Main frame, front fork, and bicycle frame comprising same

Abstract

The invention relates to a main frame (1) for a bicycle having a saddle and a front wheel and a rear wheel, which are arranged in alignment, which main frame is produced in a closed mold from a thermoplastic resin, the main frame being in the form of a single-piece hollow article (2) having a frame wall (3) which encloses the cavity thereof, and the frame wall (3) of the hollow article (2) consisting of one piece produced by means of rotational molding in a rotary mold that can be heated from the outside. The invention also relates to a front fork and to a bicycle frame comprising the main frame and the front fork.

Description

[0001] Main frame, front fork and this comprehensive bicycle frame

[0002] The invention relates to a bicycle frame for a bicycle with a saddle and with a front wheel and a rear wheel which are arranged in a track, and relates to its main components, namely a main frame and a front wheel fork.

[0003] The invention relates, on the one hand, to a main frame manufactured from a thermoplastic material in a closed molding tool. It also relates to a front wheel fork manufactured from a thermoplastic material in a closed molding tool.

[0004] Furthermore, the invention relates to a main frame for a bicycle with a saddle and with a front wheel and a rear wheel which are arranged in a track, made of a thermoplastic material, wherein a main carrier and a one-sided rear wheel carrier are integrally comprised, wherein the rear wheel carrier is designed as a hollow body, with the proviso that the rear wheel carrier forms an encapsulating housing for a drive means, and that the rear wheel carrier is provided with a rear wheel holder.

[0005] Furthermore, the invention relates to a front wheel fork for a bicycle, which has a saddle and which is provided with a front wheel and a rear wheel, which are arranged in a single track, designed in one piece from a thermoplastic material, comprising either a fork leg provided on one side with an upper end and a lower end or two such fork legs arranged symmetrically, wherein a receiving opening is provided at the lower end of the fork leg or the lower ends of the two fork legs, and wherein the receiving opening is designed to hold a front axle.

[0006] Compared to steel and aluminum, thermoplastics exhibit lower strength as a material for bicycle frames. The elastic modulus is lower than that of steel and aluminum. Likewise, the dimensional rigidity of plastics is lower. This must be taken into account when designing a plastic main frame and front fork, as is known from DE 38 04 342 C2.

[0007] This prior art already proposes a bicycle frame made of a thermoplastic material, comprising a main frame and a front wheel fork manufactured using a die-casting process, known as thermoplastic die-casting. The known die-cast main frame includes a rear wheel carrier with reinforcing ribbing, and the front wheel fork is reinforced with longitudinal ribs. This reinforcing design is intended to compensate for the lower strength of the plastic in this prior art.

[0008] The design of the main frame with ribbing and the front fork with longitudinal ribs appears complex and the achievable strength properties unsatisfactory.

[0009] The invention is based on the object of developing the bicycle frame in such a way, or of giving the main frame and / or the front wheel fork such a spatially and physically simplified design which can provide the strength and durability which is required for a bicycle frame and the said main components.

[0010] According to the invention, this object is achieved according to claim 1 by a main frame which is designed as a one-piece hollow body with a frame wall enclosing the cavity, wherein the frame wall of the hollow body has a one-piece construction which is produced by means of rotational molding in an externally heatable rotational molding tool.

[0011] For rotational molding, the thermoplastic material is filled in powder form into the rotational molding tool, which is closed all around for the molding process. The rotational molding tool has an inner wall that forms a negative of the shape to be molded. The rotational molding tool is expediently designed as a permanent mold, which is usually made of metal, preferably aluminum. For the molding process, the rotational molding tool can be rotated about at least one axis and is heated from the outside. The plastic powder melts within it and can be distributed over the inner wall in a viscous state as a melt. Finally, the melt solidifies on the inner wall of the rotational molding tool and can then be removed as a finished hollow body after the rotational molding tool has been opened.

[0012] The main frame for a single-track bicycle requires a precisely shaped design. The inventor has discovered that it is advantageous for a main frame of a bicycle if plastic material, which expands in the tool during solidification, can expand freely inward into the hollow rotational molding tool. In this way, a stress-relieved main frame can be provided which has the shape accuracy required for a single-track bicycle and warps less than a die-cast main frame, which cannot expand in a die-cast tool and builds up stresses that lead to warping. In addition, the rotational molded main frame is seamless because of its one-piece construction, which promotes strength.

[0013] Advantageously, the hollow body has sections with varying frame wall thicknesses. This allows the main frame to be designed without internal ribbing, allowing areas of the main frame wall that are particularly subject to stress during ferry operation to be reinforced with more material to counteract cracks and fractures at these locations.

[0014] The areas of varying wall thickness in the frame wall are advantageously created by applying different levels of heat from the outside to the rotational molding tool. In more intensely heated areas, the powder melts more quickly, and a greater wall thickness can be built up over the course of the process to provide the required strength. Surprisingly, it was discovered that even for a main frame with varying wall thicknesses, a stress relief is possible, which can provide the required dimensional accuracy.

[0015] The rotational molding tool also makes it possible to integrate separate components into the molding process, which bond adhesively and / or positively to the hollow body during the molding process. These can be metallic components, such as rods, screws, rings, or tubes, which can complement and reinforce the main frame.

[0016] It is beneficial if the thermoplastic material for the frame wall is selected from one of the following plastics: polypropylene (PP), preferably polyethylene (PE), particularly preferably high-density polyethylene (HDPE). Economic cycles already exist for the types mentioned, which can recycle these plastics and make them available in a form ready for reuse. For this purpose, they are collected, for example, from the sea and in agriculture. They occur in fishing nets, trawl nets, nets for aquaculture or as net wraps for tying straw bales, and also as scaffolding nets to protect road users. The recovery of such types directly from everyday products, which are returned to the cycle without first polluting the environment, is greatly facilitated in the case of the proposed bicycle frame and its main components.

[0017] It is very beneficial for reuse if the thermoplastic is fiber-free. For the purposes of the present invention, this may also include a thermoplastic if it is sufficiently low in fibers to be processed in such a way that it is suitable for rotational molding.

[0018] Furthermore, a main frame which comprises an encapsulating housing for a drive means, as defined in claim 6, also achieves the underlying problem if the main support is designed to be hollow overall with opposing frame walls and is made in one piece with the rear wheel support. In contrast to the main frame known from DE 38 04 342 C2, the proposed main support dispenses with ribbing and is instead designed as a hollow body with opposing frame walls. This design can be achieved using different manufacturing processes. These include primary shaping processes using a shaping tool or, for example, a 3D printing process which can also process thermoplastic material. The design of the main support overall as a hollow body and in one piece with a hollow rear wheel support is regarded as an invention.

[0019] The rear wheel mount is advantageously designed in the form of two coaxial bearing openings, wherein the coaxial bearing openings are arranged in the opposite frame walls of the rear wheel carrier. One bearing opening of the rear wheel carrier is located on the left-hand side of the main frame in the direction of travel, where the rear wheel is arranged when the bicycle is ready to ride. This side of the rear wheel carrier is to be referred to as the wheel side and the opposite side of the rear wheel carrier as the drive side. The bearing openings are expediently designed to accommodate a shaft bearing for a rear wheel shaft. The bearing opening provided on the wheel side and / or the drive side is expediently hollow-cylindrical and has a stop surface for a bearing element in the axial direction. The diameter of the hollow-cylindrical bearing opening is preferably in the range from 40 mm to 130 mm.The diameter of the hollow cylindrical bearing opening on the wheel side is advantageously larger than on the drive side of the rear wheel carrier.

[0020] It is also considered particularly useful for a main frame with an encapsulating housing for a drive means if the frame wall of the hollow body is made in one piece and is produced by means of rotational molding in an externally heatable rotational molding tool, as described above.

[0021] Furthermore, this hollow body can also have sections with varying wall thicknesses. This can be achieved through rotational molding or, for example, 3D printing.

[0022] As described above, thermoplastics can also be selected for this purpose, such as polypropylene (PP), preferably polyethylene (PE), particularly preferably hard polyethylene (HDPE); for these types, economical cycles already exist which can recycle these plastics and make them available in a form prepared for reuse, which can be suitable for rotational molding or 3D printing. It is also beneficial for this purpose if the thermoplastic is, as mentioned above, fiber-free, whereby in the sense of the present invention this is also understood to mean a low-fiber plastic if it can be processed and is suitable for rotational molding or 3D printing.

