JP6739125B2 - Folding bicycle - Google Patents

Description

The present invention relates to a folding bicycle.

If the nearest station to the workplace does not have a bicycle parking lot and the bus is inconvenient, one-way 20-30 minutes from the nearest station will lead you to the workplace. In such cases, it would be convenient to be able to take a folding bicycle, take a train, and travel from the station to the workplace by bicycle.

Examples of conventional folding bicycles include a rear wheel drive type disclosed in Patent Document 1 and a front wheel drive type disclosed in Patent Document 2. Further, Patent Document 3 proposes a lightweight and small-sized folding bicycle in consideration of carrying.

JP, 2005-8053, A Japanese Utility Model Publication No. 7-19084 JP, 2003-34283, A

In order to carry a folding bicycle for daily commuting or attending school, it is desired to reduce the weight of the folding bicycle and to reduce the size of the folding bicycle. However, in the rear wheel drive type folding bicycle disclosed in Patent Document 1, the rear wheel is large. It is not suitable for carrying on a daily basis because it does not become so small even when folded in, and no consideration is given to weight reduction.

In the front wheel drive type folding bicycle disclosed in Patent Document 2, although the rear wheel is smaller than the front wheel, when the front wheel is steered since the pedal is provided above the front wheel, the pedal is difficult to bend along with the pedal. There are challenges. Further, due to the above-mentioned structure, there is a problem that the entire bicycle is bulky and is bulky in the height direction even when folded.

Further, in the case of a lightweight and small-sized folding bicycle that considers portability, such as the folding bicycle described in Patent Document 3, most of them have small diameters of both wheels, which impairs traveling performance such as difficulty in climbing over steps. There were many things.

That is, considering that the folding bicycle is carried every day when commuting, the weight of the folding bicycle is preferably 3 kg to 5 kg. Further, from the viewpoint of running performance, the wheel diameter is preferably 14 inches or more. However, the larger the wheel, the heavier the bicycle as a whole, which hinders weight reduction and size reduction. Most of the 14-inch folding bikes currently on the market weigh more than 15 kg, which is too heavy to carry on a daily basis and bulky even when folded. Therefore, it is possible to reduce the size by reducing the diameter of the wheel to about 8 inches, but as described above, if the wheel is small, it is easy to get caught in a slight step, which makes it difficult to run smoothly and pedals. Due to the small diameter of the wheels, the amount of forward movement is small, which hinders running. Also, most of the 8-inch folding bicycles on the market are about 7-8 kg, which is too heavy to carry every day. Therefore, it is conceivable to improve the material to reduce the weight, but this is too costly and not realistic.

As described above, the conventional folding bicycle that can be normally run for commuting has a large wheel diameter and is bulky even when folded. In addition, a folding bicycle having smaller wheels in order to reduce bulk has a problem in running performance, and there is a trade-off relationship between bulkiness and running performance. Further, the conventional folding bicycle has a problem that it is heavy to carry every day regardless of the size of the wheels.

The present invention aims to provide a folding bicycle that can be folded smaller.

Another object of the present invention is to provide a folding bicycle that can be made lighter.

Another object of the present invention is to provide a folding bicycle that is smaller, more suitable for weight saving, and has sufficient running performance.

As a result of addressing the above problems, the present inventor first came to the conclusion that the front wheel must be sufficiently large in consideration of climbing over a step, and considering the folded shape on top of that, in order to reduce the weight and size, It turns out that it is necessary to reduce the diameter of the rear wheel.

Next, in the case of a folding bicycle with such a shape, it is best to adopt the method of driving the front wheel with a large diameter as the driving method, and for comfortable steering performance, drive force to the front wheel without difficulty. I thought that it was necessary to devise a transmission gear.

A folding bicycle according to the present invention includes a front wheel, an operating portion including a handle, a frame that rotatably holds the operating portion, a crank pivotally supported at an intermediate portion of the frame, and a pivotal support at a rear end of the frame. And a rear wheel that is formed on the frame, the frame being provided with a first hinge mechanism for folding the frame about a first turning axis. When the frame is folded about the first turning axis, The rear wheel is positioned between the front wheel and the rotation axis of the crank.

The rear wheel is smaller than the front wheel and is a bicycle dedicated to rowing.

According to the folding bicycle of the present invention, when the frame is folded around the first turning axis, the rear wheel is positioned between the front wheel and the rotation axis of the crank, so that the folding bicycle can be folded compactly. Further, since the bicycle is exclusively for rowing, no saddle is required, and the rear wheel is smaller than the front wheel, so that the weight of the folding bicycle can be reduced and the folding bicycle can be compactly folded.

Also, since the front wheels having a wheel diameter equivalent to that of a general folding bicycle can be used, the vehicle can travel without being restricted by the unevenness or steps of the road, and the front wheels are the driving wheels. You can secure the amount of advance.

