JPH01237283A - Bicycle - Google Patents

Abstract

PURPOSE:To realize a multipurpose bicycle with a simple structure by installing two sprockets having different diameters on each of front and rear gears making the gear ratio of a front-gear small-diameter sprocket to a rear-gear large- diameter sprocket approx. 1 suited to a trial match while making the other gear ratio suited to ordinary traveling. CONSTITUTION:Two sprockets 8-11 are installed on each of a front gear 1 and a rear gear 2 and, when a chain 2 is put around the small-diameter sprocket 8 of the front gear and the large-diameter sprocket 9 of the rear gear, the gear ratio is made approx. 1, obtaining a gear ratio suited to a trial match or a bicycle motocross match. As the chain is put around the large-diameter sprocket 10 of the front gear and the small-diameter sprocket 11 of the rear gear, the gear ratio is approx. 2.3, obtaining a gear ratio suited to ordinary general traveling. Thus, one bicycle can be made a multipurpose bicycle with a simple structure.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a bicycle configured to be used both as a general vehicle and as a trial competition vehicle.

[Conventional technology]

Recently, various sports competitions involving bicycles are becoming more and more contradictory, and the representative ones include bicycle motocross (BMX), which competes to overcome rough roads, and competitions such as steep slopes and convex circuits that are difficult for the country to drive on. There are trial competitions to test driving skills. Usually, in these competitions, specially designed bicycles made for the competition are used. 1llll, and each competition event has running performance that is consistent with the content of the competition. Among these, the bicycles used in the above trial competitions are particularly distinctive in that the gear ratio between the front and rear gears is very small compared to other bicycles. The ratio is set to approximately l. This makes it possible to easily generate a large drive torque when driving up steep slopes. In addition, since trial competitions require the ability to adjust the bicycle's progress very slightly, the ratio of the amount of rotation of the wheels to the amount of rotation of the crank is made smaller than that of other bicycles to finely adjust the distance traveled. It also has the meaning of making it easier to do so.

[Problem to be solved by the invention]

By the way, the use of a trial competition horse-drawn carriage whose gear ratio is set to approximately l in this way is limited to use in trial competitions, and is also a bicycle that is not suitable for -a running. In other words, the wheels rotate only approximately once when the crank is rotated once, so if the bicycle is used for general driving, it will place a heavy physical burden on the rider. For this reason, when competitors head to the stadium, they usually do not use the trial competition itself, but rather load a trial competition horse into a car and drive to the competition venue. However, having to use a car every time is inconvenient, and is especially troublesome when a competition is held nearby. The present invention was devised under the above circumstances, and can also be used in the trial competitions mentioned above.
The purpose is to provide a bicycle with a wide range of uses that can also be used for riding.

[Means to solve the problem]

In order to solve the above problem, the present invention takes the following technical measures. That is, in the bicycle according to the present invention, the front gear and the rear gear on which the chain is wound are each constructed with two different diameter sprockets, and the gear ratio of the small diameter sprocket of the front gear and the large diameter sprocket of the rear gear is set as follows. In addition to determining that the latter rotates approximately once when the latter rotates once, the sum of the number of teeth of the small-diameter sprocket of the front gear and the large-diameter sprocket of the rear gear, and the teeth of the large-diameter sprocket of the front gear and the small-diameter sprocket of the rear gear are determined. The sprocket is characterized in that the size of each of the sprockets is determined so that the sum of the numbers is approximately equal.

[Effect]

The size of each sprocket of the front and rear gears is such that the sum of the number of teeth of the small diameter sprocket of the front gear and the large diameter sprocket of the rear gear is approximately equal to the sum of the number of teeth of the large diameter sprocket of the front gear and the small diameter sprocket of the rear gear. It is determined to become. Therefore, there are two ways to hook the chain to the front and rear gears: to hook it to the small diameter sprocket of the front gear and the large diameter sprocket of the rear gear, or to hook it to the large diameter sprocket of the front gear and the small diameter sprocket of the rear gear. be able to. With a chain running around the small diameter sprocket of the front gear and the large diameter sprocket of the rear gear, the gear ratio between the two is determined so that when the small diameter sprocket makes one revolution, the large diameter sprocket makes almost one revolution. There is. In other words, when the chain is hung in this way, the gear ratio between the front gear and the rear gear is approximately 1, which is
This is the same as the gear ratio setting in the trial racing horse carriage explained in the section ``Prior Art''. In addition, the gear ratio of the small diameter sprocket of the front gear and the large diameter sprocket of the rear gear is approximately 1, which means that the ratio of the number of teeth on both sides is approximately 1:l, and the number of teeth on the sprocket is approximately 1:1. It corresponds to the size (larger diameter). In other words, since the small-diameter sprocket of the front gear and the large-diameter sprocket of the rear gear are almost the same in size, the large-diameter sprocket of the front gear is made larger than the small-diameter sprocket of the rear gear, and the gear ratio of the former to the latter is It can be set to a value larger than 1, which is suitable for general driving. Therefore, by setting the gear ratio of the large-diameter sprocket of the front gear and the small-diameter sprocket of the rear gear to the above-mentioned values suitable for general riding, the bicycle of the present invention can be configured such that when a chain is attached to each of the above-mentioned sprockets of the front and rear gears, This is a bicycle that can be easily ridden in general.

