JP2014237368A - Bicycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bicycle which allows an elderly person or the like to ride.SOLUTION: A bicycle includes: a first frame 11 provided with multiple front wheels 20; a second frame 14 extending from the first frame 11 to the rear side; a driving part 50 which rotates a crank part 53 thereby transmitting a driving force; and a cover part 58 which covers the driving part 50. An upper end part of the cover part 58 is positioned below an upper surface part of the second frame.

Description

  The present invention relates to a bicycle.

  Two-wheeled bicycles require leg strength or a sense of balance when running. Therefore, elderly people and those with physical illnesses or disabilities may give up or refrain from using it as a means of transportation because of fear of falling. On the other hand, it is known that the operation of riding a bicycle has a physical strength and a rehabilitation effect.

  Thus, many bicycles having two front wheels and two rear wheels that can be used by elderly people have been proposed (for example, Patent Document 1). Such a conventional front two-wheel rear two-wheel bicycle has excellent stability and is prevented from falling because both the front two wheels and the rear two wheels are in contact with the ground or the like when stopping or going straight. For example, a conventional bicycle with two front wheels and two rear wheels can be stopped with a foot on the pedal. Therefore, it is mainly used by elderly people.

  However, in such a conventional bicycle, a chain ring that transmits the rotational driving force of the pedal to the rear wheel or the like from the down tube and a chain ring cover that covers the chain ring protrude from the down tube. There is a risk of getting in the way, for example, when a leg gets caught when straddling the down tube in order to get on.

  Therefore, it is desired that such a conventional bicycle with two front wheels and two rear wheels is easy to get on even for elderly people.

Japanese Patent No. 4875405

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a bicycle that is easy for an elderly person or the like to get on.

  The bicycle according to the present invention transmits a driving force by rotating a first frame provided with a plurality of front wheels, a second frame extending rearward from the first frame, and a crank portion. A drive unit and a cover unit that covers the drive unit are provided, and an upper end portion of the cover unit is positioned below an upper surface portion of the second frame.

  Furthermore, the crankshaft constituting the crank portion may be provided on the lower surface portion of the second frame.

  Further, the second frame provided with the crankshaft may be shaped to rise rearward.

  Furthermore, the second frame may be made of a single hollow member.

  The bicycle according to the present invention has a first frame provided with a plurality of front wheels, a second frame extending rearward from the first frame, and a driving force by rotating a crank portion. And a crankshaft constituting the crank portion is provided on a lower surface portion of the second frame.

  In the present invention, the crankshaft constituting the crank portion is provided on the lower surface portion of the second frame so that the upper end portion of the cover portion that covers the drive portion is positioned below the upper surface portion of the second frame. It is possible to prevent the cover part covering the driving part as well as the driving part from protruding from the upper surface part of the second frame. Therefore, the present invention can prevent the foot from being caught on the cover portion or the like when straddling the second frame for the user to get on, and can easily straddle, and the user can easily get on. Can do. Therefore, the present invention can be easily boarded even by an elderly person or the like.

1 is a perspective view showing a bicycle to which the present invention is applied. It is the left view which showed the bicycle to which this invention is applied. It is the bottom view which showed the bicycle to which this invention is applied. It is the rear view which showed the bicycle to which this invention is applied. It is the longitudinal cross-sectional view which showed the main tube. 1 is a front view showing a bicycle to which the present invention is applied. 1 is a plan view showing a bicycle to which the present invention is applied. It is the right view which showed the bicycle to which this invention is applied. It is the figure which showed a mode that the bicycle to which this invention was applied was parked in a bicycle parking lot, (A) is a top view, (B) is a side view. (A) is the left view which showed the bicycle of the reference example, (B) is the figure which showed a mode that the bicycle of a reference example drive | works an uphill slope, (C) shows this invention. It is the figure which showed a mode that the applied bicycle drive | works an uphill slope.

  Hereinafter, a bicycle to which the present invention is applied will be described in detail with reference to the drawings. In addition, this invention is not limited to the following examples, It can change arbitrarily in the range which does not deviate from the summary of this invention.

  As shown in FIG. 1, the bicycle 1 to which the present invention is applied has, for example, four wheels to increase the stability at the time of start and stop, which are particularly unstable in a two-wheeled bicycle. It is a bicycle that has stability that is difficult to fall even for those with a disease or disorder, and has operability that can be easily operated.

  Specifically, as shown in FIG. 1, a bicycle 1 to which the present invention is applied has a main frame 10, twin front wheels 20, 20 provided on the lower front side of the main frame 10, and a rear side of the main frame 10. The provided rear wheels 30 and 30 are provided in front of the main frame 10, the operation unit 40 for operating the front wheels 20, and the drive provided on the lower side of the main frame 10 to drive the rear wheels 30 and 30. Part 50.

