OF THE INVENTIONA variety of tubular sleeve fasteners and fastening systems are known to those skilled in the art. These are usually used in the connection of two components to one another, especially when a plastic component is to be fastened to a metal component. In this case, the tubular sleeve is provided in the plastic component.Since a force flow should be present during the connection between the first and the second component through the tubular sleeve and not through the first component, a metal bushing is usually arranged as the tubular sleeve in the plastic component. If there is a need to realize additional functions, such as, for example, a rotation prevention means, this leads to a more complicated production method with additional production steps, which increases the overall costs. Moreover, hybrid components made of metal and plastic in particular lead to recycling problems, since these have to be separated in a complicated manner. For this reason, in recent years, plastic has also been increasingly used as starting material for the tubular sleeve.An example thereof is found in JP H06-173988 A, which relates to a vibration control device. It is desirable to securely fix a nut to a bracket by molding the bracket from a plastic material, fixedly connecting a rubber to the bracket, and inserting the nut into the bracket with both surfaces of the nut exposed. This is accomplished by curing a rubber and then adhering it around an inner cylinder and then inserting it into an injection mold. After a nut is received in the die, a plastic material is injected. The rubber is compressed in a state where the resin material is cooled and solidified, and the nut is inserted into a holder. Since the nut is inserted into the bracket so as to expose at least one surface thereof, it is possible to eliminate crack or deformation of the bracket made of plastic material and achieve light weight and reduction of man-hours as a whole.DE 10 2012 207 118 A1 describes a component made of plastic for a motor vehicle, comprising at least one first section made of a base material made of at least plastic and at least one second section made of a reinforcing material for the base material. The second section consists of fiber-reinforced plastic and is connected to the first section in a form-fit and / or force-fit manner.Finally, a tubular sleeve, in particular for use as a force-absorbing sleeve, is described in DE 10 2022 103 924 A1. The sleeve comprises a jacket wall with a through-opening, wherein the sleeve is formed from plastic. A modulus of elasticity of the plastic is between 15,000 MPa and 25,000 MPa.The object of the present invention is therefore to provide an alternative insert element which is further optimized compared to the prior art and implements a multiplicity of functions without additional production steps. It is likewise an object to specify a corresponding component structure, a component connection and a production method for the component structure.3. SUMMARY OF THE INVENTIONThe above object is achieved by a force-absorbing insert element made of plastic according to independent patent claim 1, a component structure according to independent patent claim 5, a component connection according to independent patent claim 8 and a production method of a component structure according to independent patent claim 10.A force-absorbing insert element according to the invention made of plastic has an axial extent and a central through-opening which extends through the insert element in the axial direction and defines a central longitudinal axis and an inner diameter of the insert element, wherein a radial outer side of the insert element has a contour which provides a rotation prevention means, in particular a polygonal or non-round cross-sectional shape with respect to the central longitudinal axis, and the insert element consists of a plastic, in particular a fiber-reinforced or self-reinforcing plastic, having a creep resistance under tensile load and / or compressive load with c c ≥0.8.The force-absorbing insert element made of plastic is explained below on the basis of its use in a component structure and a component connection. The component structure comprises a first component made of plastic and the force-absorbing insert element embedded therein. The embedding of the insert element in the first component is preferably effected in such a way that the insert element is encapsulated by the plastic of the first component by injection molding. Accordingly, the component structure can be produced in the context of a 2K injection molding process.In order to prevent the insertion element from rotating in the first component, the radial outer side of the insertion element has the contour which provides a rotation prevention means. This is realized in particular via the polygonal or non-round cross-sectional shape with respect to the central longitudinal axis. Polygonal denotes any cross-sectional shape which is formed angularly even when the corners are rounded. Non-round refers to any cross-sectional shape that varies periodically from circle or circular motion.The plastic of the insert element has the creep resistance of c c ≥0.8. The plastic preferably has the creep resistance of c c ≥0.8at an ambient temperature of 23° C. to 180° C., particularly preferably at 80° C. to 150° C. The proportion of fibers in the case of fiber-reinforced plastics comprising fibers made of glass or carbon is preferably at least 30% by weight to at most 60% by weight. Advantageously, the fibers are oriented in the direction of the central longitudinal axis of the insert element. In the direction of the central longitudinal axis, an orientation in an angle