NL2025018B1

NL2025018B1 - Bicycle frame tube

Info

Publication number: NL2025018B1
Application number: NL2025018A
Authority: NL
Inventors: Van Der Mik Robert; Hilgerink Tom
Original assignee: Hartmobile B V
Priority date: 2020-02-28
Filing date: 2020-02-28
Publication date: 2021-10-14

Abstract

Bicycle frame tube adapted for receiving an electric battery pack, which frame tube comprises a U-shaped profile having a bottom portion and at least two lateral walls defining a recess to receive the battery pack. The U-shaped profile is formed from an extruded metal profile having inwardly extending longitudinal flanges formed on an inner side of the lateral walls at a distance from the bottom. Alternatively the U-shaped profile is formed as a (die) cast metal Ushaped profile wherein at the intersection of the bottom and each of the lateral walls a series of in longitudinal direction spaced apart support bulges is formed, which form a support surface at a distance from the bottom. The frame tube comprises a plate which is supported by and attached to the flanges or the support bulges, thereby forming a support for the battery pack spaced apart from the bottom.

Description

P34448NL0O0/CHO Title: Bicycle frame tube The invention relates to a bicycle frame tube adapted for receiving an electric battery pack, which frame tube comprises a U-shaped profile having a bottom portion and at least two lateral walls defining a recess to receive the battery pack. Bicycles having an electrical motor are more and more popular and are often referred to as e-bikes. In many of the known e-bikes a battery pack to provide the power for the electrical motor is incorporated in the frame. One of the typical solutions to store the battery pack is that one of the frame tubes, often the down tube of the frame, has a recess in which the battery pack is received. Examples of such solutions are found in EP 2 134 592 A1, EP 2 653 371A1, WO 2018/134006 A1 and DE 20 2014007 473 U1.

The invention has for an object to provide an alternative frame tube and an alternative frame for an electrical bicycle.

According to a first aspect of the invention this object is achieved by a bicycle frame tube adapted for receiving an electric battery pack, which frame tube comprises a U-shaped profile having a bottom wall and at least two lateral walls defining a recess to receive the battery pack, wherein the U-shaped profile is formed from an extruded metal profile having inwardly extending longitudinal flanges formed on an inner side of the lateral walls at a distance from the bottom wall, and wherein the frame tube comprises a plate which is attached to the flanges thereby forming a support for the battery pack spaced apart from the bottom wall.

In one possible embodiment according to the first aspect of the invention the extruded metal profile is an extruded open U-shaped profile.

In another possible embodiment according to the first aspect of the invention the extruded metal profile is an extruded closed tubular profile, and wherein a cut-out is provided in the closed metal profile to obtain the U-shaped profile.

According to a second aspect of the invention this object is achieved by a bicycle frame tube adapted for receiving an electric battery pack, which frame tube comprises a U-shaped profile having a bottom wall and at least two lateral walls defining a recess to receive the battery pack, wherein the U-shaped profile is formed as a (die) cast metal U-shaped profile, wherein

2. at the intersection of the bottom wall and each of the lateral walls a series of in longitudinal direction spaced apart support bulges is formed, which form a support surface at a distance from the bottom wall, and wherein the frame tube comprises a plate which is supported by and attached to the bulges thereby forming a support for the battery pack spaced apart from the bottom wall. In a preferred embodiment according to either of the two aspects of the invention the bicycle frame tube is a down tube of a bicycle frame, although also other tubes of the frame may be adapted to receive a battery pack. The downtube produced according to the aspects of the invention can hold a battery and is very stiff, which is important for lowstep model bicycles, without a top tube. Such a downtube maintains the right driving behaviour of the bicycle without a reinforcing top tube.

In a possible embodiment of the frame tube according to either of the two aspects of the invention the plate is a metal plate having lateral regions welded to the flanges or to the support bulges.

Preferably, the metal plate has a series of in longitudinal direction spaced apart recessed edge portions at the lateral edges of the plate, wherein welds to attach the plate to the flanges or the support bulges are provided at said recessed edge portions.