<Mainframe>
As shown in FIG. 2, the main frame 10 includes a head tube 11 that is disposed vertically at the front end portion, a rear portion extending from the head tube 11, a curved down tube portion 12, and a linear back tube. A main tube 14 having a portion 13. Further, the main frame 10 is provided on the down tube portion 12 side of the back tube portion 13 and is provided between the seat tube 15 and the back tube portion 13 which are erected while being inclined backward. A sheet reinforcing tube 15a. Further, as shown in FIGS. 3 and 4, the main frame 10 includes a pair of first reinforcing tubes 16 and 16 provided in an inverted V shape from the back tube portion 13 toward the rear, and the first frame. Rear tubes 17, 17 projecting inward from the end of the reinforcing tube 16, second reinforcing tubes 18, 18 provided between the rear tube 17 and the back tube portion 13, 2 is provided between the reinforcing tube 18 and the back tube portion 13, and a loading platform mounting tube 19 to which the rear loading platform 60 is attached. Furthermore, the head tube 11, the main tube 14 (down tube portion 12), and the seat tube 15 are provided so as to form a substantially U shape with these three parts, and an opening when a user or the like straddles his / her foot to get on. It is greatly secured.

  And as shown in FIG. 2, between the head tube 11 and the down tube part 12 of the main tube 14, between the back tube part 13 and the seat tube 15 of the main tube 14, the seat tube 15 and the sheet reinforcing tube 15a Between the seat reinforcing tube 15a and the back tube portion 13, between the back tube portion 13 and the first reinforcing tube 16, between the first reinforcing tube 16 and the rear tube 17, and between the rear tube 17 and the first tube. Between the second reinforcing tube 18, between the second reinforcing tube 18 and the back tube portion 13, and between the second reinforcing tube 18 and the loading platform mounting tube 19, for example, a conventionally known joint such as welding. Joined by any of the methods.

  Further, as shown in FIG. 2, the head tube 11 is provided to be inclined with respect to the vertical so as to have a predetermined caster angle θ1. Here, the caster angle θ1 of the head tube 11 is provided so as to be, for example, 12 degrees to 26 degrees, preferably 15 degrees to 20 degrees with respect to the vertical. By turning the front wheel 20 into a twin wheel and providing a caster angle θ1, the handle 42 is cut from a straight traveling state, and when the predetermined angle is reached, one front wheel 20 is lifted, the operation load on the handle 42 is reduced, and the inner ring difference is also eliminated. The When the steering wheel turning angle is small (the turning radius is large), the difference between the inner wheels is not a problem. However, when the steering wheel turning angle is large (the rotation radius is small), a pair of left and right front wheels (wheels) 20 and 20 are caused by the inner wheel difference. There is a risk that a resistance will be generated and the vehicle will deviate from the intended travel line.

  As described above, the caster angle θ1 of the head tube 11 is set to be 12 degrees to 26 degrees with respect to the vertical. When the angle is smaller than 12 degrees, for example, an elderly person or the like continues a heavy load operation of the handle 42 when turning the handle 42, and when the angle is larger than 26 degrees, the floating amount of the front wheel 20 increases. The impact when the front wheels land on the road surface from the state in which the front wheels 20 are lifted increases, and the riding comfort is deteriorated.

Furthermore, by providing a caster angle, when the handle 42 is turned from a straight traveling state, the direction of the tire changes according to the angle, and the vehicle body is lifted. Distributed in the direction (vertical direction). By providing a caster angle when the vehicle stops due to this action, the steering wheel works to stabilize in a straight-ahead position. As the caster angle θ1 is increased, the float of the vehicle body is increased and the stability is increased. Considering the use of elderly people whose muscle strength has declined, it is preferable that the component force in the vertical direction is 50% or less of the force used to change the direction of the original tire by the operating force of the handle 42. From tan ⁻¹ (0.5) = 26.6 °, the caster angle is preferably 26 degrees or less.

  Further, a front loading platform 61 is attached to the outer peripheral portion of the head tube 11 toward the front. Further, an operation unit 40 is rotatably mounted in the head tube 11.

  Further, as shown in FIG. 2, the main tube 14 includes a curved down tube portion 12 joined to the head tube 11 and a linear back tube portion 13 provided on the rear side of the down tube portion 12. Have. The down tube portion 12 and the back tube portion 13 are provided by processing and molding a single hollow member, such as processing and molding a single round pipe or the like. Therefore, since the down tube portion 12 and the back tube portion 13 do not have a joint portion by welding or the like between them, there is no need to perform processing quality control of the joint portion, and the strength is stronger than when the joint portion is present. Further, since it is not necessary to perform joining processing such as welding, the cost can be reduced as compared with the case where joining processing such as welding is performed.

  Specifically, the down tube portion 12 is curved in a convex arc shape downward (ground). That is, the down tube portion 12 has an R shape and is bent at an obtuse angle. Furthermore, the down tube portion 12 has a downward slope portion 12a that descends so as to approach the ground from the front wheel 20 side toward the rear wheel 30 side, and an upward slope portion 12b that rises so as to be separated from the ground, From the front wheel 20 side toward the rear wheel 30 side, the descending slope portion 12a and the ascending slope portion 12b are successively formed. In addition, it is provided so that it may become the lowest ground level position 12c of the main tube 14 between the downward slope part 12a and the upward slope part 12b.

  Further, the ascending slope portion 12b is provided at a low height so that even an elderly person can easily get on and off without having to raise his / her foot, for example. For example, here, the height of the ascending slope portion 12b from the ground is set to be 300 mm or less.

  Accordingly, since the bicycle 1 is provided with the ascending slope portion 12b lower, the user can straddle the ascending slope portion 12b without raising his / her feet higher than before, and can easily get on. Therefore, the bicycle 1 can be easily boarded even by an elderly person or the like.