[0023] If rotational forming is intended, the areas of different wall thickness of the frame wall can in turn be created by applying different heat from the outside to the rotational forming tool in certain areas, as described above.

[0024] Advantageously, opposite wall areas of the main support are provided with coaxial bearing openings which serve to accommodate a pedal drive.

[0025] One of the bearing openings for the pedal drive serves in an integral manner as a service opening for the rear wheel carrier, which is designed as an encapsulating housing for a drive means.

[0026] A further benefit may be to design the main beam as a trapezoidal structure comprising a top tube element, a down tube element, a seat tube element, and a head tube element. Since the main beam is hollow overall, all of the aforementioned tube elements of the trapezoidal structure form hollow regions of the main beam.

[0027] A further improvement provides that the trapezoidal structure has a stiffening bridge element which is arranged between the top tube element and the down tube element.

[0028] The seat tube element may have an upper seat tube extension that projects beyond the top tube element.

[0029] The rear wheel carrier has a triangular structure. This structure includes the aforementioned seat tube element, as well as an upper and lower support element. The seat tube element is therefore an integral part of both the main carrier and the rear wheel carrier, forming a kind of interface between the main carrier and the rear wheel carrier.

[0030] With this main frame design, the left side of the main frame (in the direction of travel) is also referred to as the wheel side, and the right side as the drive side, which also refers to the rear wheel carrier. In the ready-to-use state of a finished bicycle, the rear wheel is mounted on one side of the wheel side.

[0031] If the lower support element of the rear wheel carrier is designed as a housing for a drive mechanism, then it meets the seat tube element at a front end of the lower support element. This area is designed to accommodate the aforementioned pedal drive. There is space there for a bottom bracket or for a bottom bracket gear or for a bottom bracket drive, which may include an electric motor.

[0032] Additionally, a stiffening bridge element can be provided, extending from the top tube element to the seat tube extension. This bridge element reinforces the main frame and supports the seat tube extension. Furthermore, the bridge element can serve as a design element and also function as a handlebar element for lifting and carrying a bicycle when necessary.

[0033] The main frame expediently has an envelope volume which is in a range of 18 to 22 liters, preferably in the range of 19 liters to 21 liters and particularly preferably in the range of 20 liters to 20.5 liters.

[0034] The envelope volume of the main frame within the meaning of the invention is understood to be the volume of the outer surface of the main frame, with the proviso that all existing openings are interpreted as closed surface areas and are counted as the outer surface. This means, in particular, openings in the rear wheel mount, openings in the area of ​​the pedal drive mount, and in the area of ​​the head tube element and the seat tube element are considered to be part of the outer surface that defines the envelope volume.

[0035] Furthermore, it is advantageous, either on its own or in combination with the said envelope volume, if the main frame has a weight in the range of 3.5 kg to 5.5 kg, preferably in the range of 4.0 kg to 5.0 kg and particularly preferably in the range of 4.5 kg to 4.9 kg.

[0036] The main frame has a specific weight in the range of 0.16 kg / liter to 0.32 kg / liter in relation to its envelope volume.

[0037] The plastics proposed for the main frame, for example polyethylene (PE or HDPE), have relatively low strength, hardness, and stiffness. For other technical products, such polyethylenes are often reinforced with reinforcing fillers such as fibers. For reasons of recyclability, the present invention dispenses with fiber reinforcement and selects pure plastic. To provide the strength for a bicycle frame, the solution is a main frame designed as a voluminous hollow body. Its volume is significantly larger than known bicycle frames made of steel or aluminum, and also larger than the volume of a bicycle frame / main frame made of fiber-reinforced plastic. If the strength is to be increased further, the inner volume of the hollow body can be at least partially provided with a foam.

[0038] The foam is conveniently produced by foaming in the inner volume of the hollow body.

[0039] The main frame is designed so that it does not show any cracks or breaks after an impact test with a falling mass of 22.5 kg from a drop height of 180 mm in accordance with DIN-ISO 4210-6:2015, Chapter 4.1 for city and trekking bikes and in accordance with the requirements of DIN-ISO 4210-2:2015, Chapter 4.8.2.

[0040] The main frame is designed so that it does not show any cracks or breaks after a dynamic test with pedaling forces Fi of 1000 N in accordance with DIN-ISO 4210-6:2015, Chapter 4.3 for city and trekking bikes and in accordance with the requirements of DIN-ISO 4210-2:2015, Chapter 4.8.4 after a required number of 100,000 test cycles.

[0041] The main frame can also be prepared in such a way that it can be used with a mounted replacement fork after a dynamic test with a horizontal force F2 of 450 N in the direction of travel and a horizontal force F3 of 450 N against the direction of travel in accordance with DIN-ISO 4210-6:2015, Chapter 4.4 for city and trekking bikes and in accordance with the requirements of DIN-ISO 4210-2:2015, Chapter 4.8.5 after a required

[0042] Number of 100,000 test cycles shows no cracks or breaks.

[0043] In addition, the main frame can be prepared in such a way that it does not show any cracks or breaks after a dynamic test with a vertical force F4 of 1000 N in accordance with DIN-ISO 4210-6:2015, Chapter 4.5 for city and trekking bikes and in accordance with the requirements of DIN-ISO 4210-2:2015, Chapter 4.8.6 after a required number of 50,000 test cycles.

[0044] It is particularly helpful if the main frame is equipped with a data storage element, preferably a REID storage element, to store material information and / or data relating to the production of the main frame, particularly regarding the plastic material used. When a bicycle returns to the commercial cycle at the end of its service life, stored information can help recycle and reuse the plastic as a pure raw material.

[0045] Each main frame can be configured to drive a rear wheel by means of a drive means configured as a traction means with a tensioning strand and a slack strand, for example, a bicycle chain or a toothed belt. In the event that such a drive means requires a certain tension in the tensioning strand and / or slack strand, the main frame is provided with a means for providing tension. The means can be a tensioning element or simply a provision on the main frame for attaching a tensioning element.

[0046] To achieve the object, a front wheel fork is further provided if it is designed as a hollow fork body with a fork wall, wherein the fork wall of the hollow fork body is made in one piece and is produced by means of rotational molding in an externally heatable rotational molding tool.

[0047] The front fork is designed in such a way that the fork hollow body has areas with different wall thicknesses of the fork wall.

[0048] A further advantage is that the areas of different wall thickness on the front fork are created by applying different heat from the outside to the rotational forming tool in different areas.

[0049] The advantages of the different wall thicknesses of the fork wall and the generation by targeted heat supply correspond in principle to the advantages of the rotationally molded main frame described above when this has different wall thicknesses of the frame walls; these advantages are referred to here and apply equally to the front wheel fork.

[0050] In addition, a front wheel fork, if it has either a fork leg provided on one side or two such symmetrically arranged fork legs, solves the problem in that a fork bridge area is formed at the upper end of the fork leg, to which a fork arm is attached on one side, which is directed upwards, or two symmetrically arranged fork arms are attached, which are directed upwards.

[0051] In the center of the fork bridge, a fork stem is conveniently provided. This fork stem can be a metal tube that can be connected to the fork bridge area in a rotationally fixed manner and can be replaceable. Alternatively, the fork stem can be inserted into a rotational mold to connect to the fork hollow body as an integral part of the front fork. It is helpful if the fork arm has an upper end, with the upper end of the fork arm being connected to a handlebar element.

[0052] The handlebar element is expediently designed as a single piece as part of the fork hollow body.

[0053] The handlebar element can also be split in the middle and have a left handlebar half and a right handlebar half, each of which is connected to the corresponding left or right fork arm. The division of the handlebar element simplifies the assembly of the front fork. The fork arms are advantageously designed so that they can be elastically spread apart. This allows the handlebar halves to be moved apart sufficiently to insert the front fork, or rather its fork tube, into a headset of a bicycle frame. The fork arms then spring back and are fixed in place.

[0054] A connecting system is advantageously provided for fixing. The handlebar halves are advantageously designed as part of the connecting system. For this purpose, the handlebar halves can each be provided with an upwardly and a downwardly pointing cone piece. The two cone pieces belonging to a handlebar half are advantageously formed integrally with this handlebar half. When the cone pieces of both handlebar halves are joined together, they advantageously form a double cone element. The double cone element is thus divided in a vertical plane and comprises a double cone side assigned to each handlebar half. The double cone sides are advantageously an integral part of the fork hollow body.

[0055] It is also useful to provide a lower cup-shaped clamping element. It is conveniently arranged on the fork stem and has a conical inner surface. The inner surface is conveniently designed to conform to the downward-facing conical portions of the two handlebar halves when the handlebar halves are joined in the middle to form the described double-conical element.