The plate may also be made of a non-metal material such as a composite material. In that case welding may not be a suitable option, but in that case the plate may be glued, riveted or bolted to the profile.

In a preferred embodiment of the frame tube according to either of the two aspects of the invention the plate is a mesh plate. The use of a mesh plate saves weight while still a sturdy cross connection is provided between the lateral walls of the profile.

In a possible embodiment according to either of the two aspects of the invention the plate is planar. In another possible embodiment according to either of the two aspects of the invention the plate has a central region and lateral regions, wherein the central region is elevated with respect to the lateral regions. Either of the two may be a mesh plate or a non-perforated plate. By providing plates with varying heights with respect to the lateral regions which rest on the flanges or the support bulges, the frame tube may be easily adapted to support different battery packages with different height dimensions. The more expensive to produce extruded

-3- profile or die cast profile may thus be universal for different frame tubes adapted for different battery packs. In both the first aspect as the second aspect of the invention the upper end of the lateral walls may have an inwardly bent portion. This inwardly bent end portion provides rigidity to the profile. Furthermore it may provide lateral support to the battery pack inserted in the interior of the frame tube. The invention also relates to a bicycle frame comprising a frame tube as described in the above. Furthermore, the invention relates to a method for manufacturing a bicycle frame tube according to the first aspect of the invention, wherein the U-shaped profile is extruded, and wherein the plate is placed on the flanges and attached thereto. In this method a universal metal profile may be extruded, and depending on the battery pack the frame tube must be adapted for a suitable plate form can be selected and arranged in the U-shaped profile. In this method a metal plate is preferably welded to the flanges, but may alternatively or additionally be glued, bolted or riveted to the flanges. If the plate is for example made of a composite material, it may glued, bolted or riveted to the flanges. The invention furthermore relates to a method for manufacturing a bicycle frame tube according to the second aspect of the invention, wherein the U-shaped metal profile is die cast, and wherein the metal plate is placed on the bulges and attached thereto.

In this method a metal plate is preferably welded to the bulges, but may alternatively or additionally be glued, bolted or riveted to the support bulges. If the plate is for example made of a composite material, it may glued, bolted or riveted to the flanges.

The invention will be described in further detail in the following description with reference to the drawings, wherein: Fig. 1 shows an isometric view of an extruded tubular profile for a frame tube according to the invention, Fig. 2 shows a cross section of the extruded tubular profile of Fig. 1,

-4- Fig. 3 shows an isometric view of the tubular profile of Fig. 1 provided with a cut-out in a top side, Fig. 4 shows an isometric view of an extruded U-profile for a frame tube according to the invention, Fig. 5 shows a cross section of the U-profile of Fig. 4, Fig. 6 shows an isometric view of a mesh plate for a frame tube according to the invention,

Fig. 7 shows an isometric view of an embodiment of a frame tube according to the invention, Fig. 8 shows a front view of the frame tube of Fig. 7, Fig. 9 shows a top elevational view of the frame tube of Fig. 7, Fig. 10a — 10d show respective cross sections through the lines A-A, B-B, C-C, D-D indicated in Fig. 9, Fig. 11 shows a top elevational view of an alternative mesh plate for a frame tube according to the invention, Fig. 12 shows a top elevational view of another alternative plate for a frame tube according to the invention,

Fig. 13 shows an isometric view of an embodiment of a frame tube including the plate of Fig. 12, Fig. 14 shows an isometric view of an embodiment of a frame tube including the plate of Fig. 11, Fig. 15 shows an isometric view of a die cast profile for a frame tube according to another aspect of the invention, Fig. 16 shows a front view of the profile of Fig. 15, Fig. 17 shows a top elevational view of the profile of Fig. 15,