range between 0° and 40°, preferably 0° and 20° and particularly preferably between 0° and 10°, with respect to the central longitudinal axis, is designated here. In a particularly advantageous embodiment, the fibers are arranged unidirectionally.The creep resistance c c describes the creep behavior or the temporal decrease of the material stiffness. The greater this characteristic number, the smaller the creep tendency of the respective plastic, and vice versa. Extreme case c c= 1 describes a material with constant stiffness over time, i.e. without creep. In contrast to the creep modulus E c, which represents an instantaneous state variable, the creep resistance expresses the rigidity behavior of a plastic over the course of the load time. In this regard, reference is also made to the article by Johannes Kunz: "Creep Modulus Estimation and Creep Resistance", KunststoffTra, 03 / 2014, pages 23-26, Sigwerb GmbH, 6301 Zuck, Switzerland.The creep resistance c c is calculated as follows:E c( t 0) denotes the creep modulus of the material at E c( t 0= 1 h) and E c( t 3) denotes the creep modulus of the material at E c( t 3= 103 h). These values are often available from material databases.Taking these values into account, the creep modulus under tensile load is consideredFor the general determination of the creep modulus E c( t) and of the creep behavior in the creep rupture test, reference is made to DIN EN ISO 899-1 from March 2018. The creep rupture tests for determining the creep modulus under compressive load are carried out on the basis of the standards DIN EN ISO 899-1 and -2.An example of a corresponding high-strength plastic is PPA-GF60. In addition to this fiber-reinforced plastic, self-reinforcing plastics can also meet the abovementioned criterion of creep resistance. Self-reinforcing plastics are also referred to in this context as monomaterial systems. For example, the self-reinforcing plastics achieve their strength with rigid elements embedded in the macromolecules. An example of this is liquid crystal polymer (LCP). Another example is the self-reinforcing polylactide composite material developed by the Fraunhofer Institute for Chemical Technology.In contrast to the insert element, the first component of the component structure consists, for example, of a plastic with creep resistance under tensile load and / or compressive load with c c< 0,8. Alternatively or additionally, the plastic of the first component of the component structure has a coefficient of thermal expansion which corresponds to the coefficient of thermal expansion of the plastic of the insert element. As a result, the temperature-dependent behavior of the insert element and of the first component is similar, which has a positive effect on the durability of the component structure.The first component of the component structure has a thickness adjacent to the insert element which, in a variant, is at most equal to an axial extent of the insert element. Alternatively, the first component has a thickness adjacent to the insert element which is slightly greater than an axial extent of the insert element. As a result, the respective material of the first component can be taken into account particularly accurately, such that the insert element is in particular associated with a compression limiting function, which is explained below on the basis of the corresponding component connection.The component connection comprises, in addition to the component structure made of the first component and the insert element embedded therein, a second component and a connecting element. The connecting element extends, in use, through the through-opening of the insert element, so that the second component is fastened to the component structure by the connecting element. The corresponding connecting element can therefore be a connecting screw which engages into an internal thread on the second component. Alternatively, the connecting element may be a threaded projection which protrudes from the second component. By way of example, the inner diameter of the insert element is greater than an outer diameter of the connecting element, so that tolerances in the fastening plane can be compensated. For this reason, the insert element preferably also has no internal thread in the through-opening.An advantage of the insert element according to the invention is that without additional method steps, there are several functions such as anti-rotation, tolerance compensation in two directions, as well as increased resistance to hydrolysis and increased resistance to relaxation.In a preferred embodiment of the force-absorbing insert element made of plastic, a circumferentially arranged and circular flange is present on the radial outer side, which flange is preferably arranged centrally with respect to an extension of the insert element in the axial direction. An advantage of this embodiment is that the positioning accuracy in the axial direction is improved.It is furthermore advantageous that a ratio of the inner diameter to the axial extension of the insert element is ≥1. As a result, the insert element is suitable in particular for thin-walled regions in the first component.In addition, the force-absorbing insert element made of plastic preferably has a sealing contour, preferably a sealing lip, running around the central longitudinal axis on an end face. In this way, sealing connections between the first and second component can be achieved within the scope of the subsequent component connection. In this context, it is likewise preferred that a sealing contour is present on both end sides. In this way, when embedding the insert element, attention does not have to be paid to a desired alignment