Bicycle and derailleur thereof

Abstract

A bicycle derailleur, comprising a four-bar linkage mechanism and a chain tensioning assembly arranged on the four-bar linkage mechanism, wherein the four-bar linkage mechanism comprises a base member, a movable member and a linkage mechanism; a first end portion of the linkage mechanism is connected to the base member, and a second end portion of the linkage mechanism is connected to a first end portion of the movable member; the chain tensioning assembly comprises a chain guide pulley, a tension pulley and a tension arm; a first end portion of the tension arm is rotatably connected to a second end portion of the movable member; the tension pulley is rotatably arranged at a second end portion of the tension arm; and the chain guide pulley is rotatably arranged on the movable member, and a reset assembly is provided at the position in which the tension arm is rotatably connected to the movable member.

Description

Bicycles and their derailleurs

[0001] Cross-reference to related applications

[0002] This disclosure claims priority to Chinese patent application CN202520262822.0, filed on February 15, 2025, and Chinese patent application CN202520389828.4, filed on March 7, 2025, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to the field of bicycle technology, and more particularly to bicycles and their derailleurs. Background Technology

[0004] In a bicycle, power is transmitted from the crankset to the freewheel, which contains at least one sprocket, via a chain, thus transferring power to the rear wheel. The chain interacts with the teeth on the sprockets in the crankset and also with the sprockets on the freewheel arranged around the rear wheel hub, enabling power transmission. In a single-speed bicycle, the freewheel uses a single sprocket. When the user pedals, the crankset rotates, moving the chain, which in turn causes the sprocket on the freewheel to rotate, ultimately rotating the rear wheel. In a multi-speed bicycle, the freewheel uses multiple sprockets. To allow the chain to switch between sprockets of different diameters, a derailleur is typically used for shifting gears.

[0005] Existing derailleurs typically include a base component, a moving component, and a chain guide. The moving component is movably connected to the base component via a linkage mechanism. Under the action of a control cable on the shift lever, the chain guide moves laterally relative to the base component to achieve gear shifting. During shifting, due to the lateral movement of the chain guide required for switching the chain between multiple sprockets, the linkage mechanism, moving component, and chain guide all extend a considerable distance outward along the outer edge of the bicycle, especially when the chain engages with the outermost sprocket of the freewheel. When a coil spring is sandwiched between paired linkages, this consequence is further amplified because the linkages must be spaced apart to accommodate the spring; this consequence becomes more severe with an increasing number of sprockets, thus increasing the lateral distance the chain guide must travel. Therefore, a chain guide with a large outward extension is susceptible to impacts or tangling with nearby objects during riding; it is also easily damaged in the event of a fall. Summary of the Invention

[0006] The purpose of this disclosure is to solve at least one of the above-mentioned problems.

[0007] The first aspect of this disclosure provides a bicycle derailleur that offers a wide chain tension range and absorbs excess chain slack. It maintains tension not only when the chain moves between different sprockets but also when the bicycle is folded. Furthermore, the derailleur has a compact structure with minimal outward extension, and the entire derailleur is almost entirely concealed within the frame, improving riding safety and effectively preventing damage to the derailleur in the event of a crash.

[0008] A second aspect of this disclosure provides a bicycle including the aforementioned bicycle derailleur.

[0009] To address at least one of the aforementioned problems, this disclosure provides the following technical solution:

[0010] A bicycle derailleur includes a four-bar linkage and a chain tensioning assembly disposed on the four-bar linkage. The four-bar linkage includes a base component, a movable component, and a linkage mechanism. A first end of the linkage mechanism is connected to the base component, and a second end of the linkage mechanism is connected to the first end of the movable component. The chain tensioning assembly includes a chain guide wheel, a tension wheel, and a tension arm. A first end of the tension arm is rotatably connected to the second end of the movable component. The tension wheel is rotatably disposed at the second end of the tension arm. The chain guide wheel is rotatably disposed on the movable component, and a reset assembly is provided at the rotatable connection between the tension arm and the movable component.

[0011] In some embodiments, the movable component includes an inner guide plate and an outer guide plate, the outer guide plate is fixed to the side of the inner guide plate, and the guide sprocket is rotatably disposed between the inner guide plate and the outer guide plate; the linkage mechanism is hinged to the first end of the outer guide plate; and the tensioning arm is rotatably connected to the second end of the inner guide plate.

[0012] In some embodiments, the inner guide plate is a flat plate structure, and the sides of the inner guide plate are divided into inner and outer sides. The side closer to the bicycle frame is the inner side, and the side closer to the outer guide plate is the outer side. The outer guide plate and the outer side of the inner guide plate are fixedly connected by screws. The tensioning arm is rotatably connected to the second end of the outer side of the inner guide plate.

[0013] In some embodiments, the outer guide plate and the tensioning arm are disposed separately from each other.

