Frame and fork system for an electric bicycle and electric bicycle with this

Abstract

Frame-fork system for electric bicycles, comprising a bicycle frame (1) comprising a steering head tube (4) with an end-face insertion opening 14 and at least one frame strut (2) connected to the steering head tube, which has a cavity for internally receiving a power supply unit (13) for an electric auxiliary drive that can be inserted through the insertion opening into the cavity of the frame strut, and comprising a fork assembly for a front wheel rotatably supported or supported on the steering head tube (4) via an upper bearing arrangement (31) and a lower bearing arrangement (32), characterized in that the fork assembly (20; 120) is pivotably supported relative to the bearing arrangements by means of an upper fork bridge (21; 121) and a lower fork bridge (22; 122), and has at least one connecting web (25, 26; 129) which connects the two fork bridges (21, 22;121, 122) with the fork assembly mounted outside the steering head tube (4) in a rotationally fixed manner, whereby the fork assembly (20; 120) allows the power supply unit to be mounted / dismounted with the fork assembly mounted.;

Description

The invention relates to a frame-fork system for electric bicycles, comprising a bicycle frame comprising a steering head tube with an end-face insertion opening and at least one frame strut connected to the steering head tube, which has a cavity for internally receiving a power supply unit for an electric auxiliary drive that can be inserted into the cavity through the insertion opening, and a fork assembly for a front wheel that can be rotatably supported or supported on the steering head tube via an upper bearing arrangement and a lower bearing arrangement. For several years now, it has been common practice on e-bikes to mount the power supply unit, usually a battery, not on the luggage rack or behind the seat tube. Instead, the more aesthetically pleasing solutions involve integrating the battery within one of the frame stays. In most cases, the battery is positioned in the down tube, specifically in a recess into which it can be swung from above or from the side. There are also e-bike models where the battery is inserted from below and then swung upwards into the recess. This pivoting motion can be facilitated by special swivel bearings or a hinged cover to which the battery is attached.The housing of the power supply unit is provided with a protrusion or recess that interacts with a correspondingly shaped counter-protrusion within the recess or with a contact plug during assembly and disassembly. All of the aforementioned solutions allow for relatively easy disassembly of the power supply unit, protecting it from theft and enabling battery charging, if necessary, even when the power supply unit is disassembled. A solution is known from the generic document DE 2019 100 323 U1, in which the power supply unit is inserted into the completely enclosed down tube through an insertion opening in the head tube or steering head tube of the bicycle frame. In the also generic document DE 10 2015 007 111 A1, the head tube even has two openings to allow a power supply unit consisting of a multitude of individual battery cells to be inserted into both the top tube and the down tube through one of the two insertion openings. In both generic solutions, the fork, which is pivotally mounted on the head tube, must be removed, which offers the particular advantages of comparatively good theft protection and tamper resistance for the power supply unit. The object of the invention is to create a frame-fork system for electric bicycles and electric bicycles which is particularly user-friendly, enables the complete arrangement and integration of the energy supply unit in a frame strut, and combines the advantages of solutions known from the prior art. To solve this problem, the invention proposes a frame-fork system for electric bicycles in which the fork assembly is pivotably supported relative to the bearing arrangements by means of an upper fork crown and a lower fork crown, and furthermore has at least one connecting web that non-rotatably connects the two fork crowns to each other outside the head tube when the fork assembly is mounted, thus enabling the power supply unit to be mounted / dismounted while the fork assembly is in place. The particular advantage of the solution according to the invention is that the power supply unit can, in principle, be conveniently and quickly removed at any time without having to disassemble the fork or parts of the fork assembly.The steering head tube remains open with a clearance due to the modified mounting of the fork assembly according to the invention by means of fork bridges on the mounting arrangements inside, which is precisely not penetrated by any tube section of the front fork that follows this movement during steering movements in driving operation, which is why cable connections can also be routed elegantly and completely invisibly from the outside from the down tube into a possibly