[0056] Similarly, a cover-shaped upper clamping element can be provided. This can advantageously close the free end of the fork steerer tube. It is also simply provided with a conical inner surface. This inner surface is conveniently designed to nestle against the upwardly facing conical pieces of the two handlebar halves when the handlebar halves are joined in the middle.

[0057] The upper clamping element can further be provided with a through-hole for an adjustment screw which can protrude into the fork shaft and can be screwed into a nut element, as is usual with an ahead headset.

[0058] The adjusting screw precisely secures the handlebar halves and simultaneously connects them to the fork steerer tube. Furthermore, the adjusting screw can be used to adjust the axial play of a headset bearing.

[0059] The proposed connection system is therefore designed so that it can connect the two handlebar halves and secure them to the fork stem with a single adjusting screw. Furthermore, it is useful if the fork leg's receiving opening, intended for mounting a front axle, forms a downwardly open dropout into which the front axle can be inserted sideways. A locking element is advantageously provided with which the downwardly open dropout can be closed.

[0060] The closure element can be a separate component from the fork hollow body. Therefore, it is possible to use a different plastic material for the closure element and a different manufacturing process than for the fork hollow body.

[0061] Preferably, at least one connecting means is provided which serves to fasten the closure element to the fork leg so that the front axle can be fixed. The fixation can be positively and / or non-positively. The dropout and the closure element are simply in the form of semi-cylindrical shells, between which a clamping slot remains. The closure element can then be fastened to the dropout using screws as a connecting means. For this purpose, the region of the dropout on the fork hollow body is expediently provided with at least one threaded insert, preferably two threaded inserts. Matching this, the closure element is provided with at least one through-opening for a screw, or two through-openings. In this way, a receiving opening is created with which a clamping effect can be generated in order to fix an axle element.

[0062] It is particularly expedient if the front wheel fork has an envelope volume in the range of 3.5 liters to 6.5 liters, preferably in the range of 4.5 liters to 5.5 liters and particularly preferably in the range of 4.7 liters to 5.3 liters.

[0063] In the sense of the invention, the envelope volume of the front wheel fork is understood to be the volume of the outer surface of the front wheel fork, with the proviso that all existing openings, as in the definition of the envelope volume of the main frame, are interpreted as closed surface areas and are attributed to the outer surface of the front wheel fork.

[0064] Furthermore, it is advantageous, either on its own or in combination with the aforementioned envelope volume, if the front wheel fork has a weight in the range from 1.9 kg to 3.7 kg, preferably from 2.4 kg to 3.2 kg and particularly preferably from 2.7 kg to 2.9 kg.

[0065] Advantageously, the front fork has a specific weight of 0.29 kg / liter to 1 kg / liter in relation to its envelope volume.

[0066] A further benefit is also seen for this front wheel fork if the one-piece design of the hollow fork body is produced by means of rotational molding in an externally heated rotational molding tool.

[0067] The fork hollow body can have areas with different wall thicknesses of the fork wall.

[0068] The areas of different wall thickness of the fork wall can be created by a locally different heat supply from the outside into the rotational forming tool.

[0069] The advantages of the different wall thicknesses of the fork wall and the generation through targeted heat supply also correspond for this front wheel fork in principle to the advantages of the main frame described above, if the frame walls have different wall thicknesses due to rotational forming.

[0070] It is very advantageous that the front fork is assigned a front axle as a structural component.

[0071] The front axle can comprise two cup-shaped or two hollow cylindrical axle elements, each axle element having a bearing seat for a wheel bearing and a fitting area for connection to the dropout of a fork leg. The bearing seat and the fitting area are arranged circumferentially. The fitting area has a cylindrical or polygonal cross-section, with the proviso that the unit comprising dropout and closure element has a matching hollow cylindrical or hollow polygonal cross-section. The front axle is arranged so as to be non-rotatable relative to the rest of the front fork. When assembled, the front axle forms a structural reinforcement of the front fork.

[0072] The two axle elements of the front axle can be easily connected in alignment to form an axle connection. Each axle element has a connecting end. The axle connection is established using the connecting ends.

[0073] The connecting ends of the two axle elements are designed in such a way that the axle connection can be made by means of a screw connection.

[0074] The screw connection can have a separate screw and a separate nut or a nut thread is integrated in one of the axle elements and can interact with a screw.

[0075] Preferably, the screw connection is provided by a connecting end which is designed in the form of an external thread on a cylindrical outer surface of one of the axle elements, wherein the connecting end of the other axle element is designed in the form of a matching internal thread. This design allows the axle elements to be designed as hollow cylinders. This can save weight. Furthermore, the hollow design represents an attractive design element. The front wheel fork, like the main frame, can be provided with a data storage element, preferably with an RFID storage element, in order to store material information and / or data relating to the processing of the plastic material used for the front wheel fork.

[0076] The plastics proposed for the front fork are the same as those used for the main frame. In the case of polyethylene (PE or HDPE), for example, they have relatively low strength, hardness, and stiffness because reinforcing fillers such as fibers are omitted for reasons of recyclability and pure plastics are used instead. To provide strength for a bicycle frame, the solution is to design the front fork as a voluminous hollow fork body. Its volume is significantly larger than that of conventional front forks made of steel or aluminum, and also larger than the volume of a front fork made of a fiber-reinforced plastic, such as a carbon front fork.

[0077] The invention further comprises a bicycle frame for a bicycle with a saddle and with a front wheel and a rear wheel in a track, comprising a main frame according to one of claims 1 to 25 and comprising a front wheel fork according to one of claims 26 to 46.

[0078] Advantageously, the front fork has two fork legs. This provides a bicycle frame that combines a single-sided rear wheel carrier for the rear wheel with a double-sided bearing for the front wheel.

[0079] Bicycle frame according to claim 41 or 42, characterized in that the main frame and the front wheel fork form a unit in the assembled state, wherein when the unit is subjected to an impact test, after the impact test with a falling total mass of 90 kg, which is made up of partial masses, namely a mass Mi of 50 kg on the seat tube element, a mass M2 of 10 kg on a test steering head and a mass M3 of 30 kg on a test bottom bracket, at a drop height of 200 mm according to DIN ISO 4210-6: 2015, Chapter 4.2 for city and trekking bikes and according to the requirements of DIN ISO 4210-2: 2015, Chapter 4.8.3, it does not have any cracks or breaks.

[0080] The bicycle frame proposed here, or rather the main frame and / or the front wheel fork, are designed to be used in an economic cycle. To this end, the material used to manufacture the main frame and / or the front wheel fork should be an easily recyclable thermoplastic. A plastic is easily recyclable when it is produced in pure form. Pure form facilitates processing prior to reuse and simplifies the circular economy. In this way, an old bicycle frame can serve as raw material, for example, to manufacture a new bicycle frame.

[0081] The proposed main frame and / or front fork favor the use of a recyclable thermoplastic. The proposed solution includes the use of recycled plastic for initial production.

[0082] A50 Finally, a bicycle component from the group: main frame, front wheel fork and wheel is proposed. This bicycle component comprises a one-piece hollow body with a component wall enclosing its cavity, wherein the component wall of the hollow body is produced in a closed molding tool from a thermoplastic and has a one-piece design which is produced by means of rotational molding in an externally heatable molding tool provided for rotational molding, with the additional proviso that a foam is arranged in the cavity and that the foam extends at least partially as a foam layer over the inside of the component wall or preferably completely fills the cavity.

[0083] The foaming process is advantageously carried out inside the cavity. Preferably, the foaming process is carried out while the rotational molding of the component wall is still in progress using molten thermoplastic for rotational molding of the component wall. A starting material for the foam is filled into the resulting cavity through at least one suitable filling means provided on the molding tool, in order to foam therein. Simply, the starting material is filled into the same opening in the molding tool as the thermoplastic for the component wall. A feed tube can be used which can be inserted into the molding tool. It can be inserted so deeply that it penetrates the layer of molten thermoplastic that has already formed on the inside of the molding tool.The foam starting material can be easily filled while the rotation of the forming tool is stopped. The rotation of the forming tool is not merely a circular motion, but advantageously a complex three-dimensional movement in space. To fill the foam starting material, it is possible, for example, to stop one component of the complex movement, then insert the feed tube into the filling means of the forming tool and fill the foam starting material into the remaining cavity.

