TWI909871B - Bicycle rear derailleur - Google Patents

Abstract

A bicycle rear derailleur is configured to be mounted on a bicycle frame. The bicycle rear derailleur includes a base component, a movable component, a first shaft, a second shaft, a third shaft, a fourth shaft, a linkage assembly and a chain guide. The base component is configured to be mounted on the bicycle frame. The linkage assembly includes an outer link and an inner link. One end of the outer link and one end of the inner link are respectively pivotably connected to the base component via the first shaft and the second shaft. Another end of the outer link and another end of the inner link are respectively pivotably connected to the movable component via the third shaft and the fourth shaft. The chain guide is pivotably connected to the movable component. A distance between a central axis of the first shaft and a central axis of the second shaft is greater than a distance between a central axis of the third shaft and a central axis of the fourth shaft.

Description

bicycle rear derailleur

This invention relates to a rear derailleur for bicycles.

In commonly used bicycle rear derailleurs, a four-bar linkage consisting of a base component, moving components, inner links, and outer links is employed, forming a parallelogram shape. However, this parallelogram-shaped four-bar structure makes it difficult for the chain guide component to tilt along with the chain during gear shifting, leading to interference between the chain guide component and the chain and affecting the smoothness of gear shifting. In light of this, researchers in this field are working to solve the aforementioned problems.

The present invention provides a rear derailleur for bicycles that improves the smoothness of chain-driven chain shifting.

An embodiment of the present invention discloses a bicycle rear derailleur for mounting on a frame, comprising a base component, a movable component, a first pivot, a second pivot, a third pivot, a fourth pivot, a linkage assembly, and a chain guide component. The base component is used for mounting to the frame. The linkage assembly includes an outer link and an inner link, one end of the outer link and one end of the inner link being respectively connected to the base component via the first pivot and the second pivot, respectively; the other ends of the outer link and the other end of the inner link are respectively connected to the movable component via the third pivot and the fourth pivot, respectively. The chain guide component is linked to the movable component. The distance from the center line of the first axis to the center line of the second axis is greater than the distance from the center line of the third axis to the center line of the fourth axis.

According to the bicycle rear derailleur disclosed in the above embodiment, one end of the outer connecting rod and one end of the inner connecting rod are respectively connected to the base component via a first pivot and a second pivot, respectively. The other ends of the outer connecting rod and the other ends of the inner connecting rod are respectively connected to the movable component via a third pivot and a fourth pivot, respectively. The distance from the center line of the first pivot to the center line of the second pivot is greater than that of the third pivot. The arrangement of the distance between the centerline of the base component and the centerline of the fourth pivot allows the base component, movable component, outer link, and inner link to form a non-parallelogram four-link structure. This allows the guide chain component connected to the movable component to tilt along with the chain during gear shifting, thereby reducing interference between the guide chain component and the chain and improving the smoothness of gear shifting.

The above description of the contents of this invention and the following description of the embodiments are used to demonstrate and explain the principles of this invention, and to provide a further explanation of the scope of the patent application of this invention.

Please refer to Figures 1 and 2. Figure 1 is a perspective view of the bicycle rear derailleur and frame disclosed in the first embodiment of the present invention. Figure 2 is a top view of the bicycle rear derailleur in Figure 1 in the lowest gear.

In this embodiment, the bicycle rear derailleur 1 is, for example, a mechanical rear derailleur. The bicycle rear derailleur 1 includes a base component 10, a movable component 20, a first pivot 30, a second pivot 40, a third pivot 50, a fourth pivot 60, a connecting rod assembly 70, and a chain guide component 80.

Next, please refer to Figures 2 and 3. Figure 3 is a partially enlarged top view of Figure 2.

