Seat tube for a bicycle

Abstract

The present invention relates to a hydroformed seat tube (10) for a bicycle comprising a battery, the seat tube comprising an interior housing suitable for receiving a seat post (30) extending along a main axis (X), characterized in that the seat tube (10) has a longitudinal bulge (12) extending along the main axis (X) and an interior face (121) of which defines, in the seat tube (10), a cavity (120) entirely open onto the interior housing, the cavity (12) forming a passage for an electric cable outside of the interior housing.

Description

[0001] BICYCLE SEAT TUBE

[0002] FIELD OF INVENTION

[0003] The invention relates to a seat tube for a bicycle incorporating a battery, such as an electric bicycle, and in particular to the arrangement of an electrical power cable within a bicycle frame comprising such a tube. The invention also relates to a method for assembling a bicycle incorporating a battery.

[0004] STATE OF THE ART

[0005] The market for electric bicycles is growing rapidly, allowing users to travel longer distances and / or tackle steep inclines. Electric bicycles are equipped with a main battery that powers the bicycle.

[0006] In other bicycles, without electric assistance for propulsion, a battery can be used to power several electrical devices arranged in different positions on the bicycle.

[0007] Bicycles can be equipped with rear lights, improving visibility, especially at night, and increasing road safety. Such lights also help comply with regulations in certain situations and / or geographical areas. Bicycles may also include other equipment requiring a power supply, such as a radar system to detect approaching vehicles.

[0008] For powering lights and other accessories, the main battery is generally used. This avoids the need for secondary batteries that require regular recharging. Alternatively, the bicycle can be equipped with a main battery to power the motor and a secondary battery to power one or more accessories.

[0009] For a rear light or other equipment mounted on the seat tube or seatpost, an electrical cable must be run between the battery powering the equipment and the top opening of the seat tube. External cable routing exposes the cable, posing a high risk of damage, and is aesthetically unappealing. Internal routing through the seat tube and seatpost is not compatible with all seatpost types and cannot be used with certain types, such as dropper posts with hydraulic and / or pneumatic cartridges. Furthermore, internal routing creates constraints when inserting or replacing the seatpost, making it difficult for the cyclist to perform.It is essential to ensure that adjustments made by the user, particularly saddle height adjustment, are not obstructed by any cable routing. Similarly, adjusting or replacing the seatpost must not damage any electrical cables powering equipment such as lights located at the seat tube.

[0010] US 11,932,342 describes a seat tube comprising an internal housing for a seatpost and a cavity for cable routing. The housing is separated from the seat tube by a partition. EP 3428051 A1 describes a seat tube comprising a cavity with a narrow opening to the housing. The cavity is separated from the housing by a constriction inside the seat tube. Such tubes are generally produced by extrusion. In both cases, the limited opening of the cavity makes cable routing difficult, and the geometry of the cavities makes manufacturing the seat tubes complex. Furthermore, these geometries result in an increased weight for the seat tube.

[0011] DESCRIPTION OF THE INVENTION

[0012] One aim of the invention is to design a bicycle seat tube incorporating a battery, allowing the passage of a cable from the battery to the level of the upper opening of the seat tube, which is compatible with any type of seat post, without exposing the cable to risks of damage, particularly during handling of the seat post.

[0013] To this end, the invention proposes a hydroformed seat tube for a bicycle comprising a battery, said seat tube comprising an internal housing adapted to receive a seat post extending along a main axis, characterized in that said seat tube has a longitudinal bulge extending along said main axis and of which an internal face defines, in the seat tube, a cavity entirely open to the internal housing, said cavity forming a passage for an electrical cable out of the internal housing.

[0014] Hydroforming makes it possible to obtain the geometry of the open cavity, without involving the use of complex and expensive techniques such as molding around a sand core.

[0015] In some embodiments, the seat tube has a longitudinal slot extending from a top opening of the seat tube, the longitudinal bulge extending along the main axis from a bottom edge of the slot.

[0016] In other embodiments, the longitudinal bulge extends along the main axis from an upper opening in the seat tube.

[0017] Preferably, the inner face of the longitudinal bulge has a rounded or curved cross-section. Advantageously, the longitudinal bulge is oriented towards the rear of the bicycle.

