Bicycle frame for a suspension bicycle, and method for producing same

Abstract

The invention relates to a bicycle frame (10, 30) for a suspension bicycle, the bicycle frame having been injection-moulded at least predominantly in one piece from a fibre-reinforced thermoplastic, comprising a plurality of frame tubes which are selected from a group of frame parts, comprising a top tube (16), a down tube (14), a seat tube (12), chain stays (18) and seat stays (19), wherein: the bicycle frame has at least one main frame (11) comprising at least the seat tube (12) and the down tube (14), a bottom bracket housing or motor mounting frame (13) connecting them in one piece, and a rear swing arm (17) moulded on in one piece; the rear swing arm (17) of the bicycle frame (10, 30) is formed with seat stays (19) and chain stays (18), and the rear swing arm (17) resiliently yields about a virtual bottom bracket axis (Z); at least the rear swing arm (17) comprises at least one further frame part which is designed as a spring element (21, 31) and defines an at least substantially linear suspension travel; and at least the further spring element (21, 31) is designed as an integral component of the bicycle frame (10, 30). The invention also relates to a method for producing the bicycle frame.

Description

[0001] Bicycle frame for a sprung bicycle and methods for its manufacture

[0002] The invention relates to a bicycle frame for a sprung bicycle, which is injection molded in one piece from a fiber-reinforced thermoplastic material.

[0003] The invention further relates to a method for manufacturing a bicycle frame for a sprung bicycle from a fiber-reinforced thermoplastic material.

[0004] In particular, off-road bicycles or mountain bikes are often equipped with front and rear shock absorber assemblies positioned between the bicycle frame and the front and rear wheels. These shock absorber assemblies typically improve the handling and ride quality of the bicycle by dampening bumps and other unevenness in the road, which can occur especially when riding off-road. The shock absorber assemblies contribute significantly to the overall weight of the bicycle. Electrically powered bicycles, in particular, also include an electric motor and a battery, which further increase the overall weight considerably.

[0005] The need for weight reduction is generally addressed by increasingly manufacturing mountain bike frames as particularly lightweight carbon frames. Thermosetting plastics, especially epoxy resins, are predominantly used as matrix materials. Such bicycle frames are characterized by a particularly favorable stiffness-to-weight ratio, but have the disadvantage that the epoxy resin-based plastic can easily break, for example, in a crash. Furthermore, the recyclability of such frames or other components based on epoxy resin is less guaranteed. The fibers used in the production of carbon frames are generally bonded together as woven or non-woven fabrics according to a predetermined cut and then manually inserted into a mold.An epoxy resin-based plastic is injected into the closed mold in such a way that the resin penetrates the fiber fabric or woven material. The component is then cured by applying heat. This manufacturing process is complex and requires a high degree of manual labor, both before the component is formed and in the form of the necessary finishing work. This results in a high price for such bicycles.

[0006] In the prior art, approaches are known to provide sprung bicycle frames that do without the known hydraulic / pneumatic shock absorber assemblies with complex connection to the frame of the bicycle via joint transmissions.

[0007] From EP 4 242 740 A1, a sprung bicycle frame is known in which the seat stays extend beyond the seat tube towards the head tube and have an elastic extension in this area, which interacts at its leading end with an adjustable damping system. The damping system comprises double-acting hydraulic pistons that are displaceable within cylindrical housings. The elastic extensions and the damping system with which they interact allow linear displacement of the seat stays of the rear triangle. The rear triangle includes flexible chainstays that allow oscillation / displacement of the rear triangle around a virtual or imaginary bottom bracket axis.

[0008] The invention is based on the objective of providing a bicycle frame and a method for manufacturing a bicycle frame that is, on the one hand, easy and inexpensive to produce and, on the other hand, ensures simple and lightweight suspension and / or damping. This objective is achieved by a bicycle frame with the features of claim 1, which is injection-molded in one piece from a fiber-reinforced thermoplastic. The objective is further achieved by a method for manufacturing a bicycle frame injection-molded in one piece from a fiber-reinforced plastic.

[0009] It is generally known in the art to manufacture bicycle parts, and in particular bicycle frames, from fiber-reinforced thermoplastic. Thermoplastics are easier to recycle than thermosetting plastics and can be molded, for example, by injection molding. The invention is based on the understanding that a suspension and / or damping system can be implemented in a particularly simple way on a bicycle frame injection-molded from thermoplastic. This system relies solely on the material properties of the bicycle frame and can be achieved through its shape, for example, by designing the frame cross-section. In this way, a one-piece sprung bicycle frame with a good stiffness-to-weight ratio can be provided.

