JP3838429B2 - Bicycle crank drive chain device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bicycle crank drive chain device.
[0002]
[Prior art]
In general, a crank drive chain device for a bicycle is provided with a crankshaft and a pair of crank arms and a crankchain gear integrated with the crankshaft on a bottom bracket of the bicycle, and a rear chain gear is provided on a rear wheel hub. The drive chain is stretched between the rear chain gear and the torque generated by depressing the pedal connected to the crank arm is transmitted from the crank chain gear to the rear chain gear via the drive chain to drive the rear wheels. I try to ride a bicycle.
[0003]
As shown in FIG. 12, the pedaling operation during the bicycle operation is as follows. The knee joint B of the driver A serves as a piston of the reciprocating engine, and the shin C serves as a connecting rod. The rotating mechanism is a typical reciprocating crank rotating mechanism. For this reason, when the knee joint B, the pedal E, and the crankshaft D are positioned on a straight line (the state of FIG. 12), the top dead center is obtained, and no rotational torque is generated. Further, at a position where the crankshaft D is rotated 180 ° counterclockwise (in the figure) from the position shown in FIG. Torque is generated by the driver A depressing the pedal E while the crankshaft D rotates 180 ° from the top dead center to the bottom dead center, and this is generated from the crank chain gear F through the drive chain G to the rear chain gear. H is transmitted to drive the rear wheel I.
[0004]
Since the crank pedal depression speed is proportional to the effective crank arm length, a slow sine wave curve is drawn at the beginning (near the top dead center of the crankshaft) and at the end (near the bottom dead center). (See FIG. 13). Moreover, most ordinary people who have not received special training generate effective torque only by depressing the pedal, and the effective crank angle is about 90 ° between 45 ° and 135 ° after top dead center. Is an angle range (horizontal line region in the lower diagram of FIG. 13). In other words, if the actual length of the crank length is r, the effective crank length L at the crankshaft angle θ is L = rsinθ, so that the region where the effective crank length L is 70% or more of the crank length r is the torque generation. It is considered to be a practical area. In the step-down region outside this range, torque conversion efficiency is low and inefficient pedaling operation is forced.
[0005]
As means for solving such problems, it has been conventionally proposed to make the crank chain gear non-circular such as an ellipse (Japanese Patent Publication No. 62-43906, Japanese Patent Publication No. 62-43907, (Kaihei 9-20281, JP-A-10-291493, Utility Model Registration No. 3024134, etc.). For non-circular crank chain gears, the pitch diameter is different for each tooth, so even if the rear chain gear is a true circle, the gear ratio can be continuously changed during the pedaling cycle, so an appropriate gear ratio is set. By doing so, the torque conversion efficiency by stepping on the pedal is improved.
[0006]
[Problems to be solved by the invention]
However, in spite of many proposals for adopting a non-circular crank chain gear as described above, the current situation is that it has not generally been established.
[0007]
There are several possible reasons for this, but one is the difficulty in producing non-circular gears and the associated increased manufacturing costs. Making the crank chain gear non-circular is necessary because the pitch diameter of each tooth must correspond to the pitch of the drive chain, and the pitch diameter must be set to obtain the desired gear ratio. Is difficult, and since general versatility is poor, general commercial products cannot be diverted, resulting in increased manufacturing costs.
[0008]
Also, extreme non-circularity of the crank chain gear (increasing the ellipticity (ratio of major axis / minor axis)), load is concentrated on a part of the pedaling, and the bending angle of the drive chain is increased. For this reason, there is a problem that sufficient durability cannot be ensured. Furthermore, when a load is applied in a state where the long axis of the non-circular crank chain gear is substantially horizontal, there is a problem that the drive chain slips in a region close to the horizontal and the chain is easily detached. For this reason, even if the crank chain gear is made non-circular, its ellipticity is about 1.3, which is a practical limit, but this degree of ellipticity is only a change rate of about ± 15%. The improvement effect compared with the chain gear was not obtained from the experience.
[0009]
[Means for Solving the Problems]
In view of the above circumstances, the present invention provides a novel mechanism capable of converting a linear pedal depression force by a driver into an optimum torque characteristic according to a traveling load state in a bicycle driving state. For the purpose.