-5- Fig. 18 shows a top elevational view of a frame tube including the profile of Fig. 15 combined with a mesh plate of Fig. 6, Fig. 19a — 19d show respective cross sections through the lines A-A, B-B, C-C, D-D indicated inFig. 18, Fig. 20 shows an isometric view of a bicycle frame including a frame tube shown in Fig. 7 as a downtube, Fig. 21 shows a side elevational view of the frame of Fig. 20, Fig. 22 illustrates in an isometric view a battery pack received in the frame tube of Fig. 7, Fig. 23 illustrates in a front elevational view the frame tube with battery pack of Fig. 22,

Fig. 24 shows an isometric view of another mesh plate for a frame tube according to the invention, and Fig. 25 shows an isometric view of an embodiment of a frame tube according to the invention including the profile of Fig. 15 and the mesh plate of Fig 24. The present invention relates to frames for electrical bicycles (e-bikes). The e-bike has a battery pack in which the electrical power is stored needed to provide power to the electrical motor of the bicycle.

The frame is of the type having a storage or receiving space for a battery pack arranged in one of the frame tubes of the frame.

In Figs. 20 and 21 a bicycle frame 1 according to the present invention is shown by way of example.

The bicycle frame in this example comprises a seat tube 2 and a downtube 3 which are interconnected by a bridge part 4. A headtube 5 is attached to a top end of the down tube 3. The frame 1 furthermore has a rear fork 6 attached to the seat tube 2. In a non-shown embodiment of a frame there may be top tube extending between the seat tube and the headtube.

In the frame 1 the downtube 3 is designed to receive a battery pack.

Although this might be the preferred embodiment, this may not be considered as a limitation of the invention.

Within the scope of the claimed invention it is conceivable to have other frame tubes in which the battery pack may be received, for example in a top tube, or in the seat tube.

However, the

-6- frame tube designed for receiving the battery pack will be described here as a downtube 3 by way of example. The downtube 3 of the frame 1 can be made in different ways.

In Figs. 1-2 is illustrated that first an elongate tubular profile 30 is extruded from a metal, such as steel or aluminium. The tubular profile 30 has a bottom wall 31, lateral walls 32 and a top wall 33 opposite the bottom wall 31. The bottom wall 31 has a concave inner surface 35 facing the top side. In the shown embodiment the bottom wall 31 has a through or channel shape.

At the transition between the bottom wall 31 and the lateral walls 32 on the inside of the profile 30 an inwardly extending longitudinal flange 34 is formed at each side. In height direction the flanges 34 are spaced apart from the concave surface 35 of the bottom wall 31.

It is conceivable that the bottom wall (31) is less curved or not curved at all, whereby a tubular profile with a substantially rectangular cross section would be obtained. In that case the flanges may be located a bit more remote from the bottom wall than is shown in Figs. 1-2.

Inthe top wall 33 of the tubular profile 30 a cut-out 36 is provided by for example laser or water cutting, CNC machining or punching, such that an access opening to the interior of the tubular profile 30 is created.

In Figs. 4 and 5 is illustrated an elongate profile 130 which is extruded from a metal, such as steel or aluminium. The profile 130 has generally a U-shape having a bottom wall 131 and lateral walls 132. The top side 136 opposite the bottom wall 131 is open and provides access to the interior of the profile 130. The bottom wall 131 has a concave inner surface 135 facing the top side. In the shown embodiment the bottom wall 131 has a through or channel shape.

At the transition between the bottom wall 131 and the lateral walls 132 on the inside of the profile 130 an inwardly extending longitudinal flange 134 is formed at each side. The flanges 134 are spaced apart in height direction from the concave surface 135 of the bottom wall 131. The lateral walls 132 have an upper end portion 137 which is bent inside. The longitudinal interior flanges 134 and the bent wall end portions 137 provide initial rigidity to the open profile 130.

-7- The profile 30, 130 is combined with an elongate interior plate that is attached to the flanges 34, 134. This will be described with reference to the embodiment comprising the profile 130 of Figs. 4 and 5, but will be the same for an embodiment comprising the profile 30 of Fig 3.