[0010] One aspect of the invention relates to a bicycle frame that is at least predominantly injection-molded in one piece from a fiber-reinforced thermoplastic material, comprising several frame tubes selected from a group of frame parts including a top tube, a down tube, a seat tube, chainstays and seat stays, wherein the bicycle frame has at least one main frame comprising at least one seat tube and a down tube and a bottom bracket housing or motor bearing housing connecting these in one piece and a rear triangle molded in one piece, wherein the rear triangle of the bicycle frame is designed with seatstays and chainstays, the rear triangle is designed to be resiliently compliant about a virtual bottom bracket axis, wherein at least the rear triangle comprises at least one further frame part designed as a spring element which defines at least an approximately linear spring travel.and wherein at least the further spring element is designed as an integral part of the bicycle frame .,

[0011] The virtual bottom bracket axis within the meaning of the invention is understood to be the imaginary axis in which a crankshaft of the bottom bracket extends.

[0012] A main frame of a bicycle according to the present invention is that part of the bicycle frame which includes at least a seat tube, a bottom bracket shell or a motor housing, depending on whether the bicycle is designed as an e-bike or as a bicycle without a motor, a down tube and a head tube. The main frame may further include a top tube which is connected to the head tube and the seat tube. According to one embodiment, the main frame of the bicycle frame according to the invention may include a top tube, whereas in another embodiment, the main frame may be designed without a top tube. A rear triangle is also an integral component of the bicycle frame according to the invention. A rear triangle within the meaning of the present invention is understood to be the seat stays and the chain stays of the bicycle frame.The term "chainstays" encompasses the corresponding structurally load-bearing elements of the bicycle frame, even in bicycles that, for example, include a belt drive. Generally, a fork is also considered part of a bicycle frame; however, it is not the subject of the present application and is naturally not an integral part of the bicycle frame.

[0013] The bicycle frame according to the invention can be designed as a mountain bike frame, in particular as a bicycle frame for a preferably fully suspended electric mountain bike.

[0014] A linear spring travel within the meaning of the present invention is a spring travel that is essentially tangential to a virtual bottom bracket axis. The bicycle frame according to the invention allows a vertical, resilient deflection of the chainstays, also referred to as "Elex," and further comprises, i.e., additionally, a linear displacement of the seat stays of the bicycle frame by means of at least one further distinguished or specially designed spring element. A spring element within the meaning of the present invention is not necessarily an ideally elastic spring, but may rather also have inherent damping properties, whereby, however, the functionality as a spring predominates. A spring element within the meaning of the invention may further interact with at least one damping system and / or damping element provided for this purpose.

[0015] In an advantageous embodiment of the bicycle frame according to the invention, it can be provided that the at least one further spring element is formed in a single material with a frame part, preferably with a seat stay or a seat stay crown or a seat stay extension. "In a single material" within the meaning of the present invention means one-piece and preferably injection-molded in a single shot with a thermoplastic component.

[0016] A seat stay crown, as defined in the present invention, is a fork-shaped connection area of ​​two seat stays. A seat stay extension, as defined in the invention, is a section of a frame tube or frame profile that forms an extension of two joined seat stays, which are connected in this area to a seat tube of the bicycle frame.

[0017] Advantageously, at least one further spring element is designed to compensate for a movement of the rear triangle around the bottom bracket axis forced by driving dynamics, preferably via at least one linear degree of freedom of the rear triangle with respect to a top tube and / or with respect to a head tube.

[0018] The at least one spring element is expediently designed in such a way that it allows an essentially linear displacement of the seat stay arrangement when the rear suspension compresses or rebounds.

[0019] At least one spring element can still be used for at least one

[0020] Damping elements, preferably as elastomeric elements, further preferably as elastomeric elements detachably inserted into a frame section. Alternatively, an elastomeric element injected by two-component injection molding, consisting, for example, of a TPE, may be provided.

[0021] Advantageously, the chainstays are designed to be spring-elastic and form the first spring elements, whereby the spring elasticity of the chainstays is set or structurally predetermined by a cross-sectional profile that varies over their length.