[0010]
When the bicycle is running steadily, the rotation of the wheel by the driver and the mass of the bicycle is the reference. Therefore, the present inventor provides an eccentric intermediate idle gear that meshes with the drive chain on the tension side between the crank chain gear and the rear chain gear, thereby periodically changing the tension-side path length in synchronization with the rotation of the crankshaft. And found that a change in angular velocity occurs in the rotation of the crankshaft.
[0011]
Since two crank arms are connected to the bicycle crankshaft at an interval of 180 °, when rotating eccentrically by engaging a circular eccentric idle gear in the tight chain path, it is twice the rotational speed of the crankshaft. What is necessary is just to synchronize so that it may rotate at speed, ie, the gear with half the number of teeth of a crank chain gear should just be used. Further, the change in the chain path length due to the eccentric gear repeats the maximum and minimum every 180 °, and therefore every 90 ° on the crankshaft. Here, if the crankshaft angular speed change rate increase side by the eccentric intermediate gear is + and the decrease side is-with respect to the reference crankshaft angular speed,
Increase-side change rate (+%) = (Rp−1) × 100
Decreasing rate of change (-%) = (Rm-1) × 100
It becomes. Here, Rp is a ratio between the input side maximum effective radius and the output side minimum effective radius of the eccentric gear, and Rm is a ratio between the input side minimum effective radius and the output side maximum effective radius of the eccentric gear.
[0012]
When prototypes were made so that the rate of change was ± 15% to ± 50% according to the above formula, all of them worked without any mechanical problems, but the movement of the human leg was the angular velocity of the crankshaft. It was found that the range that can follow the change was ± 30%. It was also confirmed that the change in the angular velocity of the crankshaft due to the circular eccentric intermediate idle gear is a substantially sinusoidal curve and has sufficient characteristics to correct the depression speed of the crank pedal.
[0013]
The present invention has been completed on the basis of the above knowledge and experiment. A crankshaft, a pair of crank arms and a crank chain gear that rotate integrally with the crankshaft, and a rear wheel hub are provided. In a crank drive chain device for a bicycle having a rear chain gear that rotates coaxially and a drive chain stretched between the crank chain gear and the rear chain gear, the crankshaft By engaging an eccentric intermediate idle gear that operates at half the rotation cycle of the drive chain and meshing with the drive chain, the chain side chain path length is periodically changed, and the angular speed change is given to the running crankshaft. It is a feature.
[0014]
The eccentric intermediate idle gear is preferably configured as a circular gear having half the number of teeth of the crank chain gear.
[0015]
The bicycle crank drive chain device according to the present invention has a crankshaft rotation angle of 0 ° and 180 ° when one crank arm is positioned at the top dead center and the bottom dead center during 180 ° rotation of the crankshaft. It is possible to implement the first setting in which the tension side chain path is the shortest when the shaft rotation angle is 45 ° and the tension side chain path is the longest when the crankshaft rotation angle is 135 °.
[0016]
Similarly, when one crank arm is positioned at the top dead center and the bottom dead center during the 180 ° rotation of the crankshaft, the crankshaft rotation angle is 0 ° and 180 °, respectively. It is also possible to implement a second setting in which the tension side chain path is sometimes the shortest and the tension side chain path is the longest when the crankshaft rotation angle is 90 °.
[0017]
Furthermore, setting change means for enabling a plurality of settings including the first and second settings can be provided. The setting changing means includes a plurality of engagement holes formed concentrically in the eccentric intermediate idle gear, a lock pin that can be engaged with one of these engagement holes, and a lock pin that is one of the engagement holes. It is possible to adopt a configuration having a spring that urges the lock pin in a direction in which the lock pin is engaged, and an operation knob that releases the lock pin from being engaged with the engagement hole against the urging of the spring. . Further, as another setting changing means, the rotation shaft of the eccentric intermediate idle gear is provided so as to be movable between a plurality of positions, and a switching lever for moving the position of the rotation shaft of the eccentric intermediate idle gear is provided. It is possible.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
The ideal configuration of a crank drive chain device for a bicycle according to the present invention is shown in FIG. In the figure, reference numeral 1 is a crank chain gear, 2 is a rear chain gear, 3 is a drive chain stretched between them, 4 is an eccentric intermediate idle gear that meshes with the tension side of the drive chain 3, and 5 is the present invention. A tensioning device not directly related to the subject.
