JP2025032550A - Bicycle with rear suspension - Google Patents

Abstract

To provide a technique for providing progressive cushion characteristics in a bicycle with a rear suspension.SOLUTION: A bicycle with a rear suspension according to the present disclosure is a bicycle 1 including: a frame; a swing arm 10 swingably attached via a suspension pivot 9 to the frame; a pivot link 30 connected to the swing arm 10; and a rear suspension 13 connected between a front body 6 and the pivot link 30 to generate damping force proportional to stroke speed. The pivot link 30 includes three pivot mounts of a first pivot mount 31 pivotally coupled the swing arm 10, a second pivot mount 32 pivotally coupled to the rear suspension 13, and a third pivot mount 33 pivotally coupled via an arm 40 to the frame.SELECTED DRAWING: Figure 2

Description

The present invention relates to a bicycle with a rear suspension that can achieve progressive cushioning characteristics.

It has been known for some time that mountain bikes and other bicycles use frames with rear suspension. In general, bicycles with rear suspension are divided into single-point pivot and multi-point pivot types, and in either type, the rear suspension operates when riding on rough roads, allowing the rider to ride smoothly over uneven terrain.

And in multi-point pivot rear suspensions, which allow for greater freedom in designing cushioning characteristics, a four-bar link mechanism with four links is sometimes used.

For example, Patent Document 1 discloses a bicycle with a four-bar linkage mechanism, which has four links provided by a pivot link, a seat stay, a chain stay, and a seat tube. The bicycle also includes a main frame that defines a spring mount, a pivot mount, and a reinforcing strut that substantially directly connects the spring mount to the pivot mount.

US Patent Application Publication No. 2019/0233046

Conventionally known multi-point pivot rear suspensions allow greater freedom in designing cushioning characteristics, which may allow for smoother riding even on uneven terrain. Here, bicycles such as mountain bikes can be used on flat paved roads as well as on uneven unpaved roads, and various types (cross-country, trail, enduro, downhill, etc.) have been developed to suit different fields. However, from the user's perspective, it is desirable to have one bicycle that can be used in a variety of fields.

The present inventors have now discovered that by providing a bicycle with rear suspension with non-linear cushioning characteristics, it is possible to ride comfortably on everything from flat paved roads to rough unpaved roads. Note that the technology described in Patent Document 1 provides a bicycle with rear suspension with a frame that has improved lateral or torsional rigidity, but does not achieve progressive cushioning characteristics.

The purpose of this disclosure is to provide technology that can achieve progressive cushioning characteristics in bicycles with rear suspension.

The bicycle with rear suspension disclosed herein comprises a frame composed of a seat tube, a head tube, and a front body, a swing arm swingably attached to the frame via a suspension pivot, a pivot link connected to the swing arm, and a rear buffer section connected between the front body and the pivot link and generating a damping force proportional to the stroke speed, the pivot link having three pivot mounts, a first pivot mount pivotally connected to the swing arm, a second pivot mount pivotally connected to the rear buffer section, and a third pivot mount pivotally connected to the frame via an arm.

In the above-mentioned bicycle with rear suspension, the pivot link and arm provide progressive cushioning characteristics, making it possible to ride comfortably on everything from flat paved roads to rough unpaved roads. In more detail, when the bicycle is riding on a flat paved road, the rebound force in the rear buffer is relatively small, resulting in a smooth ride. On the other hand, when the bicycle is riding on a rough unpaved road, the rebound force in the rear buffer is relatively large, resulting in a firm ride.

In the above bicycle with rear suspension, the pivot link may have at least three vertices, and any one of the three pivot mounts may be located at that vertex.