[0022] A particularly advantageous embodiment of the bicycle frame according to the invention is characterized in that at least some frame tubes are at least partially designed as continuous hollow profiles, closed over at least a portion of their length and largely smooth-walled on the inside, with a defined wall thickness and a defined profile cross-section, wherein the frame tubes are connected to one another without fasteners and with a uniform material, and that preferably a one-piece injection-molded rear triangle of the bicycle frame with seat stays and chain stays is formed, which are essentially injection-molded as solid profiles, preferably with guide grooves for cables and / or hoses formed in them. This ensures, in particular, that the bicycle frame according to the invention has a defined frame weight, thus preventing mass differences between components of a series during mass production.

[0023] In one embodiment of the bicycle frame according to the invention, the seat stays may be connected to the top tube via at least one additional linear guide. Such an additional linear guide can be advantageous, for example, if the seat stays are articulated to at least one shock absorber, preferably hydraulically and / or pneumatically actuated, which counteracts driving-dynamically induced shocks acting in the longitudinal direction of the top tube. Such a hydraulically and / or pneumatically actuated shock absorber is not strictly necessary in the bicycle frame according to the invention; however, an embodiment of the bicycle frame in which such a shock absorber is additionally provided may be advantageous.Preferably, the thermoplastic material from which the bicycle frame is manufactured according to the invention is selected from a group of plastics comprising PA, PP, PPA, PS, PE, PE, ABS, PC, POM, PEK, PEEK, PA6, PA6.1, HPPA, PARA, PBT, PK.

[0024] Preferably, the thermoplastic polymer is filled with tensile-resistant short fibers, which are preferably selected from a group of fibers comprising carbon fibers, glass fibers, aramid fibers, Kevlar fibers and basalt fibers.

[0025] According to the invention, it can be provided that at least some frame parts comprise wound, laid and / or woven tensile-strength long fibers comprising a thermoplastic matrix material, wherein the tensile-strength long fibers are selected from a group of fibers comprising carbon fibers, glass fibers, aramid fibers, Kevlar fibers and basalt fibers.

[0026] Another aspect of the invention relates to a method for manufacturing a bicycle frame from a fiber-reinforced thermoplastic, preferably for manufacturing a bicycle frame with one or more of the features of the bicycle frame described above, wherein the method comprises injection molding the bicycle frame as a one-piece molded part in a multi-part injection mold and forming at least some of the frame tubes, preferably at least all frame tubes of the main frame as continuous hollow profile sections closed at least over a partial length, using a plurality of movable mold parts of the injection mold, in particular using a plurality of movable mold slides, which are movable from a demolding position to a functional position within a part cavity of the injection mold and from the functional position to the demolding position.the process involves manufacturing the bicycle frame in a single shot.

[0027] In the context of the invention, a functional position of a mold slide or other movable tool part is defined as the position in which the thermoplastic material is injected into the closed part cavity. After the injection-molded part has been formed, the movable tool parts are moved to a position outside the part cavity to ensure the part can be demolded. This position is hereinafter referred to as the demolding position.

[0028] In the context of the present invention, an article cavity is defined as the cavity within the injection mold that forms the article, i.e., that is designed as a negative of the article. Accordingly, gates, distributors, or the like are not part of the article cavity.

[0029] The method according to the present invention preferably comprises a one-piece manufacturing of the bicycle frame without the use of inserts. Inserts in this sense are understood to be semi-finished components lost in the injection mold, in particular made of thermoplastic material or other materials.

[0030] A particular aspect of the method according to the present invention is that preferably all frame tubes of the main frame are formed as continuous hollow profile sections, closed at least over a partial length, and these are formed exclusively by means of movable forming slides according to the invention. The method according to the invention does not require fluid injection technology or lost cores. The product or bicycle frame manufactured according to the method comprises frame tubes as hollow profile sections with a defined wall thickness and a defined and preferably smooth-walled inner contour.

[0031] A particular advantage of the method according to the invention is that particularly light and stable bicycle frames with a favorable weight-to-stiffness ratio and defined cross-sections and cavities can be produced by plastic injection molding.

[0032] "At least over a partial length" means, in the context of the present invention, that at least some frame tubes may have openings for the passage of cables, wires or the like, or in the form of battery compartments and / or a battery compartment cover, so that the frame tubes do not have a fully enclosed frame cross-section in the relevant areas.

[0033] The cross-section of the frame tubes can be round, oval, square, or in the shape of any other desired contour.

[0034] The method for manufacturing the bicycle frame according to the invention comprises injection molding of a thermoplastic material, preferably a polyolefin.