  In the bicycle 1, since the down tube portion 12 includes the downward slope portion 12 a and the upward slope portion 12 b between the head tube 11 and the seat tube 15, the front wheel 20 and the rear wheel 30 having a larger diameter than the conventional one are provided. Even if it is attached, the lowest ground height position 12c of the down tube portion 12 can be provided between the head tube 11 and the seat tube 15 in the same manner as in the past or lower than in the past, and it is easy for the user to straddle and get on easily. can do.

  Furthermore, since the bicycle 1 can be provided with larger diameters of the front wheels 20 and the rear wheels 30 while maintaining low flooring and improving riding performance, the traveling speed can be increased as compared with the prior art. You can easily get over even if there are steps. Accordingly, the bicycle 1 has a high riding performance while maintaining a low floor property and has a high ride performance, and has a large diameter of the front wheels 20 and the rear wheels 30.

  Further, in the bicycle 1, the down tube portion 12 has a descending slope portion 12a and an ascending slope portion 12b, and the descending slope portion 12a and the ascending slope portion 12b are formed in this order from the front wheel 20 side toward the rear wheel 30 side. Therefore, when a user gets on, the toe side of a foot becomes low, and it is easy to straddle. Therefore, the user can easily ride the bicycle 1.

  Further, as shown in FIG. 1, the ascending slope portion 12b is provided with a footrest member 90 for placing a foot when the user gets on and off. The foot placement member 90 is formed of, for example, a plate-like member, and is attached to the upper surface of the ascending slope portion 12b of the down tube portion 12 so as to be integrated or detachable by any conventionally known fixing means such as a bolt or welding. Therefore, the user can easily get on and off even a person who is difficult to raise his / her foot such as an elderly person by placing his / her foot on the footrest member 90 when getting on and off.

  In addition, although it is preferable that the height from the ground of the up-gradient part 12b of the down tube part 12 is provided in 300 mm or less, it is not limited to this, It can change suitably.

  Further, as shown in FIG. 5, the main tube 14 is disposed on the lower surface 12c of the down tube portion 12 between the descending slope portion 12a and the ascending slope portion 12b of the down tube portion 12 or the lower surface in the vicinity thereof. A drain port 12d is formed for discharging rainwater or the like that has entered the inside to the outside. Here, since the main tube 14 is formed of a hollow member, there is a possibility that rainwater or the like may enter inside. Furthermore, since the main tube 14 is provided so that the distance between the descending slope portion 12a and the ascending slope portion 12b of the down tube portion 12 is the lowest ground height position 12c, rainwater or the like that has entered the interior is provided at this lowest level. It accumulates at the ground height position 12c. Accordingly, the main tube 14 can efficiently drain rainwater and the like that have entered the inside from the drain port 12d.

  As shown in FIG. 2, the saddle 80 is attached to the upper end portion of the seat tube 15 by inserting a saddle column tube 80 a into the seat tube 15. The saddle 80 is provided with a backrest 81 at the rear. Therefore, the user can drive in an easy posture while leaning on the backrest 81 when driving.

  Further, as shown in FIG. 1, an opening 63 is provided on the front surface of the rear cargo bed 60, and further, an accommodation portion 62 is provided on the upper surface of the back tube 13, so And the bottom of a bar-shaped luggage such as a cane or an umbrella is stored in the storage 62, and the upper part of the bar-shaped luggage such as a cane or an umbrella is provided in the backrest 81. It can be fixed with a tool (not shown), and the user can be prevented from receiving a bar-shaped baggage such as a cane or an umbrella, and the bar-shaped baggage can be prevented from falling during traveling.

<Operation unit>
As shown in FIG. 2, the operation unit 40 includes a control tube 41 rotatably supported by the head tube 11, a handle 42 attached to the upper end of the control tube 41 via a stem 42a, and the control tube. And a front fork 43 connected to the lower end of 41.

  The control tube 41 is inserted into the head tube 11 and is rotatably supported by bearing portions (not shown) provided at the upper and lower ends of the head tube 11, for example. Furthermore, one front fork 43 disposed below the head tube 11 is connected to the lower end of the control tube 41.

  Furthermore, as shown in FIG. 6, a horizontal cylindrical front wheel bearing box 45 is provided at the lower end of the front fork 43. And in this front wheel bearing box 45, one front wheel shaft with which a pair of front wheels 20 and 20 are attached to both ends via bearings (not shown) provided on both left and right ends of the front wheel bearing box 45. 46 is rotatably supported. Accordingly, the front wheel 20 is rotated in conjunction with the rotation of the control tube 41. Furthermore, since only one front fork 43 is provided between the pair of front wheels 20, the user can easily grasp the position of the front wheel 20.

  Moreover, the handle | steering-wheel 42 is attached to the upper end part of the control pipe 41 via the stem 42a, as shown in FIG. Such a handle 42 is, for example, an up handle or the like, and is formed to be substantially U-shaped. Furthermore, the grip part 42b which a user hold | grips is provided in the both ends of the handle | steering-wheel 42. As shown in FIG. Further, a front wheel brake lever 74 for braking the front wheel 20 with a front wheel brake (not shown) is attached to one end of the handle 42. Further, a rear wheel brake lever 110 for braking the rear wheel 30 with a rear wheel brake (not shown) is attached to the other end portion of the handle 42. The rear wheel brake lever 110 may be attached to one end portion of the handle 42 and the front wheel brake lever 74 may be attached to the other end portion of the handle 42. Furthermore, the handle 42 is not limited to the up handle, and may be any other conventionally known handle.