[0084] In principle, the foaming process can be a physical process or it can be based on a chemical reaction. The foam starting material, in the form of granules, is conveniently filled through the filling device of the forming tool into the resulting cavity. For chemical foaming, the granules of the starting material can simply be provided with a blowing agent. The blowing agent is preferably designed so that it can be evaporated upon application of heat. If the application of heat also melts the starting material, the evaporated blowing agent can foam the molten starting material.

[0085] The invention is illustrated below by way of example in a drawing and described in detail with reference to several figures. They show:

[0086] Fig. 1 is a perspective view of a main frame according to the invention,

[0087] Fig. 2 is a view of the right side of the main frame according to Fig. 1,

[0088] Fig. 3 is a rear view of the main frame according to Fig. 1,

[0089] Fig. 4 is a plan view of the main frame according to Fig. 1,

[0090] Fig. 5 a detailed view of the rear wheel mount according to section V - V in Fig. 2,

[0091] Fig. 6 is a detailed view along section line V - V in Fig. 2 concerning a rear wheel mount for a standard axle, Fig. 7 is a detailed view of the pedal drive mount along line VII - VII in Fig. 2,

[0092] Fig. 8 Detailed view of an alternative pedal drive mount according to VII - VII in Fig. 2,

[0093] Fig. 9 is a perspective view of a front wheel fork according to the invention,

[0094] Fig. 10 is a view of the right side of the front fork according to Fig. 8,

[0095] Fig. 11 Sectional view through the front wheel fork according to Fig. 9,

[0096] Fig. 12 a front view of the front fork with a mounted front axle,

[0097] Fig. 13 the front axle from Fig. 12,

[0098] Fig. 14 a partial sectional view of the front axle in the mounted state at the dropouts of the front fork,

[0099] Fig. 15 an alternative design of the partial sectional view of the dropouts of the front fork for a standard axle,

[0100] Fig. 16 a detailed view according to XVI - XVI in Fig. 12 of a connection system for handlebar halves,

[0101] Fig. 17 is a perspective view of a bicycle frame according to the invention, comprising a main frame and a front fork

[0102] Fig. 18 is a perspective view of an alternative front fork, based on the front fork of Fig. 9, designed as a bicycle component with a rotationally molded hollow body and a foam filling,

[0103] Fig. 19 is a right side view of another alternative front fork based on the front fork of Fig. 10, designed as a bicycle component with a rotationally molded hollow body with a layer of foam.

[0104] Fig. 1 shows an embodiment of a main frame 1 according to the invention for a bicycle which is ridden in an upright position with a saddle and with a front wheel and a rear wheel. These wheels are arranged in the same track. The main frame 1 shown is produced as a hollow body 2 with a frame wall 3 enclosing the hollow space. The hollow body 2 is formed in one piece, or rather its frame wall 3. The one-piece main frame 1 is produced by means of rotational molding in an externally heatable rotational molding tool from a fiber-free thermoplastic, here a pure recycled hard polyethylene (HDPE). The frame wall 3 is provided with a data storage element 3c, in which material information and / or data relating to the production of the main frame are preferably stored, in particular information about the plastic material used.

[0105] To provide the strength required for a bicycle frame, the main frame 1 is designed as a voluminous hollow body 2. Its external volume is significantly larger than the external volume of known main frames made of steel, aluminum, or carbon.

[0106] The main frame 1 comprises a main support 4 and a one-sided rear wheel support 5, on which a rear wheel can only be mounted on one side. The structure of the main support 4 has regions Ti, T2 and T3 with greater wall thickness of the frame wall 3. Furthermore, according to Fig. 1, it is trapezoidal in shape. A top tube element 6, a down tube element 7, a seat tube element 8 and a head tube element 9 are provided. All of the mentioned tube elements of the trapezoidal structure are voluminous and hollow and form regions of the hollow main support 4. The down tube element 7 and the seat tube element 8 meet at a lower node 10 and there form a pedal drive mount 11 in the form of a closed pedal drive housing 12.

[0107] The head tube element 9 is arranged at the front in the direction of travel. It is designed to accommodate a headset bearing that interacts with a fork shaft. The head tube element 9 is hollow and cylindrical. It is constructed to accommodate a headset bearing. A headset bearing is understood to mean, for example, a so-called ahead headset, which comprises a lower bearing, which is to be arranged at the bottom in the head tube element 9, and an upper bearing, which is to be arranged at the top in the head tube element 9, as well as a clamping device with an adjusting element for the fork shaft. The bearing play in the upper and lower bearings of the ahead headset can be adjusted by means of the clamping device. In general, the terms “bottom” and “top” in this description always refer to the main components of the bicycle frame, namely when a bicycle equipped with one is in an upright position, such as when traveling straight ahead.

[0108] The rear wheel carrier 5 has a triangular structure 13.

[0109] This includes the already mentioned seat tube element 8 as well as an upper support element 14 and a lower support element 15.

[0110] The seat tube element 8 essentially forms an interface between the main carrier 4 and the rear wheel carrier 5. The left side of the rear wheel carrier 5 in the direction of travel is referred to as the wheel side W, and the right side of the rear wheel carrier 5 is referred to as the drive side D. When a bicycle having this main frame is in the ready-to-use state, the rear wheel is arranged on the wheel side W.

[0111] The lower support element 15 of the rear wheel carrier 5 is designed as a housing 16 for a drive means. At a front end 15a of the lower support element 15, it meets the down tube element 7 and the seat tube element 8 at the lower node 10. The area of ​​the lower node 10 is designed as the aforementioned pedal drive housing 12. The pedal drive housing 12 provides space for a bottom bracket and, alternatively, there is sufficient space for a bottom bracket gear. It would also be possible to accommodate a bottom bracket drive, which may include an electric motor.

[0112] The upper support element 14 of the rear wheel carrier 5 meets the seat tube element 8 and the top tube element 6 of the main carrier 4 at an upper node 17. In a rear region 5a of the rear wheel carrier 5, the upper support element 14 and the lower support element 15 meet at a rear node 18 and there form a rear wheel receptacle 19. The rear wheel receptacle 19 is designed in the form of bearing openings. A bearing opening 20 is provided on the wheel side W, and a bearing opening 21 is provided on the drive side D. The bearing openings 20 / 21 can be designed to accommodate a shaft bearing for a drive shaft (not shown), which rotates relative to the rear wheel carrier 5 and to which a rear wheel can be fastened.Alternatively, the bearing openings 20 and 21 may be adapted to receive a rear axle (not shown) that is fixed relative to the rear wheel carrier 5, so that a rear wheel mounted on the rear axle rotates. The rear axle may be a standard rear axle.

[0113] Furthermore, the trapezoidal structure of the main beam 4 is provided with a stiffening hollow bridge element 22, which is arranged between the top tube element 6 and the down tube element 7. According to Fig. 1, the bridge element 22 is arranged approximately parallel and close to the head tube element 9. A polygonal open area 23 is provided between the bridge element 22 and the head tube element 9. The bridge element 22 thus designed reinforces the main beam 4 of the main frame 1.

[0114] Furthermore, the seat tube element 8 is provided with an upper seat tube extension 24, which projects upward from the top tube element 6. A reinforcing hollow bridge element 25 is provided on the seat tube extension 24 and extends to the top tube element 6. The seat tube extension 24 is supported in this way. Furthermore, the bridge element 25 serves as a handle element 26 for lifting and easily carrying a bicycle when necessary.

[0115] Furthermore, Fig. 1 shows that a large service opening 27 is provided on the drive side D in the area of ​​the pedal drive housing 12, which provides access to the housing 16 for the drive means for service and assembly purposes, which can be accommodated in an encapsulated manner in the lower support element 15 of the rear wheel carrier 5.

[0116] Fig. 2 shows a view of the right side of the main frame 1, i.e., the drive side D. The pedal drive housing 12 can be seen, the large service opening 27 of which is closed here with a service cover 28. The service cover 28 is in turn provided with a bearing opening 29 for receiving a bearing element, for example, for a pedal crankshaft.

[0117] On the left side of the main support 4, the pedal drive housing 12 can be dispensed with without a service cover; here, only a bearing opening 30 for a pedal crankshaft is provided, as best seen in Fig. 7. In order to provide stable bearing openings 29 and 30, the area Ti of the frame wall 3 is reinforced. A region T2 of the frame wall 3, which forms the head tube element 9, is also reinforced.