[0035] The thermoplastic material can generally be selected from a group of plastics including PA (polyamide), PP (polypropylene), PPA (polyphthalamide), PS (polystyrene), PE (polyethylene), ABS (acrylonitrile butadiene styrene), PC (polycarbonate), POM (polyoxymethylene), PEK (polyetherketone ketone), PEEK (polyetheretherketone), PA6 (polyamide 6), PA6.1 (polyamide 6.1), PA 12 (polyamide 12), HPPA (high-performance recycled polyamide), PARA (polyarylamide), PBT (polybutylene terephthalate), and PK (polyketones).

[0036] The method according to the invention particularly preferably comprises the injection molding of a polyamide, more preferably of polyamide 6 (PA6) or a blend of PA66+PA6I / 6T as the matrix material, wherein the injected thermoplastic material can be filled with short fibers made of a tensile-strength material. For the purposes of this application, short fibers are understood to be fibers with a length greater than 0 mm and less than 50 mm, whereas long fibers are tensile-strength fibers that can have a length greater than 50 mm up to an infinite length. The tensile-strength fibers can comprise carbon fibers, aramid fibers, glass fibers, or basalt fibers.

[0037] The part cavity of the injection mold used according to the invention corresponds to a negative of the complete bicycle frame without the fork, making the method according to the invention particularly suitable for mass-producing bicycle frames made of thermoplastic material. A preferred embodiment of the method is characterized in that at least one frame tube is formed by means of at least two forming slides that interact in a functional position within the part cavity of the injection mold. In this way, it is possible to form relatively long frame tubes. Forming a single long cavity of a frame tube by means of at least two interacting forming slides facilitates the displacement of the forming slides from the functional position to a demolding position. Furthermore, this makes it possible to form frame tubes that have an internal cross-section that varies along their length.This can be advantageous, for example, in the area of ​​a seat tube, in order to form a section of the seat tube with a cylindrical inner cross-section.

[0038] As is well known, mold slides without draft angles can only be pulled out of the molded article by applying relatively high forces, so this fact limits the length of the cavity to be formed with a uniform internal cross-section.

[0039] Preferably, at least one frame tube is molded with two first and second forming slides cooperating as a first slide pair, wherein the first and second forming slides of the first slide pair, in their functional position within the part cavity of the injection mold, interlock at their ends leading into the functional position in the feed direction or abut each other with a parting contour. Such a parting contour within the meaning of the invention can be a parting plane in which the leading ends of the forming slides abut each other in the functional position. However, a parting contour can also be formed by mutually offset or jagged surfaces.

[0040] In a particularly advantageous embodiment of the method according to the invention, it can be provided that, for example, the first forming slide of the first pair of slides has a contour that facilitates demolding, preferably with draft angles, and that the second forming slide of the first pair of slides has a cylindrical contour. This makes it possible, for example, to produce an inner contour of a seat tube that has a cylindrical inner cross-section at least in an area intended for mounting a seat post, whereas the frame tube designed as a seat tube can open accordingly towards a bottom bracket shell or a motor bearing housing. Accordingly, in the embodiment of the method described above, it can be provided that a seat tube of the bicycle frame is formed with the first pair of slides.In this case, it is advantageous if the first forming slide of the first slide pair is used to mold a bottom bracket housing or a motor bearing housing of the bicycle frame.

[0041] In a preferred and advantageous embodiment of the method according to the invention, at least one frame tube, preferably at least one further frame tube, is molded using two first and second forming slides that cooperate as a second pair of slides. Preferably, a first forming slide of the second pair of slides is held or captured in its functional position by a second forming slide of the second pair of slides, which extends at an angle to the first forming slide, preferably at an end leading into the functional position in the feed direction. The angle between the second forming slide of the second pair of slides and the first forming slide of the second pair of slides is preferably greater than 90° and less than 180°.With this variant of the process, it is possible to mold relatively long article cavities, since the cooperating form slides of the second slide pair stabilize in the functional position.

[0042] For example, it can be provided that the second forming slide of the second pair of slides molds a first short tube section of the bicycle frame in the article cavity, preferably as the head tube of the bicycle frame, that the second forming slide of the second pair of slides is moved into the functional position first, that the first forming slide of the second pair of slides molds a second long tube section of the bicycle frame, preferably as the down tube of the bicycle frame, that the first forming slide of the second pair of slides is moved into the functional position after the second forming slide, and that the first forming slide of the second pair of slides is caught at its end leading in the feed direction by the second forming slide of the second pair of slides.

