Bicycle frame structure and motorized bicycle

Abstract

To enhance variability of a set position in a longitudinal direction and in a height direction of a seat on which a rider is seated and enhance load bearing of a frame bearing the seat.SOLUTION: A bicycle frame structure comprises a rear tube 5 extending obliquely upward, from a vicinity of a place on which feet of a rider 100 are put toward a rear side, in which one end of a left U-shaped pipe material 151 and one end of a right U-shaped pipe material 152 are fixed at the same height to a middle between an upper end and a lower end of the rear tube 5; the other end of the left U-shaped pipe material 151 and the other end of the right U-shaped pipe material 152 are fitted to each other to constitute a seat support tube 15 in a nearly rectangle shape in a planar view supporting a placed seat 17; one end of a left support stay 161 and one end of a right support stay 162 are fixed at the same height to the rear tube 5; the other end of the left support stay 161 is fixed to a lower side of the left U-shaped pipe material 151; and the other end of the right support stay 162 is fixed to a lower side of the right U-shaped pipe material 152.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a bicycle frame structure and a motorized bicycle.

Background Art

[0002] Conventionally, the frame structure disclosed in Patent Document 1 is known as a bicycle frame structure. The frame structure of Patent Document 1 includes a head pipe to which an operating handle is attached, two down tubes extending obliquely downward and rearward from the head pipe, and a seat tube extending obliquely upward and rearward from the rear ends of the down tubes. A saddle is attached to the upper end of the seat tube such that a seat post is inserted into the seat tube.

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] By the way, in the frame structure of Patent Document 1, it is necessary to set the saddle on which a driver sits on the extension line of the seat tube in order to suppress the load applied to the joint between the saddle and the seat post. For this reason, the adjustment range for the longitudinal position and the height position of the seat on which the driver sits is extremely limited, resulting in a structure with low variability in the set position of the seat on which the driver sits.

[0005] The present invention has been proposed in view of the above problems, and an object of the present invention is to provide a bicycle frame structure that can increase the variability of the set positions in the longitudinal direction and the height direction of the seat on which a driver sits, and can improve the load bearing capacity of the frame that supports the seat, and a motorized bicycle including the bicycle frame structure.

Means for Solving the Problem

[0006] The bicycle frame structure of the present invention has a single tube extending diagonally upward toward the rear from the vicinity where the rider's feet are positioned, one end of a left U-shaped pipe and one end of a right U-shaped pipe are fixed at the same height midway between the upper and lower ends of the single tube, the other end of the left U-shaped pipe and the other end of the right U-shaped pipe are fitted together to form a seat support tube that is roughly rectangular in plan view and supports the seat on which it is placed, one end of a left support stay and one end of a right support stay are fixed to the single tube at the same height, the other end of the left support stay is fixed to the lower side of the left U-shaped pipe, and the other end of the right support stay is fixed to the lower side of the right U-shaped pipe. According to this design, by adjusting the installation height of the left and right U-shaped pipes and left and right support stays relative to the single tube, the forward-backward direction and height of the seat where the driver sits can be changed. Therefore, the variability of the forward-backward direction and height of the seat where the driver sits can be increased. Furthermore, by fixing the left and right U-shaped pipes and left and right support stays to the single tube and fitting the left and right U-shaped pipes together, the load-bearing capacity of the seat support tube, which is the frame that supports the seat, and the seat placed on it can be increased.

[0007] The bicycle frame structure of the present invention is characterized in that the fitting allowance between the other end of the left U-shaped pipe material and the other end of the right U-shaped pipe material is greater than or equal to the maximum width of the single tube. According to this, the load-bearing capacity of the sheet support tube and the sheet placed on it can be further improved.

