Method for producing a structural component for a bicycle, method for producing a bicycle frame, and bicycle frame

Abstract

The invention relates to a method for producing a structural component, at least part of which is in the form of a hollow profiled element, for a bicycle (1), comprising the method steps of: providing an injection molding device; producing and / or providing at least one lost core (30) which can be melted out and / or dissolved and / or mechanically destroyed and which is adapted at least to a first part of an inner contour of the structural component; introducing the lost core (30) into a mold tool; closing the mold tool and keeping it closed and overmolding the lost core (30) with a thermoplastic material; opening the mold tool and removing an injected-molded intermediate product; melting out and / or dissolving out and / or mechanically removing the lost core (30). The method is in particular characterized in that at least one further part of the inner contour of the structural component is molded by means of at least one movable tool core (31) or movable mold slide of the mold tool. The invention also relates to a structural component of a bicycle (1).

Description

[0001] METHOD FOR PRODUCING A STRUCTURAL COMPONENT FOR A BICYCLE, METHOD FOR PRODUCING

[0002] A BICYCLE FRAME AND A BICYCLE FRAME

[0003] The invention relates to a method for producing a structural component for a bicycle which is at least partially designed as a hollow profile and which is made at least predominantly from thermoplastic material by injection molding using at least one lost mold core.

[0004] The invention further relates to a method for producing a bicycle frame, a structural component for a bicycle frame and a bicycle frame.

[0005] It is generally known in the art to manufacture bicycle parts, and in particular bicycle frames, from fiber composite materials. In the course of optimizing the weight of bicycles, composite components made of carbon are particularly widespread. Temperature-curing plastics, in particular epoxy resin, are largely used as matrix materials. Such bicycle frames are characterized by a particularly favorable stiffness-to-weight ratio. However, they have the disadvantage that the epoxy resin-based plastic can easily break, for example in the event of a fall. Furthermore, the recyclability of such frames or other epoxy resin-based components is not guaranteed.

[0006] The fibers used in the manufacture of carbon frames are usually glued together as woven or non-woven fabrics according to a predetermined cut and then manually inserted into a tool. An epoxy resin-based plastic is introduced into the closed tool in such a way that the resin penetrates the fiber woven or non-woven fabrics. The component is then cured by heat. This manufacturing process is complex and requires a high degree of manual labor, both before the component is formed and in the necessary rework.

[0007] It is also generally known in the art to manufacture bicycle parts, and in particular bicycle frames, from fiber-reinforced thermoplastics. Thermoplastics are easier to recycle than thermosetting plastics and can be formed, for example, by injection molding.

[0008] Production by injection molding, particularly for hollow profiles, has the disadvantage that the required tools must be designed with movable mold slides or mold cores / tool ​​cores. Furthermore, the production of components with undercuts is difficult due to demolding of the finished component.

[0009] In principle, thermoplastic structural components can also be manufactured as hollow profiles by extrusion blow molding, rotational sintering, or fluid injection molding. These processes have the disadvantage that the resulting structures do not have a defined wall thickness and, in particular, do not have a smooth-walled inner contour.

[0010] DE 10 2016 015 538 A1 discloses a method for manufacturing a bicycle frame from several modules, each obtained by injection molding using fluid injection technology. The fluid injection technology offers a cost-effective way of forming the individual components as hollow bodies with optimized weight.

[0011] However, as already mentioned above, such a process has the disadvantage that the components do not have a constant and defined wall thickness and, in particular, do not have a consistently smooth surface within the cavities. This is not advantageous for a variety of reasons. For example, it results in mass differences between components within a series. It may also make it difficult to pass cables through the frame.

[0012] The use of a lost core process for manufacturing bicycle frames is known from WO 99 / 29484. These frames or hollow profiles are injection-molded from thermoplastic in a multi-part mold, whereby an lost core previously inserted into the mold is coated with the injected thermoplastic. This lost core corresponds to the negative of the hollow frame. It is held in the parting plane of the mold with core holders so that approximately uniform wall thicknesses of the hollow frame are ensured. After the article has been removed from the injection mold, the lost mold core is melted out. This consists of a low-melting metal that melts below the plasticizing temperature of the thermoplastic and thus creates or releases the cavity by heating the component.