[0014] In some embodiments, there are two screws, one of which fixes the first end of the inner guide plate to the first end of the outer guide plate, and the other screw fixes the middle part of the inner guide plate to the second end of the outer guide plate.

[0015] In some embodiments, a column is provided on the first end of the tensioning arm, the column is hinged to the second end of the inner guide plate, and the second end of the tensioning arm is inclined toward the outer side of the inner guide plate.

[0016] In some embodiments, the second end of the tensioning arm is provided with two parallel guide discs, and the tensioning wheel is disposed between the two guide discs.

[0017] In some embodiments, the tensioning arm is provided with a plurality of opening slots.

[0018] In some embodiments, the column and the second end of the inner guide plate are hinged together by a hinge shaft; the hinge shaft has an annular groove at the end away from the inner guide plate, the column has a mounting post that passes through the annular groove, and the mounting post and the column are connected by threads.

[0019] In some embodiments, a derailleur is used to mount on a bicycle frame, the frame including a chainstay with its rear end connected to a rear axle; a base member is used to mount on the chainstay and is located at the front end of the rear axle.

[0020] In some embodiments, a derailleur is used to mount on a bicycle frame, the frame including a chainstay with its rear end connected to a rear axle; a base member is used to mount on the rear end of the chainstay and located behind the rear axle.

[0021] In some embodiments, the rear end of the rear lower fork is provided with a downward-opening n-shaped groove for mounting the rear axle, and a downward-extending mounting extension is provided on the rear side of the n-shaped groove, and the base member is mounted on the mounting extension.

[0022] In some embodiments, the base component includes a base body, a mounting portion disposed on the outside of the base body, and a connecting arm disposed between the base body and the mounting portion and inclined inward. A first end of the connecting arm is connected to the mounting portion, and a second end of the connecting arm is connected to the base body. A first end of the linkage mechanism is hinged to the base body. The mounting portion is mounted on the mounting extension portion by mounting bolts, and the mounting bolts are parallel to the rear axle.

[0023] In some embodiments, the linkage mechanism includes a first link and a second link. The movable component includes a plate-shaped outer guide plate, an inner guide plate disposed on the inner side of the outer guide plate, a first mounting protrusion disposed on the outer side of the outer guide plate, and a second mounting protrusion disposed on the upper surface of the outer guide plate. The first end of the first link is hinged to the base component, and the second end of the first link is hinged to the first mounting protrusion. The first end of the second link is hinged to the base body, and the second end of the second link is hinged to the second mounting protrusion. The guide sprocket is rotatably disposed between the outer guide plate and the inner guide plate. The first end of the tensioning arm is rotatably connected to the outer side of the inner guide plate.

[0024] In some embodiments, the inner guide plate is a flat plate structure; the first end of the outer guide plate extends obliquely upward in the direction of bicycle movement, the first end of the outer guide plate is fixedly connected to the first end of the inner guide plate, and the second end of the outer guide plate is fixedly connected to the middle of the outer side surface of the inner guide plate; the first mounting protrusion and the second mounting protrusion are located at the rear end of a vertical plane passing through the axis of the guide sprocket.

[0025] In some embodiments, the first end of the tensioning arm is rotatably connected to the second end of the outer side of the inner guide plate; the outer guide plate and the tensioning arm are separately disposed from each other.

[0026] In some embodiments, the inner side of the base body is provided with a wire hole for installing the speed change guide tube.

[0027] In some embodiments, a clamping arm extends inward from the inner side of the first link, and the end of the clamping arm is provided with a clamping assembly for clamping a metal wire.

[0028] In some embodiments, the lower end of the mounting extension is provided with a limiting surface, the inner side of the connecting arm is provided with a reinforcing rib between it and the base body, and an adjusting screw is provided on the reinforcing rib, with the end of the adjusting screw pressed against the limiting surface.

[0029] In some embodiments, a mounting nut is provided at the bottom of the rear lower fork, an arc-shaped washer is provided between the base component and the bottom of the rear lower fork, the upper end of the mounting nut is fixedly connected to the bottom of the rear lower fork, and the lower end passes through the arc-shaped washer and extends into the interior of the base component. The base component is fixedly connected to the mounting nut by mounting bolts.

[0030] This disclosure also provides a bicycle, including a bicycle frame, a crank assembly, a freewheel, a chain, and the aforementioned bicycle derailleur; the crank assembly, freewheel, and derailleur are all mounted on the bicycle frame, and the chain is connected to the crank assembly, freewheel, and bicycle derailleur respectively; when the bicycle is folded, the distance between the axis of the crank assembly and the axis of the freewheel decreases, and the derailleur is used to tension the chain.

[0031] The beneficial effects of this disclosure include:

[0032] 1. The bicycle derailleur disclosed herein, because the chain guide wheel is set on the movable component and the tension wheel is set on the tension arm, the distance between the chain guide wheel and the tension wheel can be changed, so that the chain tensioning assembly has a large tensioning range on the chain and can absorb additional slack in the chain; it can not only maintain tension when the chain switches between different chain guides, but also maintain tension when the bicycle is folded. After the rear wheel is folded, the chain is still in a taut state and the chain does not fall off.