[0008] The motorized bicycle of the present invention is characterized by having a single tube that extends diagonally upward toward the rear from the vicinity where the driver's feet are positioned, with one end of a left U-shaped pipe and one end of a right U-shaped pipe fixed at the same height midway between the upper and lower ends of the single tube, the other end of the left U-shaped pipe and the other end of the right U-shaped pipe fitted together to form a seat support tube that is roughly rectangular in plan view and supports the seat on which it is placed, with one end of a left support stay and one end of a right support stay fixed to the single tube at the same height, the other end of the left support stay fixed to the lower side of the left U-shaped pipe, and the other end of the right support stay fixed to the lower side of the right U-shaped pipe, and comprising a bicycle frame structure. According to this design, by adjusting the installation height of the left and right U-shaped pipes and left and right support stays relative to the single tube, the forward-backward direction and height of the seat where the driver sits can be changed. Therefore, the variability of the forward-backward direction and height of the seat where the driver sits on a motorized bicycle can be increased. Furthermore, by fixing the left and right U-shaped pipes and left and right support stays to the single tube and fitting the left and right U-shaped pipes together, the load-bearing capacity of the seat support tube, which is the frame that supports the seat, and the seat placed on it can be increased.

[0009] The motorized bicycle of the present invention is characterized in that it travels at a low speed of 20 km / h or less, and the vehicle body frame is formed by a single frame comprising a down tube extending diagonally downward from a head pipe to which an operating handle is attached, a bent portion provided at the lower end of the down tube, and a rear tube extending diagonally upward from the bent portion, and the single tube is composed of the rear tube. According to this, by forming the vehicle frame with a single frame consisting of a down tube, a curved section at the lower end of the down tube, and a rear tube extending diagonally upward from the curved section, even drivers such as short people or the elderly can easily straddle the single frame and get on and off the motorized bicycle while it is traveling at low speed. [Effects of the Invention]

[0010] According to the present invention, it is possible to increase the variability of the front-to-back direction and height setting position of the seat on which the cyclist sits, and to increase the load-bearing capacity of the frame that supports the seat. [Brief explanation of the drawing]

[0011] [Figure 1] A side view of a motorized bicycle equipped with a bicycle frame structure according to an embodiment of the present invention. [Figure 2] Side view of the head pipe, down tube, curved section, and rear tube in the bicycle frame structure of the embodiment. [Figure 3] (a) is a plan view of the head pipe, down tube, bend, and rear tube in the bicycle frame structure of the embodiment, and (b) is an enlarged end view AA of the same figure (a). [Figure 4] An enlarged plan view showing the area around the seat support tube in a modified bicycle frame structure of the embodiment. [Modes for carrying out the invention]

[0012] [Embodiment of bicycle frame structure and motorized bicycle] The motorized bicycle 1 equipped with the bicycle frame structure of the embodiment of the present invention is preferably a motorized bicycle 1 that travels at a low speed of 20 km / h or less. As shown in Figures 1 to 3, the bicycle frame structure comprises a head pipe 2, a down tube 3 extending diagonally downward from the head pipe 2, a bent portion 4 provided at the lower end of the down tube 3, and a rear tube 5 extending diagonally upward from the bent portion 4. The down tube 3, bent portion 4, and rear tube 5 that constitute the vehicle frame are formed as a substantially cylindrical single frame that extends in a straight line in a plan view. The rear tube 5 corresponds to a single tube that extends diagonally upward toward the rear from the vicinity where the feet of the driver 100 are placed. In this embodiment, the down tube 3, bent portion 4, and rear tube 5 are formed from bent pipes of the same metal material, such as stainless steel, aluminum alloy, or aluminum-carbon-steel.

[0013] The down tube 3, curved section 4, and rear tube 5, which are composed of a single frame, preferably have the required strength as a bicycle frame structure for a motorized bicycle 1 traveling at a low speed of 20 km / h. Furthermore, from the viewpoint of ensuring the required strength as a vehicle frame and from the viewpoint of making it easier for the driver to put their feet on the ground when stopped, the left and right widths of the down tube 3 and curved section 4 are preferably formed to be 350 mm to 450 mm, more preferably 350 mm to 400 mm, and the left and right widths of the rear tube 5 are preferably formed to be 600 mm to 700 mm, more preferably 600 mm to 650 mm.

[0014] A cylindrical handle post 6 is provided on the upper side of the head pipe 2 and is fixed to the head pipe 2 by fitting or welding, and a cylindrical operating handle 7, which is roughly U-shaped in plan view, is provided at the upper end of the handle post 6. In other words, the operating handle 7 is attached to the head pipe 2 via the handle post 6. An operating part 8 is provided at the gripping part of the tip of the operating handle 7 for the driver 100 to operate the motorized bicycle 1 for driving, stopping, decelerating, accelerating, etc. A front fork 9 is provided on the lower side of the head pipe 2 and is fixed to the head pipe 2 by fitting or welding, and the front wheel 10 is rotatably pivoted at the lower end of the front fork 9.