[0013] The method known from WO 99 / 29484 is particularly suitable for the production of large-volume hollow profiles, in particular for the production of a one-piece bicycle frame. Such relatively large components require correspondingly large tools, which are expensive. In particular, the production of bicycle frames requires a large number of large tools, since bicycle frames usually have to be provided in different sizes. Furthermore, the method according to

[0014] WO 99 / 29484 is only partially suitable for forming cavities with complex structures.

[0015] The invention is therefore based on the object of providing a method of the type mentioned above with which structural components for a bicycle with complex internal contours can be manufactured relatively easily. Such complex internal contours are useful and necessary, for example, in the area of ​​bottom bracket shells or cable feedthroughs.

[0016] The invention is further based on the object of providing a method by which a modular and, in particular, cost-effective production of bicycle frames is possible, which are made at least predominantly of thermoplastic material. Finally, the invention is based on the object of providing a structural component advantageously designed in this sense and, in particular, also a method for producing a bicycle frame.

[0017] An object of the invention is achieved by providing a method for producing a structural component which is at least partially designed as a hollow profile and has the features of claim 1.

[0018] A further object of the invention is achieved by providing a method for producing a bicycle frame using at least one structural component made of thermoplastic material and designed as a hollow profile, which structural component was preferably produced according to the method according to one of claims 1 to 12.

[0019] A further object of the invention is achieved by providing a structural component having the features of claim 16 and by providing a bicycle frame having the features of claim 21.

[0020] Advantageous embodiments of the invention result from the features described in the subclaims.

[0021] A first aspect of the invention relates to a method for producing a structural component for a bicycle which is at least partially designed as a hollow profile, comprising the method steps:

[0022] - Providing an injection molding device with at least one injection unit with means for providing and introducing a plasticized thermoplastic under pressure into a multi-part mold with at least one cavity, wherein the at least one cavity at least partially defines the shape of the structural component,

[0023] - producing and / or providing at least one meltable and / or dissolvable and / or mechanically destructible lost core which is adapted to at least a first part of an inner contour of the structural component,

[0024] - Inserting the lost core into the mold,

[0025] - Closing and holding the mould and over-molding the lost core with a thermoplastic material,

[0026] - Opening the mold and removing an injection-molded intermediate product with the overmolded, lost core,

[0027] - melting out and / or releasing and / or mechanically removing the lost core from the intermediate product, wherein the method according to the invention is particularly characterized in that at least a further part of the inner contour of the structural component is molded by means of at least one movable tool core or at least one movable mold slide of the mold.

[0028] In the context of the present invention, a distinction is made between a lost core and a lost

[0029] A mold core on the one hand, and a tool core or a mold slide of the mold on the other. The tool core or the mold slide are integral parts of the mold. The terms core or mold core in connection with the lost core are used synonymously below.

[0030] A lost core or lost mold core is a component that is inserted into the mold and temporarily held or fixed therein, and which is designed as a negative for an inner contour of the injection-molded part to be produced from thermoplastic material. The lost core is removed from the mold with the finished intermediate product. For the purposes of the present invention, the intermediate product refers to the structural component that still encloses the lost core.

[0031] The procedure according to the invention has the advantage that structural components can be produced as hollow profiles with a complex internal structure.

[0032] A structural component within the meaning of the present invention is a component of a bicycle that, during intended use, is subjected to structural stress, i.e., to operating forces induced by the user or forces resulting from riding. A structural component in this sense will therefore generally be a component subject to tensile and / or bending stress.

[0033] A structural component within the meaning of the present invention can be, for example, a bicycle frame, a part of a bicycle frame or an attachment to a bicycle frame, such as a handlebar, a handlebar stem, a wheel, a rim of a wheel or a seat post.

[0034] The structural component in the sense of the present invention can further be designed as a frame profile section of a bicycle frame or, for example, as a main frame or fork or as a rear swing arm or the like.

[0035] A frame profile section of the bicycle frame can be designed, for example, as a top tube, down tube, head tube, seat tube, seat stay or seat stay, chainstay or as a battery housing for an electric bicycle or as a motor mount or bottom bracket housing.