The base component 10 is mounted on the frame F along a mounting axis I. The linkage assembly 70 includes an outer linkage 71 and an inner linkage 72. One end of the outer linkage 71 and one end of the inner linkage 72 are respectively connected to different parts of the base component 10 via a first pivot 30 and a second pivot 40, and the other end of the outer linkage 71 and the other end of the inner linkage 72 are respectively connected to different parts of the movable component 20 via a third pivot 50 and a fourth pivot 60. The distance T1 from the center line C1 of the first axis 30 to the center line C2 of the second axis 40 is greater than the distance T2 from the center line C3 of the third axis 50 to the center line C4 of the fourth axis 60, resulting in a non-parallelogram four-bar linkage. For example, the distance T1 from the center line C1 of the first axis 30 to the center line C2 of the second axis 40 is 23.29 mm, and the distance T2 from the center line C3 of the third axis 50 to the center line C4 of the fourth axis 60 is 22.20 mm.

In this embodiment, the centerline C1 of the first axis 30, the centerline C2 of the second axis 40, the centerline C3 of the third axis 50, and the centerline C4 of the fourth axis 60 are all, for example, perpendicular to the mounting axis I. Furthermore, the distance T3 from the centerline C1 of the first axis 30 to the mounting axis I is, for example, greater than the distance T4 from the centerline C2 of the second axis 40 to the mounting axis I. For example, the distance T3 from the centerline C1 of the first axis 30 to the mounting axis I is 17.22 mm, and the distance T4 from the centerline C2 of the second axis 40 to the mounting axis I is 16.47 mm. Furthermore, the distance T5 from the center line C1 of the first axis 30 to the center line C3 of the third axis 50 is, for example, equal to the distance T6 from the center line C2 of the second axis 40 to the center line C4 of the fourth axis 60. For example, the distance T5 from the center line C1 of the first axis 30 to the center line C3 of the third axis 50 and the distance T6 from the center line C2 of the second axis 40 to the center line C4 of the fourth axis 60 are 36 mm.

The chain guide component 80 includes a frame 81 and two guide wheels 82 and 83. The frame 81 is connected to the movable component 20, for example, via a pivot (not shown), and the two guide wheels 82 and 83 are rotatably mounted on the frame 81. The pivot axis R1 of the frame 81 relative to the movable component 20 is, for example, parallel to the rotation axes R2 and R3 of the two guide wheels 82 and 83. The guide wheel 82 is a guide wheel used to guide the chain (not shown), while the guide wheel 83 is a tension wheel used to tension the chain.

In this embodiment, a damping mechanism (not shown) may be provided at the junction of the pivot connected to the frame 81 and the movable component 20 to prevent the guide wheel 83 from loosening the chain due to the swing of the frame 81 by external force.

Next, please refer to Figures 2 and 4. Figure 4 is a top view of the bicycle in Figure 1 with the rear derailleur in the highest gear.

In this embodiment, the bicycle rear derailleur 1 can shift between multiple gears. When the bicycle rear derailleur 1 is in at least one of these gears, the pivot axis R1 of the chain guide member 80 frame 81 and the rotation axes R2 and R3 of the two guide wheels 82 and 83 are, for example, not parallel to the mounting axis I. In one gear, the pivot axis R1 of the chain guide member 80 is, for example, not parallel to the pivot axis R1 of the chain guide member 80 in another gear. At the lowest gear position, the tilt direction of the pivot axis R1 of the chain member 80 relative to the mounting axis I is different from that at the highest gear position.

For example, the rear derailleur 1 of a bicycle can shift between twelve gears, which are the first to the twelfth gears and correspond to twelve sprockets S1-S12 with different outer diameters. As shown in Figure 2, the first gear is the lowest gear, and the chain guide component 80 in this state corresponds to the sprocket S1 with the smallest outer diameter. As shown in Figure 4, the twelfth gear is the highest gear, and the chain guide component 80 in this state corresponds to the sprocket S12 with the largest outer diameter.