The conceptual diagram of the folding bicycle which concerns on 1st Embodiment of this invention. It is a functional schematic diagram of the folding bicycle shown in FIG. 1, (a) is a figure which shows the expanded state, (b) is a figure which shows the folded state. FIG. 2 is a perspective view showing a gear transmission device included in the folding bicycle shown in FIG. 1 and a peripheral structure thereof. The perspective view which shows the connection part of the folding bicycle shown in FIG. 1, and its surrounding structure. FIG. 4 is a partial cross-sectional plan view showing the gear transmission shown in FIG. 3. It is an enlarged perspective view which shows the principal part of the gear transmission shown in FIG. 3, (a) is the basic state, (b) is a figure which shows a turning state. FIG. 4 is a perspective view showing a first gear included in the gear transmission shown in FIG. 3. Explanatory drawing explaining the turning of the 2nd gearwheel with respect to the 1st gearwheel in the gear transmission of FIG. It is a functional schematic diagram of the folding bicycle which concerns on 2nd Embodiment of this invention, (a) is a figure which shows the unfolded state, (b) is a figure which shows the folded state. The schematic front view of the folding bicycle which concerns on 3rd Embodiment of this invention. The principal part expansion perspective view which shows the operation part of the folding bicycle shown in FIG. It is a functional schematic diagram of the folding bicycle which concerns on 4th Embodiment of this invention, (a) is a figure which shows the unfolded state, (b) is a figure which shows the folded state. The conceptual diagram explaining the transmission mechanism in the folding bicycle shown in FIG. The functional schematic diagram of the folding bicycle which concerns on 5th Embodiment of this invention. FIG. 15 is a functional schematic diagram of an operation unit in the folding bicycle shown in FIG. 14. The top view which shows the modification of a handle. The principal part conceptual diagram which shows the modification of the folding bicycle of this invention. It is a top view showing a modification of a crank, (a) is a figure showing the state where it was developed, and (b) is a figure showing the state where it was folded. The top view which shows the modification of a pedal. The perspective view which shows the modification of a 1st gearwheel. The top view which shows the modification of the gear transmission shown in FIG. FIG. 22 is an explanatory diagram for explaining the turning of the second gear with respect to the first gear of the gear transmission shown in FIG. 21.

[First Embodiment]
Hereinafter, a folding bicycle according to a first exemplary embodiment of the present invention will be described with reference to the accompanying drawings. Referring to FIGS. 1 and 2, a folding bicycle (hereinafter also referred to as a “bicycle”) 1 illustrated is a front-wheel-drive type that travels by transmitting rotation of a crank 6 to front wheels 3, and has a saddle-free rowing. It is a dedicated bicycle.

The bicycle 1 includes the above-described front wheel 3, an operation unit 4 for operating the front wheel 3, a frame 5, a crank 6 to which the pedal 2 is attached, and a drive transmission mechanism 7 that transmits the rotation of the crank 6 to the front wheel 3. And a rear wheel 8. In the present embodiment, the front, rear, left, and right directions are based on the traveling direction of the bicycle 1.

The operation unit 4 includes a handle 41 gripped by a user, a support shaft portion 42 extending downward from the handle 41, a front fork 43 located below the support shaft portion 42, a support shaft portion 42, and a front fork 43. And a connecting portion 44 (see FIG. 3) for connecting. The handle 41 is for performing a handle operation for changing the direction of the front wheel 3, and has a substantially U shape in a plan view. Further, a pair of brake levers (not shown) are provided on both left and right sides of the handle 41. The front wheel 3 is rotatably supported at the lower end of the front fork 43.

The frame 5 extends in the front-rear direction, and a shaft support portion 51 that rotatably holds the operation portion 4 (upper side portion of the front fork 43) is provided at a front end of the frame 5. A crank 6 is rotatably supported at a middle portion of the frame 5 about a rotary shaft R1 extending in the left-right direction, and a rear wheel 8 is rotatably supported at a rear end thereof.

The drive transmission mechanism 7 includes a sprocket (chain ring) 71 that rotates integrally with the crank 6, a gear transmission M (FIG. 3), a first chain 72 that transmits a rotational force from the sprocket 71 to the gear transmission M, and a rotation. The second chain 73 that transmits the force from the gear transmission M to the front wheels 3 is configured such that when the pedal 2 is pedaled, the rotational force thereof is transmitted to the front wheels 3 via the drive transmission mechanism 7. .. A metal shaft or a shaft module having an internal transmission mechanism may be used for the rotation shaft R1 of the crank 6. Details of the gear transmission M will be described later.

Further, in the present embodiment, hinge mechanisms H1 and H2 are provided to enable the bicycle 1 to be folded from the deployed state (running state) shown in FIG. 2A to the state shown in FIG. 2B. .. The hinge mechanisms H1 and H2 are widely used in general folding bicycles, and their configurations are well known, so detailed description thereof will be omitted.

The hinge mechanism H1 (second hinge mechanism) makes the operation portion 4 (the support shaft portion 42 in the present embodiment) foldable, and is provided slightly above the connecting portion 44 as shown in FIG. There is. That is, the support shaft portion 42 has the upper support shaft portion 42A and the lower support shaft portion 42B connected to the upper support shaft portion 42A via the first hinge mechanism H1, and by loosening the hinge mechanism H1. 2, the upper support shaft portion 42A can be folded toward the sprocket 71 in the clockwise direction in FIG. 2 so as to be folded around the pivot axis P1 extending in the left-right direction (direction perpendicular to the paper surface of FIG. 2). When the operation portion 4 (support shaft portion 42) is folded around the turning axis P1 in this manner, the upper support shaft portion 42A extends rearward along the frame 5, and the handle 41 is positioned near the sprocket 71. In addition, the left and right ends of the handle 41 are located on both the left and right sides of the sprocket 71.