[0118] Fig. 3 shows a view of the main frame 1 from the rear. It can be seen that the rear wheel mount 19 on the rear wheel carrier 5 on the drive side D (right) projects the furthest to the side. This serves to provide sufficient distance between the bearing opening 21 on the drive side D and the bearing opening 20 on the wheel side W in order to be able to absorb forces / moments that are introduced into the rear wheel carrier 5 by a rear wheel arranged on one side. In order to provide stable bearing openings 20 and 21, the area T3 of the frame wall 3 is reinforced.

[0119] Fig. 4 is a plan view of the main frame 1 according to Fig. 1, which shows the position of a center line M of the main carrier 4. This center line M corresponds to the track in which the wheels of the bicycle are to be arranged. In the area of ​​the rear wheel carrier 5, its asymmetrical one-sided position is evident, namely on the right-hand side of the track in the direction of travel. The frame wall 3 of the main frame 1 has two opposing frame walls 3a and 3b. The plan view also shows on the drive side D that the rear wheel mount 19 on the rear wheel carrier projects the furthest to the side on the drive side D. It is also shown that the pedal drive housing 12 is aligned with the lower support element 15 of the rear wheel carrier 5. Furthermore, the top view provides a view of an upper opening 31 of the head tube element 9 and an upper opening 32 of the seat tube element 8.

[0120] Fig . 5 shows a cross section through the rear wheel mount

[0121] 19 of the rear wheel carrier 5 according to the section line V - V in Fig. 2, specifically in the direction of view indicated. Two bearing openings are then provided, one bearing opening

[0122] 20 on the wheel side W . A second bearing opening 21 is arranged coaxially to the bearing opening 20 and specifically on the opposite drive side D of the rear wheel carrier 5 . The bearing openings 20 / 21 are prepared to receive a shaft bearing for a rear wheel shaft (not shown). The bearing openings are hollow cylindrical in design to receive the shaft bearings. The bearing opening 20 has an inner stop surface 33 in the axial direction, which serves as an axial stop surface for a bearing element. The cylindrical inner surface 33a serves as a seat for a bearing element.

[0123] The diameter of the bearing opening 20 and the quality of the inner surface 33a must be designed to match the desired bearing element, i.e., they must be within a required tolerance. The inner surface 33a can be a plastic surface. The rotational molding process makes it possible to create a precisely fitting bearing opening with a plastic surface. Alternatively, a precisely prefabricated metal ring can be integrated during rotational molding. A dash-dot line in the area of ​​the inner surface 33a indicates an alternative, precisely fitting, integrated aluminum ring 34. The aluminum ring 34 is connected to the plastic of the rear wheel carrier by adhesion and / or positive locking.

[0124] The bearing opening 21 arranged on the wheel side W has an inner stop surface 35 and a cylindrical inner surface 35a. The dash-dot line in the area of ​​the inner surface 35a indicates the alternative of an integrated, precisely fitting aluminum ring 36. The aluminum ring 36 is also connected to the plastic of the rear wheel carrier 5 by adhesion and / or positive locking.

[0125] The bearing opening 20 has a larger diameter than the bearing opening 20 provided on the drive side D. This is advantageous when the drive means arranged in the encapsulated housing 16 is arranged closer to the wheel side W and higher forces are to be expected there.

[0126] The diameter of the hollow cylindrical bearing openings 20 and 21 is preferably in the range of 40 mm to 130 mm. In the present example, the wheel-side bearing opening 20 has a diameter of 120 mm, and the bearing opening 21 arranged on the drive side D has a diameter of 90 mm.

[0127] Fig. 6 also shows a cross-section according to section line V - V in Fig. 2, wherein this sectional view shows the rear wheel mount 19 together with a rear wheel 100 indicated as a dashed line. In this example, a fixed, solid rear axle 101 is provided. The one-sided rear wheel carrier 5 corresponds to that according to Fig. 5, i.e. it has bearing openings 20 and 21. Arranged in the bearing opening 21 is a cylindrical disk element 102 which is provided with a through opening 102a for the rear axle 101. The rear wheel 100 has a hub sleeve 103 which forms a seat 103a on the outside for a rolling bearing 104, specifically for an inner ring of the rolling bearing 104. The corresponding outer ring of the rolling bearing 104 is mounted in the rear wheel carrier 5, specifically in the bearing opening 20 of the rear wheel carrier 5.The hub sleeve 103 further has a hollow cylindrical interior 105, which provides space for a rolling bearing 106 and a freewheel element 107. The rolling bearing 106 is designed to be preloaded in the axial direction. The preload is provided by the rear axle 101, which for this purpose has threaded ends 101a and 101b for preloading it with axle nuts 108 and 109.

[0128] On the rear axle 101, two roller bearings 110 and

[0129] 111 supports a pinion 112, which is part of a bicycle drive. In the assembled state, the pinion 112 interacts with a bicycle chain (not shown) as a drive means, wherein the drive means is arranged within the rear wheel carrier 5. The rear wheel carrier 5 serves as an encapsulating housing 16 for the drive means and the pinion 112.

[0130] The mentioned freewheel element 106 is arranged between the pinion

[0131] 112 and the hub sleeve 103 , the transmission of a rotary movement is only permitted in one direction of rotation of the rear wheel and can transmit a torque .

[0132] Using the example of Fig. 6, a rear wheel can be equipped with a conventional hub gear, for example, which has a fixed axle. The axle can be a solid axle or, alternatively, a hollow axle.

[0133] Fig. 7 shows a cross-section through the pedal drive mount 11 of the main frame 1 according to the section VI I - VI I, which is noted in Fig. 2. The pedal drive mount 11 comprises on the drive side D the service opening 27, which is prepared to receive a service cover 28. The service cover 28 has a bearing opening 29, preferably for a plain bearing element 120, which serves to mount a pedal crankshaft (not shown). The plain bearing element 120 has a diameter of 30 mm in the example. On the opposite side, the pedal drive mount 11 has a bearing opening 30, in which a bearing element (not shown) for the pedal crankshaft can also be received, preferably also a plain bearing element. The service opening 27 for the service cover 28 has a diameter of 120 mm in the example.

[0134] Fig. 8 also shows a cross-section through the pedal drive mount 11 of the main frame 1 along section line VII - VII, as noted in Fig. 2. This is an alternative design of the pedal drive mount 11, which differs in the modified bearing openings 121 and 122. Both bearing openings 121 and 122 have a large cross-section. In the example, they each have a diameter of 120 mm. The large bearing openings serve, for example, to accommodate a roller bearing whose inner ring and / or outer ring are made of a plastic.

[0135] This design makes it possible, for example, to accommodate a pedal drive that includes a bottom bracket gear or a bottom bracket drive with an electric motor.

[0136] The main frame shown in Figs. 1 to 4 has an envelope volume of 20.25 liters with a tolerance of ±0.25 liters. Its weight is 4.75 kg with a tolerance of ±0.2 kg.

[0137] Fig. 9 is a perspective view of a front fork 40 according to the invention. The front fork is designed for a bicycle which is ridden in an upright position with a saddle. The bicycle is provided with a front wheel and a rear wheel which are arranged in a track. The front fork 40 has a stable fork bridge area 41 . Two fork legs 42 and 43 are arranged symmetrically and pointing downwards on the fork bridge area . In addition, a fork arm 44 or 45 is attached to the top of each fork leg, which extends to an integrated handlebar element 46 and is connected thereto. In the middle of the fork bridge there is a fork shaft 47 which is shown in dashed lines. In the present example the fork shaft 47 is a metal tube which is connected to the fork bridge area 41 in a rotationally fixed manner.

[0138] The handlebar element 46 is clearly split in the middle. It has a left handlebar half 48 and a right handlebar half 49, each of which is connected to the corresponding fork arm. The division serves to simplify assembly of the front fork 40. The fork arms 44 and 45 are designed such that they can be elastically spread apart so that the handlebar halves 48 and 49 move sufficiently far apart so that the fork shaft 47 of the front fork can be inserted into a headset of a bicycle frame. The fork arms then spring back and are finally fixed by means of a connection system, which is shown in Fig. 11 and best in Fig. 17.

[0139] The proposed front wheel fork 40 is manufactured in a closed rotational molding tool from a thermoplastic. It forms a hollow fork body 50 with a fork wall 51. The hollow fork body 50 is one-piece, its fork wall 51 is seamless. In the present example, as mentioned, only the fork shaft 47 has been subsequently inserted and connected to the fork bridge area 41 of the hollow fork body 50. The one-piece design was produced by means of rotational molding in an externally heatable rotational molding tool, specifically from a fiber-free thermoplastic, in this case a pure recycled high-density polyethylene (HDPE). Alternatively, the subsequently inserted fork shaft 47 can also be inserted into the rotational molding tool in order to bond with the thermoplastic of the hollow fork body 50 during the rotational molding process.In this way, the metal tube of the fork shaft is also provided as an integral part of the front fork.

