A bicycle derailleur

Abstract

The present invention discloses a derailleur for a bicycle, comprising a guide tensioning mechanism for guiding and tensioning a chain and a derailleur driving mechanism for driving the chain to switch back and forth, wherein the guide tensioning mechanism comprises a mounting frame, a guide sprocket and a tensioning wheel, wherein the guide sprocket and the tensioning wheel are both rotatably connected to the mounting frame; the derailleur driving mechanism is connected to a derailleur rope, and comprises a four-link structure, wherein the four-link structure comprises a frame, two connecting frame rods of equal length, and a connecting rod whose length is greater than the frame; the mounting frame is connected to the connecting rod of the four-link structure. The derailleur can gradually adjust its own posture when driving the derailleur, thereby reducing the matching angle of the chain, reducing the resistance and wear of riding, and improving the use experience.

Description

Technical Field

[0001] The invention relates to a bicycle speed regulating device, in particular to a bicycle derailleur. Background Art

[0002] In a bicycle equipped with a speed regulating device, the chain can be switched to cooperate with sprockets of different sizes by turning the finger shifter on the handlebar; when adjusting the speed, the push rod of the finger shifter is turned to pull the chain puller through the guide rope to shift the chain from the current sprocket to the next sprocket, completing the gear switching, thereby adjusting the transmission ratio of the front and rear sprockets and the driving pedaling force to meet different usage requirements.

[0003] Generally, in an existing speed-adjustable bicycle, a plurality of rear sprockets with different diameters are coaxially arranged on the rear wheel shaft, and the plurality of rear sprockets are arranged in sequence according to the diameters, so as to facilitate the gear-shifting action when the chain is progressively or decrementally shifted. Specifically, when the chain is hung on the rear sprocket on the same vertical plane as the front sprocket (middle gear position), see the attached Figure 1 a, the chain connects the front sprocket and the rear sprocket in a straight line, which is the best posture for chain drive; when the chain is hung on the largest or smallest rear sprocket (lowest gear or highest gear), see the attached Figure 1 In addition, the chain is connected obliquely between the front sprocket and the rear sprocket, forming a large angle θ with the center line. According to the force analysis, during the transmission process, the chain will exert a driving force on the front and rear sprockets to rotate forward, and will also generate a lateral extrusion force, which will not only increase the riding resistance, but also cause certain wear on the chain and sprockets. The user experience needs to be improved. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned problems and provide a bicycle derailleur, which can gradually adjust its own posture when driving the derailleur, thereby reducing the matching angle of the chain, reducing riding resistance, and improving the user experience.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] A bicycle derailleur comprises a guide tensioning mechanism for guiding and tensioning a chain and a derailleur driving mechanism for driving the chain to switch back and forth, wherein the guide tensioning mechanism comprises a mounting frame, a guide chain wheel and a tensioning wheel, and the guide chain wheel and the tensioning wheel are both rotatably connected to the mounting frame;

[0007] The derailleur driving mechanism is connected to the derailleur rope and comprises a four-bar linkage structure, wherein the four-bar linkage structure comprises a frame, two frame connecting rods of equal length and a connecting rod longer than the frame; the mounting frame is connected to the connecting rod of the four-bar linkage structure.

[0008] The working principle of the above derailleur is:

[0009] When working, the rider drives the rear derailleur drive mechanism by toggling the finger shifter on the handlebar of the bicycle through the derailleur rope, thereby adjusting the gear of the rear wheel. Specifically, in the process of adjusting the gear, for example, adjusting from the middle gear to the high gear (or low gear), the finger shifter rotates in the corresponding direction, so that the derailleur rope (or the return spring) drives the connecting rod of the four-bar structure to rotate around the frame, thereby driving the mounting frame to move. Since the guide sprocket and the tensioning wheel are rotatably connected to the mounting frame, as the mounting frame moves, the chain on the guide sprocket also moves and rotates to the rear sprocket of the adjacent gear. At the same time, the tensioning wheel tensions the chain switched to the current gear under the action of the derailleur rope (or the tensioning spring) to ensure normal driving.

[0010] Furthermore, since the length of the middle link of the four-bar linkage is greater than the length of the frame, and the two connecting rods are of equal length, the connecting rod gradually deflects during the swinging process, that is, the connecting rod does not move in a posture parallel to the original state, but moves with an inclined angle. Among them, since the mounting frame is connected to the connecting rod, the mounting frame not only moves, but also gradually deflects, causing the posture of the guide sprocket to deflect. At this time, the axis of the guide sprocket is not parallel to the axis of the gear. When the connecting rod moves to the highest gear with the connecting rod (the chain switches to the smallest flywheel), the angle formed by the posture of the connecting rod and the posture in the middle gear is the largest, and it is close to the inclined posture of the chain, thereby driving the guide sprocket to deflect toward the inclined posture of the chain, reducing the angle when the guide sprocket cooperates with the chain, and at the same time reducing the angle between the chain and the rear sprocket, so that the chain can drive more smoothly, reduce riding resistance, reduce wear, and improve the user experience. Similarly, when the connecting rod moves to the lowest gear along with the connecting rod (the chain switches to the largest flywheel), the guide wheel deflects toward the inclined posture of the chain (the deflected posture at this time is opposite to the posture at the highest gear), reducing the angle between the guide wheel and the chain.