[0033] 2. The bicycle derailleur disclosed herein absorbs chain slack when the bicycle is folded and moves the chain between different sprockets during gear shifting without the need for an additional chain tensioner, thus avoiding unnecessary weight increase to the bicycle due to an additional chain tensioner.

[0034] 3. In the bicycle derailleur disclosed herein, the guide wheel and tension wheel move simultaneously during gear shifting, resulting in more precise gear shifting.

[0035] 4. The bicycle derailleur disclosed herein has a base component installed at the bottom of the rear chainstay and at the front end of the rear axle or at the rear end of the rear chainstay and at the rear side of the rear axle. This makes the derailleur closer to the inside of the frame after installation. It is not only compact in structure and has a small outward extension distance, but also almost completely hidden inside the frame after installation. Attached Figure Description

[0036] Figure 1 is a partial structural diagram of a bicycle in an unfolded state according to the first embodiment of this disclosure.

[0037] Figure 2 is a partial structural diagram of a bicycle in a folded state according to the first embodiment of this disclosure.

[0038] Figure 3 is a front view of a bicycle derailleur according to a first embodiment of this disclosure.

[0039] Figure 4 is a front view of the bicycle derailleur of the first embodiment of this disclosure in another state.

[0040] Figure 5 is a three-dimensional structural diagram of a bicycle derailleur according to the first embodiment of this disclosure.

[0041] Figure 6 is a three-dimensional structural diagram of the bicycle derailleur of the first embodiment of this disclosure from another perspective.

[0042] Figure 7 is a right view of a bicycle derailleur according to the first embodiment of this disclosure.

[0043] Figure 8 is a three-dimensional structural diagram of the movable component and part of the chain tensioning assembly of the first embodiment of this disclosure.

[0044] Figure 9 is a top view of the movable component and part of the chain tensioning assembly of the first embodiment of this disclosure.

[0045] Figure 10 is a three-dimensional structural diagram of the inner guide plate, tensioning wheel, and tensioning arm according to the first embodiment of this disclosure.

[0046] Figure 11 is a three-dimensional structural diagram of the inner guide plate, mounting post, hinge shaft and reset assembly of the first embodiment of this disclosure.

[0047] Figure 12 is an exploded view of the frame and bicycle derailleur of the first embodiment of this disclosure.

[0048] Figure 13 is a schematic diagram of a bicycle rear derailleur mounted on a frame according to a second embodiment of the present disclosure.

[0049] Figure 14 is a three-dimensional structural diagram of a bicycle derailleur mounted on a frame according to the second embodiment of this disclosure.

[0050] Figure 15 is a three-dimensional structural diagram of a bicycle rear derailleur installed on a frame according to a second embodiment of the present disclosure, viewed from another angle.

[0051] Figure 16 is a partial structural diagram of the vehicle frame according to the second embodiment of this disclosure.

[0052] Figure 17 is a front view of a bicycle derailleur according to a second embodiment of the present disclosure.

[0053] Figure 18 is a top view of a bicycle derailleur according to a second embodiment of the present disclosure.

[0054] Figure 19 is a three-dimensional structural diagram of the base component and linkage mechanism of the second embodiment of this disclosure.

[0055] Figure 20 is a three-dimensional structural diagram of the base component according to the second embodiment of this disclosure.

[0056] Figure 21 is a three-dimensional structural diagram of the base component of the second embodiment of this disclosure from another perspective.

[0057] Figure 22 is a three-dimensional structural diagram of the movable component and chain tensioning assembly according to the second embodiment of this disclosure.

[0058] Figure 23 is a three-dimensional structural diagram of the movable component and part of the chain tensioning assembly according to the second embodiment of this disclosure.

[0059] Figure 24 is a front view of the movable component and part of the chain tensioning assembly of the second embodiment of this disclosure. Detailed Implementation

[0060] To facilitate a better understanding of the purpose, structure, features, and effects of this invention, the invention will now be further described in conjunction with the accompanying drawings and specific embodiments. It should be noted that the features shown in the figures are not necessarily drawn to scale. Furthermore, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the described embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0061] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms "first," "second," and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," "right," "front," and "rear" are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described object changes. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0062] If any structure or feature in the description of one embodiment is not described or described in detail in other embodiments, such structure or feature shall also be applicable to other embodiments without conflict. The composition and construction of similar structures in different embodiments may differ or be identical. Any structures in different embodiments may be combined with each other without conflict.

