System for clamping an energy storage device in a frame, comprising a cover, and bicycle

Abstract

The invention relates to a system for clamping an energy storage device (12) in a frame (4) of a bicycle (2). The system has a cover (16), the frame (4), and the energy storage device (12). The cover (16) is designed to cover a section (8) of a down tube (6) of the frame (4), and the cover (16) is additionally designed to clamp the energy storage device (12) in the frame (4) by covering the section (8) when the energy storage device (12) is inserted into the section (8). The invention additionally relates to a bicycle (2) comprising such a system for clamping an energy storage device (12) in a frame (4).

Description

[0001] ZF Friedrichshafen AG

[0002] Friedrichshafen

[0003] System for clamping an energy storage device in a frame with a cover and bicycle

[0004] The present invention relates to a system for bracing an energy storage device in a frame with a cover. Furthermore, the present invention relates to a bicycle with such a system for bracing the energy storage device in the frame.

[0005] Bicycles with an energy storage device are known from the prior art, with the energy storage device located in the frame. Such bicycles are powered by energy from the energy storage device. There are various systems for locking the energy storage device in the frame.

[0006] From DE 10 2019 204 572 B3 a locking device for an energy supply device for a bicycle is known.

[0007] Based on the cited prior art, the object of the present invention is to provide an improved system for bracing an energy storage device in a bicycle frame. This object is achieved by the subject matter of the independent patent claims. Further advantageous embodiments are set out in the subclaims.

[0008] The present invention relates to a first aspect of a system for bracing an energy storage device in a bicycle frame. The energy storage device can comprise a battery, an accumulator, or another chemical or, alternatively or additionally, electrical energy storage device. The bicycle can, for example, be an electrically powered bicycle such as an (S-)Pedelec, a cargo bike, a velomobile, or the like. The frame can comprise a top tube, a down tube, and a seat tube. The frame can be configured to accommodate the energy storage device. For this purpose, the frame can comprise a cutout, which can be arranged in at least one part of the frame, such as the down tube, the seat tube, or the top tube. By providing the cutout in a part of the frame, side walls can be formed in this part of the frame.For example, the down tube of the frame can have the cutout and thus two unsupported side walls are formed on the long sides of the cutout.

[0009] The system comprises a cover as well as the frame and the energy storage device. The cover can be made of plastic, aluminum, or carbon, for example. The cover is designed to cover the cutout in the down tube of the frame. The cover can be designed to completely cover the cutout in the down tube, i.e., such that the cutout is closed and can form a closed cavity within the frame. The energy storage device can be accommodated in this cavity. Furthermore, when the energy storage device is inserted into the cutout, the cover is designed to brace the energy device in the frame by covering the cutout. For example, a force can act from the energy storage device on the frame, and a counterforce of the same amount can act from the frame on the energy storage device, and this can represent the bracing.A user of the bicycle system, for example a bicycle of the bicycle, can apply this force to clamp the energy storage device in the frame. For example, the user can insert the energy storage device into the recess in the frame. The user can then place the cover onto the cutout, thereby creating clamping between the energy storage device and the frame. For example, the spatial extent of the energy storage device can be slightly larger than the space formed by the cutout when the cover covers the cutout. When the cover rests completely on the cutout, the cover can reduce the cavity so that the space provided for the energy storage device is reduced. In doing so, the cover can engage or penetrate at least partially into the recess.Thus, a bracing force must be applied to completely cover the cutout once the energy storage device has been inserted into the cutout. This necessary bracing force is then stored in the bracing. Thus, covering the cutout can causally tighten the energy storage device in the frame.

