Rear derailleur of bicycle

Abstract

The utility model discloses a rear derailleur of a bicycle. The rear derailleur is installed on a frame of the bicycle. Comprising a four-connecting-rod mechanism and a chain tensioning assembly. The four-connecting-rod mechanism comprises a base component, a movable component and a connecting rod mechanism. The connecting rod mechanism is connected with the base component and the movable component; the chain tensioning assembly comprises a guide plate, a guide chain wheel, a tensioning wheel and a tensioning arm. The guide chain wheel is rotationally arranged between the movable component and the guide plate; the first end of the tensioning arm is rotationally connected to the guide plate, and the tensioning wheel is rotationally arranged at the second end of the tensioning arm. The frame comprises a rear lower fork, and the rear end of the rear lower fork is connected with a rear shaft; the base member is mounted on the lower rear fork and located at the front end of the rear shaft or mounted at the rear end of the lower rear fork and located on the rear side of the rear shaft. The rear derailleur is compact in structure and small in outward extending distance, the whole rear derailleur is almost hidden on the inner side of a frame, the riding safety can be improved, and damage to the rear derailleur is effectively avoided when the bicycle falls.

Description

TECHNICAL FIELD

[0001] The utility model relates to a bicycle technical field, concretely relates to a bicycle rear derailleur. BACKGROUND

[0002] In a bicycle, power is transmitted from a crankset to a freewheel comprising at least one sprocket by a chain, thereby transmitting power to a rear wheel. The chain interacts with teeth on the sprocket in the crankset and also with sprockets arranged around the hub of the rear wheel of the bicycle in the freewheel, enabling power transmission. In a single-speed bicycle, the freewheel employs one sprocket. When a user operates the pedals, the crankset rotates, causing the chain to move, which in turn causes the sprocket of the freewheel with which it interacts to rotate, thereby causing the rear wheel to rotate. In a variable-speed bicycle, the freewheel employs multiple sprockets. In order to enable the chain to be switched between sprockets of different diameters, a derailleur is usually provided to shift gears.

[0003] The existing derailleur usually comprises a base member, a movable member and a chain guide, etc. The movable member is movably coupled to the base member by a linkage mechanism, and under the action of a control cable on a gear shift lever, the chain guide moves laterally relative to the base member to achieve the purpose of gear shifting. When shifting gears, due to the characteristics of the lateral movement of the chain guide required for switching the chain between multiple sprockets, the linkage mechanism, the movable member and the chain guide all extend outwardly a considerable distance along the outside of the bicycle, especially when the chain engages with the outermost sprocket of the freewheel. In the case where a coil spring is clamped between the pair of linkage mechanisms, since the linkage mechanisms must be spaced apart from each other in order to accommodate the spring, this further increases the lateral distance that the chain guide must travel; this becomes even more serious as the number of sprockets increases. Therefore, the chain guide that extends outwardly a considerable distance is prone to being hit or entangled with nearby objects when riding; when falling off the bicycle, the chain guide is prone to being damaged. SUMMARY

[0004] The utility model aims at overcoming the above-mentioned problems, providing a bicycle rear derailleur, the rear derailleur, compact structure, outwardly extends distance is smaller, the rear derailleur as a whole hides in the inside of the frame can improve the safety of riding, when falling off the bicycle, effectively avoid the damage of the rear derailleur.

[0005] The utility model discloses a purpose is realized through the following technical scheme:

[0006] A bicycle rear derailleur is installed on the frame of a bicycle. The rear derailleur comprises a four-bar linkage mechanism and a chain tensioning assembly arranged on the four-bar linkage mechanism. Wherein,

[0007] 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 movable component; the chain tensioning assembly includes a guide plate, a guide sprocket, a tensioning wheel, and a tensioning arm; the guide sprocket is rotatably disposed between the movable component and the guide plate; the first end of the tensioning arm is rotatably connected to the guide plate, and the tensioning wheel is rotatably disposed at the second end of the tensioning arm;

[0008] The frame includes a chainstay, the rear end of which is connected to the rear axle; the base member is mounted on the chainstay and located at the front end of the rear axle or mounted on the rear end of the chainstay and located at the rear side of the rear axle.