In Fig. 6 is shown a possible embodiment of an elongate interior plate, indicated with reference numeral 10 which is arranged inside the U-shaped profile 130 and is positioned on top of the longitudinal interior flanges 134 as is illustrated in Figs. 7 and 8. Such an interior plate 10 is preferably made of metal, preferably sheet metal, but it is conceivable to make it from another rigid material, such as a composite material.

The interior plate 10 is in this embodiment a planar mesh plate made of metal characterized by a mesh structure including openings 11 and 12. In the mesh plate 10 the openings 11 and 12 have a square and triangular shapes, respectively. However, the mesh plate can have another design, as is for example shown in Figs 11 and Fig. 14, wherein a mesh plate 10 is shown having circular openings 16. A mesh plate as shown provides sufficient rigidity when attached to the flanges and providing the cross connection between the lateral walls 132, while the weight is reduced compared to a full plate without openings. The plate 10 may be made by any suitable manufacturing method from a sheet of metal or another suitable material such as a composite material. Suitable cutting methods are stamping, laser or water cutting etc. The elongate plate 10 has opposite lateral edges 13. In the lateral edges 13 of the plate 10 a series of in longitudinal direction spaced apart recessed edge portions 14. The plate 10 is welded to the flanges 134 at the recessed edge portions 14 as can be seen in Figs. 7-10 wherein the welds to attach the plate 10 are indicated by reference numeral 15. The interior plate 10 welded in the profile 130 provides an open chamber 138 in which a battery pack can be received at the top side of the interior plate 10. The chamber can be accessed by the open top end of the U-shaped profile 130. The interior plate 10 provides a support platform for the battery pack as is shown in Figs. 22 and 23, wherein the battery pack is illustrated schematically and indicated by reference numeral 50. The inwardly bent portions 137 of the lateral walls 132 provide lateral support to the battery pack 50. The plate 10 which is rigidly connected to the flanges and thus forms a transverse connection to the lateral walls 132 provides rigidity to the open frame tube in this case the downtube 3, which is important for the overall stiffness and mechanical strength of the bicycle frame. Underneath the plate a chamber 139 is created which may for example be used to pass through electrical cables or

-8- brake cables. Additionally, this space may be used to store other parts or devices such as GPS devices (including accelerometer), acoustic devices or other electronic devices. As an alternative for welding the interior plate may be attached to the flanges 134 by means of fasteners, such as bolts or rivets as is shown in Fig 13. In such an embodiment the interior plate 110 may advantageously have a central region 111 and lateral regions 112 (cf. Figs 12 and 13), wherein the central region 111 is elevated with respect to the lateral regions 112. In this embodiment the central region 111 of the plate 110 forms the support platform for the battery pack and provides a flat and stable support. The battery back will not rest on the projecting heads or other parts of the bolts or rivets in this way. It is noted that in this embodiment the plate is not a mesh plate, but a formed plate without openings, although openings in the plate could be provided. Also a mesh plate with central region which is elevated with respect to the lateral regions, comparable to the non-perforated plate 110 having a central region 111 and lateral regions 112 is possible within the scope of the present invention. The profile which is used to make the frame tube, for example the downtube 3 does not have to be extruded as was described in the above. It is also possible to cast a profile for making a frame tube, which will be explained with reference to Figs. 15-19. In Fig. 15-17 is shown a metal die cast profile 230. The profile 230 has generally a U-shape having a bottom wall 231 and lateral walls 232. The top side 236 opposite the bottom wall 231 is open. The bottom wall 231 has a concave inner surface 235 facing the top side. In the shown embodiment the bottom wall 231 has a through or channel shape. At the intersection between the bottom wall 231 and each of the lateral walls 232 on the inside of the profile 230 a series of in longitudinal direction spaced apart support bulges 234 is formed. The bulges 234 have a surface facing the open top side of the profile 230, which form together a support surface at a distance from the bottom wall 231 for an interior plate.

The cast profile 230 may be a portion of a larger casted part which may furthermore include a head tube, a motor mount and a bottom bridge of the frame. The lateral walls 232 may have an upper end portion 237 which is bent inside as is visible in Fig. 16.