  Furthermore, as shown in FIG. 7, the handle width W1 of the handle 42 is substantially the same as the vehicle width W2 of the rear wheels 30, 30, or is wider than the vehicle width W2 of the rear wheels 30, 30. It is provided as follows. That is, the handle width W1 of the handle 42 is at least the maximum vehicle width W3 of the bicycle 1. With such a configuration, it can be seen that if the handle 42 is wide enough to pass, the rear wheels 30, 30 are also wide enough to pass, and the rear wheel 30 inadvertently collides with the road shoulder in a narrow alley or the like. Can be prevented.

  Further, as shown in FIG. 2, since the head tube 11 is tilted with respect to the vertical so as to have a caster angle θ1, the handle 42 has a shorter distance from the saddle 80 than the conventional one. Thus, it is not necessary to take a forward leaning posture, and for example, it can be placed at a position where it can be easily operated while sitting on the saddle 80 in an easy posture leaning on the backrest 81 of the saddle 80.

  Further, as shown in FIG. 2, the operation portion 40 is provided with a stopper portion 47 that restricts the rotation of the control tube 41 and the front fork 43. The stopper portion 47 is attached to the outer periphery of the front fork 43, for example. Further, the stopper portion 47 is formed to have a substantially L-shape that protrudes in the radial direction of the front fork 43 and is bent upward so as to be substantially parallel to the axial direction of the front fork 43, for example. Has been. Therefore, for example, when the user cuts the handle 42, the stopper portion 47 abuts on the descending slope portion 12 a of the down tube portion 12 to restrict the rotation of the control tube 41. More specifically, the control tube 41 is restricted from rotating once.

  Note that the stopper portion 47 is not limited to a substantially L-shape, and when the user cuts the handle 42, the stopper portion 47 can abut the descending slope portion 12a to restrict the rotation of the control tube 41. Any shape may be used as long as it is such.

<Front wheel>
As shown in FIG. 2, the front wheel 20 is configured by attaching a tire 20b to a wheel 20a. Further, as the front wheel 20, for example, a tire 20b (wheel 20a) having a size of about 8 inches to 16 inches is used. The front wheel 20 is attached to both end portions of one front wheel shaft 46.

  The front wheel 20 having the above-described configuration is provided to be inclined with respect to the vertical so that the head tube 11 has a predetermined caster angle θ1, and the pair of front wheels 20 and 20 rotate below the head tube 11. Since it is provided on both sides of one front wheel shaft 46 that is freely supported, one wheel of the pair of front wheels 20 and 20 can be floated when the handle 42 is cut (rotated) to a certain angle. Therefore, the front wheel 20 can reduce the operation load of the handle 42 when the handle 42 is cut. Further, since the front wheels 20 and 20 are provided on both sides of a single front wheel shaft 46 that is rotatably supported below the head tube 11, the pair of front wheels 20 and 20 are independent shafts. The structure can be simplified as compared with the case where the pair of front wheels 20 and 20 is lifted, and when the one wheel of the pair of front wheels 20 and 20 floats, the rotation of the ground wheel 20 and the floating front wheel 20 rotates. The number is different, and it is possible to prevent the floating front wheel 20 from acting as a brake when it comes into contact with the ground.

  The front wheel 20 may be attached to the front wheel shaft 46 so as to have a predetermined backlash in the rotational direction with respect to the front wheel shaft 46. In this case, the bicycle 1 can idle the other front wheel 20 when the handle 42 is turned to a predetermined angle, and the operation load of the handle 42 when the handle 42 is turned can be reduced. The operability can be improved.

  Further, the front wheel 20 is provided with a front wheel brake that brakes the front wheel 20. The front wheel brake is, for example, a disc brake, and is provided on a front wheel shaft 46 between the pair of front wheels 20 and 20. The front wheel brake is connected to a front wheel brake lever 74 provided at one end of the handle 42 via a front wheel brake wire 73. The front wheel brake is not limited to the disc brake, and may be any other conventionally known brake.

  Therefore, when the front wheel brake lever 74 is operated by being gripped by the user, the front wheels 20 and 20 are braked by one front wheel brake. Further, since the front wheel brakes brake the two front wheels 20 and 20 with one front wheel brake, a braking force can be applied equally to the two front wheels 20 and 20. Furthermore, since the pair of front wheels 20 and 20 are braked by one front wheel brake, the braking adjustment between the front wheels 20 and 20 required when the front wheel brakes are provided on each front wheel 20 is unnecessary, and maintenance is good and inexpensive. It is. Further, since the front wheel brake is provided between the pair of front wheels 20 and 20, there is a low possibility that a user's hand or foot will touch, and safety is high. Further, when the front wheel brake is a disc brake, the disc brake has a high braking force. Therefore, the user can easily brake the front wheel 20 by gently grasping the front wheel brake lever 74. Therefore, even an elderly person or the like can easily perform a braking operation.