[0140] The fork leg 44 is provided with a dropout 52, and the fork leg 45 with a dropout 53 to accommodate a front axle. This is a special front axle that has a large diameter, as can be seen from the dropouts 52 and 53. The dropouts are designed to be open at the bottom, and a separate closure element is provided for each dropout 52 / 53, as described below.

[0141] The fork leg 42 is also provided with a fastening element 54 which can be used, for example, for mounting a braking device, in particular for a brake caliper of a disc brake.

[0142] The fork hollow body 50 has regions with varying wall thicknesses of the fork wall 51. The thicker regions of the fork wall 51 are created by a higher heat input from the outside into the rotational forming tool in these regions. In the present example, the lower regions 42a and 43a of the fork legs 42 and 43 are provided with a thicker fork wall.

[0143] The fork wall 51 is provided with a data storage element 51a in which material information and / or data relating to the production of the front wheel fork 40 are preferably stored, in particular information about the plastic material used.

[0144] The front wheel fork 40 according to Fig. 10, including the closure elements 55 and 57, has an envelope volume of 5 liters with a tolerance of ± 0.15 liters. Its weight lies in the range of 2.4 kg to 3.2 kg with a tolerance of ± 0.1 kg.

[0145] Fig. 10 shows a side view of the front wheel fork 40. A closure element 55 is mounted on the dropout 53 of the fork leg 43. The closure element 55 complements the dropout 53 and forms with it a receiving opening 56 for holding the special front axle. Connecting means 55a and 57a in the form of screws (not shown) are provided to fasten the closure elements 55 and 57 to the fork leg 42 and 43, respectively. For assembly, the front axle can be inserted sideways or from below and secured with the closure element 55.

[0146] In the present example, the locking element 55 creates a clamping connection that secures the front axle to the dropout in a rotationally fixed manner. Instead of a clamping connection that acts by friction, a positive-locking design could also be provided to achieve a rotationally fixed fixation of the front axle in the receiving openings of the fork legs.

[0147] To provide the fixation in this example, screws are used as connecting elements. The dropouts are therefore provided with internal threads, and the closure element has matching through holes for the screws.

[0148] Fig. 11 shows a section along the line XI-XI in Fig. 9, wherein the fork stem 47 is shown in Fig. 11. The fork stem 47 is held at the bottom in the fork bridge area 41 and at the top by means of the connection system already mentioned, which is described in detail with reference to Fig. 16. Furthermore, Fig. 11 shows a closure element 57 belonging to the dropout 52 of the fork leg 42, which thus forms a receiving opening 58 for the front axle.

[0149] As illustrated in Fig. 12, the front fork 40 is assigned a special front axle 59. The front axle 59 is a structurally important component for the proposed front fork 40. For a front fork 40 having a hollow fork body 50 made of a single-material plastic, it is advantageous to provide the front axle 59 as a stiffening component. This can significantly improve the strength of the front fork 40.

[0150] The front axle 40 comprises two cup-shaped or, as shown in Fig. 13, two hollow cylindrical axle elements 60 and 61. The two axle elements of the front axle are aligned and connected to one another. For this purpose, connecting ends 60a and 61a are provided, wherein the connecting end 60a of the axle element 60 is provided with an external thread 62 and the connecting end 61a of the axle element 61 has a matching internal thread 63, which are screwed together.

[0151] The axle element 60 has a bearing seat 64 for a wheel bearing. In addition, the axle element 60 is provided with a cylindrical fitting area 65 for the purpose of connection to the dropout 52 of the fork leg 42. The fitting area 65 comprises lateral webs 65a and 65b, as best seen in Fig. 14. The webs 65a and 65b are spaced from one another by a distance corresponding to the thickness of the fork leg 42. The fork leg 42 is fixed between the webs 65a and 65b. In the same way, the axle element 61 is provided with a bearing seat 66 for a wheel bearing and has a fitting area 67 for the purpose of connection to the dropout 53 of the fork leg 43. The fitting area 67 is also provided with webs 67a and 67b. The webs similarly fix the fork leg 43 in the axial direction of the front axle 59.

[0152] The bearing seats 64 / 66 and the fitting areas 65 / 67 are arranged on the circumference of the axle elements 60 / 61. In this example, the fitting areas 65 / 67 have cylindrical cross-sections and are clamped into the receiving openings 56 and 58 of the fork legs, respectively. In this way, the front axle 59 is arranged in a rotationally fixed manner relative to the front fork 40 and serves as a structurally stiffening element of the front fork 40.

[0153] Fig. 15 shows an alternative design of the front fork dropouts for a standard axle. The fork legs 42 and 43 correspond to those in Fig. 14. An adapter element 56a and 58a is arranged in the receiving openings 56 and 58, respectively. The adapter elements 56a and 58a are identical components. They each have a central opening 56b and 58b, respectively, designed to accommodate a standard axle. The central opening 56b / 58b is an elongated hole. This allows the alignment of a front wheel to be adjusted centrally between the fork legs 42 and 43.

[0154] Fig. 16 shows a detailed view along section XVI-XVI in Fig. 12. Visible are the handlebar half 48 of the split handlebar element 46 as well as the fork arm 44 that supports this handlebar half 48. In order to mount the front wheel fork 40 in a headset element of the main frame, the fork arms 44 / 45 with the attached handlebar halves 48 / 49 are spread apart and spring back when mounted. The handlebar halves are then secured to one another by means of a connecting system 68 and secured to the fork shaft 47.

[0155] The proposed connection system 68 is designed such that it can connect the two handlebar halves 48 and 49 as well as fasten them to the fork stem 47 with a single screw. It comprises a double-cone element 69 which is divided in a vertical plane and forms two double-cone sides 70 and 71. The double-cone side 70 is assigned to the handlebar half 48 and the double-cone side 71 to the handlebar half 49. In the present example, the double-cone sides 70 and 71 are an integral part of the fork hollow body 50.

[0156] The double cone side 70 comprises an upwardly facing cone piece 70a and a downwardly facing cone piece 70b and the double cone side 71 comprises an upwardly facing cone piece 71a and a downwardly facing cone piece 71b.

[0157] In addition, a lower cup-shaped clamping element 72 is provided, which is arranged on the fork shaft 47. An inner surface 73 of the clamping element 72 is conical and fits snugly against the downward-facing conical pieces 70b and 71b of the two handlebar halves 48 / 49 in order to fix them.

[0158] In the same way, a cover-shaped upper clamping element 74 is provided which closes the free end of the fork stem 47. It has a conical inner surface 75. The inner surface 75 nestles against the upwardly pointing conical pieces 70a and 71a in order to fix them, or rather to fix the split handlebar halves 48 / 48. The upper clamping element 73 is provided with a through-opening 76 for an adjusting screw 77. The adjusting screw 77 projects into the fork stem 47 and is screwed into a nut element 78 which can be fixed in the hollow cylindrical fork stem 47 by frictional engagement. In the example, this is a claw nut 79 which can be fixed by means of spring-loaded claws 80.

[0159] The adjusting screw 77 precisely fixes the handlebar halves 48 and 49 and simultaneously connects them to the fork shaft 47. Furthermore, the adjusting screw 77 can be used to adjust the axial play of a headset bearing.

[0160] Fig. 17 shows a bicycle frame 81 comprising a main frame 1 and a front wheel fork 40.

[0161] Fig. 18 shows a perspective view of an alternative bicycle component. Using a front wheel fork as an example, it is explained how the alternative bicycle component is constructed and how it is manufactured. The example of the alternative bicycle component is based on the front wheel fork in Fig. 9. According to Fig. 18, the bicycle component is designed as a one-piece hollow body, here the fork hollow body 50, with a component wall, here the fork wall 51, which encloses its hollow space. The fork wall 51 is produced in a closed molding tool from a thermoplastic. The one-piece nature of the fork wall 51 is produced by means of rotational molding in a molding tool that can be heated from the outside and is provided for rotational molding. The alternative in Fig. 18 therefore differs from the example in Fig.9 that a foam 125 is additionally arranged in the fork hollow body 50, which in the present example fills the cavity. The foaming process was carried out inside the cavity while the rotational molding of the fork wall 51 was still in progress using molten thermoplastic material for the fork wall 51. The starting material for the foam was filled into the molding tool as granules using a suitable filling agent. The granules used are foamable through chemical reaction. For this purpose, they contain a blowing agent. In the present example, the blowing agent is designed to evaporate when heat is applied. The application of heat also melts the starting material, which subsequently foams as a result of the evaporating blowing agent.