[0018] Advantageously, the longitudinal bulge extends over an upper portion of the seat tube with a length of at least 5 cm along the main axis.

[0019] The wall of the seat tube may have at least two zones, the thickness and / or cross-section of a first zone being less than the thickness and / or cross-section of at least a second zone, each junction between said zones having a curved profile, devoid of sharp angles.

[0020] The seat tube may further include at least one opening arranged in the second zone, said opening being suitable for the passage of a cable, the attachment of an electrical connector, and / or the attachment of a mechanical element.

[0021] The invention also relates to a frame for a bicycle comprising a battery, said frame comprising a seat tube as described above and a sleeve adapted to be inserted into the seat tube around a seat post, the cable passage being delimited by a portion of the outer face of the sleeve and the inner face of the longitudinal bulge.

[0022] Preferably, the frame also includes a seat post clamp, said clamp supporting electrical equipment suitable for connection to one end of an electrical cable passing through the cavity formed by the longitudinal bulge to connect the electrical equipment to a bicycle battery.

[0023] Advantageously, the electrical equipment is a rear lighting lamp or a vehicle detection radar.

[0024] The invention also relates to a bicycle comprising a battery, said bicycle comprising

[0025] • a frame as described above, with the sleeve inserted into the seat tube,

[0026] • a battery,

[0027] • an electrical cable electrically connected to the battery, said electrical cable passing through the inside of the seat tube to the upper opening of the seat tube, said cable being at least partially arranged in the cavity delimited by the inner wall of the longitudinal bulge and by an outer face of the sleeve to electrically power an electrical equipment of the bicycle.

[0028] Preferably, a seatpost is inserted into the sleeve.

[0029] Advantageously, the bicycle further includes a motor for propelling the bicycle, said motor being connected to the battery. The invention also relates to a method for assembling a bicycle comprising a battery, said method comprising:

[0030] • the provision of a framework as described above,

[0031] • the passage of an electrical cable between the upper and lower openings of said cavity

[0032] • the insertion of a sleeve into the upper opening of the seat tube, so as to delimit a cavity between the inner face of the longitudinal bulge and an outer face of the sleeve.

[0033] Preferably, said method includes the electrical connection of a first end of the cable at the upper opening of the seat tube to an electrical device, preferably a rear light of the bicycle.

[0034] Preferably, said method further includes the electrical connection of a second end of the cable to the bicycle battery.

[0035] BRIEF DESCRIPTION OF THE FIGURES

[0036] Other features and advantages will become apparent from the detailed description that follows, with reference to the attached drawings, on which:

[0037] - Figure 1 is a side view of a bicycle including a battery;

[0038] - Figure 2 is a side view of a bicycle frame including a battery and electrical cables;

[0039] - Figure 3 is a top view of a seat tube;

[0040] - Figure 4 is a perspective view of a portion of a seat tube;

[0041] - Figure 5 is a perspective view of the seat tube in Figure 4;

[0042] - Figure 6 is a perspective view of the portion of the seat tube in Figure 4 with a sleeve;

[0043] - Figure 7 illustrates a seat tube, a sleeve and a stem with a saddle;

[0044] - Figure 8 is a perspective view of a portion of the seat tube of Figure 4 with a fixing collar including a lamp for the rear light;

[0045] - Figure 9 is a side view of a bicycle frame.

[0046] DETAILED DESCRIPTION OF IMPLEMENTATION METHODS

[0047] In this text, the terms "front" and "rear," "anterior" and "posterior," refer to the direction of travel of the bicycle. The terms "right," "left," "horizontal," "upper," and "lower" refer to the position of the bicycle when rolling on a horizontal surface. Figure 1 is an overview of an electrically assisted bicycle 100. In such a bicycle, the battery for powering the motor can be housed, for example, in the downtube 70 or in a lower portion of the tube 10 designed to support the saddle 40. A rear light can be mounted at the upper opening 11 of the seat tube 10. In some cases, one or more other electrical devices, for example, a radar for detecting the presence of a vehicle, can be mounted on the seat post.

[0048] In some embodiments (not illustrated), the bicycle includes a main battery for powering the motor, and a secondary battery for powering one or more devices.