[0019]
In the configuration of FIG. 1, a circular gear having a diameter of 194.6 mm is used as the crank chain gear 1, a circular eccentric gear having a diameter of 97.3 mm and an eccentric amount of 8.5 mm is used as the eccentric intermediate idle gear 4, and the eccentric intermediate idle gear 4 is The change rate of the crankshaft angular velocity, which is changed by meshing with the tension side (drive side) by approximately 90 °, is + 28% and −22% from the following calculation formula, and is approximately ± 25%.
((54.5 / 42.5) -1) × 100 = + 28 (%)
((42.5 / 54.5) -1) × 100 = −22 (%)
[0020]
For comparison, when the crank chain gear is an elliptical gear based on the prior art, the radius change rate becomes ± 23% when the ellipticity (ratio of major axis / minor axis) is 1.6 ( As described above, FIG. 14) shows that such an ellipticity greatly exceeds the practical limit and cannot be adopted in an actual product.
[0021]
FIG. 2 shows a more specific embodiment of the present invention, in which the crank chain gear 1 that rotates integrally with a crankshaft (not shown) and the rear wheel hub 6 rotate integrally. A circular eccentric intermediate idle gear 4 is meshed with the tension side of the drive chain 3 stretched between the rear chain gear 2 and the rear chain gear 2. A pair of crank arms 7a and 7b are attached to both ends of the crankshaft at intervals of 180 °, and rotate integrally with the crankshaft. Pedals 8a and 8b are connected to the ends of the crank arms 7a and 7b, respectively, so as to be rotatable.
[0022]
FIG. 2A shows the case where the center of the eccentric gear 4 is at the uppermost position of the rotary shaft 10 and the tension side path length of the drive chain 3 is the shortest. In this embodiment, one crank arm The crankshaft rotation angle when 7a (depressing the right foot with the pedal 8a) is at the top dead center is set to 0 °, and the tension side drive chain path length is set to the shortest when the crankshaft rotation angle is 45 °. (This setting is called “standard setting” in the following description). FIG. 2B shows the case where the center of the eccentric gear 4 is at the lowest position of the rotating shaft 10, the crankshaft rotation angle is 135 °, and the tension side path length of the drive chain 3 is the longest. .
[0023]
FIG. 3 is a graph showing the relationship (A) between the crankshaft rotation angle and the crankshaft angular velocity and the relationship (B) with the rear wheel drive torque in this embodiment. In FIGS. 3A and 3B, the solid line indicates the relationship in this embodiment, and the broken line indicates a case where the eccentric gear 4 is not used for reference. When an eccentric gear is not used on the tension side of the drive chain, the crankshaft rotates at a constant speed and there is no change in angular speed as shown by the broken line in FIG. The relationship is as shown by a broken line in FIG. 3B, and as described above, assuming that 70% or more of the peak torque is in the practical range, 45 (out of 180 ° pedaling angle range). Effective torque generation can be obtained in the crankshaft rotation angle range of about 90 ° from ° to 135 °.
[0024]
On the other hand, according to the embodiment of the present invention of the standard setting of FIG. 2, as shown by the solid line in FIG. 3 (A), the angular velocity is reduced within the range of 45 ° to 135 ° and 90 °. At this time, the decrease in angular velocity peaks, and accordingly, as shown by the solid line in FIG. 3B, a slightly flat torque curve is drawn as compared with the case without the eccentric gear. FIG. 4 shows the torque curves of the case without the eccentric gear shown in FIG. 3B (broken line) and the case of the embodiment of the present invention (solid line) together with their peaks, which is 70% of the peak torque. Assuming that the above is a practical range, effective torque generation can be obtained in the range of the crankshaft rotation angle of about 90 ° from 45 ° to 135 ° as described above when there is no eccentric gear. In the case of the embodiment of the present invention that draws a curve, it can be seen that effective torque generation is obtained over a wide range of about 120 ° from about 30 ° to 150 °, and the effective torque generation region is expanded.
[0025]
Now, with reference to FIG. 5 together with FIG. 2, it will be described that the torque curve as shown by the solid line in FIG. A dead point where the path length does not change at the position (crankshaft rotation angle = 135 °) in FIG. 2B (crankshaft rotation angle = 135 °) where the same path is the longest position (crankshaft rotation angle = 45 °). Therefore, the generated torque is the same as that without the eccentric gear with a constant crankshaft angular velocity (see FIG. 3B).