The hinge mechanism H2 (first hinge mechanism) makes the frame 5 foldable, and is provided slightly behind the sprocket 71. That is, the frame 5 has a front frame portion 5A that extends rearward from the shaft support portion 51 and pivotally supports the sprocket 71, and a rear frame portion 5B that pivotally supports the rear wheel 8, and the rear frame portion 5B has a hinge mechanism. It is connected to the front frame portion 5A via H2, and in the present embodiment, the front frame 5A is set longer than the upper support shaft portion 42A. When the hinge mechanism H2 is loosened, the rear frame portion 5B can be swung forward in the clockwise direction in FIG. 2 to be folded around the turning axis P2 (FIG. 2B) extending in the left-right direction. When the frame 5 is folded around the turning axis P2 in this way, the rear frame portion 5B extends from the hinge mechanism H2 toward the front wheel 3, and the rear wheel 8 is between the front wheel 3 and the rotation axis R1 of the crank 6 (this embodiment). In the form, in particular, it is located between the front wheel 3 and the sprocket 71 ). The hinge mechanism H2 is configured such that the rear frame portion 5B can be folded forward (clockwise in FIG. 2) as shown, but not in the opposite direction.

Here, the diameter of the front wheel 3 is preferably 14 to 16 inches. If the front wheel 3 is smaller than 14 inches, it tends to be caught by a small step, which makes smooth running difficult. On the other hand, if it exceeds 16 inches, it will hinder downsizing and weight reduction. The rear wheels 8 are smaller than the front wheels 3 and preferably have a diameter of 4-8 inches. By making the rear wheel 8 smaller than the front wheel 3 in this way, the weight of the bicycle 1 as a whole can be reduced and the bicycle 1 can be folded compactly. Further, since the rear wheels 8 follow the front wheels 3 and rotate, even if the rear wheels 8 are small, the running performance does not deteriorate significantly.

Next, the gear transmission M will be described. With reference to FIGS. 3 to 5, the gear transmission M includes a sprocket 12A on the upstream side on which the first chain 72 is spanned, a gear train T, and a sprocket on the downstream side on which the second chain 73 is spanned. 12B, and the gear train T is composed of three gears (first gear 13, second gear 14, third gear 15) that mesh with each other. The first gear 13 rotates integrally with the sprocket 12A, and the third gear 15 rotates integrally with the sprocket 12B. Therefore, the rotation of the pedal 2 is transmitted from the first chain 72 to the sprocket 12A, and further transmitted to the front wheel 3 via the gear train T, the sprocket 12B, and the second chain 73.

The sprocket 12A and the first gear 13 are rotatably supported by a pair of first supporting members 61, and the first supporting member 61 is connected to the frame 5. The second gear 14, the third gear 15, and the sprocket 12B are rotatably supported by a connecting portion 44 serving as a second support member. More specifically, the connecting portion 44 includes an upper plate member 44a provided at a lower end of the support shaft portion 42, a lower plate member 44b provided at an upper end of the front fork 43, an upper plate member 44a and a lower plate member 44b. And a pair of left and right side plate members 44c for connecting to each other. The gear train T and the sprockets 12A and 12B are omitted in FIG. Shaft holes T1 and T2 are provided in each side plate member 44c, the second gear 14 is rotatably supported by the side plate member 44c via a rotation shaft inserted in the shaft hole T1, and the third gear 15 and the sprocket 12B are It is rotatably supported by the side plate member 44c via a rotary shaft that is inserted through the shaft hole T2.

Therefore, when the user grips the handle 41 and operates the handle, the support shaft portion 42 rotates together with the connecting portion 44 with respect to the frame 5 (the shaft support portion 51 of the frame 5) about the pivot axis P3. Along with this, the second gear 14, the third gear 15, and the sprocket 12B also rotate about the rotation axis P3. That is, when the shaft supporting portion 42 is rotated about the pivot shaft P3 relative to the frame 5 by operating the handle, the second gear 14, the third gear 15, and the sprocket 12B pivotally supported by the connecting portion 44 move to the first position. A state shown in FIG. 6(a) in which the rotary shaft R2 of the first gear 13 and the rotary shaft R3 of the second gear 14 extend in parallel with each other around the rotary shaft P3 with respect to the first gear 13 (hereinafter referred to as "basic state"). 6), the rotation shafts R2 and R3 of the first and second gears 13 and 14 extend in a direction intersecting with each other (hereinafter, referred to as “turning state”). The turning axis P3 extends substantially perpendicular to a plane including the rotation axis R2 of the first gear 13 and the rotation axis R3 of the second gear 14.

With reference to FIGS. 7 and 8, the first gear 13 includes a gear substrate 131 and a plurality of teeth 132 annularly arranged on the outer peripheral surface 131 a of the gear substrate 131. The gear substrate 131 has an expanded cylindrical shape in which the diameter of the central portion in the rotation axis direction D1 is enlarged, and the tooth tips 132a of each tooth 132 have a convex curved cross-section through the rotation axis R2 of the first gear 13. There is. That is, the distance from the rotation axis R2 to the addendum 132a of each tooth 132 is configured to gradually decrease toward the outside of the rotation axis direction D1. In other words, in the cross section passing through the rotation axis R2 of the first gear 13, the contour line of the outer peripheral surface (here, the tooth tip 132a) has a convex shape (convex curved shape). Then, the cross-sectional shape of the tooth tip 132a is set such that the center point of the convex curve of the tooth tip 132a of the first gear 13 is located on or near the turning axis P3 (the turning axis P3 is the first gear 13). The center point of the convex curve of the tooth tip 132a or the vicinity thereof is preferable, and it is more preferable that the center point is located on the turning axis P3. On the other hand, the second gear 14 and the third gear 15 are spur gears. Note that the spur gear as the second gear 14 may have linear tooth tips like a normal spur gear, but in the present embodiment, the spur gear is composed of the second gear 14 and the first gear 13. As shown in FIG. 8, both sides of the tip of the second gear 14 in the tooth width direction are chamfered in order to allow good turning while maintaining the meshed state. The chamfered portion may have an R shape or a convex curve shape, and the shape thereof is not limited as long as it can mesh with the first gear 13.