existing top tube. In a particularly preferred embodiment, the upper bearing arrangement comprises an upper headset bearing and the lower bearing arrangement comprises a lower headset bearing, wherein the upper headset bearing is arranged in an upper bearing receptacle at the upper end of the steering head tube and the lower headset bearing is arranged in a lower bearing receptacle at the lower end of the steering head tube. It is particularly advantageous in this embodiment if the upper headset bearing is rigidly, preferably detachably, connected to the upper fork crown, and / or if the lower headset bearing is rigidly, preferably detachably, connected to the lower fork crown. The respective headset bearings, which must absorb the entire force exerted on the front fork and transfer it to the steering head tube of the bicycle frame, can then be easily maintained and preferably dimensioned to be sufficiently large and robust to reliably absorb and transmit all loads occurring during riding. It is particularly advantageous if the rotationally fixed connection between the upper and lower fork crowns is detachable. This generally simplifies the mounting of the fork assembly to the bicycle frame or its removal from the bicycle frame, should this be necessary due to the replacement of the bearing assemblies. According to an advantageous embodiment, the two fork bridges can be connected to each other via a single connecting web arranged outside the steering head tube, with the upper fork bridge preferably being designed as a cantilever arm projecting essentially on one side beyond the steering head tube. The corresponding design of the frame-fork system is thus similar to the so-called Lefty solutions known to those skilled in the art for the mounting of the front fork, with the difference that in the known solutions the steering head tube is still penetrated by a tube section of the front fork mounting, which is precisely what is avoided in the solution according to the invention.In this design, it is particularly advantageous if the lower fork bridge is formed as an essentially T-shaped plate with a central section and a transverse section, wherein a lower bearing journal is formed on the central section, offset from the connecting web, for interaction with the lower bearing assembly, and two downward-extending fork arms are formed on the transverse section, each having a mounting device for a front wheel axle at its lower end. The wheel axle could also be supported on one side, similar to the Lefty solution mentioned above. According to an alternative advantageous embodiment, the two fork bridges can be connected to each other via two separate connecting webs, each arranged outside the steering head tube, with both fork bridges extending, preferably symmetrically, beyond the outer circumference of the steering head tube on both sides. In this embodiment, it is particularly advantageous if each connecting web has a tubular extension extending downwards beyond the lower fork bridge, at the lower end of which a mounting device for a front wheel axle is provided.This design can prove particularly advantageous if each connecting web and each pipe extension is part of a pipe section and the lower fork bridge is firmly anchored between the two pipe sections; the anchoring can be achieved by means of a welded connection, in which the lower fork bridge is welded to the two pipe sections; other types and methods of connection are also possible; the connecting web can also be formed as one piece with the pipe sections. In all configurations of the frame-fork system, a rotationally fixed connection between the upper fork crown and an upper end of the connecting piece is important; it is particularly advantageous if the upper fork crown is detachably bolted to an upper end of the connecting web. Additionally, positive locking devices can be used between the connection points to achieve the rotationally fixed connection. The above task is also solved for an electric bicycle which is equipped with a bicycle frame, an electric motor and a power supply unit for the electric motor, if the bicycle frame is equipped with a frame-fork system as described above. To achieve effective theft protection and secure anchoring of the power supply unit on an electric bicycle with a corresponding frame-fork system and a power supply unit inserted through the opening in the head tube, it is particularly advantageous to provide a cover or locking element for the opening, which can be attached to the end of the head tube. If the cover is equipped with a special screw or lock, for example, unwanted opening of the opening can be prevented.The removal opening for the power supply unit is prevented and made more difficult; the locking element can also take on additional functions and, for example, be formed by a bicycle light, or be provided with ventilation slots to achieve additional cooling of the power supply unit and better heat dissipation even when the locking element is installed during driving. A particularly advantageous feature of the electric