In this case, the pivot link is formed into a triangle having three vertices, and the second pivot mount is disposed at the highest vertex in the height direction of the bicycle among the three vertices, and the arm can be disposed so that when the rear axle arranged to be able to swing via the swing arm is in a predetermined initial state, an imaginary line in the stroke direction of the rear buffer part and an imaginary line in the longitudinal direction of the arm form an acute angle. Furthermore, the arm may be configured to be rotatable about an arm pivot provided on the frame so that the angle formed between the imaginary line in the stroke direction of the rear buffer part and the imaginary line in the longitudinal direction of the arm increases as the rear axle strokes upward. With this configuration, when the stroke amount of the rear axle is relatively small, the stroke amount of the rear buffer part is approximately linearly proportional to the stroke amount of the rear axle. On the other hand, when the stroke amount of the rear axle is relatively large, the stroke amount of the rear buffer part changes nonlinearly with respect to the stroke amount of the rear axle, and as the stroke amount of the rear axle increases, the repulsive force and damping force generated in the rear buffer part gradually increase.

The pivot link may be formed into a triangle having three vertices, and the second pivot mount may be disposed at the highest vertex in the height direction of the bicycle among the three vertices, and the bicycle may be configured to be capable of mounting various rear shock absorbers with different stroke amounts by using the pivot link in which the position of the vertex at which the second pivot mount is disposed is changed while maintaining the shapes of the frame, swing arm, and arm.

The bicycle with rear suspension disclosed herein can achieve progressive cushioning characteristics.

1 is a diagram showing a schematic configuration of a bicycle with a rear suspension in a first embodiment. 5A and 5B are diagrams for explaining an arrangement of a pivot link and an arm in the first embodiment. 5A to 5C are diagrams illustrating an example of a detailed shape of a pivot link in the first embodiment. 11A and 11B are diagrams illustrating the postures of the pivot link and the arm when the rear axle is in a predetermined initial state. 11A and 11B are diagrams illustrating the postures of the pivot link and the arm when the rear axle is in a predetermined stroke state. FIG. 4 is a diagram illustrating an example of the relationship between the stroke amount of a rear axle and the stroke amount of a rear suspension.

Embodiments of the present disclosure will be described below with reference to the drawings. The configurations of the following embodiments are examples, and the present disclosure is not limited to the configurations of the embodiments.

First Embodiment
An overview of a bicycle with rear suspension in a first embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing the general configuration of a bicycle with rear suspension in this embodiment.

The bicycle 1 according to this embodiment has a frame made up of a seat tube 3 that supports a saddle 2, a head tube 5 that supports a handlebar 4, and a front body 6. The lower parts of the seat tube 3 and the head tube 5 are joined to the front body 6. The bicycle 1 has a front fork 20 that extends diagonally downward and forward from the head tube 5, and a front wheel 21 is rotatably attached to the lower end of the front fork 20.

The bicycle 1 is equipped with a swing arm 10 that is swingably attached to the frame via a suspension pivot 9. A rear axle 12 that rotates a rear wheel 11 is supported by the swing arm 10. The bicycle 1 also has a driving side rotating member 7 that is rotatably attached to the frame, and cranks 8 that are connected to both ends of the rotating shaft of the driving side rotating member 7, have pedals attached to the tips, and rotate integrally with the driving side rotating member 7.

Furthermore, in the bicycle 1, a pivot link 30 (described later) is connected to the swing arm 10. And, a rear suspension 13 is connected between the front body 6 and the pivot link 30.

The rear suspension 13 has a damper (damping device) arranged so that the cylinder is on the upper side and the piston rod that strokes together with the piston in the cylinder is on the lower side, and a spring set so that a predetermined initial load is applied between flanges provided on the upper end of the cylinder and the lower end of the piston rod. Such a rear suspension 13 can generate a damping force proportional to the stroke speed.

The upper side of the rear suspension 13, where the cylinder is located, is supported by the front body 6 via a suspension mount 131, and the lower side, where the piston rod is located, is connected to the pivot link 30 via a yoke 132.

It is known that equipping bicycles such as mountain bikes with rear suspension allows for smooth riding over uneven terrain. However, bicycles such as mountain bikes are used not only on uneven unpaved roads but also on flat paved roads, and with conventional technology it has been difficult to adapt a single bicycle to a variety of terrains.

