NL2021658B1

NL2021658B1 - Bicycle frame, and bicycle including such a frame

Info

Publication number: NL2021658B1
Application number: NL2021658A
Authority: NL
Inventors: Van Der Wal Marten
Original assignee: Accell Nederland B V
Priority date: 2018-09-18
Filing date: 2018-09-18
Publication date: 2020-05-07

Abstract

Bicycle frame, configured for receiving a battery structure (S) for powering a bicycle motor (M), wherein the frame (1) includes a frame section (2) configured to hold the battery structure, characterized in that said frame section includes: -an inner profile (1 1), defining an inner space for receiving at least part of the battery structure; and -an outer profile (12) that substantially encloses the inner profile (11), wherein the inner profile (1 1) and outer profile (12) are fixed to each other at a plurality of spaced-apart fixation locations.

Description

Title: Bicycle frame, and bicycle including such a frame

The present invention relates to a bicycle frame and respective bicycle.

Known motor-assisted bicycles (also known as ‘eBikes’) include common bicycle operating parts, to be driven by the rider using pedaling force (the rider’s power usually being transmitted to a bicycle rear wheel via a bicycle drive train such as a chain or shaft or the-like). Also, the known bicycle is fitted with an auxiliary motor for assisting the rider, the auxiliary motor usually being powered -or powerable- only in case the rider exerts driving force him/herself. The auxiliary motor can be e.g. a motor that is part of a rear wheel or front wheel of the bicycle, for example a hub motor. Usually, the bicycle includes a motor controller, configured for controlling the auxiliary motor, for example based on input from one or more ride monitoring sensors that can be fitted for detecting rider action or other bicycle ride related parameters (such as a sensor or sensor system that is configured to detect rider induced drive train force, torque, movement and/or power, and/or bicycle speed or wheel speed). Further, a battery structure is provided, usually including a high capacity battery storing electrical power, for example of the lithium-ion type, capable of delivering DC up to e.g. several tens of Volts.

Bicycle types having fully integrated battery structures are known. Also, it is known to fit a detachable battery pack to the bicycle, so that it can be removed after use e.g. for safe storage or remote charging.

For example, EP 2 134 592 discloses a bicycle frame with integrated and detachable battery, wherein the frame comprises a load-bearing multiple chamber tube having a cut-out at a point to receive a battery pack. The cut-out extends into at least one chamber of the multiple-chamber tube. At least one chamber of the multiple-chamber tube is substantially intact.

The present invention aims to improve the bicycle. In particular, the invention aims to provide a bicycle that has a sleek design, and improved user experience.

According to an aspect of the invention, there is provided a bicycle frame that is defined by the features of claim 1.

Advantageously, there is provided a bicycle frame, configured for receiving a battery structure for powering a bicycle motor, wherein the frame includes a frame section configured to hold the battery structure, wherein the frame section includes:

-an inner profile, defining an inner space for receiving at least part of the battery structure; and

-an outer profile that substantially encloses the inner profile, wherein the inner profile and outer profile are fixed to each other at a plurality of spaced-apart fixation locations.

It has been found that in this way, a relatively lightweight yet rigid bicycle frame can be provided, in particular concerning the bicycle frame section that is to receive the (preferably removable) battery structure. Usually, the battery structure as such is a relatively large component, requiring a relatively large gap or opening in the frame in case battery embedding is desired. Such a large frame gap/opening can significantly deteriorate frame strength. A basic idea behind the present invention is to avoid or alleviate this problem by implementing a structure of two (substantially spaced-apart, elongated) profiles, wherein the two profiles are fixed to each other, leading to a rigid structure at/near the battery location. In particular, the provided rigidity concerns good lateral stiffness as well as good torsion rigidity (concerning torsion with respect to a longitudinal axis of the profiles). Also, in this way, application of a frame section of e.g. relatively thick, heavy metal tubular material can be avoided. Moreover, it has been found that the application of the two different profiles (that is, an inner and outer profile) can provided improved manufacturability and improved shaping of the bicycle frame. As an example, the outer (e.g. external) frame profile can be made using a process for providing a relatively smooth, sleek/slender look, wherein the inner profile that is fixed to the outer profile (the inner profile generally being embedded within the outer profile) can provide reinforcement and rigidity to the overall structure.

Each of the two profiles that provide the frame section can be manufactured in various ways and made of various materials, for providing an optimum strength/weight ratio (i.e. sufficient strength at a relatively low weight) and appearance. In particular, the frame, including the two profiles, is configured such that the respective bicycle can carry a cyclist, with or without the battery structure mounted in the respective frame section (thus, the battery structure is preferably not used as a frame strengthening part/load bearing structure as such).