bicycle is the arrangement of an electrical connector for the power supply unit within the frame recess, preferably near the end of the frame strut containing the cavity that is furthest from the insertion opening. In this configuration, the power supply unit's own weight then presses against the connector, providing additional security for the electrical connection. Additionally or alternatively, the cover, when installed, can be used to apply an axial clamping force to the power supply unit, thus securing it to the connector with a fixed and / or preloaded connection.According to a further advantageous embodiment, guides inside the frame shaft can ensure that the power supply unit can only be mounted in a specific orientation that is aligned with the coupling plug; however, this can also be achieved by ensuring that the cross-section of the frame shaft only allows mounting in a specific orientation. Further advantages and embodiments of the invention will become apparent from the following description of exemplary embodiments shown in the drawing. The drawing shows: Fig. 1 in perspective view of an electric bicycle with a frame-fork system according to the invention and a disassembled power supply unit according to a first embodiment; Fig. 2 a side sectional view of the frame-fork system of the electric bicycle from Fig. 1 with the power supply unit mounted and the insertion opening closed; Fig. 3 in perspective view a partial exploded view of the frame-fork system from Fig. 1; Fig. 4 in perspective view only the front fork for the electric bicycle from Fig. 1; Fig. 5 in perspective view a detailed view of an electric bicycle with a frame-fork system according to the invention according to a second embodiment; Fig. 6 the frame-fork system from Fig. 5 in an exploded side view; Fig.Fig. 7 shows only the front fork for the electric bicycle from Fig. 5 in perspective view; and Fig. 8 shows the front fork from Fig. 7 in side view. Figure 1 shows an electric bicycle, designated by reference numeral 10. As is known in the illustration, the electric bicycle 1 has a frame 1 with several frame stays, namely a down tube 2, a seat tube 3, and a head tube 4. In the illustrated embodiment, the electric bicycle 10 also has a top tube 5, which runs partially parallel to the down tube 2 and facilitates mounting the bicycle 10. The bicycle frame 1 further comprises, as is known per se, a rear triangle 6, on which a rear wheel 7 is supported. In the illustrated embodiment, this rear wheel 7 is equipped with a hub motor 8, which amplifies the pedaling force applied to the rear wheel by the user via the crank 9 and the gears 11 when the motor is switched on, as is known in corresponding electric bicycles, and therefore this will not be discussed further here. The front wheel 12 of the electric bicycle 10 is supported on a front fork 20, which is rotationally fixed to a handlebar 16 of the electric bicycle 10 and pivotally supported on the steering head tube 4 to steer the electric bicycle during operation. This is also generally known to those skilled in the art. A special feature of the electric bicycle compared to most known designs is that the power supply unit 13, shown here only schematically, which is a repeatedly rechargeable electric battery with a battery housing of almost any suitable design, is integrated into a cavity in the down tube 2 of the electric bicycle 10, such that the installation and removal of the power supply unit 13 is only possible through an insertion opening 14 in the front of the steering head tube 4.The cavity of the down tube 2 is dimensioned with a suitably large cross-section and has, for example, a round or oval cross-section. The insertion opening 14 on the head tube 4 can and is closed with a locking element 15, shown here only schematically as a cover, in order to protect the mounted power supply unit in the inner cavity of the down tube 2 from environmental influences and to secure it against theft. The mounting and dismounting of the power supply unit 13 is only possible through the insertion opening 14, as is already known in principle from the prior art mentioned above; however, the special feature of the invention is that the mounting and dismounting can also take place when the front fork 20, as shown in Fig. 1, is fully functional and mounted on the bicycle frame 1 of the electric bicycle 10.For this purpose, the electric bicycle 10 is equipped with a frame and fork system adapted accordingly to enable this special function. Figures 2, 3, and 4, which are now referred to, show in detail the front fork 20 installed on the electric bicycle according to Figure 1. The sectional view in Figure 2 clearly shows that the power supply unit is arranged in the cavity of the down tube 2, which is located in line with the insertion opening 14 on the head tube 4. The down tube 2 runs diagonally downwards from front to back, thus against the direction of travel, and the insertion opening 14 accordingly allows the power supply unit 13 to be mounted axially parallel to the course of the down tube 