[0009] The working principle of the above-mentioned bicycle rear derailleur is:

[0010] The derailleur cable drives the chain tensioning assembly via a four-bar linkage, actuating the chain to switch between different sprockets, thus achieving the gear shifting process. The moving component is a sliding component; the guide sprocket moves with the moving component, actuating the chain, and the tensioner and tension arm tension the chain. Because the base component is mounted on the rear chainstay at the front of the rear axle or at the rear of the rear chainstay at the rear side of the rear axle, the rear derailleur, after installation, is closer to the inside of the frame. This results in a compact structure with minimal outward extension; the rear derailleur is almost entirely hidden inside the frame after installation.

[0011] In a preferred embodiment of this invention, the rear end of the lower fork is provided with a downward-opening n-shaped groove for mounting the rear axle. A downward-extending mounting extension is provided on the rear side of the n-shaped groove, and the base component is mounted on the mounting extension. In the above structure, the rear axle is the axle of the bicycle's rear wheel. The downward-opening n-shaped groove facilitates the installation of the rear axle, and the mounting extension facilitates the installation of the entire rear derailleur.

[0012] In a preferred embodiment of this utility model, the base component includes a base body, a mounting portion disposed on the outer side 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 a mounting extension portion via mounting bolts, which are parallel to the rear axle. In this structure, by providing the connecting arm, the base body is located inside the mounting portion, ensuring that the base body is closer to the wheel, thereby minimizing the outward extension distance of the rear derailleur. The mounting bolts being parallel to the rear axle facilitate easy assembly and disassembly.

[0013] Preferably, the connecting rod mechanism comprises a first connecting rod and a second connecting rod; the movable component comprises a plate-shaped plate body, a first mounting protrusion arranged on the outer side surface of the plate body, and a second mounting protrusion arranged on the upper end surface of the plate body; the first end of the first connecting rod is hingedly connected to the base body, and the second end of the first connecting rod is hingedly connected to the first mounting protrusion; the first end of the second connecting rod is hingedly connected to the base body, and the second end of the second connecting rod is hingedly connected to the second mounting protrusion; the guide plate is arranged on the inner side surface of the plate body, and the chain guide wheel is rotatably arranged between the plate body and the guide plate; the first end of the tensioning arm is rotatably connected to the outer side surface of the guide plate. By arranging the above structure, the installation of the connecting rod mechanism is facilitated; since the plate body on the movable component is in a plate-shaped structure and the guide plate is arranged on the inner side surface of the plate body, the inner side surface of the plate body is the side close to the wheel, so that the rear derailleur is compact in structure and has a small outward extension distance, and after the rear derailleur is installed, the whole rear derailleur is almost hidden inside the frame; the safety of riding can be improved, and the damage of the rear derailleur can be effectively avoided when the bicycle falls.

[0014] Preferably, the guide plate is in a flat plate structure; the first end of the plate body extends upwardly and obliquely toward the direction in which the bicycle advances, the first end of the plate body is fixedly connected to the first end of the guide plate, and the second end of the plate body is fixedly connected to the middle portion of the outer side surface of the guide plate; the first mounting protrusion and the second mounting protrusion are located at the rear end of the vertical plane passing through the axis of the chain guide wheel. That is, the chain guide wheel is located in front of the hinged positions of the first connecting rod and the second connecting rod with the plate body, and the guide plate is in a flat plate structure and the plate body is in a plate-shaped structure, which are easy to process and simple in structure, so that the whole rear derailleur is very compact in structure.