[0015] A cylindrical rear stay 11 is provided on the rear side of the curved section 4. The rear stay 11 is fixed to the rear side of the curved section 4 by welding or the like, and is positioned to extend approximately horizontally to the rear. The upper end of a seat stay 12, which extends diagonally downward toward the rear, is fixed to the upper part of the rear tube 5 by welding or the like, and the seat stay 12 and rear stay 11 are arranged in approximately a V shape in a side view. The rear wheel 13 is pivotally supported at the intersection of the rear end of the seat stay 12 and the lower end of the rear stay 11, and a motor device 14 is provided to control the operation of the rear wheel 13, including driving, stopping, decelerating, and accelerating. The motor device 14 and the operating unit 8 are connected by connecting wires that are routed through the inside of the operating handle 7, handle post 6, head pipe 2, down tube 3, curved section 4, and rear stay 11 (not shown).

[0016] A seat support tube 15 is provided above the fixing point of the seat stay 12 on the rear tube 5, positioned approximately horizontally and slightly inclined downwards toward the rear. The seat support tube 15 is composed of a left U-shaped pipe material 151 located on the left side in plan view and a right U-shaped pipe material 152 located on the right side in plan view. One end of the left U-shaped pipe material 151 and one end of the right U-shaped pipe material 152, located on the rear side, are fixed at the same height to the upper and lower ends of the rear tube 5, which corresponds to a single tube, by welding or the like. The other end of the left U-shaped pipe material 151 and the other end of the right U-shaped pipe material 152, located on the front side, are fitted together to form a seat support tube 15 that is approximately rectangular in plan view and supports the seat 17 on which the seat 17 is placed and fixed. Note that it is up to the discretion of which end of the left U-shaped pipe material 151 and the other end of the right U-shaped pipe material 152 are fitted together externally.

[0017] The fitting allowance between the other end of the left U-shaped pipe material 151 and the other end of the right U-shaped pipe material 152 is appropriate within the range that ensures the required load-bearing capacity of the seat support tube 15 when the driver 100 is riding the motorized bicycle 1. However, from the viewpoint of improving the load-bearing capacity of the seat support tube 15, it is preferable to make the fitting allowance M between the other end of the left U-shaped pipe material 151 and the other end of the right U-shaped pipe material 152 equal to or greater than the maximum width W of the rear tube 5, which corresponds to a single tube, as shown in the modified seat support tube 15 of Figure 4. For example, if the maximum width W of the rear tube 5 is 90 mm, it is preferable to make the fitting allowance M equal to 90 mm or more, which corresponds to the maximum width W, and more preferably to make the fitting allowance M equal to 180 mm or more. Furthermore, in a configuration in which the other end of the left U-shaped pipe material 151 and the other end of the right U-shaped pipe material 152 are fitted together, welding the periphery of the other end of the outer fitting to the inner fitting right U-shaped pipe material 152 or left U-shaped pipe material 151 in a circumferential manner is preferable, as it further enhances the load-bearing capacity and installation stability of the sheet support tube 15. In this welded structure, it is preferable to set the fitting allowance M to 7 mm or more from the viewpoint of improving the reliability of welding between the left U-shaped pipe material 151 and the right U-shaped pipe material 152 and suppressing welding distortion.

[0018] The lower side of the front end of the seat support tube 15 is supported by a left support stay 161 and a right support stay 162 that are substantially V-shaped in side view. One end of the left support stay 161 and one end of the right support stay 162, which are arranged on the lower side, are fixed to the rear tube 5 at the same height by welding or the like at an intermediate position of the rear tube 5 that is lower than the fixing position of the seat stay 12. The other end of the left support stay 161 arranged on the upper side is fixed to the lower side of the left U-shaped pipe member 151 by welding or the like, and the other end of the right support stay 162 arranged on the upper side is fixed to the lower side of the right U-shaped pipe member 152 by welding or the like.