[0063] Example 1

[0064] Referring to Figures 1 and 2, this embodiment discloses a bicycle, including a bicycle frame 1, a crank assembly 2, a freewheel 3, a chain 4, and a bicycle derailleur 100. The crank assembly 2, freewheel 3, and bicycle derailleur 100 are all mounted on the bicycle frame 1. The chain 4 is connected to the crank assembly 2, freewheel 3, and bicycle derailleur 100 respectively. When the bicycle is folded, the distance between the axis of the crank assembly 2 and the axis of the freewheel 3 decreases. That is, when the bicycle is not folded, the distance between the axis of the crank assembly 2 and the axis of the freewheel 3 is greater than the distance between the axis of the crank assembly 2 and the axis of the freewheel 3 when the bicycle is folded. The bicycle derailleur 100 is used to tension the chain 4. The axis of the crank assembly 2 is the axis of the sprocket on the crank assembly 2. The freewheel 3 can be composed of one sprocket 31 (freewheel plate 31) or multiple sprockets 31.

[0065] Referring to Figures 1-7, the bicycle rear derailleur 100 includes a four-bar linkage 7 and a chain tensioning assembly 40 mounted on the four-bar linkage 7. The four-bar linkage 7 can drive the chain tensioning assembly 40 to move, thereby realizing the functions of undulating chain 4 and tensioning chain 4.

[0066] Referring to Figures 1-7, the four-bar linkage 7 includes a base component 5, a movable component 6, and a linkage mechanism 7; the base component 5 is mounted on the bicycle frame 1; the first end of the linkage mechanism 7 is connected to the base component 5, and the second end of the linkage mechanism 7 is connected to the first end of the movable component 6.

[0067] Referring to Figure 1, the direction in which the bicycle moves forward is defined as forward, front end, or front side, and the opposite direction is defined as rear, rear end, or rear side. The frame 1 includes a rear top fork 25 and a rear chain fork 21, with the rear end of the chain fork 21 connected to the rear axle 26. The rear ends of the top fork 25 and the chain fork 21 are connected together. In this embodiment, the base member 5 is installed at the bottom of the chain fork 21 and located at the front end of the rear axle 26, so that the rear derailleur 100, after installation, is closer to the inside of the frame 1, resulting in a compact structure, a smaller outward extension distance, and the rear derailleur 100 being almost entirely hidden inside the frame 1 after installation. In other embodiments, the base member 5 may also be installed on the side of the chain fork 21 and located at the front end of the rear axle 26.

[0068] Referring to Figure 12, a mounting nut 22 is provided at the bottom of the chainstay 21 of the frame 1. An arc-shaped washer 23 is provided between the base component 5 and the bottom of the chainstay 21. The upper end of the mounting nut 22 is fixedly connected to the bottom of the chainstay 21, and the lower end passes through the arc-shaped washer 23 and extends into the interior of the base component 5. The base component 5 is fixedly connected to the mounting nut 22 by mounting bolts (not shown). Since the rear derailleur 100 is mounted on the chainstay 21, the above structure can ensure that the structure of the rear derailleur 100 is more compact, while also ensuring chain tension; and better concealing the rear derailleur 100 within the frame 1.

[0069] The base component 5 is provided with an installation position 55 (also referred to as an installation area), which is the location (area) where the base component 5 is connected to the bicycle frame 1. In this embodiment, the installation position 55 is located on the arc-shaped pad 23.

[0070] Referring to Figure 7, the sprocket 8 has a wheel plane 811 perpendicular to its axis and located at its center, parallel to the sprocket. A reference point 511 is located at mounting position 55, which is the closest reference point 511 to the center plane of the bicycle's rear wheel (a plane located at the center of the rear wheel, parallel to the rear wheel, and perpendicular to the axis of rotation of the rear wheel). For the relationship between the wheel plane 811 and the reference point 511, see, for example, Chinese Patent Application No. CN202520667875.0, the entire contents of which are incorporated herein by reference for all purposes.

[0071] Referring to Figures 2-11, the chain tensioning assembly 40 includes a sprocket 8, a tensioning wheel 9, and a tensioning arm 10. The first end of the tensioning arm 10 is rotatably connected to the second end of the movable member 6. The tensioning wheel 9 is rotatably disposed at the second end of the tensioning arm 10. The sprocket 8 is rotatably disposed on the movable member 6. A reset assembly is provided at the rotatable connection between the tensioning arm 10 and the movable member 6. When the bicycle shifts gears or is folded, the elastic force of the reset assembly causes the tensioning arm 10 to swing backward, tensioning the chain 4. That is, when the chain 4 switches between different sprockets or when the bicycle is folded, the chain tensioning assembly 40 keeps the chain under tension. Referring to Figures 2-11, the movable member 6 includes an inner guide plate 61 and an outer guide plate 62. The outer guide plate 62 is fixed to the side of the inner guide plate 61. The sprocket 8 is rotatably disposed between the inner guide plate 61 and the outer guide plate 62. The linkage mechanism 7 is hinged to the first end of the outer guide plate 62. The tensioning arm 10 is rotatably connected to the second end of the inner guide plate 61. In the above structure, the movable component 6 is composed of an inner guide plate 61 and an outer guide plate, making the structure simpler; the first end of the outer guide plate 62 constitutes the first end of the movable component 6, and the second end of the inner guide plate 61 constitutes the second end of the movable component 6.