2 through the head tube 4. Figures 2 and 3 clearly show that the steering head tube 4, which connects the front ends of the down tube 2 and the top tube 5, is provided with an insertion opening 14 closed by the cover 15. The power supply unit 13 can be inserted into or removed from the cavity of the down tube 2 (not shown in detail) through this opening. As Figures 3 and 4 particularly illustrate, the front fork 20 has an upper triple clamp 21 and a lower triple clamp 22 above the front wheel. The upper triple clamp 21 has an upper bearing pin 23 projecting downwards beyond the underside of the triple clamp 21, and the lower triple clamp 22 has a lower bearing pin 24 projecting upwards beyond the top of the lower triple clamp 22. The two bearing pins 23, 24 are designed such that they can interact with an upper bearing arrangement 31 and a lower bearing arrangement 32 inside the steering head tube 4, shown schematically in Fig. 2, in such a way that the front fork can pivot relative to the steering head tube 4 transversely to the longitudinal axis of the steering head tube 4, particularly when the handlebars are actuated, while at the same time axial movements parallel to the longitudinal axis of the steering head tube are prevented by the bearings and the fork bridges 21, 22, which are at a fixed distance from each other in the assembly state of the fork arrangement.The lower bearing arrangement 32 is preferably located inside the steering head tube near its lower end, with a headset bearing 33 mounted there in a bearing receptacle and thus replaceable, and the upper bearing arrangement 31 is correspondingly preferably located inside the steering head tube 4 near its upper end, with a headset bearing 34 mounted there in a corresponding bearing receptacle and thus replaceable, wherein the bearing arrangements or headset bearings and bearing receptacle are positioned in particular such that they do not restrict the free space behind the insertion opening 14 in the steering head tube or the cross-section in front of the cavity of the lower tube 2; the headset bearings 33, 34 can, for example, be bearing cups with integrated ball or roller bearings, so that they can be easily replaced by removing the headset bearings 33, 34 from the bearing receptacles in the steering head tube 4; likewise, the projecting length orThe height of the two bearing journals 23, 24 is dimensioned such that they do not restrict the clearance behind the insertion opening 14 in the head tube 4 or the cross-section in front of the cavity of the down tube 2. This ensures that even with the front fork 20 mounted on the bicycle frame of the e-bike 10, the power supply unit 13 can be removed or installed at any time, provided the end cap 15 on the front of the head tube 4 is removed. The headset bearings could also be both, or just one of them, detachably mounted on the fork crown or the bearing journal, so that they can be replaced in case of wear. In the front fork 20 according to the embodiment shown in Figs. 1, 2, 3 to 4, both fork crowns 21, 22 extend transversely to both sides of the bearing journals 23, 24, and each fork crown 21, 22 is connected at each of its two lateral ends by a tube section 25, 26. Both tube sections 25, 26 extend from the upper fork crown 21 beyond the lower fork crown 22 to approximately the level of the axle of the front wheel 12, with a mounting device 27, 28 provided with a bearing eye being formed at the lower end of each tube section 25, 26, to which the axle of the front wheel 12 can be attached. The lower fork crown 22 extends between the two tube sections 25, 26 and is firmly connected to them, for example by welding. However, it could also be formed as a single unit with the pipe sections.The upper fork bridge 21, on the other hand, is detachably connected to the tube sections 25, 26, for example, as in the illustrated embodiment, by detachable screws to the respective upper tube end of each of the two tube sections 25, 26. To remove the front fork 20 from the steering head tube 4, essentially only this screw connection between the fork bridge 21 and the tube sections 25, 26 needs to be loosened. This allows the upper fork bridge 21, possibly together with the handlebar or a handlebar mounting bushing, to be pulled upwards out of the steering head tube, and simultaneously the lower fork bridge 22 to be pulled downwards out of the steering head tube 4. However, loosening the front fork 20 is not necessary to remove the power supply unit from the down tube 2, because the cavity of the down tube 2 is always accessible through the insertion opening 14 in the end face of the steering head tube 4, even with the front fork 20 installed. Figures 5, 6, 7 to 8, to which reference is now made, show a second modified embodiment of a frame-fork system according to the invention. The bicycle frame 1 of the electric bicycle 10 has the identical construction as in the previous embodiment, which is why identical reference numerals are used; reference is made to the above description in its entirety without repetition. The