[0026]
More specifically, in the mechanism of the present invention in which the eccentric idle gear 4 is engaged with the tension side of the drive chain, the effective radius of the eccentric gear on the torque input side (crank chain gear 1 side) (the contact with the drive chain 3 and the eccentric gear). 4) and the eccentric gear effective radius on the torque output side (rear chain gear 2 side) determines the output torque. FIG. 2 (A) = FIG. At the dead point A), the effective radius of the eccentric gear 4 is the same on the torque input side and the torque output side (RA = RA), so that no torque change occurs. Similarly, even at the dead point in FIG. 3 (B) = FIG. 5 (B), the effective radius of the eccentric gear 4 is the same on the torque input side and the torque output side (RC = RC), so that no torque change occurs.
[0027]
On the other hand, when the crankshaft rotation angle is between 45 ° and 135 °, as shown in FIG. 5C, the eccentric gear effective radius (RS) on the torque input side and the eccentric gear on the torque output side Since the relationship with the effective radius (RL) is RL> RS, the generated torque is reduced as compared to the case without the eccentric gear (see FIG. 3B), but the rear wheel drive speed is increased. The ratio of RL / RS becomes maximum when the position shown in FIG. 5C, that is, when the crankshaft rotation angle is 90 °, in other words, when the crank arms 7a and 7b are substantially horizontal. In addition, the generated torque is relatively minimum, but the rear wheel drive speed is maximum.
[0028]
Since the embodiment of the present invention at the time of standard setting has the above-described characteristics, a relatively flat torque generation is obtained in pedaling from the top dead center to the bottom dead center, and the effective torque generation region is 45 to 135 in the conventional case. Over a wide range from about 90 ° to about 120 ° from about 30 ° to 150 °. In addition, according to this standard setting, the maximum rear wheel drive speed is obtained when the crankshaft rotation angle is 90 °, so that pedaling is felt lightly when the load is the highest in normal bicycle driving, and smooth driving A feeling is obtained.
[0029]
Details of the eccentric gear 4 shown in the embodiment of FIG. 2 are shown in FIG. The shaft 9a of the eccentric shaft unit 9 is fitted in the central opening (not indicated) of the eccentric gear 4, and the hollow shaft (not indicated) extending in parallel with the eccentric shaft 9a serves as the rotation shaft of the eccentric gear 4. The lock pin 10 is inserted in a state of being biased downward in FIG. A knob 10 a is provided at one end of the lock pin 10, and the other end of the engagement hole 11 arranged concentrically with the eccentric gear 4 at a predetermined equal angle (30 ° in this embodiment) by the spring bias. Engage with any one. A rotating shaft portion 9b of the eccentric shaft unit 9 is rotatably mounted on a bearing 13 fixed at an appropriate position of the bicycle via a ball bearing 12.
[0030]
In the above configuration, the knob 10a is pulled up against the bias of the spring 14, the lock pin 10 is pulled out from the engagement hole 11, and the eccentric gear 4 is manually rotated by a desired angle in this state, and then the knob 10a is removed. By releasing the hand, the lock pin 10 can be engaged with the engagement hole 11 different from the previous one, so that the setting relating to the correlation between the crankshaft rotation angle and the tension side drive chain path length can be arbitrarily changed. Can do.
[0031]
For example, when the crankshaft rotation angle is shifted by 45 ° from the standard setting described above and the crankshaft rotation angle is 0 ° (when the crank arm 7a is at the top dead center), the tension side drive chain path length Is the shortest and the crankshaft rotation angle is 90 ° (When the crank arm 7a is Middle position between top dead center and bottom dead center (In the following description, this setting is referred to as “pseudo transmission mode setting”), and the schematic configuration of the embodiment in this case is shown in FIG. 7 (A) (state diagram when crankshaft rotation angle is 0 °) and FIG. 7 (B) (state diagram when crankshaft rotation angle is 90 °) and the crankshaft in this embodiment A graph showing the relationship (A) between the rotation angle and the crankshaft angular velocity and the relationship (B) with the rear wheel drive torque is shown in FIG. 8A and 8B, the solid line indicates the relationship in this embodiment, and the broken line indicates a case where the eccentric gear 4 is not used for reference. Since the case where the eccentric gear is not used on the tension side of the drive chain has already been described with reference to FIGS. 3A and 3B, description thereof is omitted here.