【effect】

As described above, in the bicycle according to the present invention, when a chain is attached to the small-diameter sprocket of the front gear and the large-diameter sprocket of the rear gear, the gear ratio becomes suitable for trial competitions, while the large-diameter sprocket of the front gear If a chain is attached to the diameter sprocket and the small diameter sprocket of the rear gear, the bicycle can be easily ridden in general. Therefore, if the present invention is applied to a trial competition, by appropriately changing the chains for the front and rear gears, when heading to the competition venue, it is possible to ride the trial competition itself to the destination. When participating in a competition, it can be used as the original competition type.

[Explanation of Examples]

This example shows a case where the present invention is applied to a trial competition car as shown in FIG. 5, and this will be specifically explained below with reference to the drawings. As shown in FIG. 2, the front gear l includes left and right cranks 6 provided at both ends of the crankshaft 5 of the hanger portion 4, respectively.
．． It is fixedly attached to one side of 6. on the other hand,
The rear gear 2 is constituted by a freewheel attached to one end of the rear hub 7, as shown in FIG. In the present invention, as shown in FIGS. 1 to 3, the front gear 1 and the rear gear 3 each include two sprockets of different diameters. The size of each sprocket of each gear 1.2 is the sum of the number of teeth of the small diameter sprocket 8 of the front gear 1 and the large diameter sprocket 9 of the rear gear 3, and the large diameter sprocket 10 of the front gear 1 and the number of teeth of the large diameter sprocket 9 of the rear gear 3. 3 small diameter sprocket ll
The number of teeth is determined to be approximately equal, such as the sum of the number of teeth. Therefore, the chain 2 is attached to the front gear l and the rear gear 3, as shown by the two-dot chain line in FIG. (Hereinafter, this way of hanging the chain is called chain hanging for small gear ratio.) As shown by the dashed line in Fig. 1, the large diameter sprocket 10 of the front gear 1 and the small diameter sprocket 11 of the rear gear 3 are connected. When hanging the chain (hereinafter, this method of hanging the chain will be referred to as the chain hanging for large gear ratios). Further, in the present invention, when the small-diameter sprocket 8 of the front gear 1 rotates once while the small-diameter chain is engaged, the small-diameter sprocket 9 of the rear gear 3 rotates approximately once. The gear ratio of the sprocket 8 to the large diameter sprocket 9 is determined. That is, when a small gear ratio chain is attached, the gear ratio of front gear 1 to rear gear 3 becomes approximately 1, which is a gear ratio setting suitable for a trial competition. Further, since the size of the sprocket corresponds to the number of teeth thereof, the small diameter sprocket 8 of the front gear 1 and the large diameter sprocket 9 of the rear gear 3 are approximately the same in size. Therefore, the large diameter sprocket 10 of the front gear l is connected to the rear gear 3.
The gear ratio of the former to the latter can be made larger than 1, which is suitable for general driving. Specifically, in this example, the number of teeth of the small diameter sprocket 8 of the front gear 1 and the large diameter sprocket 9 of the rear gear 3 are set to 24T and 2.
I set it to 0T. These numbers of teeth are values that are generally adopted in trial competitions so that the size of the trial competition can be taken into account and a gear ratio suitable for the content of the competition can be obtained. Also, the large diameter sprocket 10 of the front gear l has 3 teeth.
The sprocket number 7 is used for the 07 sprocket, and a sprocket with a number of teeth of 13T is used for the small diameter sprocket 11 of the rear gear 3. Therefore, when the large gear ratio chain is used, the gear ratio of front gear 1 to rear gear 3 becomes a value (approximately 2.3) that allows -Jla traveling to be carried out easily. In addition, originally, the number of teeth of the above small diameter sprocket) 11 was changed to 1.
4T is the sum of the number of teeth of each front and rear sprocket 8.9 when a small gear ratio chain is used, and the sum of the number of teeth of each front and rear sprocket 10, 11 when a large gear ratio chain is used. However, as shown in Figure 1, it is preferable to have the same number of gears 1 and 3 between the front and rear gears of the chain 2. The ratio of the inclination in the vertical direction of the straddling portion is larger when a chain is attached for a large gear ratio than when a chain is attached for a small gear ratio, so the sprocket 7 with the number of teeth of 14T is attached to the small diameter sprocket 11. If a large gear ratio chain is used, the tension on chain 2 will become too tight, impairing the smoothness of the chain drive between the front and rear gears 1 and 3, and causing problems such as gear noise. It is predicted that this will happen. Therefore, in this example, the small diameter sprocket 11 of the rear gear 3 is of the size described above. Conversely, the number of teeth of the small diameter sprocket 11 of the rear gear 3 is set to 1.