In such a configuration, when the operation portion 4 is turned (rotated) together with the front wheel 3 by operating the handle, the second gear 14 is centered on the turning axis P3 with respect to the first gear 13 while maintaining the meshing state with the first gear 13. Turn to. At this time, as the second gear 14 turns, the pitch point of the first gear 13 (the portion where the first gear 13 contacts the second gear 14) also changes, and the pitch points that change in this way are continuously changed. The connected virtual line L1 has a curved shape as shown in FIG. 8, and the center point C1 of the curve of the virtual line L1 is located on the turning axis P3.

That is, according to the present embodiment, even if the second gear 14 is turned with respect to the first gear 13 about the turning axis P3, it follows an arc (L1) whose center point C1 is a point on the turning axis P3. Since the pitch points of the first gear 13 and the second gear 14 change, the meshing of the first gear 13 and the second gear 14 can be maintained. Further, since the gear base plate 131 of the first gear 13 has an expanded cylindrical shape with an enlarged central portion, the height of the tooth 132 (center of the tooth 132) in the rotation axis direction D1 is larger than that in the case of the right cylindrical shape. The original bamboo) can be reduced, and the strength of the teeth 132 can be increased.

Further, since the second gear 14 is rotated about the rotation axis P3, the maximum turning angle θ of the second gear 14 can be increased to, for example, about 110° to 120°. Usually, the turning angle of the steering wheel required for traveling on a bicycle is about 90°, which is sufficient.

As described above, since the bicycle 1 according to the present embodiment is of the front-wheel drive type, the running performance is not impaired even if the rear wheel 8 is made small, the weight is reduced, and the bicycle 1 can be folded compactly. it can. Further, since the operation portion 4 can be folded at a position near the shaft support portion 51, the height dimension of the bicycle 1 in the folded state can be reduced. In addition, since the saddle is eliminated, the weight is reduced, and the operation portion 4 does not interfere with the saddle when the operation portion 4 is folded. Therefore, the operation portion 4 (upper support shaft portion 42A) is prevented by the frame 5. The bicycles 1 can be folded so that they come close to each other, and the bicycle 1 can be folded more compactly.

Further, according to the present embodiment, the frame 5 is folded around the turning axis P2 extending leftward and rightward (parallel to the rotation axis R1 of the sprocket 71), so compared with the configuration in which it is folded around the turning axis extending vertically. The strength of the entire frame 5 can be maintained, and the front wheel 3 and the rear wheel 8 do not overlap in the folded state, and the thickness in the width direction (left-right direction) can be reduced.

Further, as shown in FIG. 1, when the bicycle 1 is deployed, since the pedal 2 is located behind the front wheel 3, the pedal 2 can be pedaled in a well-balanced manner without the saddle, and the pedal 2 does not move with respect to the front wheel 3. The height dimension in the folded state can be reduced as compared with the configuration positioned above.

In the present embodiment, the second gear 14 is a spur gear, but the second gear 14 may be a gear having the same shape as the first gear 13. The width W1 of the tooth space may be uniform over the rotation axis direction D1, or may be configured to gradually increase toward the center of the rotation axis direction D1.

In the present embodiment, the sprocket 71, the first chain 72, and the sprocket 12A form a first transmission mechanism, and the third gear 15, the sprocket 12B, and the second chain 73 form a second transmission mechanism. The sprocket 12B and the second chain 73 may be on the positions shown in the drawing or on opposite sides (on the same side as the sprocket 71, the first chain 72, and the sprocket 12).

[Second Embodiment]
Next, a folding bicycle according to the second embodiment of the present invention will be described. Referring to FIG. 9, the folding bicycle 101 shown has substantially the same configuration as the folding bicycle 1 described above, but in the folding bicycle 101 of the present embodiment, the support shaft portion 142 thereof is not folded and the frame 105 is divided into two. It is designed to be folded in place. Hereinafter, in each embodiment, the same reference numerals will be given to the substantially same configurations as those of the first embodiment described above, and the description thereof will be omitted.

More specifically, the operation unit 104 of the bicycle 101 includes a handle 41, a support shaft portion 142 extending downward from the handle 41, a front fork 43, and a connecting portion 44 (which connects the support shaft portion 142 and the front fork 43). 4)). The support shaft portion 142 is substantially the same as the support shaft portion 42 of the first embodiment, but is different in that the hinge mechanism H1 is not provided.

The frame 105 of the bicycle 101 is substantially the same as the frame 5 of the first embodiment, but differs in that a pair of hinge mechanisms H101 and H102 is provided instead of the hinge mechanism H2. The hinge mechanism H101 is provided in the front portion of the frame 5 (in the vicinity of the shaft support portion 51), and the hinge mechanism H102 is provided slightly behind the rotation axis R1 of the sprocket 71 and in front of the rear end of the sprocket 71. Therefore, the frame 105 has a front frame portion 105A including the shaft support portion 51 (see FIG. 1 ), an intermediate frame portion 105B that pivotally supports the sprocket 71, and a rear frame portion 105C that pivotally supports the rear wheel 8. The front frame portion 105A is connected to the intermediate frame portion 105B via the hinge mechanism H101 (second hinge mechanism), and the intermediate frame portion 105B is connected to the rear frame portion 105C via the hinge mechanism H102 (first hinge mechanism). ing.