[0032]
According to the embodiment of the present invention for setting the pseudo shift mode in FIG. 7, when the crankshaft rotation angle is in the range of 0 ° to 90 ° and the angular speed is reduced to 45 ° as shown by the solid line in FIG. In the crankshaft rotation angle range of 90 ° to 180 °, the angular velocity increases, and the angular velocity increases at 135 °, and the angular velocity increases at a peak. As a result, a solid line is shown in FIG. The torque curve will be drawn.
[0033]
Here, in the case of the embodiment of the present invention in which the pseudo transmission mode is set, it will be described that a torque curve as shown by a solid line in FIG. 8B is obtained. FIG. 7A where the tension side drive chain path is the shortest. 7 (Crankshaft rotation angle = 0 °) and the position (Crankshaft rotation angle = 90 °) in FIG. 7B where the same path is the longest, it becomes a dead point where the path length does not change. The generated torque is the same as in the case of no constant eccentric gear (see FIG. 8B).
[0034]
That is, as described above, in the mechanism of the present invention in which the eccentric idle gear 4 is engaged with the tension side of the drive chain, the effective radius of the eccentric gear on the torque input side (crank chain gear 1 side) (the contact with the drive chain 3) The ratio between the distance between the eccentric gear 4 and the rotating shaft 10) and the effective radius of the eccentric gear on the torque output side (rear chain gear 2 side) determines the output torque. FIG. 7 (A) and FIG. At each dead point of 7 (B), since the effective radius of the eccentric gear 4 is the same on the torque input side and the torque output side, no torque change occurs.
[0035]
On the other hand, when the crankshaft rotation angle is between 0 ° and 90 °, as shown in FIG. 9A, the eccentric gear effective radius (RS) on the torque input side and the eccentric gear on the torque output side Since the relationship with the effective radius (RL) is RL> RS, the generated torque is reduced as compared with the case without the eccentric gear (see FIG. 8B), but the rear wheel driving speed is increased. On the other hand, when the crankshaft rotation angle is between 90 ° and 180 °, as shown in FIG. 9B, the eccentric gear effective radius (RS) on the torque input side and the eccentric gear effective radius (RS) on the torque output side ( RL) and RL <RS, the generated torque increases as compared to the case without the eccentric gear (see FIG. 8B), and the rear wheel drive speed becomes slower.
[0036]
The embodiment of the present invention at the time of setting the pseudo shift mode has the above-described characteristics, so that it is difficult to obtain a sufficient stepping force when pedaling by a general person who has not received special training up to 90 ° from the top dead center. In the region, although the torque generation is small, the rear wheel drive speed becomes fast, so a light driving feeling can be obtained. On the other hand, the region from 90 ° to the bottom dead center where a large stepping force can be obtained, especially the maximum stepping force can be obtained. Since a very large torque can be generated around 135 °, high torque can be generated by fully depressing the pedal using the speed obtained by driving from 0 ° to 90 °. Efficient driving with reduced physical burden is sometimes possible.
[0037]
In addition, according to this running characteristic, the driver performs intensive pedaling in the crankshaft rotation angle range of 90 ° to 180 °, which is the latter half of the pedaling cycle, and light pedaling with less load in the first half of 0 ° to 90 °. Since it is sufficient to concentrate on gaining speed, it is possible to perform a sharp driving operation that is free from simple repeated operations, and to reduce fatigue during long-distance driving.
[0038]
Further, when there is no eccentric gear, the feeling of burden in traveling in the second half of the pedaling cycle of 90 ° to 180 ° is large because the angular velocity is constant and torque generation is gradually reduced (see FIGS. 3 and 8). (Dashed line) This is not only a torque characteristic but also a load to lift a foot opposite to the foot in charge of pedaling is added at this time, which increases the physical burden on the driver. According to the pseudo shift mode setting of the present invention, the torque generation during this period is increased, so there is little fatigue even with a load for lifting the opposite foot.
[0039]
In the above description, “standard setting” and “pseudo transmission mode setting” have been described as the setting of the bicycle running characteristics according to the present invention, but the relationship between the crankshaft rotation angle and the tension side drive chain path length, in other words, the crankshaft Various settings can be made by arbitrarily changing the relationship between the rotation angle and the crank arm position.