<Rear wheel>
As shown in FIG. 2, the rear wheel 30 is configured by attaching a tire 30 b to a wheel 30 a as in the case of the front wheel 20. Further, as with the front wheel 20, the rear wheel 30 is a tire 30b (wheel 30a) having a size of about 8 inches to 16 inches, for example. Furthermore, the rear wheel 30 is composed of two wheels, and is supported by a bearing portion (not shown) provided in each rear tube 17 so as to be independently rotatable. Further, as shown in FIG. 4, one rear wheel 30 is connected to the first rear wheel drive shaft 100a, and the other rear wheel 30 is connected to the second rear wheel drive shaft 100b. The first rear wheel drive shaft 100a and the second rear wheel drive shaft 100b are connected via a differential gear 100c.

  Therefore, when turning left and right, the rotational speed of the rear wheel 30 on the outside of the turn increases, so that it can run smoothly without slipping and stably support loads including centrifugal force during turning. While driving safely. Therefore, it is possible to make a U-turn while riding even if the road is narrow, for example, even if the road is narrow.

  The rear wheel 30 is provided with a rear wheel brake (not shown) for braking the rear wheel 30. The rear wheel brake is a disc brake, for example, and is provided on at least one of the rear wheel drive shafts 100a and 100b (hereinafter also simply referred to as the rear wheel drive shaft 100) between the pair of rear wheels 30 and 30. As shown in FIG. 1, the rear wheel brake is connected to a rear wheel brake lever 110 provided at the other end of the handle 42 via a rear wheel brake wire 111. Accordingly, the rear wheels 30, 30 are braked by the rear wheel brake when the rear wheel brake lever 110 is operated by being gripped by the user. Furthermore, since the disc brake has a high braking force, the user can easily brake the rear wheel 30 by grasping the rear wheel brake lever 110 lightly. Therefore, even an elderly person or the like can easily perform a braking operation.

  Further, as shown in FIG. 5, the rear wheel brake wire 111 is provided so as to be inserted through the main tube 14. Specifically, the main tube 14 is formed with a first wire opening portion 14 a into which the rear wheel brake wire 111 is inserted on the side of the downward slope portion 12 a of the down tube portion 12, and the rear end surface of the back tube portion 13. A second wire opening 14b through which the rear wheel brake wire 111 is inserted is formed in 13a. The rear wheel brake wire 111 is inserted into the main tube 14 by being inserted from one of the first wire opening 14a and the second wire opening 14b into the inside and discharged from the other to the outside. . Accordingly, the bicycle 1 is provided so that the rear wheel brake wire 111 is inserted through the main tube 14, so that the rear wheel brake wire 111 is fixed to the main tube 14 or the like so as not to interfere with the crank 53 or the user. It is no longer necessary to apply brake wire treatment. Therefore, the work efficiency is improved and the cost can be reduced.

  The first wire opening portion 14a is not limited to be formed on the side surface of the descending slope portion 12a of the down tube portion 12, but is formed on the upper surface or the lower surface of the descending slope portion 12a. Alternatively, it may be formed on any surface of the ascending slope portion 12b, or may be formed on any surface of the back tube portion 13. Further, the second wire opening portion 14b is not limited to being formed on the rear end surface 13a of the back tube portion 13, and is formed on any one of the upper surface, the lower surface, and the side surface of the back tube portion 13. You may make it.

  Further, the rear wheel brake is not limited to the disc brake, and any other conventionally known band brake such as a band brake that tightens and brakes the outer periphery of the brake drum provided on the hub of the rear wheel 30 with a belt-like band. It may be a brake.

<Drive unit>
As shown in FIG. 8, the drive unit 50 includes a crankshaft 51 that is supported by a shaft fixing portion 57 that is welded and fixed to the lower surface of the ascending slope portion 12 b of the downtube portion 12, and the crankshaft 51. It has a fixed disc-shaped chain ring 52. The crankshaft 51 is provided on the lower surface of the ascending slope portion 12 b of the down tube portion 12 via the shaft fixing portion 57. Further, the chain ring 52 is provided such that the upper end portion is positioned below the upper surface of the ascending slope portion 12 b of the down tube portion 12. In other words, the chain ring 52 is provided such that the upper end portion does not protrude from the upper surface of the ascending slope portion 12 b of the down tube portion 12. For example, the shaft fixing portion 57 is provided so that the axis line of the crankshaft 51 that supports the shaft has a height of 180 mm to 230 mm from the ground.

  Further, a pair of cranks 53 and 53 for turning the chain ring 52 are attached to the left and right ends of the crankshaft 51 in opposite directions. At the tip of the crank 53, a pedal 54 is attached as a step board on which a user puts his / her foot and transmits force to the bicycle 1. The crank 53 is provided with a length of 130 mm to 180 mm, for example. Therefore, the crank 53 is provided with the shaft fixing portion 57 so that the height from the ground is 180 mm to 230 mm as described above, and thus has a gap of about 50 mm between the crank 53 and the ground. Therefore, the bicycle 1 can travel without the pedal 54 coming into contact with the step or the like even if there is a certain level of difference such as a step between a road and a sidewalk on a general road.

  Further, an endless chain 55 is bridged between the chain ring 52 and rear wheel sprockets (not shown) provided on the rear wheel drive shafts 100a and 100b of the rear wheel 30. The endless chain 55 transmits the rotation of the chain ring 52 to the rear wheel 30. The endless chain 55 may be prevented from loosening by an auxiliary sprocket 56 provided below the down tube portion 12 or the like. Moreover, it is not limited to the endless chain 55, You may make it use an endless toothed belt.