In this configuration, when the hinge mechanism H101 is loosened, the intermediate frame portion 105B can be swung in the direction approaching the handle 41 (counterclockwise in FIG. 9) about the turning axis P4 extending in the left-right direction. When the frame 5 is folded around the turning axis P4 in this way, the intermediate frame portion 105B extends from the turning axis P4 toward the handle 41, the handle 41 is positioned in the vicinity of the sprocket 71, and the handle 41 is provided on both left and right sides of the sprocket 71. The left and right tip ends of are located. Further, when the hinge mechanism H102 is loosened, the rear frame portion 105C can be swung toward the front wheel 3 (clockwise in FIG. 9) and folded around the turning axis P5 extending in the left-right direction. When the rear frame portion 105C is folded around the turning axis P5 in this way, the rear frame portion 105C extends from the turning axis P5 toward the front wheel 3, and the rear wheel 8 is between the front wheel 3 and the rotation axis R1 of the crank 6 ( In the present embodiment, in particular, the state is located between the front wheel 3 and the sprocket 71).

As described above, also in the bicycle 101 of this embodiment, the same effect as that of the bicycle 1 of the first embodiment can be obtained.

[Third Embodiment]
Next, a folding bicycle according to a third embodiment of the present invention will be described. With reference to FIGS. 10 and 11, the operation unit 204 included in the illustrated folding bicycle 201 includes a pair of left and right handles 241, a pair of support shafts 242 extending downward from the handles 241, a front fork 43, and a support shaft. And a connecting portion 244 that connects the portion 242 and the front fork 43. The connecting portion 244 includes a lower plate member 44b provided on the upper end of the front fork 43, and a pair of left and right side plate members 244c erected on the lower plate member 44b, and the support shaft portion 242 is supported by the side plate member 244c. Has been done. More specifically, each side plate member 244c is provided with shaft holes T1 and T2, and the support shaft portion 242 is centered on the rotary shaft (which supports the third gear 15) inserted through the pair of shaft holes T2. It is configured to be able to turn. Therefore, the rotating shaft corresponds to the hinge mechanism (second hinge mechanism) in the present embodiment. 10 and 11, the gear train T and the sprockets 12A and 12B are omitted.

The support shaft portion 242 is provided with a regulation means (not shown), and the regulation means keeps the standing state as shown in FIGS. 10 and 11. On the other hand, by loosening the restricting means, the pair of support shaft portions 242 pivot about the pivot axis P6 so as to fall rearward. As a result, the operation unit 204 can be folded.

Other configurations are the same as those of the folding bicycle 1 of the first embodiment described above. Therefore, when the operation unit 204 is folded around the turning axis P6 as described above and the frame 5 is folded around the turning axis P2 as shown in FIG. 1, the bicycle 201 becomes the bicycle 1 shown in FIG. Folds in much the same way.

As described above, also in the bicycle 201 of this embodiment, the same effect as that of the folding bicycle 1 of the first embodiment can be obtained. Moreover, since the position of the turning axis P6 can be set slightly below the turning axis P1 in the first embodiment, the folding bicycle 201 can be folded more compactly. In addition, in the present embodiment, since the pair of support shaft portions 242 stand upright in front of the turning axis P1, the connecting portion 244 serves as a stem, and the handle operation can be performed smoothly.

In addition, in the present embodiment, the support shaft portion 242 is configured to be rotatable about the rotation shaft that is inserted through the pair of shaft holes T2, but instead of this, the rotation shaft that is inserted through the pair of shaft holes T1 (first The two gears 14 that support the second gear 14) may be pivotable about a rotation axis, or a rotation axis different from the rotation axis that supports the second gear 14 and the third gear 15 may be pivoted.

[Fourth Embodiment]
Next, a folding bicycle according to a fourth embodiment of the present invention will be described. Referring to FIGS. 12 and 13, in the illustrated folding bicycle 301, when the user pedals the pedal 2, a sensor (not shown) detects the rotation of the crank 6, and the front wheel 3 is detected based on the detection signal from the sensor. The motor M provided in the front wheel 3 is operated and the front wheels 3 are rotated by the power of the motor M. Therefore, in this embodiment, the drive transmission mechanism 7 except the sprocket 71 is omitted.

The bicycle 301 includes an operating unit 304 and a frame 5, and the operating unit 304 includes a handle 41, a support shaft 42 extending downward from the handle 41, and a front fork 43 connected to a lower end of the support shaft 42. .. The connecting portion 44 described above is omitted, and the hinge mechanism H1 is provided slightly above the shaft support portion 51. The structure of the frame 5 is the same as that of the first embodiment. Therefore, by loosening the hinge mechanisms H1 and H2, the bicycle 301 can be folded from the state shown in FIG. 12(a) to the state shown in FIG. 12(b) as in the case of the first embodiment.