[0036] A structural component, which is designed, for example, as a frame profile section, can, for example, have several differently designed sections with different inner contours, which can optionally also communicate with one another or can be designed as interconnected cavities.

[0037] According to the invention, it can be provided that, for example, a cavity produced by means of the lost core is more complex than a cavity produced by means of a movable tool core or tool slide. The latter can, for example, have a smooth-walled and correspondingly easily demolded inner profile corresponding to the outer profile of the tool core, wherein the cavity produced by means of the lost mold core can have a complex, possibly undercut, contour. In this way, for example, frame tubes or frame profile sections with differently designed end sections can be produced, which can be joined together with other frame tubes or frame profile sections to form a modular frame.

[0038] Within the scope of the invention, the method can in principle also comprise the production of a one-piece bicycle frame in a single cavity of a large mold.

[0039] An advantageous variant of the method according to the invention is characterized in that the first part of the inner contour and at least one further part of the inner contour of the structural component are molded in such a way that they form a hollow profile with at least one continuous cavity, which is particularly advantageous for the passage of lines, Bowden cables, and cables. In this way, it is possible to provide communicating cavities with different cross-sections in one component.

[0040] In a particularly advantageous variant of the method according to the invention, it can be provided that the first part of the inner contour is formed over at least one partial section with a clear width that differs from the second part of the inner contour, preferably with a smaller clear width and / or with at least one undercut and / or with at least one thread.

[0041] In principle, a structural component can be provided, for example, as a node element of a bicycle frame, for example in the form of a bottom bracket shell, which forms a connector on one side, which can be joined to another frame profile of the bicycle frame. On another side of the node element, for example, an internal thread can be formed, which forms another

[0042] can accommodate a spatial component with an external thread.

[0043] A node element in the sense of the present invention is understood to be a part of a bicycle frame that is designed as a force node of the bicycle frame, which will generally be designed in such a way that the main frame tubes or main frame profile sections are brought together in the area of ​​the node elements and these main frame profile sections such as a top tube, a down tube or a seat tube are mainly designed to absorb tensile or compressive forces, whereas the node elements, for example in the form of a bottom bracket shell or a connection area for connecting the seat stays or the chain stays, are also designed to absorb bending moments.

[0044] Furthermore, a structural component produced according to the method can be designed such that it has, for example, two or more larger cavities which are connected to one another via at least one channel with a relatively smaller internal cross-section.

[0045] According to one embodiment of the method according to the invention, it can be provided that at least a partial section of an inner contour is formed with smooth walls and the structural component in this partial section preferably has a constant, defined wall thickness.

[0046] Smooth-walled in the context of the present invention means that the surface preferably has a roughness depth that corresponds to the surface quality produced by electroresistive machining of the mold cavity. The surface quality according to standard VDI 3400 can be between 12 and 45, which corresponds to a surface roughness Ra between 0.4 and 18 pm.

[0047] In a variant of the method according to the invention, it can be provided that during the injection molding process, at least one lost core is held in the mold, for example, within the parting plane of the mold, by means of at least one movable mold core or by means of at least one movable mold slide. This makes it possible to produce complex cavities with a variable internal cross-section and / or with undercuts using a mold slide that is simply designed for demoldability.

[0048] A possible variant of the method according to the invention is characterized by the use or production of at least one lost mold core from a material which is selected from a group of materials comprising low-melting metals and / or metal alloys, ceramic materials, in particular based on aluminum, zirconium, zirconium oxide, fused quartz or mixtures of quartz, zirconium and aluminum.

[0049] A ceramic suitable for forming a mold core for use with the method according to the invention is, for example, a ceramic with a zirconium content of greater than or equal to 95%. Such a core can, for example, be dissolved by means of a water jet and removed from the sprayed intermediate product. Ceramics with a zirconium content of greater than or equal to 94% can also be removed, for example, by means of a water jet and are suitable for use with the method according to the invention. Ceramic cores of a different composition for use with the method according to the invention can, for example, be leached or rinsed out using aqueous solutions. In principle, however, the use of a mold core which can be triggered by mechanical destruction, for example by the introduction of vibrations, is also suitable.