[0015] Preferably, the first end of the tensioning arm is rotatably connected to the second end of the outer side surface of the guide plate; the plate body and the tensioning arm are arranged separately from each other. That is, the tensioning arm is only connected to the guide plate and is not directly connected to the plate body, and the plate body is separated from the tensioning arm, and the plate body is indirectly connected to the tensioning arm through the guide plate; the purpose is to simplify the structure of the rear derailleur of the bicycle, make the structure more compact, and prevent the tensioning arm from interfering with the plate body, so that the tensioning arm has a larger rotation range on the guide plate, thereby improving the tensioning range of the chain.

[0016] Preferably, the inner side of the base body is provided with a wire hole for mounting a variable speed wire tube. In the above structure, the end of the variable speed wire tube is mounted in the wire hole, and the metal wire in the variable speed wire tube comes out of the wire hole and is connected to the first connecting rod. In the above structure, the wire hole is arranged on the inner side of the base body, so that the variable speed wire tube is closer to the wheel, and it is ensured that the variable speed wire tube will not be exposed outside the bicycle, thereby further improving the safety of riding.

[0017] Preferably, the inner side of the first connecting rod extends inwardly with a clamping arm, and the end of the clamping arm is provided with a clamping assembly for clamping the metal wire.

[0018] Preferably, the lower end of the mounting extension is provided with a limiting surface, a reinforcing rib is arranged between the inner side of the connecting arm and the base body, an adjusting screw is arranged on the reinforcing rib, and the end of the adjusting screw abuts against the limiting surface. In the above structure, the mounting angle of the rear derailleur can be adjusted through the adjusting screw, and the mounting stability of the rear derailleur can be further improved.

[0019] Preferably, the base member is mounted on the frame of the bicycle, the bottom of the rear lower fork of the frame is provided with a mounting nut, an arc-shaped gasket is arranged between the base member and the bottom of the rear lower fork, the upper end of the mounting nut is fixedly connected with the bottom of the rear lower fork, the lower end of the mounting nut extends into the base member through the arc-shaped gasket, and the base member is fixedly connected with the mounting nut through a mounting bolt.

[0020] Compared with the prior art, the utility model has the following beneficial effects:

[0021] The bicycle rear derailleur in the utility model is installed at the bottom of the rear lower fork and located at the front end of the rear axle or installed at the rear end of the rear lower fork and located at the rear side of the rear axle, so that the rear derailleur is closer to the inner side of the frame after installation, is compact in structure, has a small outward extension distance, and is almost entirely hidden in the inner side of the frame after installation. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a structural schematic view of a first specific embodiment of the bicycle rear derailleur mounted on the frame in the utility model.

[0023] Figure 2 It is a structural schematic view of the bicycle rear derailleur mounted on the frame in the utility model.

[0024] Figure 3 It is a structural schematic view of the bicycle rear derailleur mounted on the frame in another visual angle direction in the utility model.

[0025] Figure 4 It is a partial structural schematic view of the frame in the utility model.

[0026] Figure 5 It is a front view of the bicycle rear derailleur in the utility model.

[0027] Figure 6 It is a top view of the bicycle rear derailleur in the utility model.

[0028] Figure 7 This is a three-dimensional structural diagram of the base component and linkage mechanism in this utility model.

[0029] Figure 8 This is a three-dimensional structural diagram of the base component in this utility model.

[0030] Figure 9 This is a three-dimensional structural diagram of the base component in this utility model from another perspective.

[0031] Figure 10 This is a three-dimensional structural diagram of the movable component and chain tensioning assembly in this utility model.

[0032] Figure 11 This is a three-dimensional structural diagram of the movable component and part of the chain tensioning assembly in this utility model.

[0033] Figure 12 This is a front view of the movable component and part of the chain tensioning assembly in this utility model.

[0034] Figure 13 This is a three-dimensional structural diagram of the guide plate, mounting column, hinge shaft, and reset assembly in this utility model.

[0035] Figure 14 This is a schematic diagram of a second specific embodiment of the present invention, in which a bicycle rear derailleur is mounted on a frame.