[0162] Fig. 19 shows a further example of an alternative bicycle component. For this alternative, too, the construction and manufacture of the alternative bicycle component is explained using a front wheel fork as an example. The example is based on the representation of the front wheel fork in Fig. 10. According to Fig. 19, the bicycle component is again designed as a one-piece hollow body, here the fork hollow body 50 with a component wall, namely a fork wall 51. The fork wall 51 encloses the hollow space. It is produced in a closed forming tool from a thermoplastic material. The one-piece nature of the fork wall 51 is again produced by means of rotational molding in a forming tool which can be heated from the outside for rotational molding.

[0163] The alternative in Fig. 19 differs from the example in Fig. 10 and from the example in Fig. 18 in that a foam 126 is additionally arranged in the fork hollow body 50, which in the present example coats the component wall of this bicycle component, namely a fork wall 51 on its inner side facing the hollow space. The hollow space of the fork hollow body 50 is thereby reduced but does not disappear.

[0164] List of reference symbols

[0165] Main frame

[0166] hollow body

[0167] Frame wall a Frame wall b Frame wall c Da tenspei lieber element

[0168] Main beam

[0169] Rear wheel carrier a rear area

[0170] Top tube element

[0171] Under-ear element

[0172] Seat tube element

[0173] Steering tube element 0 Node lower 1 Pedal drive mount 2 Pedal drive housing 3 Triangular structure 4 Support element upper 5 Lower support element 5a Front end 6 Housing (drive means) 7 Upper node Node rear

[0174] Rear wheel mount

[0175] Warehouse opening

[0176] Warehouse opening

[0177] Bridge element open area

[0178] saddle tube extension

[0179] Intermediate element

[0180] Handle element

[0181] Service opening

[0182] Service cover

[0183] Warehouse opening

[0184] Bearing opening upper opening (head tube element) upper opening (seat tube element) inner stop surface (bearing opening 20) inner stop surface (bearing opening 21) Front fork Fork bridge area Left fork leg a stronger area (fork wall) Right fork leg a stronger area (fork wall) Left fork arm Right fork arm Handlebar element Fork tube Left handlebar half Right handlebar half Fork hollow body Fork wall a Data storage element Dropout 53 Dropout

[0185] 54 Fastening element

[0186] 55 locking element

[0187] 55a Connecting devices

[0188] 56 Recording opening

[0189] 56a adapter element

[0190] 56b central opening

[0191] 57 locking element

[0192] 57 a Connecting devices

[0193] 58 Recording opening

[0194] 58a adapter element

[0195] 58b central opening

[0196] 59 front axle

[0197] 60 axle element

[0198] 60a connection end

[0199] 61 axle element

[0200] 61a connection end

[0201] 62 external thread

[0202] 63 internal thread

[0203] 64 bearing seat

[0204] 65 Pass area

[0205] 65a footbridge

[0206] 65b footbridge

[0207] 66 bearing seat

[0208] 67 Pass area

[0209] 67a Footbridge

[0210] 67b Footbridge

[0211] 68 connection system

[0212] 69 double chamber element

[0213] 70 double chamber side

[0214] 70a Cone piece top

[0215] 70b Cone piece below

[0216] 71a Cone piece top

[0217] 71b Cone piece below lower clamping element inner surface (lower clamping element) upper clamping element inner surface (upper clamping element) through-hole adjustment screw nut element claw nut claws bicycle frame rear wheel rear axle a threaded end b threaded end disc element a through-hole hub shell a seat roller bearing hollow cylindrical interior roller bearing freewheel element axle nut axle nut roller bearing roller bearing pinion plain bearing element bearing opening bearing opening foam filling 126 foam layer