[0050] Although, in principle, within the scope of the invention, mold cores made of low-melting materials or metals or metal alloys can be used which can be removed by heating, the use of at least one lost mold core which can be dissolved by means of water or by means of an aqueous suspension or aqueous solution is preferred, wherein the method can comprise the method step of dissolving and rinsing the lost mold core after removal from the mold.

[0051] A variant of the method is characterized by the use of at least one filled and / or fiber-reinforced, preferably single-variety, thermoplastic, in particular a thermoplastic reinforced with tensile fibers, the fibers preferably having a length of greater than 0 mm and less than or equal to 50 mm. Tensile fibers with a length of up to 50 mm are referred to in the context of the present invention as short fibers, whereas fibers with a length of more than 50 mm up to an infinite length are referred to as long fibers. A thermoplastic suitable for producing a bicycle frame is, for example, a polyamide, for example a PA6.

[0052] As a thermoplastic material for use with the present method, for example, a thermoplastic material selected from a group of plastics comprising PA, PP, PPA, PS, PE, PE, ABS, PC, POM, PEK, PEEK, PA610, HPPA, PARA, PBT, PK can be considered.

[0053] The tensile fibers can be selected from a group of fibers comprising carbon fibers, glass fibers, aramid fibers, Kevlar fibers and basalt fibers.

[0054] As an alternative to fiber reinforcement, the use of a thermoplastic material with a granular filling, in the form of beads or minibeads, for example made of a ceramic material, can also be considered.

[0055] The filled thermoplastic preferably has a filling level of 20 to 60 percent by weight based on the total weight of the structural component.

[0056] In a particularly advantageous and preferred variant of the invention, the method also comprises the production of the lost core. It is fundamentally possible to produce the lost core by investment casting, for example from ceramic materials. However, in the method according to the invention, the lost core is generally preferably produced by an injection molding process, in particular by PIM, in particular by CIM. This allows particularly complex geometries with thin walls to be produced, for example threads or a negative of a thread to be produced by plastic injection molding.

[0057] In principle, the invention also provides for the production of at least one lost core by 3D printing. The structural component can be designed as a one-piece bicycle frame, although the invention prefers to produce a modular bicycle frame from a plurality of structural components, which are manufactured, for example, by the method described above.

[0058] A further aspect of the invention for which independent protection is sought relates to a method for producing a bicycle frame using at least one structural component made of thermoplastic material and designed as a hollow profile, which forms at least one frame profile section of the bicycle frame, wherein the bicycle frame is joined in several parts according to this aspect of the invention.

[0059] The frame profile sections can, for example, be connected to one another in a materially and / or form-fitting manner, with at least some of the frame profile sections being joined via at least one plug connection and preferably being glued and / or welded and / or screwed together in the region of the plug connection. The latter variant is particularly advantageous when the structural component is manufactured according to the method described above according to the invention.

[0060] A preferred variant of the method for producing the bicycle frame is characterized by the use of at least one structural component as a frame profile section, wherein the structural component has a defined wall thickness over its entire length and at least a first and a second partial section with a different or different wall thickness and / or with a different clear cross-section / internal dimension and / or with a varying clear cross-section / internal dimension and / or with a different internal contour.

[0061] A defined wall thickness in the sense of the present invention means that the actual dimension of the wall thickness corresponds to a target dimension or a nominal dimension of the wall thickness taking into account manufacturing tolerances caused by moisture absorption / swelling of the thermoplastic material, post-crystallization or post-shrinkage, particularly in the area of ​​material accumulation (shrinkage differences in different geometric regions of the molded part).

[0062] A further aspect of the present invention, worthy of protection in itself, relates to an injection-molded structural component made of thermoplastic material as a hollow profile, in particular as a hollow profile section of a bicycle frame, which has a defined wall thickness over its entire length and at least a first and a second partial section with a different wall thickness and / or with a different clear inner width and / or with a different inner contour. The structural component is preferably manufactured according to the method described above.

[0063] In a particularly preferred variant of the structural component according to the invention, this comprises at least one section with an internal thread, which can be produced in a particularly advantageous manner by using a correspondingly designed injection-molded ceramic lost core during production.

[0064] The frame profile section is preferably selected from a group of frame profile sections comprising a top tube, a down tube, a seat tube, seat stays, chain stays, a head tube, a bottom bracket shell, a battery compartment, a battery holder.