[0011] In a preferred embodiment of the present invention, a hinge point on the frame far from the rear sprocket is inclined forward relative to a hinge point close to the rear sprocket.

[0012] Preferably, the angle between the frame and the axis of the rear sprocket is 8°.

[0013] In a preferred embodiment of the present invention, the frame of the four-bar linkage structure is composed of a fixed frame of a derailleur drive mechanism, the fixed frame is connected to the rear axle of the bicycle, and two connecting rods are hinged on the fixed frame.

[0014] In a preferred embodiment of the present invention, the connecting rod of the four-bar connecting rod structure is composed of a swing frame of a derailleur driving mechanism, and two connecting rods are hinged on the swing frame.

[0015] A preferred embodiment of the present invention is that the mounting frame is hinged on the connecting rod, and the angle between the line between the axis of the guide chain wheel and the hinge point of the mounting frame and the line between the axis of the tensioning wheel and the hinge point of the mounting frame is 50°-95°.

[0016] A preferred solution of the present invention is that a reset structure for causing the connecting rod to automatically reset is provided on the frame, and the reset structure includes a reset spring. Through the reset structure, the connecting rod can be automatically driven to reset when the finger shift releases the limit, and the derailleur rope can be pulled in the reverse direction to achieve reverse gear.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The derailleur of the present invention can gradually adjust its own posture when driving the derailleur, thereby reducing the matching angle of the chain, reducing the riding resistance and the additional wear caused by the drive, and improving the user experience.

[0019] 2. Since the derailleur drive mechanism in the present invention is composed of a non-parallel four-bar linkage structure, when the four-bar linkage structure is driven, the connecting rod fixedly connected to the mounting frame of the guide tensioning mechanism not only translates to drive the guide sprocket to hang the chain on the next rear sprocket, but its own posture also gradually deviates in the inclination direction of the chain, while reducing the angle between the chain and the rear sprocket, so that the chain can be driven more smoothly. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the derailleur principle in the prior art.

[0021] Figure 2 The figure is a simplified structural diagram of the derailleur of the bicycle in the present invention.

[0022] Figure 3-5 FIG. 1 is a top view of the working principle diagram of the bicycle derailleur of the present invention, wherein: Figure 3 This is a simplified diagram of the chain structure when it is in the middle gear. Figure 4 This is a simplified diagram of the chain structure when it is in the highest gear. Figure 5 This is a simplified diagram of the chain structure when it is in the lowest gear position.

[0023] Figure 6-8 1 is a front view of the working principle diagram of the derailleur of the bicycle in the present invention, Figure 6 This is a simplified diagram of the chain structure when it is in the middle gear. Figure 7 This is a simplified diagram of the chain structure when it is in the highest gear. Figure 8 This is a simplified diagram of the chain structure when it is in the lowest gear position. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0025] See also Figure 2-8 The bicycle derailleur in this embodiment includes a guide tensioning mechanism for guiding and tensioning the chain 1 and a derailleur driving mechanism for driving the chain 1 to switch back and forth, the guide tensioning mechanism includes a mounting frame 2, a guide sprocket 3 and a tensioning wheel 4, the guide sprocket 3 and the tensioning wheel 4 are both rotatably connected to the mounting frame 2; the derailleur driving mechanism is connected to the derailleur rope, including a four-bar structure, the four-bar structure includes a frame 5, two equal-length connecting rods 6 and a connecting rod 7 longer than the frame 5; the mounting frame 2 is connected to the connecting rod 7 of the four-bar structure. Specifically, other structures in this embodiment are implemented with reference to the derailleur technology in the prior art.

[0026] See also Figure 3-5 The frame 5 of the four-link structure is composed of a fixed frame of a derailleur drive mechanism, the fixed frame is connected to the rear axle of the bicycle, and two connecting rods 6 are hinged on the fixed frame.

[0027] See also Figure 3-5 The connecting rod 7 of the four-bar structure is composed of a swing frame of the chain drive mechanism, and two connecting rods 6 are hinged on the swing frame.

[0028] See also Figure 2 , the hinge point on the frame 5 far away from the rear sprocket 8 is inclined forward relative to the hinge point close to the rear sprocket 8.