of the sealing contour.A component structure according to the invention comprises a first component made of plastic and a force-absorbing insert element made of plastic embedded therein. Since the component structure uses the insert element according to the invention, reference is made to the above explanations with regard to the technical effects and advantages. In particular, this results in better recycling capability, since only thermoplastic is used and no hybrid component is present.Advantageously, the first component of the component structure adjacent to the insert element has a thickness which is at most equal to an axial extension of the insert element or which is slightly greater than an axial extension of the insert element. This enhances the suitability of the insert element for thin-walled components.In addition, it is preferred that the first component of the component structure consists of a plastic with a creep resistance under tensile load and / or compressive load with c c< 0,8 and / or with a thermal expansion coefficient that corresponds to the thermal expansion coefficient of the plastic of the insert element. Precisely in this combination, the function of the insert element as a pressure limiter becomes clear, as already mentioned above. A similar coefficient of thermal expansion provides the advantage that the material behavior under the influence of temperature is similar, which benefits the stability of the component structure.A component connection according to the invention comprises a component structure according to the invention, a second component and a connecting element which extends through the through-opening of the insert element and by means of which the second component is fastened to the component structure. Since the component connection also uses the insert element according to the invention, reference is made to the above explanations with regard to the technical effects and advantages.In an advantageous embodiment of the component connection, the inner diameter of the insert element is greater than an outer diameter of the connecting element. It is precisely in this way that tolerances in a plane transverse to the longitudinal axis of the insert element can be compensated. Due to this dimensioning, the insert element usually has no internal thread in the through-opening. The through-opening is therefore designed without threads.A production method according to the invention of a component structure according to the invention has the steps: providing a force-absorbing insert element according to the invention, preferably by means of injection molding, and then embedding the insert element in a plastic, preferably a plastic having a creep resistance under tensile load and / or compressive load of c c< 0,8 and / or having a coefficient of thermal expansion which corresponds to the coefficient of thermal expansion of the plastic of the insert element, wherein the embedding is preferably effected by means of injection molding around the insert element with the plastic. With regard to the technical effects and advantages, reference is likewise made to the above explanations in order to avoid repetitions.4. Summary of the DrawingsHereinafter, the present invention will be described in detail with reference to the drawings. Identical reference numerals in the drawings denote identical components and / or elements. The following are shown: FIG. 1 shows a perspective view of a first embodiment of an insert element according to the invention, FIG. 2 shows a plan view of the insert element according to FIG. 1, FIG. 3 shows a sectional view of the insert element according to FIG. 1, FIG. 4 shows a perspective view of a second embodiment of an insert element according to the invention, FIG. 5 shows a plan view of the insert element according to FIG. 4, FIG. 6 shows a sectional view of the insert element according to FIG. 4, FIG. 7 shows a perspective view of a third embodiment of an insert element according to the invention, FIG. 8 shows a sectional view of the insert element according to FIG. 7 in a first component, FIG. 9 is an overview of the creep resistance of various types of PA6; and FIG. 10 shows a flow diagram of an embodiment of a method for producing the component structure.5. Detailed Description of the Preferred EmbodimentsReferring first to FIGS. 1 to 3, a first embodiment of an insert element 10 made of plastic according to the invention will be explained. The insert element 10 has an axial extent and a central through-opening 12 extending through the insert element 10 in the axial direction. The through-opening 12 defines a central longitudinal axis L and an inner diameter d of the insert element 10.On the radial outer side 14, the insert element 10 has a contour which provides a rotation prevention means. In the present case, this is a cross-sectional shape with rounded corners which is polygonal with respect to the central longitudinal axis L. In particular, the cross-sectional shape is a quadrilateral with rounded corners. Alternatively, this cross-sectional shape can also be characterized on the basis of the rounded corners and the straight sections connecting them. This is because, in particular, the straight sections between the rounded corners provide the anti-rotation function when the insert element 10 is embedded in the first component 1. A distance between two opposite rounded corners therefore also defines an outer diameter D of the insert element 10.As an alternative to the polygonal shape, the radial outer side 14 can also have a non-round cross-sectional shape. Non-round refers to any cross-sectional shape that varies periodically from circle or circular motion. This definition