[0019] Here, from the viewpoint of more reliably improving load bearing capacity, it is preferable that the plate thickness of each of the left U-shaped pipe member 151, the right U-shaped pipe member 152, the left support stay 161 when formed into a cylindrical shape, and the right support stay 162 when formed into a cylindrical shape is 1.5 mm or more, the outer diameter of the left U-shaped pipe member 151 and the right U-shaped pipe member 152 at portions other than the fitting portion is 35 mm or more respectively, the outer diameter of either one of the outer-fitted fitting portions of the left U-shaped pipe member 151 and the right U-shaped pipe member 152 is 35 mm or more, the outer diameter of the other inner-fitted fitting portion is 32 mm or more, and the outer diameter of each of the left support stay 161 and the right support stay 162 is 35 mm or more.

[0020] In this embodiment, the inclination angle of the rear tube 5 with respect to the horizontal is preferably 40° to 50°, more preferably 40° to 45°, the seat support tube 15 is provided at a height of preferably 300 mm to 450 mm, more preferably 400 mm to 450 mm from the lowermost end of the bent portion 4 of the rear tube 5, and a seat 17 that is substantially L-shaped in side view is placed on the seat support tube 15 installed at this height.

[0021] Furthermore, the curved section 4 in the frame structure of the motorized bicycle 1 is positioned within a range from 20% of the length of the wheelbase in front of the midpoint M to 20% of the length of the wheelbase behind the midpoint M, using the midpoint M of the line segment connecting the front axle 101 of the front wheel 10 and the rear axle 131 of the rear wheel 13 as a reference, and is positioned within the range of the curved section position setting area R in Figure 2. In addition, the distance L from the rear end 171 of the seat surface 17 to the midpoint of the front-to-rear length of the footrest 18, which will be described later, is preferably 400 mm to 500 mm, and more preferably 425 mm to 475 mm.

[0022] Footrests 18 that protrude locally to the left and right are fixedly provided at the curved section 4. In this embodiment, locking rods 19 are provided protruding from the curved section 4 in the left and right directions, and in the illustrated example, a series of cylindrical locking rods 19 are provided so as to be inserted through holes in the curved section 4. The locking rods 19 are fixed to the periphery of the through holes in the curved section 4 by welding or the like, and are fixed so that the length of the protrusions from the curved section 4 to the left and right is constant, and the footrests 18 are attached to these locking rods 19.

[0023] In this embodiment, the footrest portion 18 is composed of an upper footrest half 181 and a lower footrest half 182. The upper footrest half 181 has an engagement projection 1811 that protrudes downward as a point, and the lower footrest half 182 has an engagement projection 1821 that protrudes upward as a point. In addition, a point-shaped upper engagement portion 191, which is composed of a locking hole, is formed on the upper side of the locking rod 19, and a point-shaped lower engagement portion 192, which is composed of a locking hole, is formed on the lower side of the locking rod 19 at a position corresponding to the upper engagement portion 191.

[0024] The upper footrest half 181 is positioned by engaging its engaging projection 1811 with the upper engaging portion 191 of the locking rod 19, and the lower footrest half 182 is positioned by engaging its engaging projection 1821 with the lower engaging portion 192 of the locking rod 19, with the upper footrest half 181 and the lower footrest half 182 being positioned together. The upper footrest half 181 and the lower footrest half 182 are then bolted together with bolts 20 to form the footrest portion 18.

[0025] According to this embodiment, by adjusting the installation height of the left and right U-shaped pipe members 151, 152 and the left and right support stays 161, 162 relative to the single tube, the front-to-back direction and height setting position of the seat on which the driver 100 sits can be changed. Therefore, the variability of the front-to-back direction and height setting position of the seat 17 on which the driver 100 of the motorized bicycle 1 sits can be increased, and the front-to-back direction and height setting position of the seat 17 can be easily adjusted according to the target driver 100, such as the elderly or people of short stature. Furthermore, by fixing the left and right U-shaped pipe members 151, 152 and the left and right support stays 161, 162 to the single tube and fitting the left and right U-shaped pipe members 151, 152 together, the load-bearing capacity of the seat support tube 15, which is the frame that supports the seat 17, and the seat 17 placed on it can be increased.