As a result of intensive research, the present inventors have newly discovered that by adding nonlinear cushioning characteristics to a bicycle with rear suspension, it is possible to ride comfortably on everything from flat paved roads to undulating unpaved roads.

And these progressive cushioning characteristics are achieved by the pivot link 30 and the arm 40.

More specifically, in the bicycle with rear suspension in this embodiment, the pivot link 30 has three pivot mounts, the first pivot mount is pivotally connected to the swing arm 10, the second pivot mount is pivotally connected to the rear suspension 13, and the third pivot mount is pivotally connected to the frame via an arm 40. This will be explained below with reference to FIG. 2.

Figure 2 is a diagram illustrating the arrangement of the pivot link 30 and the arm 40 in this embodiment.

As shown in FIG. 2, the pivot link 30 in this embodiment is formed into a triangle having three vertices. One of the three pivot mounts described above is disposed at each of these vertices.

Specifically, the second pivot mount 32, which is pivotally connected to the rear suspension 13, is disposed at the highest vertex in the height direction of the bicycle 1 among the above three vertices. The first pivot mount 31, which is pivotally connected to the swing arm 10, is disposed at the vertex on the rear wheel 11 side of the remaining two vertices, and the third pivot mount 33, which is pivotally connected to the frame via the arm 40, is disposed at the vertex on the front wheel 21 side of the remaining two vertices.

In this embodiment, the pivot link 30 is formed symmetrically in the width direction of the bicycle 1, and a triangular shape is formed on each side of the bicycle 1 when viewed from the side. Here, FIG. 3 is a diagram illustrating the detailed shape of the pivot link 30 in this embodiment, and as shown in FIG. 3, a second pivot mount 32 and a third pivot mount 33 are arranged on each side. Then, by connecting an arm 40 to each third pivot mount 33, the pivot link 30 is connected to the frame via the two arms 40. Also, a bridge-shaped yoke 132 is connected to each second pivot mount 32. Here, the triangular shapes formed on each side when viewed from the side of the bicycle 1 are rigidly connected at the first pivot mount 31, and the left and right swing arms 10 are pivotally connected to the first pivot mount 31.

Next, the progressive cushioning characteristics achieved by the pivot link 30 and the arm 40 will be explained with reference to Figures 4 to 6.

Figure 4 shows the posture of the pivot link 30 and the arm 40 when the rear axle 12 is in a predetermined initial state.

The initial state is, for example, when the bicycle 1 is stopped, in which the rear axle 12 is not stroking up or down. In this case, the rear suspension 13 is also in an extended state, as shown in FIG. 4(a).

When the rear axle 12 is in this initial state, the arm 40 forms an acute angle with the stroke direction of the rear suspension 13. Here, FIG. 4(b) is a diagram showing the positional relationship of each pivot of the bicycle 1, and the triangular shape of the pivot link 30 can be expressed by the first pivot mount 31, the second pivot mount 32, and the third pivot mount 33. The swing arm 10 can be expressed by the suspension pivot 9 and the rear mount point 121. Furthermore, FIG. 4(b) shows an imaginary line L1 in the stroke direction of the rear suspension 13, and an imaginary line L2 in the longitudinal direction of the arm 40. The imaginary line L2 in the longitudinal direction of the arm 40 is a line connecting the third pivot mount 33 and the arm pivot 41 that supports the arm 40 so that it can pivot relative to the frame.

In this way, when the rear axle 12 is in its initial state, the arm 40 is positioned so that an imaginary line L1 in the stroke direction of the rear suspension 13 and an imaginary line L2 in the longitudinal direction of the arm 40 form an acute angle.

On the other hand, Figure 5 shows the posture of the pivot link 30 and the arm 40 when the rear axle 12 is in a specified stroke state.

The stroke state mentioned above is, for example, a state in which the rear axle 12 has made a large upward stroke, such as when the bicycle 1 is traveling on a rough road surface. In this case, the rear suspension 13 is also in a stroked state (compressed state) as shown in FIG. 5(a).