[0043] In an advantageous and expedient embodiment of the method according to the invention, it can be provided that the first forming slide of the second pair of slides engages in a form-fitting manner at an end leading in the feed direction into the second forming slide of the second pair of slides in the functional position, preferably immersing itself in a catch opening of the second forming slide of the second pair of slides.

[0044] In an advantageous embodiment, the method may include forming a down tube of the bicycle frame with at least two profile chambers parallel in the direction of extension, preferably using a double-slide forming die. The double-slide may, for example, comprise a first elongated core that forms a main chamber of the down tube. Parallel to this, a further core may extend, forming a closed second chamber of the down tube.

[0045] In a suitable variant of the process, it can further be provided that at least two mold slides interpenetrate each other in a functional position within the part cavity. This "slide-by-slide" concept makes it possible, within a limited installation space of the injection mold, whose dimensions are essentially determined by the dimensions of the main mold that defines the part cavity of the main frame, to mold the part to be formed using a multitude of mold slides.

[0046] In this variant of the method according to the invention, it is advantageous if the first forming slide of the second pair of slides is moved into its functional position through the first forming slide of the first pair of slides. It is practical and expedient to first move the second forming slide into its functional position and then move the first forming slide of the second pair of slides into its functional position through the first forming slide of the first pair of slides.

[0047] The process is preferably characterized by the fact that the thermoplastic polymer is filled with tensile-resistant short fibers, which are preferably selected from a group of fibers comprising carbon fibers, glass fibers, aramid fibers, Kevlar fibers and basalt fibers.

[0048] Preferably, additionally or alternatively, wound, laid and / or woven tensile-strength long fibers are introduced at least in partial areas into the article cavity, which are overmolded with the thermoplastic matrix material, preferably with a polyamide, wherein the tensile-strength long fibers are selected from a group of fibers comprising carbon fibers, glass fibers, aramid fibers, Kevlar fibers and basalt fibers.

[0049] The method according to the invention can include introducing tensile-strength continuous fibers in the form of tapes (UD tape) or in the form of prepregs with a thermoplastic matrix into the injection molding tool before closing the complementary molded parts forming the article cavity.

[0050] The process can further include introducing the fiber reinforcement described above into the part cavity in a load-optimized manner with respect to the bicycle frame to be manufactured. Load-optimized means that the fiber reinforcement is introduced into the tool in such a way that the fibers are aligned in the direction of the main load direction of the bicycle frame to be manufactured.

[0051] In an advantageous embodiment of the method according to the invention, it can be provided that a rear section of the bicycle frame is formed with seat stays and chain stays, which are essentially injection-molded as solid profiles with guide grooves for cables and / or hoses formed within them. The guide grooves can, for example, also be formed with movable molded parts or slides / slide jaws that can be relocated at a corresponding position in the tool.

[0052] The invention is explained below with reference to and based on an embodiment illustrated in the accompanying drawings.

[0053] They show:

[0054] Figure 1 shows a side view of a first embodiment of the bicycle frame according to the invention.

[0055] Figure 2 is a perspective view of the bicycle frame shown in Figure 1.

[0056] Figure 3 shows an enlarged view of a detail of the bicycle frame according to the invention.

[0057] Figure 4 shows a side view of a second embodiment of the bicycle frame according to the invention.

[0058] Figure 5 is a perspective view of the bicycle frame shown in Figure 4.

[0059] Figure 6 shows another view of the bicycle frame shown in Figures 4 and 5 and

[0060] Figure 7 shows a view of an injection mold for producing a one-piece injection-molded bicycle frame using the method according to the invention.

[0061] Figures 1 to 3 show a first embodiment of the bicycle frame 10 according to the invention, which is designed as the frame of a suspension electric mountain bike. The bicycle frame 10 comprises a main frame 11 and a rear triangle 17, which is formed integrally with the main frame 11. The main frame 11 includes a seat tube 12 for receiving a seat post, a motor mounting housing 13 for receiving an electric motor (not shown), and a down tube 14, which is designed to receive a battery, as well as a head tube 15 and a top tube 16, which form a frame triangle in a known manner.

[0062] In the illustrated embodiment, the battery is inserted from below through the motor mount housing 13 into the frame profile of the down tube 14. The motor mount housing 13 is integrally connected to a lower part of the seat tube 12, the down tube 14, and the chainstays 18 of the rear triangle 17.

[0063] The rear triangle 17 further comprises seat stays 19, which are designed as injection-molded solid profiles. The chainstays 18, which are also designed as injection-molded solid profiles, include integrated cable guides 20 (see Figure 5) in the form of grooved channels on their underside facing away from a user of the bicycle frame 10.