[0026] Furthermore, by forming the down tube 3, the curved section 4 provided at the lower end of the down tube 3, and the rear tube 5 extending diagonally upward from the curved section 4 with a single frame that constitutes the vehicle frame, even drivers 100 such as short people or elderly people can easily straddle the single frame and get on and off the motorized bicycle 1 while it is traveling at a low speed.

[0027] [Scope of the Invention Disclosed herein] The inventions disclosed herein include, in addition to the inventions and embodiments listed herein, those specified by modifying some of these to the extent applicable, or by adding other to these, or by deleting some of these to the extent that some effects are obtained and defining them as broader concepts. Furthermore, the inventions disclosed herein also include the modifications and additions listed below.

[0028] For example, the bicycle to which the bicycle frame structure of the present invention is applied is not limited to the low-speed motorized bicycle 1 of the above embodiment, but can also be a regular motorized bicycle or a non-motorized bicycle. Furthermore, the configuration of the seat support tube and seat in the present invention is not limited to the seat support tube 15 and seat 17 of the above embodiment, but can be appropriate within the scope of the spirit of the present invention. [Industrial applicability]

[0029] This invention can be used, for example, in a motorized bicycle traveling at low speed. [Explanation of Symbols]

[0030] 1…Motorized bicycle 2…Head pipe 3…Down tube 4…Bend 5…Rear tube 6…Handle post 7…Operating handle 8…Operating part 9…Front fork 10…Front wheel 101…Front axle 11…Rear stay 12…Seat stay 13…Rear wheel 131…Rear axle 14…Motor unit 15…Seat support tube 151…Left U-shaped pipe material 152…Right U-shaped pipe material 161…Left support stay 162…Right support stay 17…Seat 171…Rear end of seat surface 18…Footrest 181…Upper footrest half 1811…Engaging projection 182…Lower footrest half 1821…Engaging projection 19…Locking rod 191…Upper engaging part 192…Lower engaging part 20…Bolt 100…Driver M: Midpoint of the line segment connecting the front and rear axles H: Wheelbase R: Area for setting the curved section L: Distance from the rear end of the seat surface to the midpoint of the length of the footrest in the front-to-back direction M: Fitting allowance between the other end of the left U-shaped pipe and the other end of the right U-shaped pipe W: Maximum width of the single tube

Claims

1. It has a single tube that extends diagonally upward towards the rear from the area where the driver's feet are positioned, One end of the left U-shaped pipe and one end of the right U-shaped pipe are fixed at the same height between the upper and lower ends of the single tube. The other end of the left U-shaped pipe and the other end of the right U-shaped pipe are fitted together to form a sheet support tube that is roughly rectangular in plan view and supports the sheet on which it is placed. A bicycle frame structure characterized in that one end of the left support stay and one end of the right support stay are fixed to the single tube at the same height, the other end of the left support stay is fixed to the lower side of the left U-shaped pipe material, and the other end of the right support stay is fixed to the lower side of the right U-shaped pipe material.

2. The bicycle frame structure according to claim 1, characterized in that the fitting allowance between the other end of the left U-shaped pipe material and the other end of the right U-shaped pipe material is greater than or equal to the maximum width of the single tube.

3. It has a single tube that extends diagonally upward towards the rear from the area where the driver's feet are positioned, One end of the left U-shaped pipe and one end of the right U-shaped pipe are fixed at the same height between the upper and lower ends of the single tube. The other end of the left U-shaped pipe and the other end of the right U-shaped pipe are fitted together to form a sheet support tube that is roughly rectangular in plan view and supports the sheet on which it is placed. A motorized bicycle characterized by having a bicycle frame structure in which one end of the left support stay and one end of the right support stay are fixed to the single tube at the same height, the other end of the left support stay is fixed to the lower side of the left U-shaped pipe material, and the other end of the right support stay is fixed to the lower side of the right U-shaped pipe material.

4. It will travel at a low speed of 20 km / h or less, The vehicle body frame is formed by a single frame consisting of a down tube extending diagonally downward from the head pipe to which the operating handle is attached, a bend provided at the lower end of the down tube, and a rear tube extending diagonally upward from the bend. The motorized bicycle according to claim 3, characterized in that the single tube is composed of the rear tube.

Images