Please see Table 1, which lists the tilt angle θ of the pivot axis R1 of the chain guide component 80 relative to the mounting axis I when the rear derailleur 1 of the bicycle is in different gears. Since the pivot axis R1 of the chain component 80 is a distance away from the mounting axis I, and the tilt angle θ of the pivot axis R1 of the chain component 80 relative to the mounting axis I is small, it is not easy to directly represent the tilt angle θ using two axes. Therefore, the diagram uses a horizontal line H parallel to the mounting axis I and close to the pivot axis R1 of the chain component 80 to replace the mounting axis I, so that together with the pivot axis R1 of the chain component 80, it can represent the tilt angle θ of the pivot axis R1 of the chain component 80 relative to the mounting axis I. The angles shown in Table 1 are negative numbers indicating that the angle between the pivot axis R1 of the guide chain component 80 and the horizontal line H is below the horizontal line H (as shown in Figure 2), while the angles are positive numbers indicating that the angle between the pivot axis R1 of the guide chain component 80 and the horizontal line H is above the horizontal line H (as shown in Figure 4).

Table 1 Gear tilt angle First gear -1.12 degrees Second gear -0.7 degrees Third gear -0.39 degrees Fourth gear -0.1 degrees Fifth gear 0.14 degrees Sixth gear 0.4 degrees Seventh gear 0.68 degrees Eighth gear 0.98 degrees Ninth gear 1.29 degrees Tenth gear 1.58 degrees Eleventh gear 2.06 degrees Twelfth gear 2.76 degrees

As can be seen from the table above, regardless of the gear position of the rear derailleur 1 of the bicycle, the tilt angle θ of the pivot axis R1 of the frame 81 of the chain guide component 80 relative to the mounting axis I is never 0 degrees. Therefore, the pivot axis R1 of the frame 81 of the chain guide component 80 and the rotation axes R2 and R3 of the two guide wheels 82 and 83 are not parallel to the mounting axis I.

Furthermore, considering any two gear positions in the table above, in one gear position, the tilt angle θ of the pivot axis R1 of the chain member 80 relative to the mounting axis I is not equal to the tilt angle θ of the pivot axis R1 of the chain member 80 relative to the mounting axis I in the other gear position. Therefore, in one gear position, the pivot axis R1 of the chain member 80 is not parallel to the pivot axis R1 of the chain member 80 in the other gear position.

Furthermore, looking at the lowest gear (first gear) and highest gear (twelfth gear) in the table above, the tilt angle θ of the pivot axis R1 of the chain member 80 relative to the mounting axis I changes from a negative number to a positive number. Therefore, it can be seen that the tilt direction of the pivot axis R1 of the chain member 80 relative to the mounting axis I changes (from tilting to tilting to the right). In the lowest gear, the angle between the pivot axis R1 of the chain member 80 and the pivot axis R1 of the chain member 80 in the highest gear is, for example, less than 4 degrees, as shown in the table: 2.76 - (-1.12) = 3.88 degrees.

In this embodiment, one end of the outer connecting rod 71 and one end of the inner connecting rod 72 are respectively connected to the base component 10 via the first pivot 30 and the second pivot 40. The other ends of the outer connecting rod 71 and the inner connecting rod 72 are respectively connected to the movable component 20 via the third pivot 50 and the fourth pivot 60. The distance T1 from the center line C1 of the first pivot 30 to the center line C2 of the second pivot 40 is greater than that of the third pivot 50. The arrangement of the distance T2 from the centerline C3 to the centerline C4 of the fourth pivot 60 allows the base component 10, the movable component 20, the outer link 71, and the inner link 72 to form a non-parallelogram four-bar structure. This allows the guide chain component 80, which is connected to the movable component 20, to tilt along with the chain during the shifting process, thereby reducing interference between the guide chain component 80 and the chain and improving the smoothness of shifting.

Furthermore, when the bicycle rear derailleur 1 is in at least one of these gears, the pivot axis R1 of the chain guide component 80 frame 81 and the rotation axes R2 and R3 of the two guide wheels 82 and 83 are not parallel to the mounting axis I; in one gear, the pivot axis R1 of the chain guide component 80 is not parallel to the pivot axis R of the chain guide component 80 in another gear. 1; In the lowest gear of these gears, the tilt direction of the pivot axis R1 of the chain member 80 relative to the mounting axis I is different from the tilt direction of the pivot axis R1 of the chain member 80 relative to the mounting axis I in the highest gear of these gears. This configuration can further reduce the interference between the chain member 80 and the chain, and further improve the smoothness of gear shifting.