[0064] The seat tube 12, the down tube 14 and the head tube 15 are each designed as continuous hollow profiles, with the down tube 14 having a fully closed profile cross-section in the described embodiment.

[0065] The bicycle frame 10 according to the invention is manufactured entirely in one piece from an injection-molded thermoplastic material in an injection mold 100, which is shown in Figure 7. The thermoplastic material of the bicycle frame 10 is filled with tensile-strength short fibers and comprises at least partially unidirectionally oriented long fibers made of a tensile-strength material, for example in the form of carbon fibers.

[0066] The bicycle frame 10 according to the invention comprises chainstays 18, the cross-section of which is designed to be flexible or spring-elastic. For this purpose, the chainstays 18 have a cross-section that varies along their length from the motor bearing housing 13 or from a virtual bottom bracket axis Z towards the dropouts 22 of the bicycle frame 10. Starting from the virtual bottom bracket axis Z towards the dropouts 22 of the bicycle frame 10, the cross-section of the chainstays 18 initially tapers, then widens again in the region of the dropouts 22. In this way, an approximately bone-shaped contour is created, which ensures the flexible compliance of the rear triangle 17 or the dropouts 22 of the rear triangle 17 around the virtual bottom bracket axis Z. This allows a rear wheel inserted into the bicycle frame 10 to compress and rebound during driving-dynamically induced shocks.

[0067] Furthermore, according to the invention, the seat stays 19 of the rear triangle 17 are designed to compensate for the flex of the chainstays 18 via a linear displacement movement. For this purpose, the seat stays 19 comprise a linear spring element 21 in a connection area 23 to the seat tube 12, which is designed as an S-shaped or wave-shaped section or material zone of the connection area 23. This connection area 23 forms a seat stay crown in the sense of the terminology used in the introductory part of the present application. The linear spring element 21 is formed as a single piece of material or as an injection-molded geometry with the rear triangle 17 of the bicycle frame 10 and allows a linear displacement of the seat stays 19 or the upper part of the rear triangle 17 in the direction defined by the top tube relative to the head tube.The S-shaped connection area 23 includes wave troughs 24 and wave crests 25 which form a spring, wherein the clear width of the wave troughs 24 determines the spring travel and elastomer bodies can be inserted between them as damping elements, for example.

[0068] Figures 4 to 6 show a second embodiment of the bicycle frame 30 according to the invention, wherein in the second embodiment the same components are provided with reference numerals corresponding to those of the first embodiment. The second embodiment according to the invention differs essentially in the design of the spring element, as well as in the connection of the seat stays 19 to the head tube 15 and the arrangement of the seat stays 19 with respect to the top tube 16. Instead of a single sprung connection area 23, as is provided in the first embodiment according to the invention, a linear spring element 31 is provided in each of the seat stays 19. The linear spring elements 31 can be designed as damping elements that are resiliently compliant in the direction of the longitudinal extension of the seat stays 19 and can, for example, be injection-molded by two-component injection molding.Furthermore, the seat stays 19 are not connected to the seat tube 12, but rather encircle it. The ends of the seat stays 19 pointing towards the head tube 15 are articulated to a linear bearing 32, which includes a bearing axis 33 to which one end of a shock absorber 34 is articulated. The seat stays 19 and the top tube 16 are essentially aligned and slidably guided within one another. The shock absorber 34 can be designed as a hydraulic and / or pneumatic shock absorber and provides the rear triangle 17 with additional linear travel.

[0069] The method according to the invention is explained below with reference to the injection mold 100 shown in Figure 7.

[0070] The injection mold 100 comprises a base mold 110, which forms the majority of an article cavity 111. The base mold 110 can, for example, comprise at least two mold halves, which define the negative of the article to be molded, in this case the bicycle frame 10, 30.

[0071] The bicycle frame 10, 30 according to the invention is manufactured entirely in one piece from an injection-molded thermoplastic material in the injection molding tool 100.

[0072] The seat tube 12, the lower tube 14 and the head tube 15 are each formed as continuous hollow profiles using the injection mold 100 shown in Figure 7 by means of movable mold slides / mold cores.

[0073] The seat tube 12 of the bicycle frame 10, 30 and the motor bearing housing 13 are injection-molded as continuous hollow profiles, the inner cross-section of which is formed by a first pair of slides. The first pair of slides comprises a first forming slide 121, which defines the inner contour of the motor bearing housing 13 and the lower part of the seat tube 12 adjacent to the motor bearing housing 13, and a second forming slide 122, which forms the upper part of the seat tube 12.