front fork 120 differs from the previous embodiment, with the exception of the design of the front wheel 12.The front fork 120, as in the previous embodiment, has an upper fork bridge 121 and a lower fork bridge 122; the upper fork bridge 121 is provided with a bearing pin 123 that projects beyond the underside of the upper fork bridge, and the lower fork bridge 122 is provided with a bearing pin 124 that projects upwards beyond the top of the lower fork bridge, so that the two bearing pins 123, 124 can, substantially with their free axial length, penetrate into the interior of the steering head tube 4 and interact there with bearing arrangements, which preferably have appropriately designed headset bearings, in order to allow the steering movements between the front fork 120 and the bicycle frame and at the same time to support all axial forces introduced into the front fork 120 via the front wheel 12.Extending from the lower triple clamp 122 to either side of the front wheel 12 are fork arms 125 and 126, respectively, each equipped at its lower end with a fastening device 127 or 128 for the front wheel axle 12. The two fork arms 125 and 126 terminate at the level of the lower triple clamp 122 and are preferably rigidly connected to it or formed integrally with it, or alternatively, detachably and simultaneously rotationally fixed. The lower triple clamp 122 and the upper triple clamp 121 are, however, only rotationally fixed to each other via a single connecting web 129. The connecting web 129 can be rigidly connected to the lower triple clamp 122, for example, by welding, or can be formed integrally with it.The connecting web 129 is centrally attached to the lower fork bridge 122, essentially at the level of the lower bearing pin 124, and thus extends centrally above the running surface of the front wheel, or centrally between the two mounting devices for the front wheel, upwards to the upper fork bridge 121. The lower fork bridge 121 accordingly has approximately the shape of a T-shaped plate with a central section to which the bearing pin 124 is formed and to which the connecting web 129 is attached, and a transverse section on both sides of the bearing pin 124, to the lower end of which the fork arms 125, 126 are attached or formed.The connection between the lower triple clamp 122 and the upper triple clamp 121 is rotationally fixed, but detachable. This is achieved, for example, by providing the upper triple clamp 121 with a downwardly open, asymmetrical, for example oval, or polygonal connecting sleeve 130 into which the upper end of the connecting web 129 is inserted rotationally fixed and then anchored longitudinally along the connecting web 129 by means of a screw connection, for example, which can be mounted from above. To remove the front fork 120 from the steering head tube 4, as shown in Fig. 4, the detachable connection between the two triple clamps 121, 122 must therefore be loosened, since otherwise the two bearing journals 123, 124 would insert into the steering head tube 4 from above and below, respectively, and pivot the front fork 120 about the longitudinal axis of the steering head tube 4.The upper fork bridge 121 projects accordingly only on one side from the bearing pin 123; a connecting pin 135 or a connecting bushing for the handlebar can be formed on the upper side of the fork bridge 121. For a person skilled in the art, the preceding description reveals numerous modifications that fall within the scope of protection of the attached claims. The illustrated bicycle frames with low-slung top tubes are merely examples. The top tube could also run essentially horizontally in a classic style, or be omitted entirely. The electric drive could consist of a mid-drive motor instead of a hub motor. The bicycle frame can have virtually any design, as long as a cavity in one of the frame stays extends in such a way as to allow a battery to be inserted through the head tube into the cavity of this frame stay. The power supply unit could also be positioned in a top tube.A coupling plug for electrically connecting the electric motor to the power supply unit is preferably located at the lower end of the frame strut that has a cavity to house the power supply unit. The bearing journals could also be equipped with or fitted with the steering bearings. The cover could have additional functions, such as a vehicle light integrated into the steering head tube. The cover can also be used to exert a preload force, or at least a holding force, on the power supply unit or its housing when installed, so that it is held securely in the cavity along the longitudinal axis of the frame strut. QUOTES INCLUDED IN THE DESCRIPTION This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature DE 2019 100 323 U1

[0003] DE 10 2015 007 111 A1

[0003]

Claims