It should be noted that, regardless of the gear position of the bicycle's rear derailleur 1, the pivot axis R1 of the chain guide component 80 frame 81 and the rotation axes R2 and R3 of the two guide wheels 82 and 83 are not necessarily not parallel to the mounting axis I. Furthermore, in the lowest gear of these gears, the tilt direction of the pivot axis R1 of the chain guide component 80 relative to the mounting axis I is not necessarily different from the tilt direction of the pivot axis R1 of the chain guide component 80 relative to the mounting axis I in the highest gear of these gears.

For example, in one embodiment, the positions of the center lines of the first, second, third, and fourth pivots can be adjusted as needed, such that the distance from the center line of the first pivot to the mounting axis is not greater than the distance from the center line of the second pivot to the mounting axis, and the distance from the center line of the first pivot to the center line of the third pivot is not equal to the distance from the center line of the second pivot to the center line of the fourth pivot. In this way, the pivot axis of the chain link frame and the rotation axis of the two guide wheels can be parallel to the mounting axis in one of the gear positions. Alternatively, in the lowest gear, the tilt direction of the chain member's pivot axis relative to the mounting axis is the same as the tilt direction of the chain member's pivot axis relative to the mounting axis in the highest gear.

On the other hand, the center line C1 of the first pivot 30, the center line C2 of the second pivot 40, the center line C3 of the third pivot 50 and the center line C4 of the fourth pivot 60 are not limited to being perpendicular to the mounting axis I, and in other embodiments they may not be perpendicular to the mounting axis.

Next, please refer to Figure 5. Figure 5 is a perspective view of the bicycle rear derailleur and frame disclosed in the second embodiment of the present invention.

The rear derailleur 1a of this embodiment is similar to the rear derailleur 1 of the above embodiment. The following mainly describes the differences between the rear derailleur 1a of this embodiment and the rear derailleur 1 of the above embodiment. The parts that are the same can be referred to in the above paragraph and will not be repeated.

In this embodiment, the bicycle rear derailleur 1a is an electronic rear derailleur. An electronic rear derailleur means that the chain guide component 80a in the bicycle rear derailleur 1a is electrically driven. For example, the bicycle rear derailleur 1a includes a motor 90a and a control circuit board 100a that controls the motor 90a. The motor 90a and the control circuit board 100a are at least partially located within the space enclosed by the base component 10a, the movable component 20a, the outer link 71a, and the inner link 72a. The motor 90a provides power to drive the outer link 71a and the inner link 72a, so that the movable component 20a drives the chain guide component 80a to move relative to the base component 10a, thereby shifting the chain for gear changes. The control circuit board 100a is used to control the motor 90a.

In one embodiment, the control circuit board 100a may be equipped with a wireless communication unit and an antenna to wirelessly receive control signals. In addition, the control circuit board 100a may be connected to an external power source or a battery configured in the bicycle gearbox via a wire as needed to obtain power.

According to the bicycle rear derailleur disclosed in the above embodiment, one end of the outer connecting rod and one end of the inner connecting rod are respectively connected to the base component via a first pivot and a second pivot, respectively. The other ends of the outer connecting rod and the other ends of the inner connecting rod are respectively connected to the movable component via a third pivot and a fourth pivot, respectively. The distance from the center line of the first pivot to the center line of the second pivot is greater than that of the third pivot. The arrangement of the distance between the centerline of the base component and the centerline of the fourth pivot allows the base component, movable component, outer link, and inner link to form a non-parallelogram four-link structure. This allows the guide chain component connected to the movable component to tilt along with the chain during gear shifting, thereby reducing interference between the guide chain component and the chain and improving the smoothness of gear shifting.

Although the present invention has been disclosed above with reference to the preferred embodiments described above, it is not intended to limit the present invention. Anyone skilled in the art may make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of patent protection of the present invention shall be determined by the scope of the patent application attached to this specification.