[0065] Alternatively, the structural component can be designed as a handlebar, handlebar stem, fork, rear wheel swing arm, wheel, rim or seat tube of a bicycle.

[0066] In principle, it is within the scope of the invention if the structural component is reinforced with high-tensile long fibers, for example in the form of carbon fibers. For this purpose, the method according to the invention can provide for the lost core to be wrapped with a woven or non-woven fabric made of long fibers before being introduced into the mold and / or to be wound with high-tensile continuous fibers before being overmolded with thermoplastic.

[0067] The structural component can, for example, if it is designed as a frame profile section of a bicycle frame, be designed with a defined wall thickness of 3 to 8 mm, which varies abruptly or constantly over the length of the profile section. The wall thickness can, for example, vary continuously at one connecting end or joining end of the frame profile section in the direction of the other connecting end of the frame profile section, for example from a greater wall thickness at each end of the frame profile section to a smaller wall thickness in that part of the frame profile section which is subject to less bending stress during intended use and accordingly must have a lower area moment of inertia.The invention further relates to a bicycle frame which is preferably assembled in several parts and which consists at least predominantly of thermoplastic material and which is assembled at least predominantly from structural components of the type described above, wherein the structural components are preferably manufactured using the method described at the outset.

[0068] The invention is explained below with reference to and with reference to an embodiment shown in the accompanying drawings.

[0069] It shows :

[0070] Figure 1: a schematic representation of a bicycle comprising structural components manufactured by the method according to the invention;

[0071] Figure 2 : a schematic sectional view of a

[0072] Handlebar for a bicycle as a structural component according to the invention;

[0073] Figure 3A: a partial sectional view of a bicycle frame according to the invention; and

[0074] Figure 3B : an enlarged partial sectional view of the

[0075] Bicycle frame according to Figure 3A.

[0076] Figure 1, to which reference is initially made below, shows a schematic representation of a bicycle 1 according to the invention, which was manufactured predominantly from thermoplastic material by injection molding using the method according to the invention. The bicycle 1 comprises, in a known manner, a bicycle frame 2 designed approximately as a diamond frame, which, in the described embodiment, is injection-molded in one piece from a fiber-reinforced thermoplastic material.

[0077] As already mentioned at the beginning, the bicycle frame 2 according to the invention can also be designed in several parts. In the present case, the bicycle frame 2 is designed as a one-piece bicycle frame of an electric bicycle. This comprises a top tube 3, a down tube 4 and a seat tube 5, which are connected to form a frame triangle via a motor mount 6 and a head tube 7. The bicycle frame 2 also comprises chain stays 8 connected to the motor mount 6 and seat stays 9 connected to the upper end of the seat tube 5. The chain stays 8 and the seat stays 9 are each connected to one another via dropouts 10. The latter are designed in a known manner to accommodate a thru-axle for a rear wheel 11.

[0078] Corresponding to the design of the bicycle 1 as an electric bicycle, the down tube 4 comprises a battery holder 12 formed integrally with the down tube 4. The down tube 4 can, for example, have a closed hollow profile cross-section, wherein the battery holder 12 has an approximately C-shaped or U-shaped cross-sectional profile that opens downwards when the bicycle 1 is in use and can be closed by a battery or a battery compartment cover.

[0079] The functionally different parts of the bicycle frame 2 are referred to below collectively as frame profile sections, whereby those frame profile sections of the bicycle frame 2 which form force nodes or node elements of the bicycle frame 2, such as the head tube 7, the motor mount 6, the connection of the seat stays 9 to the seat tube 5 and the dropouts 10 are also referred to as frame profile sections in the sense of the invention.

[0080] All frame profile sections of the bicycle frame 2 are designed as injection-molded hollow profiles made of thermoplastic material with a largely continuous hollow profile cross-section, which was formed during production partly with a lost core 30 inserted in an injection mold and partly with movable mold slides 31 (Figure 2) as a component of the injection mold. The frame profile sections have differently designed internal cross-sections, as explained below with reference to Figures 3A and 3B. This is due in particular to the fact that it is desirable and sensible to provide hollow profile sections with differently complex internal cross-sections and internal contours on a bicycle frame.