[0072] Referring to Figures 2-11, the inner guide plate 61 is a flat plate structure. The sides of the inner guide plate 61 are divided into inner and outer sides. The side closer to the bicycle frame 1 is the inner side, and the side closer to the outer guide plate 62 is the outer side. The outer guide plate 62 and the outer side of the inner guide plate 61 are fixedly connected by screws 11. The tensioning arm 10 is rotatably connected to the second end of the outer side of the inner guide plate 61. In the above structure, the inner guide plate 61 is a flat plate structure, which is easy to process and has a simple structure. The inner guide plate 61 and the outer guide plate 62 are connected by screws 11, facilitating installation and disassembly. Furthermore, both the outer guide plate 62 and the tensioning arm 10 are located on one side of the outer side of the inner guide plate 61, making the bicycle derailleur 100 structure very compact.

[0073] The outer guide plate 62 is also a plate structure. Since the outer guide plate 62 on the movable component 6 is a plate structure, and the inner guide plate 61 is located on the inner side of the outer guide plate 62, and the inner side of the outer guide plate 62 is the side close to the wheel, the rear derailleur 100 has a compact structure and a small outward extension distance. After the rear derailleur 100 is installed, it is almost hidden inside the frame 1.

[0074] Referring to Figures 1-11, the outer guide plate 62 and the tensioning arm 10 are separately configured. That is, the tensioning arm 10 is only connected to the inner guide plate 61 and does not directly contact or connect with the outer guide plate 62. The outer guide plate 62 and the tensioning arm 10 are separate, and the inner guide plate 61 is indirectly connected to the tensioning arm 10 through the inner guide plate 61. The purpose of this is to simplify the structure of the bicycle derailleur 100, prevent the tensioning arm 10 from interfering with the outer guide plate 62, and allow the tensioning arm 10 to have a larger range of rotation on the inner guide plate 61, thereby improving the tensioning range of the chain 4.

[0075] Referring to Figures 2-11, there are two screws 11. The first end of the inner guide plate 61 is fixed to the first end of the outer guide plate 62 by one screw 11, and the middle part of the inner guide plate 61 is fixed to the second end of the outer guide plate 62 by the other screw 11. In the above structure, the middle part of the inner guide plate 61 is fixed to the second end of the outer guide plate 62 by the other screw 11, indicating that the structural length of the outer guide plate 62 is smaller than that of the inner guide plate 61, which simplifies the structure. The two screws 11 make the connection between the inner guide plate 61 and the outer guide plate 62 very stable. The simplification of the inner guide plate 61 can improve the tensioning range of the tensioning arm 10 on the chain 4.

[0076] Referring to Figures 2-11, the sprocket 8 is positioned between the middle of the outer guide plate 62 and the middle of the inner guide plate 61. The first end of the outer guide plate 62 has a mounting protrusion 621, and the second end has a positioning sleeve 622. The mounting protrusion 621 and the positioning sleeve 622 are respectively connected to the inner guide plate 61 by two screws 11. The purpose of this is to ensure that there is space between the inner guide plate 61 and the outer guide plate 62, facilitating the installation of the sprocket 8 and the connection of the screws 11. The mounting protrusion 621 also serves to prevent the chain 4 from falling off the sprocket 8.

[0077] Referring to Figures 2-11, a column 12 is provided on the first end of the tensioning arm 10. The column 12 has an inner cavity and is hinged to the second end of the inner guide plate 61. The second end of the tensioning arm 10 is inclined towards the outer side of the inner guide plate 61. The purpose is to ensure that the tensioning wheel 9 and the guide sprocket 8 are on the same plane, so that the chain 4 can be smoothly guided and tensioned on the tensioning wheel 9 and the guide sprocket 8, preventing the chain 4 from falling off and improving the stability of the chain 4 during operation.

[0078] Referring to Figures 2-11, the second end of the tensioning arm 10 is provided with two parallel guide discs 13, and the tensioning wheel 9 is disposed between the two guide discs 13. The two guide discs 13 can guide the chain 4 and prevent the chain 4 from falling off the tensioning wheel 9.

[0079] Referring to Figures 2-11, the tensioning arm 10 is provided with multiple opening slots 14. The purpose is to reduce the weight of the tensioning arm 10, simplify its structure, ensure that the reset assembly has sufficient elasticity to tension the chain 4, and also improve the structural strength of the tensioning arm 10.

[0080] Referring to Figures 2-11, the column 12 and the second end of the inner guide plate 61 are hinged together by a hinge shaft 15. The hinge shaft 15 has an annular groove 16 at the end furthest from the inner guide plate 61. A mounting post 17 is provided on the column 12, passing through the annular groove 16, and is threadedly connected to the column 12. In this structure, the mounting post 17 allows the column 12 to be mounted on the hinge shaft 15. When the tension arm 10 rotates, the mounting post 17 can rotate within the annular groove 16, which axially limits the mounting post 17, preventing the column 12 from dislodging.