[0010] Using the system presented here, the energy storage device can be attached and braced to the bicycle frame in such a way that vibrations from the frame can be transferred to the energy storage device. The energy storage device, often a heavy battery or accumulator, can act as a slowly vibrating and inertial mass. By bracing, the frame's natural frequency can be reduced by coupling the inertial mass of the energy storage device to the frame. The unsupported side walls of the frame cutout can be stiffened and additionally or alternatively supported by the bracing. Furthermore, vibration energy from the frame can be converted into thermal energy, for example into thermal energy of the energy storage device or the cover.Furthermore, the system makes it possible to compensate for manufacturing tolerances of the energy storage device, the cover, and the frame by bracing it to compensate for slight irregularities in the geometry or dimensions of the energy storage device and, alternatively or additionally, the frame. Vibrations can occur on a bicycle with an energy storage device, for example, when an electric motor is powered by energy from the energy storage device and generates vibrations during operation. These vibrations can, for example, lead to vibrations of the frame and, above all, to vibrations of the unsupported side walls. Undesirable vibration maxima can arise, particularly when the frame's natural frequencies are affected by the exciting vibrations of the electric motor.The system described herein makes it possible, on the one hand, to prevent or at least mitigate vibrations by means of the bracing between the energy storage device and the frame, since the natural frequency of the frame is reduced between the coupling with the energy storage device. On the other hand, the vibrations can also be at least partially converted into thermal energy, which can reduce the vibration energy in the frame. This can lead to improved handling of the bicycle. Alternatively or additionally, this can lead to less material fatigue of the bicycle elements, for example the energy storage device, the cover, or the frame, and this can lead to a longer service life of the bicycle elements. By selecting a suitable material for the cover, the stiffness of the cover can be manipulated and adapted to the system.By providing the cover, the clamping can be achieved in a single step by placing the cover on the cutout and the cutout can be sealed and protected from external influences such as splash water or dirt. This provides particularly easy handling of the system and the bicycle for the bicycle user.

[0011] According to a further embodiment, the cover can be configured to establish contact between the energy storage device and the down tube. One contact, or alternatively, multiple contacts can be established between the energy storage device and the down tube. The contact can be an additional contact. For example, the energy storage device in the cutout of the down tube can touch an inner wall of the cutout. This can already establish initial contact between the energy storage device and the down tube. By placing the cover on the cutout, with the energy storage device inserted in the cutout, further contact can be established between the energy storage device and the down tube. This contact enables direct power transmission from the energy storage device via the cover to the down tube.For example, an initial force can act from the energy storage device on the cover, and the force can then act from the cover to the down tube. A counterforce of the same magnitude can act from the down tube on the cover, and this can then further act on the energy storage device. In the clamped state, a force equilibrium can then prevail. This can represent a stable state of the system, with the energy storage device clamped in the frame.

[0012] Such contact enables particularly efficient force and vibration transmission between the energy storage device and the down tube. This allows vibration energy from the frame to be transferred to the cover. This vibration energy transferred to the cover can be converted into heat energy, and this vibration energy can also be transferred to the energy storage device.

[0013] According to a further embodiment, the cover can have an edge which can be configured to form a connection with the down tube. The edge can form a connection between the down tube and the cover at least over a section extending in a longitudinal extent of the cover. This section can be shorter than the longitudinal extent of the cover. Alternatively, the edge can form a connection along the entire longitudinal extent of the cover. The connection can be a positive connection and alternatively or additionally a frictional connection. With the positive connection, force can be transmitted due to a positive connection in at least one direction. With the frictional connection, a frictional connection can be ensured and force transmission can be possible by selecting the materials of the connection.For example, the cover can be made of a first material, and the frame can be made of a second material, whereby friction coefficients between the cover and the frame can ensure frictional engagement. For example, the frame can be made of carbon or aluminum, and the cover can be made of plastic.

[0014] By providing the edge and the positive or frictional connection between the cover and the down tube, a particularly efficient power transmission between the cover and the down tube can be achieved. By providing the edge, a particularly efficient power transmission between the cover and the down tube can be achieved along a longer line, for example, along the entire length of the cover.

[0015] According to a further embodiment, the cover can be configured to form an undersize when connected to the down tube. Alternatively or additionally, an oversize can be formed when connected to the down tube. On each side wall of the frame cutout, an inner surface of the cover can rest on an outer surface of the side wall. The distance between the inner surfaces of the cover can be smaller than the distance between the outer surfaces of the side walls. This allows the undersize of the connection to be formed.