[0029] Furthermore, the angle between the frame 5 and the axis of the rear sprocket 8 is 8°.

[0030] See also Figure 6-8 , the mounting frame 2 is hinged on the connecting rod 7, and the angle between the line between the axis of the guide sprocket 3 and the hinge point of the mounting frame 2 and the line between the axis of the tensioning wheel 4 and the hinge point of the mounting frame 2 is 50°-95°. Specifically, in this embodiment, the angle is 58°, and of course it can be other suitable angles.

[0031] See also Figure 2-8 , the working principle of the derailleur in this embodiment is:

[0032] When working, the rider moves the finger shifter on the bicycle handlebar to drive the rear derailleur drive mechanism through the derailleur rope, thereby adjusting the gear position of the rear wheel. Specifically, in the process of adjusting the gear position, for example, in the middle gear position (such as Figure 3 and 6) is adjusted to a higher gear (or a lower gear), and the finger shifter is rotated in the corresponding direction, so that the chain derailleur rope (or reset spring) drives the connecting rod 6 of the four-bar structure to rotate around the frame 5, thereby driving the mounting frame 2 to move. Since the guide sprocket 3 and the tensioning wheel 4 are rotatably connected to the mounting frame 2, as the mounting frame 2 moves, the chain 1 on the guide sprocket 3 also moves and rotates to the rear sprocket 8 of the adjacent gear. At the same time, the tensioning wheel 4, under the action of the chain derailleur rope (or tensioning spring), tensions the chain 1 switched to the current gear to ensure normal drive.

[0033] Furthermore, since the length of the middle link 7 of the four-bar linkage is greater than the length of the frame 5, and the two connecting rods 6 are of equal length, the connecting rod 7 gradually deflects during the swinging process, that is, the connecting rod 7 does not move in a posture parallel to the original state, but moves with an inclined angle. Among them, since the mounting frame 2 is connected to the connecting rod 7, the mounting frame 2 not only moves, but its own posture also gradually deflects, causing the posture of the guide sprocket 3 to deflect. At this time, the axis of the guide sprocket 3 is not parallel to the axis of the gear. When the connecting rod 7 moves to the highest gear position along with the connecting rod 6 (the chain 1 switches to the smallest flywheel), the angle formed by the posture of the connecting rod 7 and the posture in the middle gear position is the largest, and it is close to the inclined posture of the chain 1, thereby driving the guide sprocket 3 to deflect toward the inclined posture of the chain 1, as shown in FIG. Figure 4 and 7 , reducing the angle between the guide sprocket 3 and the chain 1, and at the same time reducing the angle between the chain 1 and the rear sprocket 8, so that the chain 1 can drive more smoothly, reduce riding resistance, reduce wear, and improve the user experience. Similarly, when the connecting rod 7 moves to the lowest gear with the connecting rod 6 (the chain 1 switches to the largest flywheel), the guide sprocket 3 deviates from the inclined posture of the chain 1 (the deviated posture at this time is opposite to the posture at the highest gear), such as Figure 5 and 6 Reduce the angle between the guide sprocket 3 and the chain 1 when they cooperate.

[0034] The above is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited to the above content. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A bicycle derailleur, characterized in that: It includes a guide tensioning mechanism for guiding and tensioning the chain and a chain drive mechanism for driving the chain to switch back and forth, the guide tensioning mechanism includes a mounting frame, a guide chain wheel and a tensioning wheel, and the guide chain wheel and the tensioning wheel are both rotatably connected to the mounting frame; The derailleur driving mechanism is connected to the derailleur rope and comprises a four-bar linkage structure, wherein the four-bar linkage structure comprises a frame, two frame connecting rods of equal length and a connecting rod longer than the frame; the mounting frame is connected to the connecting rod of the four-bar linkage structure; The hinge point on the frame far from the rear sprocket is tilted forward relative to the hinge point close to the rear sprocket; The angle between the frame and the axis of the rear sprocket is 8°; The frame of the four-link structure is composed of a fixed frame of the derailleur drive mechanism, the fixed frame is connected to the rear axle of the bicycle, and two connecting rods are hinged on the fixed frame; The connecting rod of the four-bar connecting structure is composed of a swing frame of the chain drive mechanism, and two connecting frame rods are hinged on the swing frame; The mounting frame is hinged on the connecting rod, and the angle between the line between the axis of the guide chain wheel and the hinge point of the mounting frame and the line between the axis of the tensioning wheel and the hinge point of the mounting frame is 50°-95°.

2. The bicycle derailleur according to claim 1, characterized in that: The frame is provided with a reset structure for causing the connecting rod to automatically reset, and the reset structure includes a reset spring.

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