[0081] Referring to Figures 2-11, the reset assembly is a torsion spring 18, which is sleeved on the hinge shaft 15 and located in the inner cavity. One end of the torsion spring 18 acts on the second end of the inner guide plate 61, and the other end acts on the column 12. The elastic force of the torsion spring 18 causes the tensioning arm 10 to rotate, thereby causing the tensioning wheel 9 to tension the chain 4.

[0082] Referring to Figures 2-11, the side of the column 12 is provided with a limiting protrusion 19, and the outer side of the inner guide plate 61 is provided with a limiting post 20. The limiting protrusion 19 and the limiting post 20 can prevent the tensioning arm 10 from colliding with the four-bar linkage 7 due to the excessive elasticity of the torsion spring 18, thus playing a safety limiting role.

[0083] Referring to Figures 2-11, the linkage mechanism 7 includes a first link 71 and a second link 72. The first end of the first link 71 is hinged to the base member 5, and the second end of the first link 71 is hinged to the first end of the outer guide plate 62. The first end of the second link 72 is hinged to the base member 5, and the second end of the second link 72 is hinged to the first end of the outer guide plate 62. The first link 71 and the second link 72 are hinged to the base member 5 at different positions, and the first link 71 and the second link 72 are hinged to the first end of the outer guide plate 62 at different positions.

[0084] Referring to Figures 3-12, the movable component 6 also includes a first mounting protrusion 63 and a second mounting protrusion 64 disposed on the outer side of the outer guide plate 62 and located at the first end of the outer guide plate 62. The second end of the first connecting rod 71 is hinged to the first mounting protrusion 63 of the outer guide plate 62, and the second end of the second connecting rod 72 is hinged to the second mounting protrusion 64 of the outer guide plate 62. Referring to Figure 3, viewed from the front view of the derailleur 100, the first mounting protrusion 63 and the second mounting protrusion 64 are located at the front end of the vertical plane 28 passing through the axis of the guide wheel 8 and perpendicular to the guide wheel 8, that is, the vertical plane 28 of the guide wheel 8 is located behind the hinged positions of the first connecting rod 71 and the second connecting rod 72 with the outer guide plate 62.

[0085] Referring to Figure 6, a clamping arm 30 extends inward from the inner side of the first connecting rod 71. The end of the clamping arm 30 is provided with a clamping assembly 24 for clamping the metal wire. The inward extension of the clamping arm 30 ensures that it is not exposed, minimizing the outward extension distance of the rear guide chain. The clamping assembly 24 can be a clamping screw.

[0086] Referring to Figures 1-11, the working principle of the bicycle derailleur 100 described above is as follows:

[0087] The shift cable drives the chain tensioning assembly via a four-bar linkage 7, actuating the chain 4 and causing it to move between different sprockets, thus achieving the gear shifting process. The movable component 6 is a moving component; the guide sprocket 8 moves with the movable component 6, thereby actuating the chain 4. The tension wheel 9 and tension arm 10 tension the chain 4. Because the guide sprocket 8 is located on the movable component 6 and the tension wheel 9 is located on the tension arm 10, the chain tensioning assembly 40 has a large tension range on the chain 4, absorbing any excess slack in the chain 4. When the bicycle is folded, the chain tensioning assembly 40 maintains tension on the chain 4.

[0088] Example 2

[0089] Figures 13 to 24 illustrate the second embodiment of this disclosure. In the second embodiment, the specific structure of the base member 5 of the rear derailleur 100 differs from that of Embodiment 1. Other structures of the rear derailleur 100 are the same as in Embodiment 1 unless specifically described in this embodiment.

[0090] In addition, in this embodiment, the mounting position of the derailleur 100 to the bicycle frame 1 via the base member 5 is different from that in embodiment 1. As shown in FIG13, the base member 5 is mounted on the rear end of the chainstay 21 and located behind the rear axle 26.

[0091] The rear end of the chainstay 21 has a downward-opening n-shaped groove 101 for mounting the rear axle 26 (rear wheel). A downward-extending mounting extension 102 is provided on the rear side of the n-shaped groove 101, and the base member 5 is mounted on the mounting extension 102. In this structure, the rear axle 26 is the axle of the bicycle's rear wheel. The downward-opening n-shaped groove 101 facilitates the installation of the rear axle 26, and the mounting extension 102 facilitates the installation of the entire rear derailleur 100.