-9- The U-shaped profile 230 can be assembled with an interior plate, e.g. the mesh plate 10 which is shown in Fig. 6. For a description of the plate 10 referral is made to the above. The plate 10 is positioned on the support surface provided by the series of bulges 234, wherein the recessed edge portions 14 are in register with the support bulges 234, as is visible in Figs. 18 and 19. The plate 10 is welded to the support bulges 234 at the recessed edge portions 14 as can be seen in Figs. 19a-19d, wherein the welds to attach the plate are indicated by reference numeral 15. The interior plate 10 welded in the profile 230 provides an open chamber 238 (cf. Fig. 19a-d) in which a battery pack can be received at the top side of the interior plate 10. The interior plate 10 provides a support platform for the battery pack similar to what is shown in Figs. 22 and 23. The inwardly bent portions 237 of the lateral walls 232 provide lateral support to the battery pack. The plate 10 which is rigidly connected to the flanges and thus forms a transverse connection to the lateral walls 232 provides rigidity to the open frame tube in this case the downtube 3, which is important for the overall stiffness of the bicycle frame. Underneath the plate a chamber 239 is created which may for example be used to pass through electrical cables or brake cables. It is noted that the plate 10 may alternatively be glued instead of welded to the profiles 30,130 and 230. It is furthermore noted that instead of the interior plate 10 also plates like the ones shown in Figs 11 and 12 may be combined with the profile 230. Also a mesh plate with central region which is elevated with respect to the lateral regions, comparable to the non-perforated plate 110 having a central region 111 and lateral regions 112 may be combined with the profile

230. Furthermore it is possible to use a plate which has straight edges, thus without recesses. Such a plate 10’ is shown in Fig. 24. Fig. 25 shows how this plate 10’ is welded in the cast profile 230. The plate 10 with the recesses 14 has the advantage that the weld does not have to project or at least projects less beyond the top surface of the plate. This leaves more space for the battery pack. The plate 10’ is attached to the profile 230 at the support bulges 234 of the profile 230 by welds 15’. Itis also possible to combine the plate 10° with an extruded profile 30°, 130. In that case the plate 10’ may be welded to the lateral walls 32, 132 and/or the flanges 34, 134 over the entire length, although also multiple smaller welds may be provided in that case.

-10- In any of the shown embodiments, and within the scope of the present invention, the plate 10, 110 may be given a certain shape, for example flat as is shown in Fig. 6, 7 11 and 14, or with an elevated region as illustrated by Figs 12 and 13. Thereby the plate may be adapted to support a certain size of battery pack, while the same profile 30, 130, 230 can be used for different sizes of battery packs.

Thus for example plates with different heights of the elevated portion 111 may be produced to fit with certain battery packs.

In this way the frame tube design can be easily adapted for receiving a certain battery pack having a specific height.

Therefore the profile 30, 130, 230 can be a one-size-fits-all product, which requires thus only one extrusion die or casting die.

Thereby the production of the profiles can be more efficient and less expensive.

Note that adapting a die is in general an expensive exercise.

The plates are cheaper to manufacture and their manufacturing process is easier to adapt to adapt the shape of the plate.

The overall manufacturing process proposed by the aspects of the present invention thus provides a more cost effective but flexible production of frame tubes.

Claims

-11- CONCLUSIONS

A bicycle frame tube (3) adapted to receive an electrical battery pack (50), which frame tube (3) comprises a U-shaped profile (30', 130) with a bottom wall (31, 131) and at least two side walls (32 132) forming a recess to receive the battery pack (50), the U-shaped profile (30', 130) being formed from an extruded metal profile (30, 130) with inwardly projecting longitudinal flanges (34) 134) formed on an inner side of the side walls (32, 132) spaced from the bottom wall (31, 131), and wherein the frame tube (3) comprises a plate (10, 110) attached to the flanges (34, 134 ) thereby forming a support for the battery pack (50) spaced from the bottom wall (31, 131).