[0049] In other embodiments (not illustrated), the bicycle does not have electric propulsion assistance and includes a battery intended for powering one or more electrical devices.

[0050] By way of illustration and without limitation, Figure 2 shows the arrangement of the main battery 55 and the electrical cables 50, 51, 52 for powering the lights and / or any other electrical equipment mounted on the bicycle frame. Alternatively, the battery 55 can be a secondary battery for powering one or more devices, or a battery for a bicycle without electric assistance. A first cable 50 establishes an electrical connection between the battery 55 and a position at the upper opening 11 of the seat tube 10. Other cables 51, 52 can establish electrical connections to devices at the rear wheel and handlebars of the bicycle. In other embodiments (not shown), the battery can be located in a lower portion 12 of the seat tube 10, at the bottom bracket, or in a mounting bracket located outside the bicycle frame.

[0051] The seat tube is typically made of metal, for example, an aluminum alloy. In some cases, the seat tube is made of a composite material such as a carbon fiber composite. The other frame components may be made of the same material or a different material than the seat tube.

[0052] Figure 3 shows a top view of the seat tube.

[0053] The seat tube has a main portion 13 intended for the insertion of a seat post, and a longitudinal bulge 12.

[0054] The main portion 13 has a cross-section essentially corresponding to that of a seatpost. By way of illustration and without limitation, the cross-section of the seatpost can be essentially circular or oval, teardrop-shaped, D-shaped, or any other geometry. The main portion of the seat tube defines an internal housing 110 for receiving a seatpost. The internal housing 110 has a top opening 11.

[0055] The inner face 121 of the longitudinal bulge 12 defines a cavity 120 inside the seat tube. This bulge preferably has a rounded or curved cross-section to avoid sharp angles and edges on the inside and outside of the seat tube 10. The cavity is fully open to the inner housing, meaning it opens into the inner housing across its entire width without any narrowing of the cavity at the junction 63 with the inner housing. This cavity geometry and its opening to the outer housing are achieved through hydroforming, allowing considerable freedom in the choice of tube shape and thickness. In particular, hydroforming makes it possible to create the opening to the outer housing without resorting to complex and expensive techniques, such as the use of a sand core, which is necessary when molding tubes with a specific internal geometry.

[0056] The junction between the inner housing 110 and the cavity 120 is rounded both inside and outside the tube, without sharp angles. Preferably, the tube wall thickness is constant, at least in the plane perpendicular to the main axis of the seat tube, corresponding to the cross-sectional plane in Figure 3. This geometry results in a tube with good mechanical stability without adding material that would increase the weight of the tube and thus the bicycle frame. Furthermore, the rounded shape of the inside and outside of the seat tube reduces the risk of damage to cables housed in the cavity 12 and to any equipment that may be used near the seat tube, as well as the risk of injury to the bicycle user.The bulge 12 typically has, on its inner side, a width I of between 10 and 25 mm, for example between 12 and 20 mm, and a depth p of between 3.5 and 8 mm, for example between 4 and 5 mm. These dimensions allow one or more electrical cables to be housed in the cavity 120 defined by the wall 121 of the longitudinal bulge 12. Such cables can be connected to the bicycle battery and supply power to electrical equipment at the top of the seat tube or at the seat post. This cavity 120 is open on its upper face. At its lower end, the cavity 12 defined by the bulge is typically open towards a lower portion of the seat tube, towards another element of the bicycle frame, or towards the outside of the seat tube 10. The arrangement of the lower opening will be chosen according to the arrangement of the battery to allow an electrical connection to said battery.In a preferred embodiment, the longitudinal bulge 12 extends from the main portion 13 towards the rear of the bicycle in a horizontal plane. This arrangement facilitates the mounting of a rear light. In other lighting embodiments or for other electrical equipment, the longitudinal bulge may extend horizontally in any other orientation relative to the direction of travel of the bicycle.