[0092] The base component 5 includes a base body 51, a mounting portion 53 disposed on the outside of the base body 51, and a connecting arm 52 disposed between the base body 51 and the mounting portion 53 and inclined inward. The first end of the connecting arm 52 is connected to the mounting portion 53, and the second end of the connecting arm 52 is connected to the base body 51. The mounting portion 53 is used to mount on the bicycle frame 1. The first end of the linkage mechanism 7 is hinged to the base body 51. The mounting portion 53 is mounted on the mounting extension portion 102 by mounting bolts 27, which are parallel to the rear axle 26. In the above structure, by setting the connecting arm 52, the base body 51 is located inside the mounting portion 53, ensuring that the base body 51 is closer to the wheel, thereby ensuring that the rear derailleur 100 extends outward by a smaller distance. The mounting bolts 27 are parallel to the rear axle 26, making disassembly and assembly very convenient.

[0093] The first end of the first link 71 of the linkage mechanism 7 is hinged to the base body 51, and the second end of the first link 71 is hinged to the first mounting protrusion 63; the first end of the second link 72 is hinged to the base body 51, and the second end of the second link 72 is hinged to the second mounting protrusion 64.

[0094] Referring to Figure 24, unlike Embodiment 1, in this embodiment, the first mounting protrusion 63 and the second mounting protrusion 64 are located at the rear end of the vertical plane 28 that passes through the axis of the guide sprocket 8 and is perpendicular to the guide sprocket 8. That is, the vertical plane 28 of the guide sprocket 8 is located in front of the hinge position of the first connecting rod 71 and the second connecting rod 72 with the outer guide plate 62.

[0095] The inner side of the base body 51 is provided with a wire hole 29 for installing the gear shift cable. In the above structure, the end of the gear shift cable is installed in the wire hole 29, and the metal wire in the gear shift cable comes out of the wire hole 29 and connects to the first connecting rod 71. In the above structure, the wire hole 29 is located on the inner side of the base body 51, which makes the gear shift cable closer to the wheel, ensuring that the gear shift cable is not exposed outside the bicycle, and further improving riding safety.

[0096] The lower end of the mounting extension 102 is provided with a limiting surface 103. A reinforcing rib 54 is provided between the inner side of the connecting arm 52 and the base body 51. An adjusting screw 31 is provided on the reinforcing rib 54, and the end of the adjusting screw 31 abuts against the limiting surface 103. In the above structure, the mounting angle of the rear derailleur 100 can be adjusted by adjusting the adjusting screw 31, and at the same time, the mounting stability of the rear derailleur 100 can be further improved.

[0097] In this embodiment, the base component 5 is installed at the rear end of the rear chainstay 21 and located on the rear side of the rear axle 26, so that the rear derailleur 100 is closer to the inside of the frame 1 after installation. This not only results in a compact structure and a small outward extension distance, but also means that the rear derailleur 100 is almost completely hidden inside the frame 1 after installation.

[0098] The above detailed description is only an illustration of a preferred embodiment of the present invention and is not intended to limit the patent scope of the present invention. Therefore, all equivalent technical changes made using the content of this invention are included within the patent scope of this invention.

Claims

1. A bicycle derailleur, characterized in that, It includes a four-bar linkage and a chain tensioning assembly disposed on the four-bar linkage; wherein, The four-bar linkage includes a base component, a movable component, and a linkage mechanism; the first end of the linkage mechanism is connected to the base component, and the second end of the linkage mechanism is connected to the first end of the movable component. The chain tensioning assembly includes a guide sprocket, a tensioning wheel, and a tensioning arm; the first end of the tensioning arm is rotatably connected to the second end of the movable component; the tensioning wheel is rotatably disposed at the second end of the tensioning arm; the guide sprocket is rotatably disposed on the movable component, and a reset assembly is provided at the rotatable connection between the tensioning arm and the movable component.

2. The bicycle derailleur according to claim 1, characterized in that, The movable component includes an inner guide plate and an outer guide plate. The outer guide plate is fixed to the side of the inner guide plate. The guide sprocket is rotatably disposed between the inner guide plate and the outer guide plate. The linkage mechanism is hinged to the first end of the outer guide plate. The tensioning arm is rotatably connected to the second end of the inner guide plate.

3. The bicycle derailleur according to claim 2, characterized in that, The inner guide plate is a flat plate structure. The sides of the inner guide plate are divided into inner and outer sides. The side closer to the bicycle frame is the inner side, and the side closer to the outer guide plate is the outer side. The outer guide plate and the outer side of the inner guide plate are fixedly connected by screws. The tensioning arm is rotatably connected to the second end of the outer side of the inner guide plate.

4. The bicycle derailleur according to claim 2, characterized in that, The outer guide plate and the tensioning arm are separately configured.

5. The bicycle derailleur according to claim 3, characterized in that, There are two screws. The first end of the inner guide plate is fixed to the first end of the outer guide plate by one screw, and the middle part of the inner guide plate is fixed to the second end of the outer guide plate by the other screw.

6. The bicycle derailleur according to claim 2, characterized in that, The first end of the tensioning arm is provided with a column, which is hinged to the second end of the inner guide plate. The second end of the tensioning arm is inclined toward the outer side of the inner guide plate.