[0218] D Drive side

[0219] W Wheel side M Center line

Claims

Claims: Main frame (1) for a bicycle with a saddle and with a front wheel and a rear wheel arranged in a track, manufactured in a closed molding tool from a thermoplastic material, characterized in that it is designed as a one-piece hollow body (2) with a frame wall (3) enclosing its hollow space, and that the frame wall (3) of the hollow body (2) is a one-piece structure produced by rotational molding in a rotational molding tool that can be heated from the outside. Main frame (1) according to claim 1, characterized in that the hollow body (2) has areas with different wall thicknesses of the frame wall (3).Main frame (1) according to claim 2, characterized in that the areas of different wall thickness of the frame wall (3) are produced by a region-by-regional different heat input from outside into the rotational forming tool. Main frame (1) according to any one of claims 1 to 3, characterized in that the thermoplastic material of the frame wall (3) is selected from one of the following plastics: polypropylene (PP), preferably polyethylene (PE), particularly preferably high-density polyethylene (HDPE). Main frame (1) according to any one of claims 1 to 4, characterized in that the thermoplastic material is fiber-free.Main frame (1) for a bicycle with saddle and with a front wheel and a rear wheel arranged in a track, made of a thermoplastic material, wherein a main support (4) and a one-sided rear wheel support (5) are integrally formed, wherein the rear wheel support (5) is designed as a hollow body (2), with the provision that the rear wheel support (5) forms an encapsulating housing (16) for a drive means, and that the rear wheel support (5) is provided with a rear wheel receptacle (19), characterized in that the main support (4) is entirely hollow with opposing frame walls (3a, 3b) and is integrally formed with the rear wheel support (5).Main frame (1) according to claim 6, characterized in that the rear wheel mount (19) is designed in the form of two coaxial bearing openings (20, 21), and that the coaxial bearing openings (20, 21) are arranged in the opposing frame walls (3a, 3b) of the rear wheel carrier (5). Main frame (1) according to claim 7, characterized in that the frame wall (3) of the... The hollow body (2) is a single piece produced by rotational forming in an externally heated rotational forming tool. The main frame (1) according to claim 8 is characterized in that the hollow body (2) has areas with different wall thicknesses of the frame wall (3). The main frame (1) according to claim 7 is characterized in that the areas of different wall thicknesses of the frame wall (3) are produced by applying varying amounts of heat from the outside to the rotational forming tool. The main frame (1) according to any one of claims 1 to 10 is characterized in that opposing wall areas of the main support are provided with coaxial bearing openings (29, 30) for receiving a pedal drive.Main frame (1) according to claim 11, characterized in that one of the bearing openings (29, 30) for the pedal drive serves integrally as a service opening for the rear wheel carrier (5), which is designed as an encapsulating housing (16) for a drive means. Main frame (1) according to any one of claims 6 to 12, characterized in that the main support (4) is designed as a trapezoidal structure comprising a top tube element (6), a down tube element (7), a seat tube element (8), and a head tube element (9). Main frame (1) according to claim 13, characterized in that... characterized in that the trapezoidal structure has a stiffening bridge element (22) arranged between the upper tube element (6) and the lower tube element (7). Main frame (1) according to claim 13 or 14, characterized in that the seat tube element (8) has an upper seat tube extension (24) projecting beyond the upper tube element (6). Main frame (1) according to claim 15, characterized in that a stiffening bridge element (25) is provided extending from the upper tube element (6) to the seat tube extension (24).Main frame (1) according to any one of claims 1 to 16, characterized in that the main frame (1) has a hull volume in the range of 18 to 22 liters, preferably in the range of 19 to 21 liters and particularly preferably in the range of 20 to 20.5 liters, and a weight in the range of 3.5 kg to 5.5 kg, preferably from 4.0 kg to 5.0 kg and particularly preferably from 4.5 kg to 4.9 kg. Main frame (1) according to claim 17, characterized in that the main frame (1) has a specific gravity in the range of 0.16 kg / liter to 0.32 kg / liter with respect to its hull volume. Main frame (1) according to any one of claims 1 to 18, characterized in that the inner volume of the hollow body (2) is at least partially filled with a foam. Main frame (1) according to claim 19, characterized in that... characterized in that the foam is produced by foaming in the inner volume of the hollow body (2). Main frame (1) according to one of claims 1 to 20, characterized in that it is prepared in such a way that, after an impact test with a falling mass of 22.5 kg from a drop height of 180 mm in accordance with DIN-ISO 4210-6:2015, section 4.1 for city and trekking bicycles and in accordance with the requirements of DIN-ISO 4210-2:2015, section 4.8.2, it exhibits no cracks or fractures. Main frame (1) according to one of claims 1 to 21, characterized in that it is prepared in such a way that, after a dynamic test with pedaling forces Fi of 1000 N in accordance with DIN-ISO 4210-6:2015, Chapter 4.3 for city and trekking bikes and in accordance with the requirements of DIN-ISO 4210-2:2015, Chapter 4.8.4, it has no cracks or breaks after a required number of 100,000 test cycles.Main frame (1) according to any one of claims 1 to 22, characterized in that it is prepared such that, with a replacement fork mounted, it exhibits no cracks or fractures after a dynamic test with a horizontal force F2 of 450 N in the direction of travel and a horizontal force Fs of 450 N against the direction of travel in accordance with DIN-ISO 4210-6:2015, section 4.4 for city and trekking bicycles and in accordance with the requirements of DIN-ISO 4210-2:2015, section 4.8.5, after a required number of 100,000 test cycles. Main frame (1) according to any one of claims 1 to 23. characterized in that it is designed such that, after a dynamic test with a vertical force F4 of 1000 N according to DIN-ISO 4210-6:2015, section 4.5 for city and trekking bicycles and according to the requirements of DIN-ISO 4210-2:2015, section 4.8.6, it exhibits no cracks or fractures after a required number of 50,000 test cycles. Main frame (1) according to one of claims 1 to 24, characterized in that it is provided with a data storage element (3c), preferably with an RFID storage element, to preferably store material information and / or data relating to the processing of the plastic material used for the main frame (1).Front fork (40) for a bicycle which has a saddle and which is equipped with a front wheel and a rear wheel, which are arranged in a single track, manufactured in a closed molding tool made of a thermoplastic material, wherein at least one fork leg (42, 43) is provided, characterized in that it is designed as a fork body (50) with a fork wall (51), and that the fork wall (51) of the fork body (50) is a single piece, which is produced by rotational molding in a rotational molding tool that can be heated from the outside. Front fork (40) according to claim 26, characterized in that the fork body (50) has areas with different wall thicknesses of the fork wall (51). Front fork (40) according to claim 27, characterized in that the fork body (50) has areas with different wall thicknesses of the fork wall (51). characterized in that the areas of different wall thickness of the fork wall (51) are produced by a region-by-regional different heat input from outside into the rotational forming tool.Front fork (40) for a bicycle which has a saddle and which is equipped with a front wheel and a rear wheel which are arranged in a single track, made in one piece from a thermoplastic material, comprising either a fork leg (42, 43) provided on one side with an upper end and a lower end or two such fork legs (42, 43) arranged symmetrically, wherein a receiving opening (56, 58) is provided at the lower end of the fork leg or the lower ends of the two fork legs (42, 43), and wherein the receiving opening (56, 58) is designed to hold a front axle (59), characterized in that a fork bridge area (41) is formed at the upper end of the fork leg (42, 43), to which a fork arm (44, 45) is attached on one side, which is directed upwards, or two symmetrically arranged fork arms (44, 45) are attached, which are directed upwards.Front fork (40) according to claim 29, characterized in that the fork arm (44, 45) has an upper end, and that the upper end of the fork arm (44, 45) is connected to a steering element (46). Front fork (40) according to claim 30, characterized in that the steering element (46) is formed integrally as part of the fork body (50). A front fork (40) according to any one of claims 29 to 31, characterized in that the receiving opening (56, 58) of the fork leg (42, 43) for holding a front axle (59) forms a downwardly open dropout (52, 53) into which the front axle (59) can be inserted laterally. A front fork (40) according to claim 32, characterized in that a locking element (55, 57) is provided with which the downwardly open dropout (52, 53) can be closed. A front fork (40) according to claim 33, characterized in that at least one connecting means (55a, 57a) is provided which serves to fasten the locking element (55, 57) to the fork leg (42, 43) so that the front axle (59) can be fixed. Front wheel fork (40) according to one of claims 29 to 34, characterized in that it has a casing volume in the range of 3.5 liters to 6.5 liters is preferably in the range of 4.5 liters to 5.5 liters and particularly preferably in the range of 4.7 liters to 5.3 liters, and a weight in the range of 1.9 kg to 3.7 kg, preferably from 2.4 kg to 3.2 kg and particularly preferably from 2.7 kg to 2.9 kg. Front fork (40) according to claim 35, characterized in that it has a specific weight of 0.29 kg / liter to 1 kg / liter of its outer volume. Front fork (40) according to one of claims 29 to 36, characterized in that the one-piece construction of the fork body (50) is achieved by means of a Ro- The front fork (40) is produced by rotational forming in an externally heated rotary forming tool. A front fork (40) according to claim 37, characterized in that the fork body (50) has areas with different wall thicknesses of the fork wall (51). A front fork (40) according to claim 38, characterized in that the areas of different wall thicknesses of the fork wall (51) are produced by a region-by-regional differential heat input from the outside into the rotary forming tool. A front fork (40) according to any one of claims 29 to 39, characterized in that a front axle (59) is assigned as a structural component.Front fork (40) according to claim 40, characterized in that the front axle (59) comprises two cup-shaped or two hollow cylindrical axle elements (60, 61), that each axle element (60, 61) has a bearing seat (64) for a wheel bearing and a mating area (65) for connection with the dropout (52, 53) of a fork leg (42, 43), that the mating area (65) has a cylindrical or polygonal cross-section, and with the proviso that the unit consisting of the dropout (52, 53) and the locking element (55, 57) has a corresponding hollow cylindrical or hollow polygonal cross-section. Front fork (40) according to claim 41, characterized in that the two axle elements (60, 61) can be connected to each other in alignment to form an axle connection, that each axle element (60, 61) has a bearing seat (64) for a wheel bearing and a mating area (65) for connection with the dropout (52, 53) of a fork leg (42, 43), that the mating area (65) has a cylindrical or polygonal cross-section. The axle element (60, 61) has a connecting end (60a, 61a), and the axle connection can be established by means of the connecting ends (60a, 61a). The front fork (40) according to claim 42 is characterized in that the connecting ends (60a, 61a) of the two axle elements (60, 61) are designed such that the axle connection can be established by means of a screw connection. The front fork (40) according to claim 43 is characterized in that the screw connection has a separate screw with a separate nut or a nut thread is integrated into one of the axle elements (60, 61). Front wheel fork (40) according to claim 43 or 44, characterized in that the screw connection is provided by a connecting end (60a) in the form of an external thread (62) on a cylindrical outer surface of one of the axle elements (60), wherein the connecting end (61a) of the other axle element (61) is formed in the form of a matching internal thread (63).Front fork (40) according to one of claims 29 to 45, characterized in that it is provided with a data storage element (51a), preferably with an RFID storage element, to preferably store material information and / or data relating to the processing of the plastic material used for the front fork (40). Bicycle frame (81) for a bicycle with a saddle and with a front wheel and a rear wheel in a track, comprising a main frame (1) according to one of the claims. 1 to 25 and comprising a front wheel fork (40) according to one of claims 26 to 46. Bicycle frame according to claim 47, characterized in that the front wheel fork (40) has two fork legs (42, 43). Bicycle frame according to claim 47 or 48, characterized in that the main frame (1) and the front fork (40) form a unit in the assembled state, and that when this unit is subjected to an impact test, after the impact test with a falling total mass of 90 kg, which is composed of partial masses, namely a mass Mi of 50 kg on the seat tube element, a mass M2 of 10 kg on a test head tube and a mass M3 of 30 kg on a test bottom bracket, at a drop height of 200 mm in accordance with DIN-TSO 4210-6:2015, Chapter 4.2 for city and trekking bicycles and in accordance with the requirements of DIN-ISO 4210-2:2015, Chapter 4.8.3, it shows no cracks or fractures.Bicycle component from the group: main frame, front fork and wheel, comprising a one-piece hollow body (50) with a component wall (51) enclosing its hollow space, wherein the component wall (51) of the hollow body (50) is manufactured in a closed molding tool from a thermoplastic material, wherein the component wall (51) is one-piece, having been produced by rotational molding in a molding tool designed for rotational molding that can be heated from the outside, with the additional requirement that a foam is arranged in the hollow space, and that the foam is at least partially formed as a foam layer (126) over the inner surface. extends along the inner side of the component wall (51) or completely fills the cavity with foam filling (125).

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