[0057] Referring to Figure 4, the seat tube may have a longitudinal slot 170 extending from the upper opening 11 into an upper portion 17 of the tube. This slot allows the passage of one end of a cable arranged in the cavity 120 and enables compression of the tube and the attachment of a seatpost by a clamp. Advantageously, the slot 170 is oriented in the same direction as the longitudinal bulge 12. The width of the slot 170 may be equal to the width I of the longitudinal bulge 12. The upper edge 15 of the longitudinal bulge 12 coincides with the lower edge of the slot 170. This arrangement allows a cable passing through the cavity 120 defined by the longitudinal bulge 12 to be guided to a clamp without exposing the cable outside the bicycle frame.

[0058] In other embodiments (not illustrated), the seat tube has no slot. In this case, the bulge extends from the upper opening of the tube towards the bottom bracket.

[0059] Referring to Figure 5, the longitudinal bulge 12 extends, in a direction along the principal axis X of the tube 10, along at least one insertion portion of the stem 16 of the seat tube 10. By way of illustration and without limitation, the insertion portion of the stem 16 may extend over a height of between 5 and 25 cm. In some embodiments, the longitudinal bulge 12 may extend over the entire length of the seat tube.

[0060] In the insertion portion of the 16 stem, the seat tube has a constant cross-section along the longitudinal X axis to allow for good support and the possibility of height adjustment of a seat post.

[0061] Below the seat tube insertion point 16, the seat tube may have the same or a different cross-section compared to the seat tube insertion point 16. In some cases, the cross-section may widen below the seat tube insertion point 16 to create a space for the battery's electrical connection, a housing for the battery, and / or a location for the motor intended to drive the bicycle. In other embodiments, the tube cross-section may be reduced in this area to decrease the bicycle's size and weight.

[0062] With reference to Figures 6 and 7, a sleeve 20 is inserted inside the seat tube 10 to hold a seatpost 30 in the internal housing 110 and to retain the cables in the cavity 120. The sleeve 20 is typically elastic so that it is compressed when a seatpost is attached and may include one or more slots 21 around its circumference. Such a sleeve is a common, commercially available part, typically made of metal.

[0063] The sleeve has an essentially cylindrical geometry with a circular or oval cross-section, and has a top opening 24 and a bottom opening 25.

[0064] As illustrated in Figure 6, when the sleeve 20 is positioned inside the seat tube 10, the upper opening 24 of the sleeve 20 coincides with the upper opening 11 of the tube 10. The sleeve 20 may have a flange 22 on its upper edge to secure the sleeve 20 to the edge of the upper opening 11 of the seat tube 10. The height of the sleeve corresponds to the sum of the heights of the upper portion 17 and the portion of the seat tube insertion 16 intended to receive a seatpost. Preferably, the sleeve has a constant cross-section along the longitudinal axis X, the outer contour of the sleeve 20 corresponding to the inner contour of the tube 10 in the portion of the seat tube insertion 16. This allows the sleeve 10 to slide into the seat tube 10 and provides secure support and height adjustment for a seatpost 30 sliding within the sleeve 20.

[0065] At the longitudinal slot 170 in the upper portion 17 of the tube, the main portion of the tube intended for the insertion of a seat post is delimited by the sleeve 20.

[0066] Referring to Figure 8, a mounting collar 31 surrounds the seat tube in the upper portion 17 near the upper opening 11 of the tube. The mounting collar 31 includes a clamping element 37, such as a screw or a quick-release clamp, for compressing the sleeve 20. Advantageously, the mounting collar 31 also includes electrical equipment for the bicycle, such as a rear light 35 or a vehicle detection radar. The mounting collar includes an opening (not shown) at the bulge, for example, on one of the lower faces of the mounting collar. This opening allows the electrical connection of an electrical cable arranged in the cavity defined by the bulge to the electrical equipment. Thus, the electrical cable can pass from the upper opening of the cavity 120 defined by the bulge into the lower opening of the mounting collar 31 without passing outside the bicycle.

[0067] In other embodiments, the clamp may include a through-hole allowing the electrical cable to pass to electrical equipment arranged in a different position on the seat tube or post, or to an electrical connector. Referring to Figures 7 and 9, a seatpost 30 can be inserted into the sleeve 20 located in the seat tube 10. The seatpost is held in position by the clamp. In the insertion portion of the post 16, the sleeve surrounds the seatpost 30 arranged in the main portion of the seat tube 10. Thus, the seatpost 30 and the cable located in the cavity defined by the bulge are positioned on either side of the sleeve wall and separated by this wall. The cable therefore does not interfere with the adjustment or replacement of the seatpost.Conversely, movement of the seat post inside the tube does not cause damage to the electrical cable.