[0074] Figure 7 shows the first forming slide 121 and the second forming slide 122 in their functional position, in which they collide at a parting contour. The parting contour is formed by stepped end faces of the leading ends of the first and second forming slides 121 and 122, respectively, which interlock in their functional position. The first lower forming slide 121 is designed to facilitate demolding with draft angles and is conical in the area of ​​a section leading in the feed direction, whereas the contour of the second upper forming slide 122 is cylindrical and consequently defines a cylindrical inner cross-section of the seat tube 12 in its upper region.

[0075] The head tube 15 and the down tube 14 are molded using a second pair of slides, which interlock positively in their functional position. The second pair of slides comprises a first molding slide 131 and a second molding slide 132, wherein the first molding slide 131 is held in its functional position at its end by the second molding slide 132.

[0076] In order to ensure a compact arrangement of all movable mold parts and an interaction of these mold parts for the purpose of forming the injection-molded article, the first mold slide 121 of the first slide pair and the first mold slide 131 of the second slide pair are designed such that the first mold slide 131 of the second slide pair passes through or penetrates the first mold slide 121 of the first slide pair and can be moved through the first mold slide 121 of the first slide pair into its functional position, in which it interacts with the second mold slide 132 of the second slide pair.

[0077] In the method according to the invention, first the first and second forming slides 121 and 122 of the first pair of slides and then the second forming slide 132 of the second pair of slides are moved into their functional position, then the first forming slide 131 of the second pair of slides is advanced through the first forming slide 121 of the first pair of slides into its functional position, where it engages positively in a window-like recess of the second forming slide 132.

[0078] The rear triangle 17 of the bicycle frame is formed with a rear triangle slide 170, the head tube 15 or a headset is formed with a headset slide 180.

[0079] PE-TK 24 June 2025

[0080] Applicant: igus GmbH, 51147 Cologne

[0081] Reference symbol list

[0082] 10 bicycle frames

[0083] 11 main frames

[0084] 12 seat tube

[0085] 13 Engine Mount Housings

[0086] 14 Down tube

[0087] 15 Head tube

[0088] 16 Top tube

[0089] 17 Rear triangle

[0090] 18 chainstays

[0091] 19 seat stays

[0092] 20 Train guidance

[0093] 21 Linear spring element

[0094] 22 dropouts

[0095] 23 Connection area

[0096] 24 wave troughs

[0097] 25 wave crests

[0098] 30 bicycle frames

[0099] 31 linear spring elements

[0100] 32 linear bearings

[0101] 33 Bearing axle

[0102] 34 shock absorbers

[0103] Z virtual bottom bracket axle

[0104] 100 injection molds

[0105] 110 main tool

[0106] 111 Item cavity

[0107] 121 first form slide of the first slide pair

[0108] 122 second form slide of the first slide pair first slide of the second slide pair second form slide of the second slide pair rear triangle slide headset slide

Claims

Claims 1. Bicycle frame (10, 30) for a sprung bicycle, which is at least predominantly injection-molded in one piece from a fiber-reinforced thermoplastic material, comprising several frame tubes selected from a group of frame parts, comprising a top tube (16), a down tube (14), a seat tube (12), chainstays (18) and seat stays (19), wherein the bicycle frame has at least one main frame (11) comprising at least the seat tube (12) and the down tube (14) and a bottom bracket housing or motor bearing housing (13) connecting these in one piece and a one-piece molded rear triangle (17), wherein the rear triangle (17) of the bicycle frame (10.30) is designed with seat stays (19) and chain stays (18), the rear triangle (17) is designed to be resiliently flexible about a virtual bottom bracket axis (Z), wherein at least the rear triangle (17) , at least one further as a spring element (21.31) comprised a frame part which defines at least substantially linear spring travel, and wherein at least the further spring element (21, 31) is formed as an integral part of the bicycle frame (10,30).

2. Bicycle frame (10, 30) according to claim 1, characterized in that the at least one further spring element (21, 31) is formed in a single material with a frame part, preferably with at least one seat stay (19) or a seat stay crown or a seat stay extension or with a top tube (16).

3. Bicycle frame (10,30) according to one of claims 1 to 2, characterized in that the at least one further spring element (21,31) is designed to compensate for a movement of the rear triangle (17) about the virtual bottom bracket axis (Z) forced by a driving dynamic, preferably via at least one linear degree of freedom.