Furthermore, in this embodiment, a transmission mechanism for transmitting the rotation of the sprocket 71 to the rear wheel 8 is provided. This transmission mechanism includes two coaxial sprockets S1 and S2 that are rotatably supported by the frame 5, a chain 74 that spans between the sprockets 71 and S1, and a coaxial sprockets S2 and a rear sprocket 81. The two coaxial sprockets S1 and S2 rotate integrally with each other, which is provided with a chain 75 spanned therebetween. With this configuration, when the user steps on the pedal 2, the sprocket 71 rotates, and this rotational movement is transmitted to the rear wheel 8 via the chain 74, the coaxial sprockets S1 and S2, the chain 75, and the rear sprocket 81.

The rotation axes of the coaxial sprockets S1 and S2 are set to coincide with the turning axis P2 of the hinge mechanism H2. Therefore, even if the frame 5 is folded around the turning axis P2, the problem that the chains 74 and 75 are loosened does not occur.

As described above, also in the bicycle 301 of this embodiment, the same effect as that of the folding bicycle 1 of the first embodiment can be obtained.

[Fifth Embodiment]
Next, a folding bicycle according to a fifth embodiment of the present invention will be described. Referring to FIGS. 14 and 15, the illustrated folding bicycle 401 is a rear wheel rudder type, and when the steering wheel is operated, the direction of the rear wheel 8 changes, and the traveling direction of the bicycle 401 can be changed. ..

More specifically, the bicycle 401 includes an operation unit 404 that operates the rear wheel 8 and a frame 405. The operation portion 404 includes a handle 41, a support shaft portion 42 that extends downward from the handle 41, and a connecting portion 45 that connects the support shaft portion 42 and the rear wheel 8. The connecting portion 45 includes a front crank 45a that extends laterally (rightward in the example of FIG. 15) from the support shaft portion 42, a rear wheel rudder shaft 45b that pivotally supports the rear wheel 8 and extends upward from the rear wheel 8, A rear crank 45c extending from the rear wheel rudder shaft 45b to the side opposite to the front crank 45a (left side in the example of FIG. 15), and a rod-shaped link member 45d connecting the front crank 45a and the rear crank 45c in a diagonal shape. Prepare The front and rear ends of the link member 45d are pivotally connected to the front crank 45a and the rear crank 45c, respectively, and can be disassembled into a front portion 45f and a rear portion 45r at an intermediate portion thereof.

The frame 405 is substantially the same as the frame 5 described above, except that the rear support shaft portion 52 is provided at the rear end of the rear frame portion 405B, and the rear wheel rudder shaft 45b rotates on the rear shaft support portion 52. It is supported freely. On the other hand, the front fork 443 is connected to the shaft support 51 so as not to rotate relative to the shaft support 51, and the support shaft 42 is rotatably supported.

In this configuration, when the user operates the handle, the support shaft portion 42 rotates, and accordingly, the front crank 45a turns clockwise (or counterclockwise) in plan view in FIG. Then, the rear crank 45c is pulled (or pushed) by the link member 45d, turns in the opposite direction to the front crank 45a, and the rear wheel rudder shaft 45b rotates. As a result, the direction of the rear wheel 8 changes, and the traveling direction of the bicycle 401 is controlled. Here, the front crank 45a and the rear crank 45c are diagonally connected by the link member 45d so that the operating direction of the handlebar 41 and the direction of the rear wheel 8 are reversed, and the operating direction of the handlebar 41 and the running of the bicycle 401 are reversed. This is to make the directions the same.

Further, in the present embodiment, the sprocket 71 supported by the intermediate portion of the frame 405 and the sprocket 31 of the front wheel 3 are connected by the chain 76, and when the pedal 2 is pedaled, the rotational force of the crank 6 causes the sprocket 71 and the sprocket 71 to rotate. It is transmitted to the front wheels 3 via the chain 76. Therefore, in this embodiment, the drive transmission mechanism 7 except the sprocket 71 is omitted.

Also in this embodiment, since the hinge mechanism H1 is provided on the support shaft portion 42 and the hinge mechanism H2 is provided on the frame 405, the bicycle 401 is shown from the unfolded state shown in FIG. 14(a) to FIG. 14(b). Can be folded into a folded state. When folding the bicycle 401, the link member 45d may be disassembled into a front portion 45f and a rear portion 45r as shown in FIG.

[Example]
In the bicycle 1 according to the first embodiment described above, when the height D1 is about 80 cm and the length D2 is about 120 cm, the height D3 of the bicycle 1 after folding is about 47 cm and the length D4 is about 89 cm. (See FIG. 2). Since the size of a general tennis racket case is 75 cm×32 cm, the bicycle 1 can be carried with a feeling almost the same as that of a tennis racket case.

Although the folding bicycle according to the embodiment of the present invention has been described above with reference to the accompanying drawings, the present invention is not limited to the embodiment and various modifications and corrections can be made without departing from the scope of the present invention. Is.

For example, in each of the above-described embodiments, the handle 41 is substantially U-shaped in a plan view, but it may be linear as in the handle 41' shown in FIG. Further, the handle 41 ′ (or the handle 41) is provided with a joint so that the left and right ends of the handle 41 ′ (handle 41) can turn about the turning axis R9 in a direction in which they approach each other, as shown by the dotted line in FIG. It may be foldable.