[0081] This applies not only to the bicycle frame itself, but also to certain attachments such as the wheels, a seat post (not shown) and, for example, the handlebar 20 shown in Figure 2.

[0082] The handlebar 20 shown in Figure 2 has a continuous hollow profile with an approximately circular cross-section. This is designed as a so-called tapered handlebar, i.e., its diameter tapers from a central region 22 (e.g., 31.8 mm diameter) designed for clamping in a handlebar stem toward the handlebar ends 23. Furthermore, the handlebar 20 is offset in the central region 22, which would be almost impossible to manage in conventional manufacture of the handlebar with a mold slide in a conventional injection mold due to the associated difficulties during demolding.The handlebar 20 according to the invention was therefore manufactured according to the invention using a lost core 30, which is shown schematically in Figure 2 in the closely hatched central region 22, and using two cylindrically shaped, movable mold cores 31 of the molding tool, which is not shown for the sake of simplicity. By combining the use of a lost core 30, for example made of a water-soluble ceramic, and mechanically movable mold cores 31 as components of the molding tool, a hollow structure with different internal cross sections / diameters can be produced relatively inexpensively by injection molding, as in the case of the handlebar shown in Figure 2. For example, the handlebar 20 can be manufactured such that at least one of the movable mold cores 31, preferably both, accommodate the lost core 30 between them.After the lost core 30 and the movable mold cores 31 have been overmolded, the latter can then be drawn. The intermediate product thus produced can then be removed from the mold. The body 21 of the link 20, formed from thermoplastic material, is shown in Figure 2 as a hatched outer surface.

[0083] Figure 3A shows an enlarged view of the bicycle frame 2 which was manufactured according to the method according to the invention. In the bicycle frame shown in Figure 3A, the top tube 3, the head tube 7, the area where the seat stays 9 are connected to the seat tube 5 and a transition area 13 between the down tube 4, the head tube 7 and the motor mount 6 were injection-molded with lost cores 30. As the sectional view in Figure 3B illustrates, this transition area 13 in particular is designed with a relatively complex inner contour. The lost core 30 is highlighted by the closely hatched area in Figures 3A and 3B. The seat tube 5 and the down tube 4 were each formed using movable tool cores of the mold.

[0084] The lost cores 30 are produced as part of the method according to the invention by injection molding of ceramic material and are held in the parting plane of the mold by means of movable mold cores 31. The mold is then closed and held shut. Plasticized thermoplastic is injected under pressure into the mold via an injection unit and at least one sprue provided in the mold, while the mold is held shut. The movable mold cores 31 are then pulled out by actuating an adjustment mechanism in the mold, and the mold is subsequently opened. The intermediate product produced in this way, for example as a bicycle frame 2, is removed from the mold. In a further method step, the lost cores 30 are removed from the cavities of the bicycle frame 2, preferably using water or an aqueous solution.

[0085] Reference symbols Bicycle Bicycle frame Top tube Down tube Seat tube Motor mount Control system Chain stays Seat stays From falling rear wheel Battery mount Transition area from down tube to head tube Handlebar Body of the handlebar Middle area Lost core Movable mold cores of the mold

Claims

Patent claims 1. A method for producing a structural component for a bicycle (1) which is at least partially designed as a hollow profile, comprising the method steps: - Providing an injection molding device with at least one injection unit with means for plasticizing and introducing a plasticized thermoplastic material under pressure into a multi-part mold with at least one cavity, wherein the at least one cavity at least partially defines the shape of the structural component, - producing and / or providing at least one meltable and / or dissolvable and / or mechanically destructible lost core (30) which is adapted to at least a first part of an inner contour of the structural component, - Inserting the lost core (30) into the mold, - closing and holding the mould and overmolding the lost core (30) with a thermoplastic material, - Opening the mould and removing an injection-moulded intermediate product, - melting out and / or releasing and / or mechanically removing the lost core (30), characterized in that at least a further part of the inner contour of the structural component is molded by means of at least one movable tool core (31) or movable mold slide of the mold.

2. Method according to claim 1, characterized in that the first part of the inner contour and at least one further part of the inner contour of the structural component are shaped in such a way that they form a hollow profile with at least one continuous cavity.