The bicycle frame tube of claim 1, wherein the plate (10, 110) is a metal plate having side regions welded to the flanges (34, 134).

A bicycle frame tube according to claim 2, wherein the plate has straight side edges.

The bicycle frame tube according to claim 2, wherein the metal plate has a series of longitudinally spaced recessed edge portions (14) at the side edges {13) of the plate (10), welding (15) about the plate (10) attachable to the flanges (34, 134) are provided at the recessed edge portions (14).

A bicycle frame tube according to any one of the preceding claims, wherein the plate (10) is a mesh plate.

A bicycle frame tube according to any one of the preceding claims, wherein the plate (10) is flat.

The bicycle frame tube according to any one of claims 1 to 5, wherein the plate (110) has a central region (111) and side regions (112), the central region (111) being raised relative to the side regions (112).

Bicycle frame tube according to one of the preceding claims, wherein the bicycle frame tube (3) is a down tube.

A bicycle frame tube according to any one of claims 1-8, wherein the extruded metal profile is an extruded open U-shaped profile (130).

-12-

A bicycle frame tube according to any one of claims 1-8, wherein the extruded metal profile is an extruded closed tube profile (30), and wherein a recess (36) is provided in the closed metal profile around the U-shaped profile (30'} to obtain.

A bicycle frame tube according to any one of the preceding claims, wherein the upper end of the side walls (132) has an inwardly curved portion (137).

12. Bicycle frame tube (3) adapted to receive an electrical battery pack (50), which frame tube comprises a U-shaped profile (230) with a bottom wall (231) and at least two side walls (232) forming a recess around the battery pack (50), wherein the U-shaped profile (230) is formed as a cast U-shaped metal profile, wherein at the intersection of the bottom wall (231) and each of the side walls (232) a longitudinal series on spaced support projections (234) are formed forming a support surface spaced from the bottom wall (231), and wherein the frame tube (3) comprises a plate (10, 110) supported by and secured to the support projections (234 ), thereby forming a support for the battery pack (50) spaced from the bottom wall (231).

The bicycle frame tube of claim 12, wherein the plate (10) is a metal plate with side regions welded to the support bosses (234).

A bicycle frame tube according to claim 12 or 13, wherein the plate has straight side edges.

The bicycle frame tube of claim 12 or 13, wherein the metal plate (10) has a series of longitudinally spaced recessed edge portions (14) on the side edges (13) of the plate, the recessed edge portions (14) being on the positions of the support projections (234) are provided and welds (15) for securing the plate (10) to the support projections (234) on the recessed edge portions (14) are provided.

A bicycle frame tube according to any one of claims 12-15, wherein the plate (10) is a mesh plate.

A bicycle frame tube according to any one of claims 12-18, wherein the plate (110) has a central region (111) and side regions (112), the central region (111) being raised relative to the side regions (112).

A bicycle frame tube according to any one of claims 12-17, wherein the bicycle frame tube (3) is a down tube.

-13-

A bicycle frame tube according to any one of claims 12-18, wherein the upper end of the sidewalls (232) has an inwardly curved portion (237).

A bicycle frame (1) comprising a frame tube (3) according to any one of the preceding claims.

The method of manufacturing a bicycle frame tube according to claim 1, wherein the metal profile (30, 130) is extruded, and wherein the plate (10, 110) is placed on the flanges (134) and secured thereto.

The method of manufacturing a bicycle frame according to claim 21, wherein the plate is a metal plate welded to the flanges (134).

The method of manufacturing a bicycle frame according to claim 21, wherein the metal plate is glued, screwed or riveted to the flanges.

The method of manufacturing a bicycle frame tube according to claim 12, wherein the U-shaped profile is molded, and wherein the plate is placed on the support bosses (234) and secured thereto.

The method of manufacturing a bicycle frame according to claim 24, wherein the plate is a metal plate welded to the support bosses (234).

The method of manufacturing a bicycle frame according to claim 24, wherein the plate is glued, screwed or riveted to the support bosses (234).