  Further, as shown in FIG. 2, the drive unit 50 is attached to the main frame 10 via the main tube 14, the first reinforcing tube 16, and the like, and has a chain cover 58 that covers the chain ring 52 and the endless chain 55. ing. The chain cover 58 is provided, for example, so as to cover the entire circumference of the chain ring 52 and the upper endless chain 55 between the chain ring 52 and the rear wheel sprocket. Further, dirt and biting caused by the skirt hem and the like coming into contact with the endless chain 55 are prevented. Further, the chain cover 58 is provided so that the upper end portion is located below the upper surface of the ascending slope portion 12 b of the down tube portion 12 and does not protrude from the upper surface of the ascending slope portion 12 b of the down tube portion 12. In other words, the crankshaft 51 is arranged so that the upper end portion of the chain cover 58 is positioned below the upper surface of the ascending slope portion 12b of the down tube portion 12 and does not protrude from the upper surface of the ascending slope portion 12b of the down tube portion 12. It is provided on the lower surface of the ascending slope portion 12 b of the down tube portion 12 via the fixing portion 57.

  Furthermore, the drive unit 50 is set so that a GD value that is a distance (m) that the bicycle travels by one rotation of the pedal is 1.75. For example, since the GD value of the general bicycle is around 5.5, the GD value of the bicycle 1 is set lower than that of the general bicycle. The standard number of pedals per minute (cadence) is 60 times / minute, and the speed at this time is expressed in km / h: (GD value) x (cadence) x (60 minutes) ÷ 1000 Become. Therefore, in a general bicycle, 5.5 × 60 × 60 ÷ 1000 = 19.8 km / h. On the other hand, in the bicycle 1, 1.75 × 60 × 60 ÷ 1000 = 6.3 km / h. That is, the bicycle 1 is set so that it does not go too fast, and is substantially equivalent to the walking speed, for example. The walking speed varies depending on the person, but is generally 3 to 7 km / h, and the GD value is preferably 0.8 to 2.0.

<Bicycle dimensions>
As shown in FIG. 7, the bicycle 1 having the above configuration has, for example, a total length L1 that is a horizontal distance from the front end portion of the front wheel 20 to the rear end portion of the rear wheel 30 to be 1000 mm to 1500 mm. Is provided. Furthermore, the bicycle 1 is provided so that the vehicle width (maximum vehicle width) W3 is 800 mm or less. Therefore, this bicycle 1 has excellent stability.

  Here, as shown in FIG. 9, the bicycle parking racks 121 that support the general two-wheel bicycle 120 in a bicycle parking lot such as a station or an apartment are generally arranged at intervals of 400 mm. Therefore, the bicycle 1 can be parked in the parking space 122 between the parking racks 121 and 121 by providing the maximum vehicle width W3 to be 800 mm or less.

  Furthermore, the general two-wheeled bicycle 120 supported by the bicycle parking rack 121 often has an overall length X of about 1800 mm. Therefore, the bicycle 1 is provided with a length L1 that is at least about 300 mm shorter than the general two-wheel bicycle 120, thereby preventing the handle 42 of the bicycle 1 and the handle 120a of the general two-wheel bicycle 120 from interfering with each other. Can do. Further, the bicycle 1 is located at substantially the same position as the rear portion of the adjacent general two-wheel bicycle 120 in which the rear portions such as the rear wheel 30 and the rear loading platform 60 are adjacent, and protrudes rearward from the rear portion of the adjacent general two-wheel bicycle 120. This can be prevented.

  Furthermore, in general, a storage passage 123 is provided behind the bicycle parking space 122 of the bicycle parking lot so that bicycles or the like that can park the bicycle can pass therethrough and the bicycles can be taken in and out freely. The road width of the storage passage 123 is standard at 1.8 m for parking lots with many face-to-face traffic, and 1.5 m for other parking lots (Bicycle Parking Lot Maintenance Center / Bicycle Parking Lot Installation Technology) (Refer to the guidance study report). Therefore, by setting the total length L1 of the bicycle 1 within 1500 mm, the bicycle 1 can be drawn straight out from the parking space 122 to the storage passage 123. Furthermore, by setting the total length L1 of the bicycle 1 within 1450 mm, the bicycle 1 can be pulled straight out from the parking space 122 to the storage passage 123 with a margin of about 50 mm with respect to the road width. Therefore, for example, there is no need to enter a narrow space between the bicycle 1 and the adjacent two-wheel bicycle 120 adjacent to the bicycle 1 as shown in S1 of FIG. 9 and pull the handle 42 while turning it to the right or left. For example, the rear portion of the bicycle 1 may be simply pulled from the rear and pulled straight back, and the bicycle 1 can be easily pulled out from the parking space 122.

  Further, as shown in FIG. 2, the bicycle 1 has a horizontal distance L10 from the center position of the saddle 80 to the rotation shaft of the rear wheel 30 (rear wheel drive shaft 100). It is provided to be larger than a horizontal distance L11 to 50 crankshafts 51. For example, the horizontal distance L10 from the center position of the saddle 80 to the rotation axis of the rear wheel 30 is set to be 300 mm to 800 mm. Further, a horizontal distance L11 from the center position of the saddle 80 to the crankshaft 51 of the drive unit 50 is provided to be 200 mm to 300 mm. Here, the center position of the saddle 80 is the maximum height position where the center of gravity is the most rearward because the saddle 80 can be moved up and down according to the user's physique to adjust the saddle height. This is the center position of the saddle 80.