[0068] The invention also relates to a method for assembling a bicycle equipped with a battery. The method begins by providing a bicycle frame including a seat tube as described above. During the manufacture of the seat tube, the bulge is created by hydroforming with the other portions of the seat tube. Creating the bulge may further include one or more machining steps on the inner and / or outer face of the tube.

[0069] Hydroforming, unlike other manufacturing processes such as extrusion, allows for the creation of different zones within the seat tube, each with varying shapes and / or thicknesses. This optimizes the weight-to-strength ratio of the tube by reinforcing it only in the most stressed areas. For example, the tube thickness can be increased compared to a standard thickness in certain areas subject to particular stress during bicycle use, or in areas around mounting points or cable routing, for instance, for shock absorbers or additional cables. The ability to optimize geometry and create reinforced zones improves the reliability of the bicycle frame while simultaneously optimizing the weight of the seat tube.

[0070] A hydroforming process also allows the shape of the seat tube to be adapted to fulfill additional functions such as cable routing and mounting points for pivots or shock absorbers. For example, with reference to Figure 6, the seat tube may include a zone 61 adapted to receive a suspension pivot, for example by welding, and / or a zone 62 adapted to receive a motor mounting plate. The tube may also include a first zone Z1 in which the tube wall has a first thickness, for example a standard thickness, and a second zone Z2 in which the tube wall has a second thickness, for example a reinforced thickness, greater than the standard thickness. However, the arrangement of the zones is not limited to the illustrated example and may be radial, axial, or have a geometry adapted to mechanical constraints or manufacturing or assembly constraints of the seat tube.

[0071] Hydroforming also allows for the optimization of the geometry of the junctions between the seat tube and other parts of the bicycle frame, and for limiting the number of welds required for these junctions.

[0072] In some embodiments, the seat tube is welded to the other parts of the frame. The wheels, handlebars, and other parts of the bicycle can be arranged on the frame or mounted later.

[0073] A battery is inserted into the bicycle frame or a designated mounting point. If necessary, the battery can be electrically connected to a motor to power the electric bicycle. One end of an electrical cable, intended to power electrical equipment, is connected to the battery. A free end of the electrical cable is routed, preferably internally to the frame, to a lower opening in the seat tube. The electrical cable is then threaded through the seat tube, and the free end of the cable is routed to the upper opening in the seat tube and passed through it.

[0074] The electrical cable is held in the cavity formed by the longitudinal bulge in the seat tube. A sleeve for carrying the seatpost is inserted into the seat tube from the top opening of the seat tube until it is fully inserted.

[0075] Alternatively, the electrical cable can be passed through the cavity defined by the inner wall of the bulge before being connected to the battery and / or after the sleeve is inserted. The cable can be routed from the top opening of the seat tube, or from a lower or side opening of the seat tube.

[0076] The sleeve wall now defines the cavity formed by the bulge. The cable is thus confined within this cavity and cannot be moved inside the sleeve into the main portion of the tube intended to receive the seatpost.

[0077] The free end of the electrical cable is then connected to an electrical device, for example, a light mounted in a seatpost clamp. In other cases, the free end of the cable passes through an opening in the seatpost clamp and / or is connected to an electrical connector at the top of the seat tube, allowing for a subsequent electrical connection to an electrical device.

[0078] If necessary, the seatpost clamp is mounted around the seat tube near the top opening of the tube. The clamp may cover the top opening of the longitudinal bulge to prevent damage to the electrical cable and obstruction of the cavity. When the seat tube has a slot, the seatpost clamp is positioned to cover that slot.

[0079] A seatpost can now be inserted into the upper opening of the seat tube and seat stay. If necessary, during seatpost insertion, the seat clamp is loosened in its position without disconnecting the electrical connection to the cable passing through the cavity defined by the bulge. The seatpost can be adjusted in height, removed, and reinserted while maintaining the electrical connection of the equipment to the cable arranged in the cavity defined by the longitudinal bulge. A 38mm saddle can be attached to the 30mm seatpost.