[0040]
Further, in order to change the setting of the bicycle running characteristics according to the present invention, the setting change is performed by inserting and removing the lock pin 10 using the eccentric gear 4 with a variable mechanism configured as shown in FIG. However, any configuration can be adopted as the setting change means.
[0041]
For example, the tip of the switching lever 15 as shown in FIGS. 10 and 11 is rotatably connected to the movable rotating shaft 17 of the eccentric gear 4 and the intermediate point thereof is pivotally supported by the fulcrum 16 so that the driver However, by operating the switching lever 15, the rotation shaft 17 of the eccentric gear 4 may be moved so that the positions of the crank arms 7 a and 7 b can be rotated relative to the crank shaft. . 10A and 10B show the dead point positions of 45 ° and 135 ° in the standard setting corresponding to FIGS. 2A and 2B, and the switching lever 15 is centered on the fulcrum 16 from this standard setting. As shown in FIGS. 11 (A) and 11 (B), the pseudo shift mode setting corresponding to FIGS. 7 (A) and 7 (b) can be obtained by rotating the counterclockwise direction in FIG.
[0042]
Although several embodiments of the present invention have been described in detail with reference to the drawings, the present invention is not limited thereto, and various modifications can be made within the scope of the invention described in the claims. I can take it. For example, a planetary gear can be used in place of the eccentric gear 4 as an intermediate eccentric idle gear for periodically changing the tension side drive chain path length.
[0043]
【The invention's effect】
As described above, according to the present invention, the crankshaft, the pair of crank arms and the crank chain gear that rotate integrally with the crankshaft, and the rear that rotates coaxially with the rear wheel hub. In a bicycle crank drive chain device including a chain gear and a drive chain stretched between a crank chain gear and a rear chain gear, the cycle is half the rotation cycle of the crankshaft in the tension side path of the drive chain. By meshing with the drive chain via an operating eccentric middle idle gear, the tension side chain path length is periodically changed to change the angular speed of the running crankshaft. The driver's linear pedal depression force can be converted into an optimal torque characteristic that matches the driving load condition. It can be significantly improved click conversion efficiency.
[0044]
According to the present invention, since circular gears can be used for all gears including the eccentric intermediate idle gear, the manufacturing cost can be reduced, and the disadvantages of using non-circular gears such as elliptical gears for the crank chain gear. Can be eliminated.
[0045]
Furthermore, according to the present invention, the degree of freedom in setting the number of teeth of each gear, the eccentric amount of the eccentric intermediate idle gear, the eccentric shaft angle with the crank arm, etc. is great, and the effective crank angle is set to 30 ° to 150 after top dead center. Compared to the range of about 90 ° between 45 ° and 135 °, the effective crank angle in the case of the conventional circular crank chain gear system can be expanded to the range of about 120 ° between A significant improvement effect can be obtained.
[0046]
Further, according to the present invention, the correlation between the crankshaft rotation angle and the tension side drive chain path length or the bicycle running characteristics can be arbitrarily set, and the setting according to the load state and the driver's preference during bicycle running It can be set to perform a pseudo-shift operation without attaching a transmission gear, and by adding a simple transmission gear of about 2 to 3 steps, further running performance is improved. Can be achieved.
[Brief description of the drawings]
FIG. 1 is a conceptual configuration diagram of a bicycle crank drive chain device according to the present invention.
FIG. 2 is an apparatus configuration diagram showing a more specific embodiment of the present invention as a standard setting, in which FIG. (A) shows a tension side drive chain when the tension side drive chain becomes the shortest path, and FIG. It is a state diagram when a chain becomes the longest path.
FIG. 3 is a graph showing a relationship (A) between a crankshaft rotation angle and a crankshaft angular velocity and a relationship (B) with a rear wheel drive torque in the presently set embodiment of the present invention.
FIG. 4 is a graph showing torque curves of the case without the eccentric gear shown in FIG. 3B (broken line) and the case of the embodiment of the present invention (solid line) together with their peaks.
FIG. 5 is an explanatory diagram of each state at a crankshaft rotation angle of 45 ° (A), 135 ° (B), and 90 ° (C) in the presently set embodiment of the present invention.
6 is a cross-sectional view (A) and a plan view (B) of the eccentric gear shown in the embodiment of FIG. 2. FIG.