[0036] Figure 15 This is an exploded view of a second specific embodiment of the frame and rear derailleur of the bicycle in this utility model.

[0037] Figure 16 This is a front view of the second specific embodiment of the bicycle rear derailleur of this utility model. Detailed Implementation

[0038] To enable those skilled in the art to fully understand the technical solution of this utility model, the present utility model will be further described below in conjunction with the embodiments and accompanying drawings, but the implementation of this utility model is not limited thereto.

[0039] Example 1

[0040] See Figures 1-6 This embodiment discloses a bicycle rear derailleur, which is mounted on the bicycle frame 10. The rear derailleur includes a four-bar linkage 3 and a chain tensioning assembly disposed on the four-bar linkage 3. The four-bar linkage 3 can drive the chain tensioning assembly to move, thereby realizing the functions of undulating the chain and tensioning the chain.

[0041] See Figures 1-6 The four-bar linkage 3 includes a base component 1, a movable component 2, and a linkage mechanism 3; the first end of the linkage mechanism 3 is connected to the base component 1, and the second end of the linkage mechanism 3 is connected to the movable component 2.

[0042] See Figures 1-6 and Figures 10-13 The chain tensioning assembly includes a guide plate 4, a guide wheel 5, a tensioning wheel 6, and a tensioning arm 7. The guide plate 4 is disposed on the inner side of the movable component 2, and the guide wheel 5 is rotatably disposed between the movable component 2 and the guide plate 4. The first end of the tensioning arm 7 is rotatably connected to the outer side of the guide plate 4, and the tensioning wheel 6 is rotatably disposed on the second end of the tensioning arm 7. A reset assembly is provided at the rotatable connection between the tensioning arm 7 and the guide plate 4. When the bicycle shifts gears, the elastic force of the reset assembly causes the tensioning arm 7 to swing backward, tensioning the chain. Both the guide plate 4 and the plate body 2-1 have inner and outer sides. The inner side is the side closer to the bicycle wheel, and the outer side is the side farther away from the bicycle wheel.

[0043] See Figures 1-6 and Figures 10-13 The frame 10 includes a rear top fork 25 and a rear bottom fork 21, the rear end of which is connected to a rear axle 12; the base member 1 is mounted on the rear end of the rear bottom fork 21 and located behind the rear axle 12. With the direction of the bicycle's forward movement as the front, the rear ends of the rear top fork 25 and the rear bottom fork 21 are connected together.

[0044] See Figures 1-9 The rear end of the lower fork 21 is provided with a downward-opening n-shaped groove 10-1 for mounting the rear axle 12 (rear wheel). A downward-extending mounting extension 10-2 is provided on the rear side of the n-shaped groove 10-1, and the base member 1 is mounted on the mounting extension 10-2. In this structure, the rear axle 12 is the axle of the bicycle's rear wheel. The downward-opening n-shaped groove 10-1 facilitates the installation of the rear axle 12, and the mounting extension 10-2 facilitates the installation of the entire rear derailleur.

[0045] See Figures 1-9The base component 1 includes a base body 1-1, a mounting portion 1-3 disposed on the outside of the base body 1-1, and a connecting arm 1-2 disposed between the base body 1-1 and the mounting portion 1-3 and inclined inward. The first end of the connecting arm 1-2 is connected to the mounting portion 1-3, and the second end of the connecting arm 1-2 is connected to the base body 1-1. The mounting portion 1-3 is used to mount on the bicycle frame 10. The first end of the linkage mechanism 3 is hinged to the base body 1-1. The mounting portion 1-3 is mounted on the mounting extension portion 10-2 by mounting bolts 11, which are parallel to the rear axle 12. In this structure, by setting the connecting arm 1-2, the base body 1-1 is located inside the mounting portion 1-3, ensuring that the base body 1-1 is closer to the wheel, thereby ensuring a smaller outward extension distance of the rear derailleur. The mounting bolts 11 are parallel to the rear axle 12, making disassembly and assembly very convenient.