When the rear axle 12 is in this stroke state, the arm 40 forms an obtuse angle with the stroke direction of the rear suspension 13. Figure 5(b) is a diagram showing the positional relationship of each pivot of the bicycle 1, and compared to Figure 4(b) where the rear axle 12 is in the initial state, it can be seen that the imaginary line L2 in the longitudinal direction of the arm 40 rotates around the arm pivot 41. As a result, the imaginary line L1 in the stroke direction of the rear suspension 13 and the imaginary line L2 in the longitudinal direction of the arm 40 form an obtuse angle.

In this way, the arm 40 is configured to be rotatable around the arm pivot 41 provided on the frame so that the angle between the imaginary line L1 in the stroke direction of the rear suspension 13 and the imaginary line L2 in the longitudinal direction of the arm 40 increases as the rear axle 12 strokes upward.

The above can be explained by focusing on the line segment between the arm pivot 41 and the intersection point of the imaginary line L2 in the longitudinal direction of the arm 40 with the imaginary line L1 (hereinafter sometimes referred to as the "arm rotation radius").

Here, FIG. 6 is a diagram illustrating the relationship between the stroke amount of the rear axle 12 and the stroke amount of the rear suspension 13.

In the bicycle 1 of this embodiment, the angle between the imaginary lines L1 and L2 when the rear axle 12 is in the initial state is an acute angle close to 90°. Then, as the rear axle 12 strokes upward from the initial state, the angle between the imaginary lines L1 and L2 increases from an acute angle close to 90° to an obtuse angle close to 90°. At this time, since the angle changes near 90°, the arm rotation radius is an approximately constant length. Then, as shown in the low stroke proportional characteristic shown in Figure 6, the stroke amount of the rear suspension 13 is approximately linearly proportional to the stroke amount of the rear axle 12.

On the other hand, as the stroke amount of the rear axle 12 increases further, the angle between the imaginary lines L1 and L2 increases from an obtuse angle close to 90°. As a result, the arm rotation radius increases gradually as the angle between the imaginary lines L1 and L2 increases, and the stroke amount of the rear suspension 13 changes nonlinearly with respect to the stroke amount of the rear axle 12, as shown in the high stroke proportional characteristic in Figure 6.

In other words, according to the above-mentioned arrangement of the pivot link 30 and the arm 40, the change in the stroke amount of the rear suspension 13 is greater on the high stroke side where the stroke amount of the rear axle 12 is greater than on the low stroke side where the stroke amount of the rear axle 12 is smaller. As a result, the repulsive force generated by the rear suspension 13 gradually increases as the stroke amount of the rear axle 12 increases. Also, the stroke speed of the piston of the rear suspension 13 on the high stroke side where the stroke amount of the rear axle 12 is greater is greater than the stroke speed of the piston of the rear suspension 13 on the low stroke side where the stroke amount of the rear axle 12 is smaller. As a result, the damping force generated by the rear suspension 13 gradually increases as the stroke amount of the rear axle 12 increases.

In this way, the pivot link 30 and the arm 40 provide progressive cushioning characteristics, making it possible to ride comfortably on everything from flat paved roads to undulating unpaved roads. In more detail, when the bicycle 1 is riding on a flat paved road, the change in stroke amount of the rear axle 12 is relatively small (in this case, the stroke characteristics of the rear suspension 13 are the low-stroke proportional characteristics shown in FIG. 6 above), so the repulsive force in the rear suspension 13 is relatively small, resulting in a smooth ride. On the other hand, when the bicycle 1 is riding on an undulating unpaved road, the change in stroke amount of the rear axle 12 is relatively large (in this case, the stroke characteristics of the rear suspension 13 are the high-stroke proportional characteristics shown in FIG. 6 above), so the repulsive force in the rear suspension 13 is relatively large, resulting in a firm ride.

The bicycle 1 described above can provide optimal progressive cushioning characteristics.

Second Embodiment
A bicycle with a rear suspension according to the second embodiment will be described below. The structure of the bicycle 1 according to this embodiment is the same as that described in the first embodiment above, and in the bicycle 1 according to this embodiment, the rear suspension 13 and the pivot link 30 are configured so that they can be replaced as a set.