Claims

DEMANDS 1. Hydroformed seat tube (10) for a bicycle comprising a battery, said seat tube comprising an internal housing (110) adapted to receive a seat post (30) extending along a main axis (X), characterized in that said seat tube (10) has a longitudinal bulge (12) extending along said main axis (X) and of which an internal face (121) defines, in the seat tube (10), a cavity (120) fully open to the internal housing (110), said cavity (120) forming a passage for an electrical cable out of the internal housing (110).

2. Seat tube (10) according to claim 1, wherein the seat tube (10) has a longitudinal slot (170) extending from an upper opening (11) of the seat tube (10), the longitudinal bulge (12) extending along the main axis (X) from a lower edge (15) of the slot (170).

3. Seat tube (10) according to claim 1, wherein the longitudinal bulge (12) extends along the main axis (X) from a top opening (11) of the seat tube (10).

4. Seat tube (10) according to any one of claims 1 to 3, wherein the inner face (121) of the longitudinal bulge (12) has a rounded or curved section.

5. Seat tube (10) according to any one of the preceding claims, wherein the longitudinal bulge (12) is oriented towards the rear of the bicycle.

6. Seat tube (10) according to any one of the preceding claims, wherein the longitudinal bulge (12) extends over an upper portion (16) of the seat tube (10) having a length of at least 5 cm along the main axis (X).

7. Seat tube (10) according to any one of the preceding claims, wherein the wall of the seat tube has at least two zones (Z1, Z2), the thickness and / or cross-section of a first zone (Z1) being less than the thickness and / or cross-section of at least a second zone (Z2), each junction between said zones (Z1, Z2) having a curved profile, devoid of sharp angles.

8. Seat tube (10) according to claim 7, further comprising at least one orifice (61, 62) arranged in the second zone (Z2), said orifice being adapted for the passage of a cable, the attachment of an electrical connector, and / or the attachment of a mechanical element.

9. Frame for a bicycle comprising a battery, said frame comprising a seat tube (10) according to any one of claims 1 to 8 and a sleeve (20) adapted to be inserted into the seat tube (10) around a seat post (30), the cable passage being delimited by a portion (220) of the outer face of the sleeve (20) and the inner face (121) of the longitudinal bulge (12).

10. Frame according to claim 9, further comprising a fixing collar (31) for the seat post (30), said collar (31) supporting an electrical equipment (35) adapted to be connected to a first end of an electrical cable (50) passing through the cavity (120) formed by the longitudinal bulge (12) to connect the electrical equipment to a battery (55) of the bicycle.

11. Frame according to claim 10, wherein the electrical equipment is a rear lighting lamp (35) or a vehicle detection radar.

12. Bicycle comprising a battery, said bicycle comprising • a frame according to any one of claims 9 to 11, the sleeve (20) being inserted into the seat tube (10), • a battery (55), • an electrical cable (50) electrically connected to the battery (55), said electrical cable (35) passing through the inside of the seat tube (10) to the upper opening of the seat tube (10), said cable being at least partially arranged in the cavity (120) delimited by the inner wall (121) of the longitudinal bulge and by an outer face (220) of the sleeve (20) to electrically power an electrical equipment of the bicycle.

13. Bicycle according to claim 12, in which a seat post (30) is inserted into the sleeve (20).

14. Bicycle according to claim 12 or claim 13, further comprising a motor for the propulsion of the bicycle, said motor being connected to the battery (55).

15. A method for assembling a bicycle comprising a battery, said method comprising: • the provision of a framework according to one of claims 9 to 11, • the passage of an electrical cable (50) between the upper opening and the lower opening of said cavity (120) • the insertion of a sleeve (20) into the upper opening (11) of the seat tube (10), so as to delimit a cavity (120) between the inner face (121) of the longitudinal bulge (12) and an outer face (220) of the sleeve (20).

16. Method according to claim 15, comprising the electrical connection of a first end of the cable at the upper opening (11) of the seat tube (10) to an electrical device, preferably a rear light (35) of the bicycle.

17. Method according to claim 16, further comprising the electrical connection of a second end of the cable (50) to the battery (55) of the bicycle.

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