[0046] See Figures 1-12 The linkage mechanism 3 includes a first link 3-1 and a second link 3-2; the movable component 2 includes a plate-shaped plate 2-1, a first mounting protrusion 2-2 disposed on the outer side of the plate 2-1, and a second mounting protrusion 2-3 disposed on the upper end face of the plate 2-1; the first end of the first link 3-1 is hinged to the base body 1-1, and the second end of the first link 3-1 is hinged to the first mounting protrusion 2-2; the first end of the second link 3-2 is hinged to the base body 1-1, and the second end of the second link 3-2 is hinged to the second mounting protrusion 2-3; the guide plate 4 is disposed on the inner side of the plate 2-1, and the guide sprocket 5 is rotatably disposed between the plate 2-1 and the guide plate 4. The above structure facilitates the installation of the linkage mechanism 3. Since the plate 2-1 on the movable component 2 is plate-shaped, and the guide plate 4 is located on the inner side of the plate 2-1 (which is close to the wheel), the rear derailleur has a compact structure and a small outward extension distance. After installation, the rear derailleur is almost entirely hidden inside the frame 10. The first linkage 3-1 and the second linkage 3-2 are hinged to the base body 1-1 at different positions.

[0047] See Figures 1-6 and Figures 10-13The guide plate 4 is a flat plate structure; the first end of the plate body 2-1 extends upward at an angle towards the direction of bicycle movement, and the first end of the plate body 2-1 is fixedly connected to the first end of the guide plate 4; the second end of the plate body 2-1 is fixedly connected to the middle of the outer side of the guide plate 4; the first mounting protrusion 2-2 and the second mounting protrusion 2-3 are located at the rear end of the vertical plane 25 passing through the axis of the guide chain wheel 5. That is, the guide chain wheel 5 is located in front of the hinge position between the first connecting rod 3-1 and the second connecting rod 3-2 and the plate body 2-1, and the guide plate 4 is a flat plate structure, while the plate body 2-1 is a plate-shaped structure, which is easy to process and has a simple structure, thus making the entire rear derailleur structure very compact. The plate body 2-1 and the guide plate 4 are arranged parallel to each other.

[0048] See Figures 1-6 and Figures 10-13 The first end of the tensioning arm 7 is rotatably connected to the second end of the outer side of the guide plate 4; the plate body 2-1 and the tensioning arm 7 are separately disposed. That is, the tensioning arm 7 is only connected to the guide plate 4 and does not directly contact the plate body 2-1. The plate body 2-1 and the tensioning arm 7 are separate, and the plate body 2-1 is indirectly connected to the tensioning arm 7 through the guide plate 4. The purpose of this is to simplify the structure of the bicycle rear derailleur, making the structure more compact, and ensuring that the tensioning arm 7 does not interfere with the plate body 2-1, so that the tensioning arm 7 has a larger range of rotation on the guide plate 4, thereby improving the tension range of the chain.

[0049] See Figures 1-9 The base body 1-1 has a wire hole 8 on its inner side for installing the gear shift cable. In this structure, the end of the gear shift cable is installed in the wire hole 8, and the metal wire in the gear shift cable exits from the wire hole 8 and connects to the first connecting rod 3-1. In this structure, the wire hole 8 is located on the inner side of the base body 1-1, which brings 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.

[0050] See Figures 1-9 A clamping arm 9 extends inward from the inner side of the first connecting rod 3-1. The end of the clamping arm 9 is provided with a clamping assembly 24 for clamping the metal wire. The clamping arm 9 extends inward so that it is not exposed, ensuring that the rear guide chain extends outward by a small distance. The clamping assembly 24 can be a clamping screw.