  Therefore, the horizontal distance L10 from the center position of the saddle 80 to the rotating shaft of the rear wheel 30 is set to be larger than the horizontal distance L11 from the center position of the saddle 80 to the crankshaft 51 of the drive unit 50. Thus, as shown in FIG. 10C, when the bicycle 1 is traveling on the uphill slope 130, the front wheel 20 is lifted or falls backward even if the center of gravity position when riding on the saddle is lowered rearward. It is possible to prevent problems from occurring. Therefore, the bicycle 1 can maintain the stability of the vehicle when riding, even when traveling on an uphill slope.

  Furthermore, since the bicycle 1 can prevent problems such as the front wheel 20 floating or falling backward, a disc brake having a higher braking force than the band brake can be employed as the rear wheel brake. Therefore, the bicycle 1 can easily brake the rear wheel 30 by lightly grasping the rear wheel brake lever 110 even for an elderly person or the like. Therefore, the bicycle 1 can easily perform a braking operation even for an elderly person or the like while maintaining the stability of the vehicle when riding, even when traveling on an uphill slope.

  In FIG. 10A, as a reference example, a horizontal distance L10 from the center position of the saddle 80 to the rotating shaft of the rear wheel 30 is a distance from the center position of the saddle 80 to the crankshaft 51 of the drive unit 50. A bicycle 140 that is smaller than or the same as the horizontal distance L11 is shown. In such a case, the angle θ2 formed by the vertical line 140a of the bicycle 140 of the reference example and the side 140b connecting the center position of the saddle 80 and the rotation axis of the rear wheel 30 is the vertical line 150a of the bicycle 1. The angle θ3 (see FIG. 2) formed by the side 150b connecting the center position of the saddle 80 and the rotation axis of the rear wheel 30 is small. For example, the angle θ3 formed by the bicycle 1 is about 23 degrees, whereas the angle θ2 formed by the bicycle 140 of the reference example is about 14 degrees.

  Therefore, as shown in FIGS. 10 (B) and 10 (C), when the center of gravity of the saddle is lowered when traveling on the uphill slope 130, the bicycle of the reference example shown in FIG. 10 (B). As compared with 140, the bicycle 1 shown in FIG. 10 (C) can prevent the front wheel 20 from floating or causing a malfunction such as falling backward. Therefore, when the bicycle 1 travels on the uphill slope 130, the stability of the vehicle when riding can be maintained as compared with the bicycle 140 of the reference example. That is, if the bicycle 1 has the same overall length as the bicycle 140 of the reference example, the stability of the vehicle when riding can be maintained more than the bicycle 140 of the reference example. On the other hand, the bicycle 1 maintains the stability of the vehicle when riding about the same level as the bicycle 140 of the reference example, while shortening the overall length and improving the turning ability, compared with the bicycle 140 of the reference example. Can do.

  Further, as shown in FIG. 2, the bicycle 1 is provided such that a horizontal distance L <b> 12 from the crankshaft 51 of the drive unit 50 to the rear end of the front wheel 20 is 200 mm to 300 mm. More preferably, the horizontal distance L12 from the crankshaft 51 of the drive unit 50 to the rear end of the front wheel 20 is substantially the same as the horizontal distance L11 from the center position of the saddle 80 to the crankshaft 51 of the drive unit 50. To be provided. In other words, the crankshaft 51 of the drive unit 50 is provided at a substantially central position between the center position of the saddle 80 and the rear end portion of the front wheel 20. Thus, the user can bend knees and ankles when pedaling 54, can reduce the knee and ankle burden when pedaling 54, and can easily pedal pedal 54. .

<Effect>
As described above, in the bicycle 1 to which the present invention is applied, as shown in FIG. 8, the upper end portion of the chain cover 58 that covers the drive portion 50 such as the chain ring 52 and the endless chain 55 is the down tube portion 12 of the main tube 14. It is located below the upper surface of the up-gradient portion 12b and is provided so as not to protrude from the upper surface of the up-gradient portion 12b of the down tube portion 12. In other words, the crankshaft 51 of the drive unit 50 is such that the upper end portion of the chain cover 58 is located below the upper surface of the ascending gradient portion 12b of the down tube portion 12 and does not protrude from the upper surface of the ascending gradient portion 12b of the down tube portion 12. As described above, it is provided on the lower surface of the ascending slope portion 12 b of the down tube portion 12 via the shaft fixing portion 57. Therefore, the bicycle 1 to which the present invention is applied can prevent the user from getting caught in the chain cover 58 and the like when getting on, and can easily straddle. You can get on without having to raise it. Therefore, the bicycle 1 to which the present invention is applied can be easily boarded even by an elderly person or the like.

  Further, in the bicycle 1 to which the present invention is applied, as shown in FIG. 2, the down tube portion 12 of the main tube 14 has a descending slope portion 12 a and an ascending slope portion 12 b, from the front wheel 20 side to the rear wheel 30 side. Since it forms in order of the downward slope part 12a and the upward slope part 12b, the toe side of a foot becomes low when a user gets on, and it is easy to straddle. Therefore, the user can easily ride the bicycle 1 to which the present invention is applied. Therefore, the bicycle 1 to which the present invention is applied can be easily boarded even by an elderly person or the like.