Traditionally, various types of mountain bikes and other bicycles have been developed for different fields (cross country, trail, enduro, downhill, etc.), and these bicycles tend to have different cushioning characteristics. In order to achieve different cushioning characteristics, it is conceivable to use rear cushioning parts with different stroke amounts, but with conventional bicycles, changing the rear cushioning part (changing the stroke amount) affects the mounting specifications for the frame and swing arm, so these had to be changed when the rear cushioning part was changed.

The bicycle 1 according to this embodiment is configured to be able to mount various rear suspensions 13 with different stroke lengths by using a pivot link 30 in which the vertex position at which the second pivot mount 32 is located is changed while the shapes of the frame, swing arm 10, and arm 40 are maintained.

In other words, the bicycle 1 described above is provided with a pivot link 30 that is formed into a triangle with three vertices, with one of three pivot mounts (first pivot mount 31, second pivot mount 32, third pivot mount 33) located at each of these vertices, and this allows the pivot link 30, which has mounting specifications that match the cushioning characteristics of the rear suspension 13, to be used in combination with the rear suspension 13. This makes it possible to mount various rear suspensions 13 with different stroke amounts without changing the mounting specifications for the frame and swing arm 10, that is, while maintaining the shapes of the frame, swing arm 10, and arm 40.

The bicycle 1 described above is a bicycle with a rear suspension that can achieve progressive cushioning characteristics, making it possible for a single bicycle to be optimally adapted to a variety of conditions.

<Other Modifications>
The above embodiment is merely an example, and the present disclosure may be modified as appropriate without departing from the spirit and scope of the present disclosure. For example, the bicycle 1 described in the above embodiment may be an electric-assisted mountain bike (eMTB).

1 . . . Bicycle 6 . . . Front body 9 . . . Suspension pivot 10 . . . Swing arm 12 . . . Rear axle 13 . . . Rear suspension 30 . . . Pivot link 31 . . . First pivot mount 32 . . . Second pivot mount 33 . . . Third pivot mount 40 . . . Arm

Claims (5)

A frame consisting of a seat tube, a head tube and a front body;
A swing arm swingably attached to the frame via a suspension pivot;
A pivot link connected to the swing arm;
a rear buffer unit connected between the front body and the pivot link and configured to generate a damping force proportional to a stroke speed;
In a bicycle having
The pivot link has three pivot mounts, a first pivot mount pivotally coupled to the swing arm, a second pivot mount pivotally coupled to the rear shock absorber, and a third pivot mount pivotally coupled to the frame via an arm.
Bicycle with rear suspension. The pivot link is
having at least three vertices, and any one of the three pivot mounts is disposed at the vertices;
2. A bicycle with a rear suspension as claimed in claim 1. the pivot link is formed into a triangle having three vertices, and the second pivot mount is disposed at the highest vertex in a height direction of the bicycle among the three vertices;
the arm is disposed such that, when a rear axle that is swingably disposed via the swing arm is in a predetermined initial state, an imaginary line in a stroke direction of the rear buffer portion and an imaginary line in a longitudinal direction of the arm form an acute angle.
3. A bicycle with a rear suspension as claimed in claim 2. the arm is configured to be rotatable around an arm pivot provided on the frame such that the angle between a virtual line in a stroke direction of the rear buffer unit and a virtual line in a longitudinal direction of the arm becomes larger as the rear axle strokes upward.
4. A bicycle with a rear suspension as claimed in claim 3. the pivot link is formed into a triangle having three vertices, and the second pivot mount is disposed at the highest vertex in a height direction of the bicycle among the three vertices;
The bicycle is
The pivot link is used in which the position of the vertex where the second pivot mount is disposed is changed while the shapes of the frame, the swing arm, and the arm are maintained, so that various rear buffer parts having different stroke amounts can be mounted.
3. A bicycle with a rear suspension as claimed in claim 2.

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