[0051] See Figures 1-9The lower end of the mounting extension 10-2 is provided with a limiting surface 10-3. A reinforcing rib 1-4 is provided between the inner side of the connecting arm 1-2 and the base body 1-1. An adjusting screw 13 is provided on the reinforcing rib 1-4, and the end of the adjusting screw 13 abuts against the limiting surface 10-3. In this structure, the mounting angle of the rear derailleur can be adjusted by the adjusting screw 13, and the mounting stability of the rear derailleur can be further improved.

[0052] See Figures 1-6 and Figures 10-13 The tensioning arm 7 has a column 19 at its first end, which is hinged to the second end of the guide plate 4. The second end of the tensioning arm 7 is inclined towards the outer side of the guide plate 4. This is to ensure that the tensioning wheel 6 and the guide sprocket 5 are on the same plane, allowing the chain to be smoothly guided and tensioned on both, preventing chain slippage and improving chain stability. Simultaneously, it also allows the tensioning wheel 6 to be closer to the wheel, reducing the distance the tensioning wheel 6 extends outward.

[0053] See Figures 1-6 and Figures 10-13 The second end of the tensioning arm 7 is provided with two parallel guide discs 15, and the tensioning wheel 6 is disposed between the two guide discs 15. The two guide discs 15 can guide the chain and prevent the chain from falling off the tensioning wheel 6.

[0054] See Figures 1-6 and Figures 10-13 The reset assembly is a torsion spring 16, located inside the cavity of the column 19. One end of the torsion spring 16 acts on the second end of the guide plate 4, and the other end acts on the column 19. The elastic force of the torsion spring 16 causes the tension arm 7 to rotate, thereby causing the tension wheel 6 to tension the chain.

[0055] See Figures 1-6 and Figures 10-13 The column 19 is hinged to the second end of the guide plate 4 via a hinge shaft 17. The hinge shaft 17 has an annular groove 18 at its end away from the guide plate 4. The column 19 has a mounting post 19 that passes through the annular groove 18 and is threadedly connected to the column 19. In this structure, the mounting post 19 allows the column 19 to be mounted on the hinge shaft 17. When the tension arm 7 rotates, the mounting post 19 can rotate within the annular groove 18, which axially limits the mounting post 19 and prevents it from dislodging.

[0056] See Figure 11The guide plate 4 is fixedly connected to the inner side of the plate body 2-1 by two screws 20. One screw 20 fixes the first end of the guide plate 4 to the first end of the plate body 2-1, and the other screw 20 fixes the middle part of the guide plate 4 to the second end of the plate body 2-1. In this structure, the fact that the middle part of the guide plate 4 is fixed to the second end of the plate body 2-1 by the other screw 20 indicates that the structural length of the plate body 2-1 is smaller than the structural length of the guide plate 4, simplifying the structure. The two screws 20 ensure a very stable connection between the guide plate 4 and the plate body 2-1. The simplification of the guide plate 4 increases the tensioning range of the tensioning arm 7 on the chain.

[0057] See Figures 1-13 The working principle of the above-mentioned bicycle rear derailleur is as follows:

[0058] The derailleur cable drives the chain tensioning assembly and actuates the chain via a four-bar linkage 3, enabling the chain to switch between different sprockets and achieve the gear shifting process. The movable component 2 is a moving component; the guide sprocket 5 moves with the movable component 2, thereby actuating the chain. The tension wheel 6 and tension arm 7 tension the chain. Because the guide plate 4 is located on the inner side of the movable component 2, and the first end of the tension arm 7 is rotatably connected to the outer side of the guide plate 4, and the base component 1 is installed at the rear end of the rear chainstay 21 and located behind the rear axle 12, the rear derailleur, after installation, is closer to the inner side of the frame 10. This results in a compact structure with a small outward extension distance; after installation, the rear derailleur is almost entirely hidden inside the frame 10.