4. Bicycle frame (10,30) according to one of claims 1 to 3, characterized in that the at least one spring element (21,31) is designed in such a way that it allows a substantially linear displacement of the seat stay arrangement.

5. Bicycle frame (10,30) according to one of claims 1 to 4, characterized in that at least one spring element (21,31) is designed as an S-shaped material zone of the seat stays (21,31) and / or a seat stay crown and / or a seat stay extension.

6. Bicycle frame (10,30) according to one of claims 1 to 5, characterized in that the at least one further spring element (21,31) comprises at least one damping body, preferably as an elastomer body.

7. Bicycle frame (10, 30) according to one of claims 1 to 6, characterized in that the chainstays (18) are designed to be spring-elastic and form first spring elements and that the spring elasticity of the chainstays (18) is set or structurally predetermined by a cross-sectional profile that varies over their length.

8. Bicycle frame (10, 30) according to one of claims 1 to 7 , characterized in that at least some frame tubes are at least partially designed as continuous hollow profiles, closed at least over a partial length and largely smooth-walled on the inside, with a defined wall thickness and a defined profile cross-section, wherein the frame tubes are free of fasteners and made of a single material are connected to each other and that preferably a one-piece injection-molded rear structure (17) of the bicycle frame (10,30) is formed with seat stays (19) and chain stays (18), which are essentially injection-molded as solid profiles, preferably with guide grooves (20) formed in them for cables and / or lines.

9. Bicycle frame (10, 30) according to one of claims 1 to 8, characterized in that the seat stays (19) are connected to the top tube (16) via at least one linear guide.

10. Bicycle frame (10, 30) according to claim 9, characterized in that the seat stays (19) are articulated to at least one preferably hydraulically and / or pneumatically acting shock absorber (34) which counteracts driving dynamically induced shocks acting in the longitudinal direction of the top tube (16).

11. Bicycle frame (10, 30) according to one of claims 1 to 10, characterized in that the thermoplastic material is selected from a group of plastics comprising PA, PP, PPA, PS, PE, PE, ABS, PC, POM, PEK, PEEK, PA6, PA6.1, HPPA, PARA, PBT, PK.

12. Bicycle frame (10, 30) according to one of claims 1 to 11, characterized in that the thermoplastic polymer is filled with tensile-strength short fibers, which are preferably selected from a group of fibers comprising carbon fibers, glass fibers, aramid fibers, Kevlar fibers and basalt fibers.

13. Bicycle frame (10, 30) according to one of claims 1 to 12, characterized in that at least some frame parts comprise wound, laid and / or woven tensile-strength long fibers comprising a thermoplastic matrix material, wherein the tensile-strength long fibers are selected from a Group of fibers including carbon fibers, glass fibers, aramid fibers, Kevlar fibers and basalt fibers.

14. Method for manufacturing a bicycle frame (10, 30) from a fiber-reinforced thermoplastic, preferably for manufacturing a bicycle frame with the features of any one of claims 1 to 13, wherein the method comprises injection molding the bicycle frame (10, 30) as a one-piece molded part in a multi-part injection mold (100) and forming at least some of the frame tubes, preferably at least all frame tubes of the main frame (11) as continuous hollow profile sections closed at least over a partial length using a plurality of movable mold parts of the injection mold (100), in particular using a plurality of movable mold slides (121, 122, 131, 132, 170) which are movable from a demolding position to a functional position within a part cavity (111) of the injection mold (100) and from the functional position to the demolding position, wherein the method comprises manufacturing the bicycle frame (10,30) in a single shot.

15. Method according to one of claims 1 to 12, characterized in that a rear structure (17) of the bicycle frame (10, 30) is formed with seat stays (19) and chain stays (18), which are essentially injection molded as solid profiles with guide grooves formed in them for cables and / or lines.

16. Method according to one of claims 14 or 15, characterized in that the thermoplastic polymer is filled with tensile-strength short fibers, which are preferably selected from a group of fibers comprising carbon fibers, glass fibers, aramid fibers, Kevlar fibers and basalt fibers.

17. Method according to one of claims 14 to 16, characterized in that wound, laid and / or woven tensile-strength Long fibers are introduced, at least in partial areas, into the article cavity, which is overmolded with a thermoplastic matrix material, preferably with a polyamide, wherein the tensile-strength long fibers are selected from a group of fibers comprising carbon fibers, glass fibers, aramid Fibers, Kevlar fibers and basalt fibers.

Images