1,1a: Rear derailleur 10,10a: Base component 20,20a: Moving component 30: First pivot 40: Second pivot 50: Third pivot 60: Fourth pivot 70: Linkage assembly 71,71a: External link 72,72a: Internal link 80,80a: Chain guide component 81: Frame 82,83: Guide wheel 90a: Motor 100a: Control circuit board I: Mounting axis F: Frame C1,C2,C3,C4: Centerline T1,T2,T3,T4,T5,T6: Distance R1: Pivot axis R2, R3: Rotation axes S1-S12: Gear discs θ: Inclination angle H: Horizontal line

Figure 1 is a perspective view of the bicycle rear derailleur and frame disclosed in the first embodiment of the present invention. Figure 2 is a top view of the bicycle rear derailleur in Figure 1 in the lowest gear position. Figure 3 is a partially enlarged top view of Figure 2. Figure 4 is a top view of the bicycle rear derailleur in Figure 1 in the highest gear position. Figure 5 is a perspective view of the bicycle rear derailleur and frame disclosed in the second embodiment of the present invention.

10: Base Components

20: Movable Components

30: First pivot

40: Second pivot

50: Third pivot

60: Fourth pivot

70: Linkage Assembly

71: External connecting rod

72: Inner Link

80: Chain Link Components

81: Frame

82,83: guide wheel

I: Install axis

F: Chassis

C1, C2, C3, C4: Center lines

R1: Rotation axis

R2, R3: Rotation axes

S1-S12: Discs

θ: Inclination angle

H: Horizontal line

Claims (8)

A bicycle rear derailleur for mounting on a frame includes: a base component for mounting on the frame; a movable component; a first pivot, a second pivot, a third pivot, and a fourth pivot; a linkage assembly including an outer link and an inner link, one end of the outer link and one end of the inner link being respectively connected to the base component via the first pivot and the second pivot, and the other ends of the outer link and the inner link being respectively connected to the movable component via the third pivot and the fourth pivot; and a chain member connected to the movable component. Wherein, the distance from the center line of the first pivot to the center line of the second pivot is greater than the distance from the center line of the third pivot to the center line of the fourth pivot; wherein the base component is used to be mounted on the frame along a mounting axis, and the distance from the center line of the first pivot to the mounting axis is greater than the distance from the center line of the second pivot to the mounting axis; wherein the bicycle rear derailleur is capable of shifting between multiple gears; when the bicycle rear derailleur is in at least one of the gears, the pivot axis of the chain guide component is not parallel to the mounting axis. The bicycle rear derailleur as described in claim 1, wherein the chain guide component includes a frame and two guide wheels, the frame being linked to the movable component, and the two guide wheels being rotatably mounted on the frame; when the bicycle rear derailleur is in at least one of the gears, the rotation axis of the two guide wheels is not parallel to the mounting axis. The bicycle rear derailleur as claimed in claim 1, wherein the pivot axis of the chain guide is not parallel to the pivot axis of the chain guide in one of the gears and in another gear. The bicycle rear derailleur as described in claim 1, wherein the gears include a lowest gear and a highest gear, wherein in the lowest gear, the tilt direction of the pivot axis of the chain member relative to the mounting axis is different from the tilt direction of the pivot axis of the chain member relative to the mounting axis in the highest gear. The bicycle rear derailleur as described in claim 4, wherein the angle between the pivot axis of the chain member in the lowest gear and the pivot axis of the chain member in the highest gear is less than 4 degrees. The bicycle rear derailleur as described in claim 1, wherein the center lines of the first pivot, the second pivot, the third pivot, and the fourth pivot are all perpendicular to the mounting axis. The bicycle rear derailleur as described in claim 1, wherein the distance from the center line of the first pivot to the center line of the third pivot is equal to the distance from the center line of the second pivot to the center line of the fourth pivot. The bicycle rear derailleur as described in claim 1, wherein the bicycle rear derailleur is a mechanical rear derailleur or an electronic rear derailleur.