[0016] By providing the undersize, a force can be exerted on the cover and sidewalls when the cover is placed on the down tube. This allows a force to be exerted from the sidewall onto the cover, and an equal counterforce from the cover onto the sidewall. This allows the cover to be clamped to the sidewalls. This can create a particularly stable connection between the cover and sidewall. Furthermore, manufacturing tolerances of the cover and down tube can be compensated. The user can build up these forces when placing the cover on the down tube.

[0017] According to a further embodiment, the cover can have an inner side which can be configured to form a positive connection with the energy storage device. Furthermore, the system can be configured to form a connection between the cover and the energy storage device. The inner side of the cover can be shaped such that an outer side or outer shape of the energy storage device can engage at least one shape of the inner side on at least one side of the energy storage device. A positive shape of the energy storage device can engage with a matching negative shape of the cover. Alternatively, a positive shape of the cover can engage with a negative shape of the energy storage device. A positive shape can have a protruding element, and a negative shape can have a recess or a notch.Matching positive and negative molds can be shaped so that the positive mold can precisely engage with the negative mold. This allows contact between the cover and the energy storage device to be established over the largest possible contact area.

[0018] The positive fit between the cover and the energy storage device allows for particularly efficient power transmission between the cover and the energy storage device. By molding either the housing of the energy storage device and, alternatively or additionally, the interior of the cover, various geometries can be provided during the manufacture of at least one of the cover and the energy storage device. Thus, the system can be used for various shapes of energy storage devices or covers.

[0019] According to a further embodiment, the cover can have at least one barb, which can be configured to non-positively connect the cover to the energy storage device. The system can have a plurality of barbs, for example the system can have eight barbs, which can be arranged symmetrically on edges of the inside of the cover. The barbs can be formed as part of the cover, whereby they can either be arranged as external parts on the cover, for example can be glued. Alternatively, the barbs can be an integral part of the cover. The energy storage device can have a groove, at least on the side facing the cover, in the inserted state, which groove can be configured to form a positive and non-positive connection with the barbs.Alternatively, or additionally, the energy storage device may not have a groove into which the barbs can engage. In this case, the barbs are tightened when the cover is placed over the cutout. This tightening of the barbs can further secure the energy storage device in the frame.

[0020] By providing the barbs, a particularly efficient, force-locking connection can be created between the cover and the energy storage device. Manufacturing tolerances of the cover, frame, and energy storage device can thus be compensated for. If necessary, a connection can always be maintained between the cover and the energy storage device during particularly rough rides, ensuring a constant power transmission between these two elements.

[0021] According to a further embodiment, the cover can have a honeycomb structure, and the rigidity of the cover can be increased by the honeycomb structure. The honeycomb structure can be formed in at least part of the inside of the cover. The honeycomb structure can be an integral part of the cover. Alternatively or additionally, the honeycomb structure can be arranged on the inside of the cover, for example, mounted, for example with a screw, or it can be glued. The honeycomb structure can have multiple elements, such as multiple walls. Different walls can be arranged at different angles to one another to form the honeycomb structure. The rigidity of the cover can be changed depending on the shape of the honeycomb structure and, in this case, depending on the arrangement and number of the individual elements, for example the walls of the honeycomb structure.The position of the honeycomb structure within the interior of the cover can influence the rigidity of the cover. For example, in a first case, it may be particularly advantageous to obtain a particularly rigid and stiff cover. In such a case, a different honeycomb structure may be used than in a second case, for example, if a comparatively softer cover may be desired.

[0022] This allows the damping behavior of the cover to be adjusted.

[0023] According to a further embodiment, the cover can have a damping layer, wherein the damping layer can be arranged at a connection. The damping layer can be arranged at a connection between the cover and the down tube. Alternatively or additionally, the damping layer or another damping layer can be arranged between the cover and the energy storage device. One damping layer can be provided, or alternatively, multiple damping layers can be provided. The damping layer can be made of aluminum butyrate, for example. The damping layer can convert vibration energy into heat.