According to a preferred embodiment, the inner profile and outer profile define one or more intermediate chambers. For example, at least one of the one or more intermediate chambers can be a hollow (e.g. gas filled or air filled) chamber, leading to relatively low frame mass.

Alternatively or additionally, at least one of the one or more intermediate chambers can be filled with a solid filler material (e.g. a rigid plastic or compound material, a cured resin etc.), which might lead to a frame mass increase but can also lead to improved frame strength/rigidity. Besides, application of a solid filler material can provide for the use of an inner and/or outer profile having a relatively low wall thickness, wherein a respective sandwich construction (of the two profiles and the intermediate solid filler material) provides for improved frame strength and load bearing capabilities. In the latter case it is preferred that the solid filler material and one or both of the profiles are firmly fixed to each other via a respective bounding or fixation interface, for example a bonding interface that is formed during a curing of a curable filler material after it has been introduced into the intermediate chamber(s) between the two profiles. It is preferred that the solid filler material is a fiber reinforced filler material.

According to a further embodiment, at least one of the inner profile and outer profile includes a longitudinal reinforcing structure. For example, the reinforcing structure can include one or more longitudinal ribs of the profile. Such ribs can provide several (other) functions, e.g. providing battery guiding and/or positioning features for engaging the battery structure during mounting. Also, such ribs can e.g. provide or define cable receiving channels for receiving bicycle cabling, such as one or more electric wires and/or brake cables and/or transmission/derailleur cables.

According to further embodiments, at least one of the inner profile and the outer profile (preferably both) is a U-shaped profile or at least includes a U-shaped section. In this way a relatively compact, sleek configuration can be achieved.

Also, for example, according to a further embodiment, the inner profile and outer profile can have respective longitudinal edges that extend along a battery entry opening of the respective frame section, wherein said longitudinal edges have preferably been joined by a bonding process, for example gluing and/or welding. The bonding can be achieved efficiently via an array of spaced-apart bonding points or bonding sections, or alternatively via a longitudinal bonding line.

Regarding manufacture of the frame, for example, the inner profile can be an extruded profile, for example made of metal, aluminium or steel. The respective profile can be made in an economical manner, and can be shaped and formed to provide a relatively high strength and rigidity. However, the inner profile as such (that is, before being fixed to the outer profile) does not yet have to provide sufficient load-bearing strength to carry e.g. a user. More in particular, the frame design is such that the overall strength of the combination of the inner profile and outer profile (after mutual fixation) provides sufficient load-bearing strength to carry e.g. a user, or such that the desired load-bearing strength is achieved by application of the optional filler material (mentioned above).

Further, according to a preferred embodiment, the outer profile can be manufactured by a moulding process, e.g. hydroforming. In this way, a highly precise, smooth shaping of the outer profile can be achieved.

Preferably, the profiles as such have relatively thin wall thicknesses.

As an example, a preferred wall thickness of the outer profile is smaller than 3 mm. The same holds for the inner profile.

The frame section (for receiving the battery structure) can be located at various frame positions, for example, the frame section can be a down tube, or part thereof, of the frame, so that a relatively low battery position can be obtained.

Further, there is provided a bicycle, including an auxiliary motor and a frame according to the invention, wherein a battery structure is substantially embedded in (i.e. enclosed by) the inner profile of the frame section, after assembly. In particular, after mounting, the battery structure can be substantially recessed within the frame, wherein lateral sides of the battery structure are located within the space that is defined within the inner profile. A top side or cover of the battery structure may e.g. extend substantially along or slightly above a top side of the inner profile of the frame section.

Furthermore, the invention provides a method for manufacturing a bicycle frame, for example a frame according to the invention, the method including:

-providing a first profile, the first provide defining an inner space for receiving a battery structure;

-providing a second profile, being formed to substantially enclose the first profile; and

-bonding the first profile and second profile to each other, in particular along respective bonding edges.

In this way, the above-mentioned advantages can be achieved. The bonding along bonding edges of the profiles is preferably achieved via a plurality of spaced-apart (separate) bonding points, in particular local welding points.

Further advantageous embodiments are describedin the dependent claims.

The invention will now be explained, with reference to the drawings which show a non-limiting example.

Figure 1 depicts a side view of part of a bicycle according to an embodiment of the invention;

Figure 2A shows part of the frame of the bicycle of Fig 1 in more detail;

Figure 2B shows the frame, wherein the inner frame section has been shown separately from a remaining frame part;

Figure 3 shows a side view of the frame part of Fig. 2A;

Figure 4 shows a view over arrow IV of Figure 3;

Figure 5 is a cross-section over line V-V of Figure 3; and

Figure 6 is a perspective view of a lower end of the frame part shown in Figure 3.