Further, in each of the above embodiments, the rear end surface of the front frame portion 5A (intermediate frame portion 105B) and the front end surface of the rear frame portion 5B (105C, 405B) are configured to contact each other when the bicycle is deployed. The present invention is not limited to this configuration, and for example, as shown in FIG. 17, the rear portion of the front frame portion (or the intermediate frame portion) 5A′ and the front portion of the rear frame portion 5B′ are vertically arranged in the unfolded state. They may be configured to overlap with each other, or the cushioning material K may be disposed between the rear portion and the front portion that overlap in the vertical direction as described above. The cushioning material K may be provided on the lower surface of the front frame portion 5A′, may be provided on the upper surface of the rear frame portion 5B′, or may be provided on both the lower surface of the front frame portion 5A′ and the upper surface of the rear frame portion 5B′. Is also good.

Furthermore, in each of the above embodiments, the turning axes P2 and P5 of the hinge mechanisms H2 and H102 are parallel to the rotation axis R1 of the sprocket 71, but the turning axes P2 and P5 are not necessarily parallel to the rotation axis R1. It is not necessary that the rear wheel 8 be positioned between the front wheel 3 and the sprocket 71 (or the rotation axis R1) when folded. Further, the crank 6 and the pedal 2 may be foldable. For example, as shown in FIG. 18, by providing a joint portion 61 at the base of the crank 6 and allowing the crank 6 to turn about the turning axis R10 of the joint portion 61, the direction of the pedal 2 is changed from the direction indicated by the solid line. The direction can be reversed in the direction shown by the dotted line. By reversing the direction of the pedal 2 in this way, the dimension in the width direction (horizontal direction) when folded can be made more compact. Alternatively, as shown in FIG. 19, the pedal 2 is provided with a joint portion so that the tip end side portion of the pedal 2 can be turned around the turning axis R11 with respect to the base end side portion. The direction of can be changed from the direction shown by the solid line to the direction shown by the dotted line. Also with this configuration, the amount of the pedal 2 protruding outward in the width direction can be suppressed, and the entire bicycle can be folded more compactly.

Further, the pedal 2 may be removed from the crank 6. By positioning the removed pedal 2 in the gap between the front wheel 3 and the rear wheel 8 and attaching it to the lower surface of the frame, the width direction of the entire bicycle can be carried compactly.

Further, the gear 203 shown in FIG. 20 may be used instead of the first gear 13 shown in FIG. The first gear 203 includes a gear base plate 231 having a right cylindrical shape, and a plurality of teeth 132 are annularly arranged on the outer peripheral surface 231a of the gear base plate 231. By forming the gear base plate 231 into a right circular column shape, it is possible to easily manufacture the first gear 203 as compared with the first gear 13. The other configuration of the first gear 203 is substantially the same as that of the gear 13.

Further, in the above embodiment, the first gear 13 and the sprocket 12A are connected to the frame 5 (105), and the second gear 14, the third gear 15 and the sprocket 12B are connected to the support shaft portion 42 (142). However, the first gear 13 and the sprocket 12A may be connected to the support shaft portion 42 (142), and the second gear 14, the third gear 15, and the sprocket 12B may be connected to the frame 5 (105). According to this structure, when the support shaft portion 42 rotates about the turning axis P3 by operating the handle, the first gear 13 rotates about the turning axis P3. It will rotate relative to the first gear 13 about. In this case, the sprocket 71 and the sprocket 12B may be connected by the first chain 72, and the sprocket 12A and the front wheel 3 may be connected by the second chain 73. By connecting in this way, the sprocket 71 The rotation can be transmitted to the front wheels 3.

Further, the first gear 303 shown in FIG. 21 may be used in place of the first gear 13, and the second gear 14 may be rotated (rotated) with respect to the first gear 303 about the rotation axis P3. The first gear 303 has a gear base plate 331 and a plurality of teeth 332 arranged in an annular shape on the outer peripheral surface 331a of the gear base plate 331. The gear base plate 331 has a small diameter at the central portion in the rotational axis direction D1. It is a shape. The tooth top 332a of each tooth 332 has a concave curved cross-sectional shape that passes through the rotation axis R2 of the first gear 303. That is, the distance from the rotation axis R2 to the tooth tip 332a of each tooth 332 is configured to gradually increase toward the outer side in the rotation axis direction D1. In other words, in the cross section passing through the rotation axis P2 of the first gear 303, the contour line of the outer peripheral surface (here, the tooth tip 332a) has a concave shape (concave curve shape). The cross-sectional shape of the addendum 332a is set such that the center point of the concave curve of the addendum 332a of the first gear 303 is located on or near the swivel axis P3 (the swivel axis P3 is the first gear It is preferable that the center point of the tooth tip 332a of the tooth 303 passes through or in the vicinity thereof, and it is more preferable that the center point is located on the turning axis P3. The turning axis P3 is perpendicular to the plane including the rotation axes R2 and R3.

Then, when the support shaft portion 42 is turned about the turning axis P3 with respect to the frame 5, the second gear 14 moves the turning axis P3 with respect to the first gear 303 while maintaining the meshing state with the first gear 303. Turn to the center. At this time, as the second gear 14 turns, the pitch point of the first gear 303 (the portion of the first gear 303 in contact with the second gear 14) also changes, and the pitch points that change in this way are continuously changed. The connected virtual line L4 has a curved shape as shown in FIG. 22, and the center point C4 of the curve of this virtual line L4 is located on the turning axis P3.

Therefore, also according to the present embodiment, even when the second gear 14 is turned with respect to the first gear 303 about the turning axis P3, along the arc (L4) whose center point C4 is a point on the turning axis P3. Since the pitch points of the first gear 303 and the second gear 14 change, the meshing of the first gear 303 and the second gear 14 can be maintained. The gear substrate 331 may have a right circular column shape instead of the drum shape.