Frame-fork system for electric bicycles, comprising a bicycle frame (1) comprising a steering head tube (4) with an end-face insertion opening 14 and at least one frame strut (2) connected to the steering head tube, which has a cavity for internally receiving a power supply unit (13) for an electric auxiliary drive that can be inserted through the insertion opening into the cavity of the frame strut, and comprising a fork assembly for a front wheel rotatably supported or supported on the steering head tube (4) via an upper bearing arrangement (31) and a lower bearing arrangement (32), characterized in that the fork assembly (20; 120) is pivotably supported relative to the bearing arrangements by means of an upper fork bridge (21; 121) and a lower fork bridge (22; 122), and has at least one connecting web (25, 26; 129) which connects the two fork bridges (21, 22;121, 122) with the fork assembly mounted outside the steering head tube (4) in a rotationally fixed manner, whereby the fork assembly (20; 120) allows the power supply unit to be mounted / dismounted with the fork assembly mounted.; Frame-fork system according to claim 1, characterized in that the upper fork bridge (21) is provided with an upper bearing pin (23) for interaction with the upper bearing arrangement (31) and the lower fork bridge (22) is provided with a lower bearing pin (24) for interaction with the lower bearing arrangement (32). Frame-fork system according to one of claims 1 or 2, characterized in that the upper bearing arrangement (31) has an upper steering bearing (34) and the lower bearing arrangement (32) has a lower steering bearing (33), wherein the upper steering bearing (34) is arranged in an upper bearing receptacle at the upper end of the steering head tube (4) and the lower steering bearing (33) is arranged in a lower bearing receptacle at the lower end of the steering head tube (4). Frame-fork system according to claim 3, characterized in that the upper headset bearing is fixedly, preferably releasably, connected to the upper fork bridge, and / or that the lower headset bearing is fixedly, preferably releasably, connected to the lower fork bridge. Frame-fork system according to one of claims 1 to 4, characterized in that the rotationally fixed connection between the upper fork bridge (21; 121) and the lower fork bridge (22; 122) is detachable. Frame-fork system according to one of claims 1 to 5, characterized in that the two fork bridges (121, 122) are connected to each other via a single connecting bridge (129) arranged outside the steering head tube, wherein preferably the upper fork bridge (121) is designed as a cantilever arm projecting substantially on one side beyond the steering head tube. Frame-fork system according to claim 6, characterized in that the lower fork bridge (122) is designed as a substantially T-shaped plate with a central section and a transverse section, wherein a lower bearing pin (124) for interaction with the lower bearing arrangement is formed on the central section offset to the connecting web (129), and two downwardly extending fork arms (125, 126) are formed on the transverse section, each having a fastening device (127, 128) for a wheel axle of a front wheel at its lower end. Frame-fork system according to one of claims 1 to 5, characterized in that the two fork bridges (21, 22) are connected to each other via two separate connecting bridges arranged outside the steering head tube, wherein both fork bridges extend, preferably symmetrically, to two sides of the steering head tube beyond its outer circumference. Frame-fork system according to claim 8, characterized in that each connecting web has a tube extension extending downwards beyond the lower fork bridge, at the lower end of which a fastening device for a wheel axle of the front wheel is formed. Frame-fork system according to claim 9, characterized in that each connecting web and each tube extension is part of a tube section (25, 26) and the lower fork bridge (22) is firmly anchored between the two tube sections (25, 26), in particular is welded on or is formed integrally with them. Frame-fork system according to one of the preceding claims, characterized in that the upper fork bridge (121) is detachably screwed to an upper end of the connecting bridge (129). Electric bicycle with a bicycle frame, with an electric motor and with a power supply unit for the electric motor, characterized in that the bicycle frame is designed with a frame-fork system according to one of claims 1 to 11. Electric bicycle according to claim 12, characterized by a closure cover (15) that can be attached to the front face of the steering head tube (4) or a locking element for the insertion opening (14). Electric bicycle according to claim 12 or 13, characterized in that an electrical coupling plug for the power supply unit is arranged in the cavity, preferably near the end of the frame strut having the cavity that is away from the insertion opening. Electric bicycle according to claims 13 and 14, characterized by the fact that, in the assembly state of the closure cover, an axial clamping force can be applied to the power supply unit, which couples the power supply unit to the coupling plug in a manner that prevents movement and / or provides a preload force.

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