[0024] By providing at least one damping layer, a particularly high amount of vibration energy can be converted into heat energy. The vibration energy transferred from the frame to the cover and further to the energy storage device can thus be reduced. This can be particularly advantageous when particularly high levels of vibration energy are present, for example, when riding a mountain bike.

[0025] According to a further embodiment, the cover can be configured to be locked to the frame by means of a locking device. When the cover is placed on the cutout, a force can be exerted on the cover by the tensioned energy storage device in the frame. The locking device can be provided to hold the cover in position and contribute to the force transmission between the energy storage device and the frame via the cover.

[0026] A second aspect of the present invention relates to a bicycle with a system according to an embodiment of the first aspect of the present invention for bracing the energy storage device in the frame. The bicycle can be an e-bike, an (S-)pedelec, an e-motorcycle, an e-scooter, or an e-scooter.

[0027] Fig. 1 shows a bicycle according to an embodiment of the invention. Fig. 2 shows a system of the bicycle of Fig. 1 according to an embodiment of the invention.

[0028] Fig. 3a-3d show elements of the system shown in Fig. 2 according to one embodiment.

[0029] Fig. 4a-4b show elements of the system shown in Fig. 2 according to one embodiment.

[0030] Fig. 5 shows a cover of a system from Fig. 2 according to an embodiment of the invention.

[0031] Fig. 6a-6b show a cover of a system from Fig. 2 according to an embodiment of the invention.

[0032] Fig. 1 shows a bicycle 2 according to an embodiment of the invention. The bicycle 2 has a frame 4. The frame 4 has a down tube 6 in which a cutout 8 is provided. The cutout 8 points downwards towards the ground on which the bicycle 2 stands. The cutout 8 forms two side walls 10, which are arranged opposite one another and laterally on the down tube 6. Furthermore, the bicycle 2 has an energy storage device 12, which in Fig. 1 is fully inserted into the cutout 8. The bicycle 2 also has an electric motor 14, which is designed to drive the bicycle using energy from the energy storage device 12.

[0033] Fig. 2 shows the frame 4, the cover 16 and the energy storage device 12 of a system according to an embodiment of the invention of a bicycle 2 from Figure 1. Schematically shown is an axial displacement direction R1 which is transverse to the down tube 6 and in a plane of the frame 4. When the energy storage device 12 is clamped in the frame 4, the cover 6 is displaced along the direction R1 towards the frame 4. This is done by a user, such as a rider of the bicycle 2. Shortly before the cover 16 rests completely on the frame 4 and covers the cutout 8, a force builds up which the user must overcome. This force represents the clamping force for clamping the energy storage device 12 in the frame 4. The force builds up between the energy storage device 12, the cover 16 and the frame 4.

[0034] Figure 3a shows elements of the system from Figure 2. It shows a cross-section through the down tube 6, wherein the energy storage device 12 is fully inserted into the down tube 6. A connection 18 will be formed between the cover 16 and the down tube 6. In comparison to Figure 3b, in the embodiment shown in Figure 3a the connection 18 is not yet fully closed. In Figure 3b the connection between cover 16 and down tube 6 is fully closed. Figure 3c shows a detailed view of the state when the energy storage device 12 is clamped in the frame 4. The connection 18 between the down tube 6 and the cover 16 is formed along an edge 16b. As can be seen in Figure 3d an undersize 22 is formed between the down tube 6 and the cover 16. Furthermore, a connection 20 is formed between the energy storage device 12 and the cover 16.The connection 20 is formed by a positive fit between the energy storage device 12 and an inner side 16a of the cover 16, as shown in Fig. 4a. The connections 18 and 20 establish contact between the down tube 6 and the energy storage device 12 via the cover 16.