[0059] Example 2

[0060] See Figure 1 And see Figures 14-16 In this embodiment, the other structures are the same as in Embodiment 1, except that the base component 1 is installed at a different location on the bicycle frame 10. Specifically, the base component 1 is installed at the bottom of the chainstay 21 and at the front end of the rear axle 12; the specific structural shape of the base component 1 is also different from that in Embodiment 1. Installing the base component 1 at the bottom of the chainstay 21 and at the front end of the rear axle 12 allows the rear derailleur to be closer to the inside of the frame 10 after installation, resulting in a compact structure, a smaller outward extension distance, and the rear derailleur being almost entirely hidden inside the frame 10 after installation. The base component 1 can also be installed on the side of the chainstay 21 and at the front end of the rear axle 12.

[0061] See Figures 14-16The bottom of the rear lower fork 21 of the frame 10 is provided with a mounting nut 22. An arc-shaped washer 23 is provided between the base component 1 and the bottom of the rear lower fork 21. The upper end of the mounting nut 22 is fixedly connected to the bottom of the rear lower fork 21, and the lower end passes through the arc-shaped washer 23 and extends into the interior of the base component 1. The base component 1 is fixedly connected to the mounting nut 22 by mounting bolts.

[0062] See Figures 14-16 The guide sprocket 5 is located between the middle of the plate 2-1 and the middle of the guide plate 4. The movable component 2 also includes a first mounting protrusion 2-2 and a second mounting protrusion 2-3 located on the outer side of the plate 2-1 near the first end. The first mounting protrusion 2-2 and the second mounting protrusion 2-3 are located at the front end of a vertical plane passing through the axis of the guide sprocket 5. Since the rear derailleur is mounted on the rear chainstay 21, the above structure ensures a more compact rear derailleur structure while maintaining chain tension, and better conceals the rear derailleur within the frame 10.

[0063] The above are preferred embodiments of the present utility model, but the embodiments of the present utility model are not limited to the above content. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present utility model shall be considered equivalent substitutions and shall be included within the protection scope of the present utility model.

Claims

1. A bicycle rear derailleur, characterized in that, The rear derailleur is mounted on the bicycle frame; the rear derailleur 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 movable component; the chain tensioning assembly includes a guide plate, a guide sprocket, a tensioning wheel, and a tensioning arm; the guide sprocket is rotatably disposed between the movable component and the guide plate; the first end of the tensioning arm is rotatably connected to the guide plate, and the tensioning wheel is rotatably disposed at the second end of the tensioning arm; The frame includes a chainstay, the rear end of which is connected to the rear axle; the base member is mounted on the chainstay and located at the front end of the rear axle or mounted on the rear end of the chainstay and located at the rear side of the rear axle.

2. A bicycle rear derailleur according to claim 1, 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.

3. A bicycle rear derailleur according to claim 2, 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.

4. A bicycle rear derailleur according to claim 3, characterized in that, The linkage mechanism includes a first link and a second link; the movable component includes a plate-shaped plate body, a first mounting protrusion disposed on the outer side of the plate body, and a second mounting protrusion disposed on the upper end face of the plate body; the first end of the first link is hinged to the base body, 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 plate is disposed on the inner side of the plate body, and the guide sprocket is rotatably disposed between the plate body and the guide plate; the first end of the tensioning arm is rotatably connected to the outer side of the guide plate.

5. A bicycle rear derailleur according to claim 4, characterized in that, The guide plate is a flat plate structure; the first end of the plate extends upward at an angle toward the direction of the bicycle's movement, and the first end of the plate is fixedly connected to the first end of the guide plate; the second end of the plate is fixedly connected to the middle of the outer side of the 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.

6. A bicycle rear derailleur according to claim 5, characterized in that, The first end of the tensioning arm is rotatably connected to the second end of the outer side of the guide plate; the plate body and the tensioning arm are separately disposed from each other.

7. A bicycle rear derailleur according to claim 3, characterized in that, The inner side of the base body is provided with wire holes for installing the speed change guide tube.

8. A bicycle rear derailleur according to claim 4, 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.

9. A bicycle rear derailleur according to claim 8, 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.

10. A bicycle rear derailleur according to claim 1, 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.

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