7. The bicycle derailleur according to any of the preceding claims, characterized in that, The second end of the tensioning arm is provided with two parallel guide discs, and the tensioning wheel is disposed between the two guide discs.

8. The bicycle derailleur according to any of the preceding claims, characterized in that, The tensioning arm is provided with multiple opening slots.

9. The bicycle derailleur according to claim 2, characterized in that, The column body is hinged to the second end of the inner guide plate via a hinge shaft; the hinge shaft has an annular groove at the end away from the inner guide plate, the column body has a mounting post, the mounting post passes through the annular groove, and the mounting post is threadedly connected to the column body.

10. The bicycle derailleur according to claim 1, characterized in that, The derailleur is used to mount on the bicycle frame, the frame including a chainstay with its rear end connected to the rear axle; the base member is used to mount on the chainstay and is located at the front end of the rear axle.

11. The bicycle derailleur according to claim 1, characterized in that, The derailleur is used to mount on the frame of a bicycle, the frame including a chainstay with its rear end connected to the rear axle; the base member is used to mount on the rear end of the chainstay and is located behind the rear axle.

12. The bicycle derailleur according to claim 10 or 11, characterized in that, The rear end of the lower fork is provided with a downward-opening n-shaped groove, which is used to install the rear axle. The rear side of the n-shaped groove is provided with a downward-extending mounting extension, and the base component is mounted on the mounting extension.

13. The bicycle derailleur according to claim 12, characterized in that, The base component includes a base body, a mounting portion disposed on the outside of the base body, and a connecting arm disposed between the base body and the mounting portion and inclined inward. The first end of the connecting arm is connected to the mounting portion, and the second end of the connecting arm is connected to the base body. The first end of the linkage mechanism is hinged to the base body. The mounting portion is mounted on the mounting extension portion by mounting bolts, and the mounting bolts are parallel to the rear axle.

14. The bicycle derailleur according to claim 13, characterized in that, The linkage mechanism includes a first link and a second link. The movable component includes a plate-shaped outer guide plate, an inner guide plate disposed on the inner side of the outer guide plate, a first mounting protrusion disposed on the outer side of the outer guide plate, and a second mounting protrusion disposed on the upper surface of the outer guide plate. The first end of the first link is hinged to the base component, and the second end of the first link is hinged to the first mounting protrusion. The first end of the second link is hinged to the base body, and the second end of the second link is hinged to the second mounting protrusion. The guide sprocket is rotatably disposed between the outer guide plate and the inner guide plate. The first end of the tensioning arm is rotatably connected to the outer side of the inner guide plate.

15. The bicycle derailleur according to claim 14, characterized in that, The inner guide plate is a flat plate structure; the first end of the outer guide plate extends upward at an angle in the direction of the bicycle's movement, and the first end of the outer guide plate is fixedly connected to the first end of the inner guide plate; the second end of the outer guide plate is fixedly connected to the middle of the outer side of the inner guide plate; the first mounting protrusion and the second mounting protrusion are located at the rear end of a vertical plane passing through the axis of the guide wheel.

16. The bicycle derailleur according to claim 15, characterized in that, The first end of the tensioning arm is rotatably connected to the second end of the outer side of the inner guide plate; the outer guide plate and the tensioning arm are separately disposed from each other.

17. The bicycle derailleur according to claim 13, characterized in that, The inner side of the base body is provided with wire holes for installing the speed change guide tube.

18. The bicycle derailleur according to claim 14, characterized in that, A clamping arm extends inward from the inner side of the first connecting rod, and the end of the clamping arm is provided with a clamping assembly for clamping the metal wire.

19. The bicycle rear derailleur according to claim 18, characterized in that, The lower end of the installation extension is provided with a limiting surface, and a reinforcing rib is provided between the inner side of the connecting arm and the base body. An adjusting screw is provided on the reinforcing rib, and the end of the adjusting screw abuts against the limiting surface.

20. The bicycle rear derailleur according to claim 10 or 11, characterized in that, The bottom of the rear lower fork is provided with a mounting nut, and an arc-shaped washer is provided between the base component and the bottom of the rear lower fork. The upper end of the mounting nut is fixedly connected to the bottom of the rear lower fork, and the lower end passes through the arc-shaped washer and extends into the interior of the base component. The base component is fixedly connected to the mounting nut by mounting bolts.

21. A bicycle, characterized in that, The bicycle includes a bicycle frame, a crank assembly, a freewheel, a chain, and a bicycle derailleur as described in any one of claims 1-20; the crank assembly, freewheel, and derailleur are all mounted on the bicycle frame, and the chain is connected to the crank assembly, freewheel, and bicycle derailleur respectively; when the bicycle is folded, the distance between the axis of the crank assembly and the axis of the freewheel decreases, and the derailleur is used to tension the chain.

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