is also realized by the first embodiment. In both cases, a rotation of the insert element 10 in the first component 1 is effectively prevented.On the end face 16 of the insert element 10, a chamfer 20 is provided adjacent to the through-opening 12. A chamfer 20 is preferably also present on the other end face 16. Both allow a connection element to be passed through the through-opening 12 more easily in comparison with a configuration without a chamfer 20.A particular feature of the insert element is the plastic used. This is because it must have a creep resistance under tensile stress and / or compressive stress of c c ≥0.8. For the determination of the creep resistance and of the creep modulus, reference is made to the above explanations and to the article mentioned therein and to DIN ISO 899-1 from March 2018. Precisely by this material selection, a material is selected which has a low creep behavior and thus a low temporal decrease in the material stiffness. This has a positive effect on the service life of the later component connection. This is because an increased resistance to hydrolysis and relaxation is achieved precisely in this way. Examples of suitable materials are PPA-GF60 and PEI. Further materials are evident from the overview shown in FIG. 9, in which the value for the creep resistance is shown on the axis of abscissa and the material on the axis of ordinate.The insert element 10 produced in this way, for example by injection molding, is inserted into an injection molding tool and encapsulated by injection molding with a thermoplastic as the first component 1. Additional mounting of a metal bushing, for example by pressing in, is dispensed with.In this way, a component structure 3 is thus obtained with a first component 1 made of plastic and the insert element 10 embedded therein. As shown later, the first component 1 adjacent to the insert element 10 has a thickness which is at most equal to an axial extension of the insert element 10. Alternatively, the thickness of the first component 1 adjacent to the insert element 10 is slightly greater than an axial extension of the insert element 10, and as a result, particular consideration can be given to the material or the properties of the material of the first component 1, such that the insert element 10 assumes the function of a pressure limiter when the component structure 3 formed in this way is fastened to a second component within the scope of a corresponding component connection.This is particularly advantageous if the first component 1 is made of a plastic with creep resistance under tensile load and / or compressive load at c c< 0,8. This is because, especially in this case, the insert element 10 protects the first component from an excessively high force flow through the first component 1.Additionally or alternatively, it is advantageous that the first component 1 consists of a material with a coefficient of thermal expansion that corresponds to the coefficient of thermal expansion of the plastic of the insert element 10. In this case, the behavior of the respective material is the same or similar just under the influence of heat, so that a particularly stable connection is present between insert element 10 and first component 1.Since the first component 1 is usually of thin-walled configuration adjacent to the insert element 10, it is advantageous that a ratio of the inner diameter d of the insert element 10 to the axial extent of the insert element 10 is greater than or equal to 1.The component connection comprises, in addition to the component structure, i.e. the first component 1 with the insert element 10, a second component and a connecting element. The connecting element extends, in use, through the through-opening 12 of the insert element 10, so that the second component is fastened to the component structure 3 by the connecting element. The corresponding connecting element can therefore be a connecting screw which engages into an internal thread on the second component. Alternatively, the connecting element may be a threaded projection which protrudes from the second component. By way of example, the inner diameter d of the insert element 10 is greater than an outer diameter of the connecting element, so that tolerances in the fastening plane can be compensated.The insert element 10 formed in this way therefore realizes the functions of anti-rotation, tolerance compensation in two directions, i.e. in the plane transversely to the central longitudinal axis L, and increased resistance to hydrolysis and relaxation.Referring now to Figures 4 to 6, a second embodiment of an insert member 110 is shown. This corresponds substantially to the first embodiment of the insert element 10.In contrast to the first embodiment, however, a flange 120 is provided on the radial outer side 114, which flange is arranged circumferentially and is formed in a circular manner. In the embodiment shown, it is formed continuously or closed circumferentially. Alternatively, it can also be designed to be interrupted.Furthermore, the flange 120 is provided centrally with respect to an extension of the insert element in the axial direction. An advantage of this embodiment is that the positioning accuracy of the insert element 10 in the axial direction in the first component 1 is improved.FIGS. 7 and 8 show a third embodiment of an insert element 210, which corresponds substantially to the second embodiment of the insert element 110.In contrast to the second embodiment, however, a sealing contour 218, preferably a sealing lip, encircling the central longitudinal axis L is provided on an end side 216. This is made of EPDM, for example. In this way, sealing connections between the first 1 