3. Method according to one of claims 1 or 2, characterized in that the first part of the inner contour is formed over at least one partial section with a clear width which differs from the second part of the inner contour, preferably with a smaller clear width and / or with at least one undercut and / or with at least one thread.

4. Method according to claim 3, characterized in that at least a partial section of the inner contour is designed to have smooth walls and the structural component in this partial section preferably has a constant, defined wall thickness. 5 . Method according to one of claims 1 to 4 , characterized in that during the injection molding process at least one lost core (30) is held in the mold by means of at least one movable mold core (31) or by means of at least one movable mold slide as a component of the mold.

6. Method according to one of claims 1 to 5, characterized by the use or production of at least one lost core (3) from a material which is selected from a group of materials comprising low-melting metals and / or metal alloys, ceramic materials, in particular based on aluminum, zirconium, zirconia, fused quartz or mixtures of quartz, zirconium and aluminum.

7. Method according to one of claims 1 to 6, characterized by the use of at least one lost core (30) which is dissolvable by means of water or by means of an aqueous suspension or aqueous solution, further comprising the method step of dissolving and rinsing the lost core (30) after removal from the mold.

8. Method according to one of claims 1 to 7, characterized by the use of at least one filled and / or fiber-reinforced, preferably single-variety, thermoplastic, in particular a thermoplastic reinforced with tensile fibers, the fibers preferably having a length of greater than 0 mm and less than 50 mm.

9. Method according to one of claims 1 to 8, characterized in that the thermoplastic plastic is selected from a group of plastics comprising PA, PP, PPA, PS, PE, PE, ABS, PC, POM, PEK, PEEK, PA610, HPPA, PARA, PBT, PK.

10. Method according to one of claims 8 or 9, characterized in that the tensile fibers are selected from a group of fibers comprising carbon fibers, glass fibers, aramid fibers, Kevlar fibers and basalt fibers.

11. Method according to one of claims 8 to 10, characterized in that the filled thermoplastic material has a filling degree of 20 to 60 percent by weight based on the total weight of the structural component.

12. Method according to one of claims 1 to 11, characterized in that the lost core (30) is produced by means of an injection molding process.

13. A method for producing a bicycle frame (2) using at least one structural component made of thermoplastic material in the form of a hollow profile, which structural component was preferably obtained by the method according to one of claims 1 to 12, and which forms at least one frame profile section of the bicycle frame (2), characterized in that the bicycle frame is joined in several parts.

14. Method according to claim 13, characterized in that the frame profile sections are connected to one another in a materially and / or form-fitting manner, wherein in particular at least some of the frame profile sections are joined via at least one plug connection and are preferably glued and / or welded and / or screwed together in the region of the plug connection.

15. Method according to one of claims 13 or 14, characterized by the use of at least one structural component as a frame profile section, which has a defined wall thickness over its entire length and at least a first and a second partial section with a different wall thickness and / or with a different clear cross-section and / or with a different inner contour.

16. Structural component as an injection-molded hollow profile made of thermoplastic material, in particular as a frame profile section of a bicycle frame (2), in particular produced according to the method according to one of claims 1 to 12, which has a defined wall thickness over its entire length and at least a first and a second partial section with a different wall thickness and / or with a different clear inner width and / or with a different inner contour.

17. Structural component according to claim 16, comprising at least one section with an internal thread and / or an undercut. 18 . Structural component according to one of claims 16 or 17, characterized in that the frame profile section is selected from a group of frame profile sections comprising a top tube ( 3 ), a down tube (4) , a seat tube (5) , seat stays (9) , chain stays (8) , a head tube (7) a bottom bracket shell, a motor mount (6) a battery compartment, a battery mount (12) .

19. Structural component according to claim 16, characterized in that it is designed as a handlebar (2) or seat tube of a bicycle (1).

20. Structural component according to one of claims 16 to 18 as a frame profile section of a bicycle frame (2) with a defined wall thickness of 3 to 8 mm, which varies abruptly or constantly over the length of the profile section.

21. Bicycle frame (2) manufactured by the method according to one of claims 13 to 15.

22. Bicycle frame (2) comprising at least one structural component having the features of one of claims 15 to 20.

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