Further, in the above embodiment, the gear train T is composed of a gear having a plurality of protruding teeth, but instead of this, it is composed of a friction gear (friction wheel) having no teeth or a magnetic gear having magnetic teeth. You may. In the case of the friction gear, the first gear is formed in an expanded cylindrical shape or a drum shape so that the operating surface is convex (convex curved surface) or concave (concave curved surface), and the second gear and the first gear are formed. The second gear may be rotated with respect to the first gear while maintaining the frictional engagement of the gears. Also, when the magnetic gear is used, similarly, the first gear is formed into an expanded cylindrical shape or an hourglass shape, and a plurality of convex (convex curved surface) or concave (concave curved surface) shapes are formed on the peripheral surface of the cylinder. It suffices to provide the magnetic teeth in an annular shape and rotate the second gear with respect to the first gear while maintaining the magnetic meshing state of the second gear and the first gear.

In the first, third, fourth, and fifth embodiments described above, the operation unit and the frame 5 (405) are each provided with a hinge mechanism so that the operation unit and the frame 5 (405) can be folded. When the total length (length in the front-rear direction) of the bicycle is relatively short, the hinge mechanism H2 in the frame 5 (405) may be omitted. When the hinge mechanism H2 is omitted in the bicycle 301 of the embodiment shown in FIGS. 12 and 13, the synchronous sprockets S1 and S2 can be omitted and the sprocket 71 and the rear sprocket 81 can be directly connected by the chain 74. .. When the hinge mechanism H2 is omitted in the bicycle of the fifth embodiment shown in FIG. 14, the link member 45d does not need to be separable.

In the above embodiment, a chain drive (a structure in which a chain is stretched between a pair of sprockets) is used in the mechanism that transmits the rotational force of the crank 6 to the front wheels 3 or the rear wheels 8, but instead of this, A belt drive (a structure in which a timing belt is stretched between a pair of timing pulleys) may be adopted, or a shaft drive may be used. When a shaft drive is used, a bevel gear may be used instead of the sprocket, and a pair of bevel gears may be connected by a drive shaft. Since the configurations of the belt drive and the shaft drive are known, detailed description thereof will be omitted.

In each of the above-described embodiments, the folding bicycle dedicated to rowing without a saddle has been described, but the frame may be provided with a detachable saddle. In this case, the saddle may be fixed to the frame with bolts or the like when traveling, and the saddle may be separated from the frame and held separately when carrying, or the saddle post (support) may be fixed to the front surface of the handle support with bolts.

Further, since the gears 13, 14 and 15 are consumable items, the gear transmission M may be modularized so that it can be easily replaced. Further, it is preferable to prepare modules having different gear ratios and use a module having a gear ratio suitable for a commuting route mainly on a flat land or a module having a gear ratio suitable for a commuting route mainly on a slope.

1, 101, 201, 301, 401 Folding bicycle 3 Front wheel 4, 104, 204, 304, 404 Operating portion 5, 105, 405 Frame 8 Rear wheel 13 First gear 14 Second gear 41 Handle 42, 142, 242 Spindle Part 71 Sprocket (chain ring)
H1, H101 hinge mechanism (second hinge mechanism)
H2, H102 hinge mechanism (first hinge mechanism)
M gear transmission

Claims (4)

Front wheels,
An operation unit with a handle,
A frame that rotatably holds the operation unit;
A crank pivotally supported in the middle of the frame,
A rear wheel pivotally supported at the rear end of the frame,
A sprocket that rotates integrally with the crank,
The frame is provided with a first hinge mechanism for folding the frame around a first turning axis,
When the frame is folded around the first turning axis, the rear wheel is positioned between the front wheel and the rotation axis of the crank,
The folding bicycle according to claim 1, wherein the front wheel is larger than the sprocket and the sprocket is larger than the rear wheel. Further comprising a drive transmission mechanism that transmits the rotation of the crank to the front wheels,
The folding bicycle according to claim 1, wherein the drive transmission mechanism includes the sprocket. The frame includes a first frame that pivotally supports the rear wheel, and a second frame that is connected to the first frame via the first hinge mechanism,
The crank is pivotally supported by the second frame, the first turning shaft is located rearward of a rotation shaft of the crank,
The drive transmission mechanism further includes a gear transmission and a chain that transmits the rotational force of the sprocket to the gear transmission, and the chain extends forward from the sprocket. The folding bicycle according to item 2. The drive transmission mechanism rotatably supports a first gear, a first transmission mechanism that transmits the rotation of the crank to the first gear, a second gear that meshes with the first gear, and the first gear. A first support portion, a second support portion that rotatably supports the second gear, and a second transmission mechanism that transmits the rotation of the second gear to the front wheel,
The first support part is connected to one of the frame and the operation part,
The second support part is connected to the other of the frame and the operation part,
When the operation unit rotates about the third turning axis with respect to the frame, the second gear turns about the third turning axis with respect to the first gear while being in mesh with the first gear. Then
The first gear has a plurality of teeth arranged in parallel in an annular shape along the rotation direction of the first gear,
The tip of each of the plurality of teeth has a convex curved cross-sectional shape passing through the rotation axis of the first gear,
The center point of the convex curve is located on or near the third turning axis,
The second gear is a spur gear,
The folding bicycle according to claim 2 or 3, wherein the first gear and the second gear are gears having protruding teeth or magnetic gears having magnetic teeth.

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