  Furthermore, in the bicycle 1 to which the present invention is applied, as shown in FIG. 2, a main tube 14 having a curved down tube portion 12 and a straight back tube portion 13 is formed by processing a single round pipe or the like. It is provided by processing and molding a single hollow member. Therefore, in the bicycle 1 to which the present invention is applied, there is no connection portion by welding or the like between the down tube portion 12 and the back tube portion 13, so there is no need to control the processing quality of the connection portion, and there is a connection portion. Since the strength is higher than that, and it is not necessary to perform joining processing such as welding, the cost can be reduced as compared with the case of performing joining processing such as welding.

  Furthermore, in the bicycle 1 to which the present invention is applied, as shown in FIG. 2, the horizontal distance L10 from the center position of the saddle 80 to the rotating shaft of the rear wheel 30 is It is provided to be larger than the horizontal distance L11 to the shaft 51. Therefore, the bicycle 1 to which the present invention is applied prevents the front wheel 20 from floating up or causing a malfunction such as falling backwards even when the position of the center of gravity when riding on the saddle is lowered when traveling on the uphill slope 130. be able to. Therefore, the bicycle 1 to which the present invention is applied can maintain the stability of the vehicle when riding, even when traveling on the uphill slope 130.

  Furthermore, the bicycle 1 to which the present invention is applied is provided such that the horizontal distance L12 from the crankshaft 51 of the drive unit 50 to the rear end of the front wheel 20 is 200 mm to 300 mm. Therefore, in the bicycle 1 to which the present invention is applied, bending of the knee and ankle is sufficient when the user pedals the pedal 54, and the burden on the knee and ankle when pedaling the pedal 54 can be reduced.

<Modification>
In addition, the bicycle 1 to which the present invention is applied is not limited to the main tube 14 made of a single hollow member, but two parts of a curved down tube and a straight back tube 13 are welded. It may be provided by joining by any of the conventionally known joining methods such as. In such a case, manufacturing and processing can be performed more easily than processing and molding a single hollow member.

  Furthermore, the bicycle 1 to which the present invention is applied includes an electric motor that outputs auxiliary power for assisting pedaling force, a battery for supplying electric power to the electric motor, a motor controller that controls the operation of the electric motor, and the like. An electric assist unit may be provided.

  Furthermore, the bicycle 1 to which the present invention is applied is not limited to the so-called rear wheel drive in which the drive unit 50 drives the rear wheels 30, 30. The drive unit 50 drives the front wheels 20, 20. So-called front wheel drive may be used.

  Furthermore, in the bicycle 1 to which the present invention is applied, the rear wheel 30 may be formed by one wheel or three or more wheels.

1 Bicycle, 10 Main frame, 11 Head tube, 12 Down tube section, 12a Down slope section, 12b Up slope section, 12c Minimum ground height position, 12d Drain port, 13 Back tube section, 13a Rear end face, 14 Main tube, 14a 1st wire opening part, 14b 2nd wire opening part, 15 sheet tube, 15a sheet reinforcement tube, 16 1st reinforcement tube, 17 rear tube, 18 2nd reinforcement tube, 19 tube for loading platform, 20 front wheel, 20a wheel, 20b tire, 30 rear wheel, 30a wheel, 30b tire, 40 operation section, 41 control tube, 42 handle, 42a stem, 42b grip section, 43 front fork, 45 front wheel bearing box, 46 front wheel shaft, 47 Stopper part, 50 Drive part, 5 1 Crankshaft, 52 Chainring, 53 Crank, 54 Pedal, 55 Endless Chain, 56 Auxiliary Sprocket, 57 Shaft Fixing, 58 Chain Cover, 60 Rear Cargo, 61 Front Cargo, 62 Storage, 63 Opening, 73 Front Wheel Brake Wire, 74 Front wheel brake lever, 80 saddle, 80a saddle strut tube, 81 backrest, 90 footrest member, 100a first rear wheel drive shaft, 100b second rear wheel drive shaft, 100c differential gear, 110 rear wheel Brake lever, 111 Rear wheel brake wire, 120 General-purpose bicycle, 120a Handle, 121 Parking rack, 122 Parking space, 123 Storage passage, 130 Uphill slope

Claims (5)

A first frame provided with a plurality of front wheels;
A second frame extending rearward from the first frame;
A drive unit that transmits a driving force by rotating the crank unit;
A cover portion covering the drive portion,
The bicycle according to claim 1, wherein an upper end portion of the cover portion is located below an upper surface portion of the second frame.   The bicycle according to claim 1, wherein a crankshaft constituting the crank portion is provided on a lower surface portion of the second frame.   The bicycle according to claim 2, wherein the second frame provided with the crankshaft is shaped to rise rearward.   The bicycle according to any one of claims 1 to 3, wherein the second frame is formed of a single hollow member. A first frame provided with a plurality of front wheels;
A second frame extending rearward from the first frame;
A drive unit that transmits a driving force by rotating the crank unit;
The crankshaft constituting the crank portion is provided on a lower surface portion of the second frame.