FIG. 7 is an apparatus configuration diagram of the embodiment of the present invention in which the pseudo transmission mode is set. FIG. 7A shows the shortest path of the tension side drive chain, and FIG. 7B shows the longest path of the tension side drive chain. It is a state diagram when becoming.
FIG. 8 is a graph showing a relationship (A) between a crankshaft rotation angle and a crankshaft angular velocity and a relationship (B) with a rear wheel drive torque in the embodiment of the present invention set to a pseudo shift mode.
FIG. 9 is an explanatory diagram of each state when the crankshaft rotation angles are 45 ° (A) and 135 ° (B) in the embodiment of the present invention in which the pseudo transmission mode is set.
FIG. 10 is a device configuration diagram when the embodiment using a switching lever as a bicycle travel characteristic setting changing means is set as a standard setting, and FIG. 10 (A) shows when the tension side drive chain becomes the shortest path. (B) is a state diagram when the tension side drive chain becomes the longest path.
FIG. 11 is an apparatus configuration diagram when the embodiment of FIG. 10 is set to the pseudo transmission mode. FIG. 11A shows the tension side drive chain when the tension side drive chain becomes the shortest path, and FIG. 11B shows the tension side drive chain. It is a state diagram when becomes the longest path.
FIG. 12 is an explanatory diagram showing pedaling operation during bicycle driving.
FIG. 13 is a diagram showing the relationship between the rotation of the crankshaft and the change in the effective crank length associated therewith.
FIG. 14 is a conceptual configuration diagram of a bicycle crank drive chain device when the crank chain gear is an elliptical gear based on the prior art.
[Explanation of symbols]
1 Chain crank gear
2 Rear chain gear
3 Drive chain
4 Eccentric gear
5 Tension device
6 Rear wheel hub
7a, 7b Crank arm
8a, 8b pedal
9 Eccentric gear unit
10 Lock pin (Rotating shaft of eccentric gear)
11 Engagement hole
12 Ball bearing
13 Bearing
14 Spring
15 Switching lever
16 fulcrum
17 Rotating shaft of eccentric gear

Claims (5)

Between the crankshaft, a pair of crank arms and crank chain gears that rotate coaxially with the crankshaft, a rear chain gear that rotates coaxially with the rear wheel hub, and between the crank chain gear and the rear chain gear In the crank drive chain device for a bicycle provided with a drive chain stretched on the drive chain, an eccentric intermediate idle gear that operates at a half cycle of the rotation speed of the crankshaft is interposed in the drive-side tension path of the drive chain. A bicycle crank drive chain device characterized in that, by engaging, a chain side chain path length is periodically changed to change an angular speed of a running crankshaft. The bicycle crank drive chain device according to claim 1, wherein the eccentric intermediate idle gear is configured as a circular gear having half the number of teeth of the crank chain gear. When one crank arm is located at the top dead center and the bottom dead center during the 180 ° rotation of the crankshaft, the crankshaft rotation angle is 0 ° and 180 °, respectively, and the tight chain is at a crankshaft rotation angle of 45 °. The bicycle crank drive chain according to claim 1 or 2, wherein the first setting is adopted in which the path is the shortest and the tight chain path is the longest when the crankshaft rotation angle is 135 °. apparatus. When one crank arm is located at the top dead center and the bottom dead center during the 180 ° rotation of the crankshaft, the crankshaft rotation angle is 0 ° and 180 °, respectively, and the tight chain is at the crankshaft rotation angle of 0 °. The bicycle crank drive chain according to claim 1 or 2, wherein the second setting is adopted in which the path is the shortest and the tight chain path is the longest when the crankshaft rotation angle is 90 °. apparatus. When one crank arm is located at the top dead center and the bottom dead center during the 180 ° rotation of the crankshaft, the crankshaft rotation angle is 0 ° and 180 °, respectively, and the tight chain is at a crankshaft rotation angle of 45 °. The first setting that the path is the shortest and the tension side chain path is the longest when the crankshaft rotation angle is 135 °, and the tension side chain path is the shortest when the crankshaft rotation angle is 0 ° and the crankshaft rotation The setting changing means for enabling a plurality of settings including a second setting that makes the tension side chain path the longest when the angle is 90 ° is provided. Crank drive chain device for bicycles.

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