and the second component can be achieved within the scope of the subsequent component connection. In this context, it is likewise preferred that a sealing contour is present on both end sides.This insert element 210 can be produced in the context of a 2K injection molding process. Precisely in conjunction with the injection molding of the insert element 210 by the material of the first component 1, a 3K injection molding method would then result.Finally, FIG. 10 shows a flow diagram of an embodiment of a method of manufacturing a component structure 3.In a first step A, a force-absorbing insert element 10; 110; 210 according to one of the embodiments described above is provided, preferably by means of injection molding.In a subsequent step B, the insert element 10; 110; 210 is embedded in a plastic, preferably a plastic having a creep resistance under tensile load and / or compressive load of c c< 0,8 and / or having a thermal expansion coefficient which corresponds to the thermal expansion coefficient of the plastic of the insert element 10; 110; 210. The embedding is preferably effected by injection molding the insert element 10; 110; 210 with the plastic.6. List of reference characters1 first component 3 component structure 10 insert element (1st embodiment) 12 through-opening 14 radial outer side 16 end face 20 chamfer 110 insert element (2nd embodiment) 112 through-opening 114 radial outer side 116 end face 120 chamfer 122 flange 210 insert element (3rd embodiment) 212 through-opening 214 radial outer side 216 end face 218 sealing contour 220 chamfer 222 flange d inner diameter of the insert element 10 D outer diameter of the insert element 10 L central longitudinal axis of the insert element 10References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedJP H06-173988 A

[0004] DE 10 2012 207 118 A1

[0005] DE 10 2022 103 924 A1

[0006] Cited Non-Patent LiteratureJohannes Kunz: "Creep Modulus Estimation and Creep Resistance", KunststoffX, 03 / 2014, pages 23-26, Sigwerb GmbH, 6301 Zuck, Switzerland

[0013] DIN ISO 899-1 from March 2018

[0037]

Claims

A force-absorbing insert element (10; 110; 210) made of plastic having a) an axial extent and a central through-opening (12; 112; 212) extending in the axial direction through the insert element (10; 110; 210), which opening defines a central longitudinal axis (L) and an inner diameter (d) of the insert element (10; 110; 210), wherein b) a radial outer side (14; 114; 214) of the insert element (10; 110; 210) has a contour which provides a rotation prevention means, in particular a polygonal or non-round cross-sectional shape with respect to the central longitudinal axis (L), and c) the insert element (10; 110; 210) is made of a plastic, in particular a fiber-reinforced or self-reinforcing plastic, having creep resistance under tensile stress and / or compressive stress with c c ≥0.8.The force-absorbing insert element (110; 210) made of plastic according to claim 1, which has on the radial outer side (114; 214) a circumferentially arranged and circular flange (122; 222), which is preferably arranged centrally with respect to an extension of the insert element (110; 210) in the axial direction.The plastic force-absorbing insert element (10; 110; 210) according to one of the preceding claims, wherein a ratio of the inner diameter (d) to the axial extension of the insert element is ≥ 1.The force-absorbing insert element (210) made of plastic according to one of the preceding patent claims, which has on an end face (216) a sealing contour (218), preferably a sealing lip, which extends around the central longitudinal axis (L).A component structure (3) comprising a first component (1) made of plastic and a force-absorbing insert element (10; 110; 210) made of plastic embedded therein according to one of the preceding patent claims.The component structure (3) according to claim 5, wherein the first component (1) adjacent to the insert element (10; 110; 210) has a thickness which is at most equal to an axial extension of the insert element (10; 110; 210) or which is slightly greater than an axial extension of the insert element (10; 110; 210).The component structure (3) according to one of claims 5 or 6, wherein the first component (1) consists of a plastic with a creep resistance under tensile load and / or compressive load with c c< 0,8 and / or with a thermal expansion coefficient that corresponds to the thermal expansion coefficient of the plastic of the insert element (10; 110; 210).A component connection comprising a component structure (3) according to one of claims 5 to 7, a second component and a connecting element which extends through the through-opening of the insert element (10; 110; 210) and by means of which the second component is fastened to the component structure (3).The component connection according to claim 8, wherein the inner diameter (d) of the insert element (10; 110; 210) is larger than an outer diameter of the connecting element.A method of manufacturing a component structure (3) according to any one of claims 5 to 7, comprising the steps of: a) providing a force-absorbing insert element (10; 110; 210) according to any one of claims 1 to 4, preferably by injection molding, and then b) embedding the insert element (10; 110; 210) in a plastic, preferably a plastic having a creep resistance under tensile load and / or compressive load of c c< 0,8 and / or having a thermal expansion coefficient corresponding to the thermal expansion coefficient of the plastic of the insert element (10; 110; 210), wherein the embedding is preferably effected by injection molding the insert element (10; 110; 210) with the plastic.

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