Corresponding or similar features are denoted by similar or corresponding reference signs in this application.

Figure 1 shows part of a two-wheeled bicycle, including an auxiliary motor M and a frame 1. In the present example, the auxiliary motor M is located at an advantageous position near a pedal driven crank of the bicycle,

i.e. at a bottom bracket BB and below (in line with) a saddle tube W of the frame 1. The frame 1 includes a frame section 2 (in this case a down tube section) configured to hold a battery structure S, for powering the motor M. As is mentioned before, usually, the bicycle also includes a motor controller, configured for controlling the auxiliary motor, for example based on input from one or more ride monitoring sensors that can be fitted for detecting rider action or other bicycle ride related parameters. Such controller and respective sensors are not depicted (the controller is preferably embedded at a suitable location within the frame of the bicycle), and is commonly known to the skilled person.

In figure 1, the battery structure S is show during placement, part of the structure S still being located externally with respect of the bicycle frame. After mounting, the battery structure S substantially resides within the frame (i.e. it is embedded in a battery structure receiving space that is defined within the respective frame section).

Referring to Figures 1-6, advantageously, the battery structure S can be substantially embedded in an inner profile 11 of the respective frame section 2, after mounting. In particular, to that aim, the inner profile 11 defines an inner space IS for receiving a major part (e.g. over 80%, in particularly at least 90%) of the battery structure S. Also, the present battery structure receiving section 2 of the frame includes an outer profile 12 that substantially encloses the inner profile 11. The two profiles 11, 12 are separately manufactured components, fixed to each other to form the respective frame section. In this way a lightweight yet sturdy construction is achieved.

In the present example, the inner profile 11 and outer profile 12 have respective longitudinal (upper) edges that extend along a battery entry opening of the respective frame section. These longitudinal edges are been joined by a bonding process, for example gluing and/or welding. Respective bonding sections are denoted by ft in Figures 5, 6. As follows from Fig. 6, the bonding sections can be local bonding sections, being spaced-apart viewed along the respective bonding edge.

Besides, the inner profile 11 and outer profile 12 abut one-another at respective bottoms, wherein opposite sides of those bottoms can be fixed to each other as well as follows from Fig. 5, to provide an extra stiff frame section. Again, the fixing of respective profile bottoms can be achieved via a number of spaced-apart bonding sections fb (being spaced-apart in longitudinal direction of the profiles 11, 12). Alternatively (i.e. alternative to using separate bonding points), a bonding line can be used.

Moreover, as follows from the drawing, each of the inner profile 11 and outer profile can be an U-shaped profile (viewed in cross-section). In this example, the outer profile 12 has a substantially constant wall thickness. Good results can be achieved in case the outer profile is manufactured by a moulding process, e.g. hydroforming. In particular, hydroforming can be applied to relatively thin sheet (e.g. metal) material, leading to smoothly shaped (outer) profiles in a cost-effective manner.

In a preferred embodiment, the profiles as such have relatively thin walls. A wall thickness of the outer profile can e.g. smaller than 3 mm. The same holds for the inner profile.

The inner profile 11 of this example is provided with a number of integral (made in one piece) longitudinal protrusions or ribs Ila, 11b, 11c, lid (see Fig. 5), providing a local thickness increase of the profile 11. In a preferred embodiment, the inner provide is manufactured by a different manufacturing process than the outer profile. For example, the inner provide can be an extruded profile (i.e. being manufactured in an extrusion process).

At least one of the inner profile 11 and outer profile 12 includes a longitudinal reinforcing structure. Preferably, the inner profile 11 includes such a structure, such as in case the outer profile is made via a hydroforming process. In the present example, the longitudinal protrusions or ribs Ila, lib, 11c, and in particular bottom ribs 11b, 11c provide the reinforcement structure of the respective frame section.

More particular, as follows from Figure 5, the two bottom ribs 11b, 11c can be formed to define a slit 16 there-between, for example to be engaged by a gripping structure of the battery structure S for positioning or retaining the battery structure S after mounting.

Also, as follows from Figure 5, the ribs Ila, 11b, 11c, lid can define longitudinal intermediate inner spaces 14 there-between, extending below a battery structure S after mounting, the inner spaces 14 e.g. to be used for receiving bicycle cabling (e.g. electric cabhng, transmission and break control cabling etc.). In a preferred embodiment, these intermediate inner spaces 14 can be covered by a respective cover, indicated by dashed lines 15 in Fig. 5, for example a removable cover 15. The covers 15 can separate the cable receiving spaces 14 from the battery structure receiving space IS located there-above. The present longitudinal ribs Ila, 11b, 11c, lid include small longitudinal slots 17 for receiving/holding the covers 15.