37, as mentioned above, it is predicted that the chain 2 will become slack when the chain is hooked for a large gear ratio. Therefore, in this example, as shown in FIG. 1, a tensioner 12 is provided, which is used when the chain is hooked to a large gear ratio. This is chainstay 13
The frame mounting fixed to section 14 and this mounting to section 1
4, the upper end is swingably supported, and the lower end is supported by chain 2.
The tensioner arm 16 rotatably supports the tensioner arm 1J15 which is hung on the tensioner arm 1J15. Further, the tensioner arm 16 is biased to rotate clockwise in the figure by a spring 17 built into the frame mounting section. This biasing force absorbs the slack in the chain 2, and
When the tensioner is not in use, it is possible to take a retracted position as shown by the imaginary line in the figure, so that the tensioner 12 and the chain 2 will not come into contact with each other inadvertently when a chain for a small gear ratio is hooked. That's what I do. Note that the tensioner arm 16 may be biased counterclockwise instead of clockwise. In this case, when hanging the chain 2 on the tension pulley 15, the chain 2 must be lowered onto the tension pulley 15. Chain 2 will work just by applying it from the side.
The replacement work becomes easier. In addition, in this case, when the tensioner is not in use, the tensioner arm 16 is
It is preferable to incorporate a stopper mechanism into the tensioner 12 so that the tensioner 12 can be held at the retracted position as shown by the curved line in the figure. Furthermore, as a method for adjusting the tension of the chain 2, the rear hub shaft holding groove may be made sufficiently long in the front-rear direction so that the position of the hub shaft within the hub shaft holding groove can be changed. In this case, the tension of the chain 2 can be appropriately set to an appropriate level by adjusting the distance between the axes of the front gear and the rear gear. In addition, in this example, as shown in FIG. 4, the small diameter sprocket 8 of the front gear 1 and the large diameter sprocket 9 of the rear gear 3 are arranged so that their positions in the crankshaft direction, hubshaft direction, and vehicle width direction are aligned. The large-diameter sprocket 10 of the front gear 1 and the small-diameter sprocket 11 of the rear gear 3
are arranged on the outside with their axial positions coincident. This makes it possible to obtain a straight chain line both when using a chain for small gear ratios and when using a chain for large gear ratios. ．． The smoothness of the chain drive between the three parts is ensured. In the trial competition bundle of this example having the above configuration, the gear ratio of the front gear 1 to the rear gear 3 becomes the gear ratio suitable for the trial competition as described above when a small gear ratio chain is attached. When a large gear ratio chain is attached, the gear ratio becomes suitable for general driving. therefore,
When heading to the stadium, by using a chain hook for a large gear ratio, you can ride the trial race vehicle itself and head to the stadium, which is very convenient. In addition, at the stadium, if the chain 2 is replaced with a small gear ratio chain hook, it can be used as a bundle for the original trial competition. Moreover, in this example, the chain tension can be set to an appropriate level and a straight chain line can be obtained, regardless of whether a large gear ratio chain is used or a small gear ratio chain is used. The drive performance is always good because we have devised ways to make it possible. In this example, a transmission is not specially provided, so loosen the hub nut of the rear hub 7, remove the rear hub 7 from the bicycle frame, or shift its position to tighten the chain. Particularly, the scope of the present invention is
It is not limited to the above-mentioned embodiments, and for example,
The size of each sprocket for the front and rear gears can be determined as appropriate depending on the desired gear ratio, the size of the bicycle, etc. Also, by installing a transmission, it is possible to easily change the chain. It may be possible to do so.

[Brief explanation of the drawing]

FIG. 1 is a side view of a bicycle chain drive mechanism according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line nn in FIG. 1, and FIG. 3 is a sectional view taken along line m-m in FIG. 4 is a diagram schematically showing the positional relationship of each sprocket of the front and rear gears according to the embodiment when viewed from the direction of arrow A in FIG. 1, and FIG. FIG.

Claims (1)

[Claims] (1) The front gear and the rear gear, on which the chain is run, each consist of two sprockets of different diameters, and the gear ratio of the small diameter sprocket of the front gear and the large diameter sprocket of the rear gear is set so that when the former makes one rotation, The latter should rotate approximately once, and the sum of the number of teeth of the small diameter sprocket of the front gear and the large diameter sprocket of the rear gear, and the sum of the number of teeth of the large diameter sprocket of the front gear and the small diameter sprocket of the rear gear should be approximately equal to each other. A bicycle characterized in that the sizes of each of the sprockets are determined so that the number of sprockets is equal.