[0035] Figure 4a shows a cover 16 of a system according to an embodiment of the invention with barbs 24. Six barbs 24 are visible, which are arranged symmetrically on an inner side of the cover 16. The barbs are an integral part of the cover 16. The barbs engage in a groove (not shown) of the energy storage device 12. When the barbs 24 engage in the groove, a force and form fit is formed between the cover 16 and the energy storage device 12. Thus, force can be transmitted between the energy storage device 12 and the cover 16 both in a first direction from the cover 16 to the energy storage device 12 and in a second direction. Figure 4b shows a tensioned state. The barbs 24 engage in the groove of the energy storage device 12. Figure 5 shows a honeycomb structure of the cover 16.The honeycomb structure 26 is an integral component of the cover 16. The honeycomb structure is formed on the inner side 16a of the cover 16 during the manufacturing process of the cover 16. By forming the honeycomb structure 26, the rigidity and torsional rigidity of the cover 16 are adjusted. This makes it possible to adapt the rigidity of the cover 16 to the application on the bicycle 2. For example, the honeycomb structure is designed differently on a city bike than on a mountain bike.

[0036] Figures 6a and 6b show further embodiments of the cover 16 of a system according to one embodiment of the invention. Here, the cover 16 has at least one damping layer 28. This damping layer 28 is applied, as shown in Figure 6a, to the cover 16 after production of the cover 16. In the exemplary embodiment shown here, this is done by gluing. The damping layer contributes to the vibrations from the electric motor 14, which are transmitted to the cover 16, being converted into thermal energy in the damping layer 28. This converted energy is no longer passed on to the energy storage device 12 as vibration energy. In Figure 6b, the damping layer 28 is shown in the applied state on the cover 16. Not visible is a symmetrically arranged further damping layer 28, which is arranged on the opposite side of the inner side 16a of the cover 16.

[0037] Reference symbol

[0038] 2 bicycles

[0039] 4 frames

[0040] 6 down tube

[0041] 8 Cutout in the down tube of the frame

[0042] 10 Side wall of the cutout

[0043] 12 Energy storage device

[0044] 14 Electric motor

[0045] 16 Cover

[0046] 16a Inside of the cover

[0047] 16b Edge of the cover

[0048] 18 Connection between cover and down tube

[0049] 20 Connection between energy storage device and cover

[0050] 22 undersize

[0051] 24 barbs

[0052] 26 Structure in Cover

[0053] 28 damping layer

[0054] R1 Axial displacement direction across the down tube

Claims

Patent claims 1. System for bracing an energy storage device (12) in a frame (4) of a bicycle (2), wherein the system comprises a cover (16) as well as the frame (4) and the energy storage device (12), and wherein the cover (16) is designed to cover a cutout (8) of a down tube (6) of the frame (4), and wherein the cover (16) is further designed, when the energy storage device (12) is inserted in the cutout (8), to brace the energy storage device (12) in the frame (4) by covering the cutout (8).

2. System according to claim 1, wherein the cover (16) is arranged to establish contact between the energy storage device (12) and the down tube (6).

3. System according to one of the preceding claims, wherein the cover (16) has an edge (16b) which is arranged to form a connection (18) with the down tube (6).

4. System according to claim 3, wherein the cover (16) is arranged to form an undersize (22) when connected (18) to the down tube (6).

5. System according to one of the preceding claims, wherein the cover (16) has an inner side (16a) which is designed to form a positive connection with the energy storage device (12).

6. System according to one of the preceding claims, wherein the cover (16) has at least one barb (24) which is configured to connect the cover (16) to the energy storage device (12) in a force-fitting manner.

7. System according to one of the preceding claims, wherein the cover (16) has a honeycomb-like structure (26), and wherein a rigidity of the cover (16) is increased by the honeycomb-like structure (26).

8. System according to one of the preceding claims, wherein the cover (16) has a damping layer (28), wherein the damping layer (28) is arranged at a connection (18; 20).

9. System according to one of the preceding claims, wherein the cover (16) is arranged to be locked to the frame (4) by means of a locking device.

10. Bicycle (2) having a system according to one of the preceding claims for clamping the energy storage device (12) in the frame (4).

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