As follows from the above, advantageously, the inner profile 11 and outer profile 12 are fixed to each other at a plurality of spaced-apart fixation locations (marked ft, lb in Figures 5-6), to provide a rigid, relatively lightweight structure. The fixing or bonding of the inner profile 11 and outer profile 12 can be achieved in various ways, depending on the material used, for example via local adhesive connections, by welding bonds or the like. The fixture/bonding can be achieved e.g. via point-type fixing (using small fixing spots to provide a local bonding), or line-type fixing (wherein the profiles 11, 12 are connected along contact lines, via a respective bonding hne).

Also, the configuration is such that the present inner profile 11 and outer profile 12 (spaced-apart) define one or more intermediate chambers

13. As follows from the drawings, each of these chambers is substantially closed from an environment viewed along a longitudinal direction of the respective frame section 2. Optionally, proximal and distal ends of tor or more of the chambers 13 can be open (as in Fig.4, showing access to interiors of the integrated/enclosed chambers 13 at a lower end thereof).

In the present example, these intermediate chambers 13 are hollow chambers (e.g. air or gas filled chambers 13). In an alternative embodiment, one or more of these chambers 13 may be substantially or entirely filled with a solid filler material (e.g. a filler compound, a plastic or a fiberreinforced plastic).

As is mentioned before, the manufacturing of the frame can advantageously include at least the following:

-providing a first profile 11, the first provide defining an inner space for receiving a battery structure;

-providing a second profile 12, being formed to substantially enclose the first profile; and

-bonding the first profile 11 and second profile 12 to each other, in particular along respective bonding edges.

The resulting frame has a relatively large design freedom, and can provide sufficient lateral stiffness and torsion rigidity for bearing usual driving loads, at low frame weight. Also, the resulting frame can be made using relatively little material, with is advantageous in view of reduced expenses and reduction of environmental impact.

It will be clear to the skilled person that the invention is not limited to the exemplary embodiments described. Various modifications are possible within the framework of the invention as set forth in the following claims.

Claims

A bicycle frame configured to receive a battery structure (S) for powering a bicycle motor (M), the frame (1) including a frame member (2) configured to hold the battery structure (S), with the feature that the said frame part comprises:

- an inner profile (11), which defines an inner space for receiving at least part of the battery structure; and

- an outer profile (12) that substantially surrounds the inner profile (11), the inner profile (11) and outer profile (12) being fixed together at various spaced-apart fixing locations.

A bicycle frame according to claim 1, wherein the inner profile (11) and outer profile (12) (spaced) define one or more intermediate chambers (13).

The bicycle frame according to claim 2, wherein at least one of the one or more intermediate chambers (13) is a hollow chamber.

Bicycle frame according to claim 2 or 3, wherein at least one of the one or more intermediate chambers (13) is filled with a solid filler material.

Bicycle frame according to any one of the preceding claims, wherein at least one of the inner profile (11) and outer profile (12) comprises a longitudinal reinforcement structure.

Bicycle frame according to any one of the preceding claims, wherein the inner profile (11) is a U-shaped profile or comprises at least a U-shaped part.

Bicycle frame according to any one of the preceding claims, wherein the outer profile (12) is a U-shaped profile or comprises at least a U-shaped part.

A bicycle frame according to any one of the preceding claims, wherein the inner profile (11) and outer profile (12) have respective longitudinal edges which extend along a battery entrance opening of the respective frame part, said longitudinal edges preferably being joined by means of a binding process, for example gluing and / or welding.

Bicycle frame according to any one of the preceding claims, wherein the inner profile is an extracted profile.

A bicycle frame according to any one of the preceding claims, wherein the outer profile is manufactured by means of a molding process, for example hydroforming.

A bicycle frame according to any one of the preceding claims, wherein a wall thickness of the outer profile is less than 3 mm.

A bicycle frame according to any one of the preceding claims, wherein a wall thickness of the inner profile is less than 3 mm.

A bicycle frame according to any one of the preceding claims, wherein the frame part is a lower housing, or part thereof, of the frame.

A bicycle, comprising an auxiliary motor and a frame according to any one of the preceding claims, wherein a battery structure is substantially embedded in the inner profile of the frame part, after assembly.

A method for manufacturing a bicycle frame, for example a frame according to any one of claims 1-13, comprising:

provided with a first profile, which first profile defines an inner space for receiving a battery structure;

provided with a second profile, which is formed to substantially surround the inner profile; and

binding the first profile and second profile together, in particular along respective binding edges.