Bicycle frame structure

Abstract

To provide a bicycle frame structure capable of securing required product-accuracy, securing a high yield, and reducing the manufacturing cost.SOLUTION: A bicycle frame structure has a down-tube 3 bent in a V-shape in a side view, the down-tube including: an upward extension portion 31 extending obliquely upward toward a head pipe 2; and a horizontal portion 33 extending substantially horizontally rearward from a bent portion 32 located near a position of a driver's foot and bent from a lower end of the upward extension portion 31. The down-tube 3 is composed of a single frame formed by joining a pair of right and left half bodies 34, 35 to each other in a width direction. An engagement holding stay 38 of an ECU 9 mounted in the down-tube 3 is provided inside the upward extension portion 31. The upward extension portion 31 is provided with an opening 353 for mounting the ECU 9 therethrough.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a bicycle frame structure in which an electric unit is mounted inside the down tube. [Background technology]

[0002] Conventionally, a bicycle frame structure in which an electric unit is installed inside the down tube is disclosed in Patent Document 1. This frame structure is for an electric bicycle having a battery unit and an electric motor that operates by receiving power from the battery unit, and includes a down tube that extends linearly and inclined diagonally downward from the head pipe toward the rear of the vehicle body, with the battery unit installed inside the down tube over most of its length, and part of the electric motor installed inside the down tube by screwing part of it into the opening at the rear end of the down tube.

[0003] Furthermore, an opening is formed on one side of the middle part of the down tube which is closed by a lid member connected to the outer circumferential surface of the down tube, and a battery unit equivalent to an electric unit is stored in the storage space inside the down tube so that it can be taken out and inserted through the opening. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2000-238675 A Summary of the Invention [Problem to be solved by the invention]

[0005] The down tube is a part equivalent to the skeleton that ensures the main strength of the bicycle frame, and must be formed with sufficient strength, but for bicycles such as certain motorized bicycles that travel at speeds of 20 km / h or less, it is desirable to use a down tube that is bent in a V-shape in side view at the bend near the rider's feet to extend the length in the fore-aft direction of the body and thus has increased strength. In a down tube that is bent in a V-shape in side view and in which an electric unit is installed, it is usually necessary to have parts with different cross-sectional shapes and cross-sectional sizes, for example, a part in front of the bend in which the electric unit is installed and a rear end part to which the rear stays are joined are formed with different cross-sectional shapes.

[0006] However, when a down tube is bent in a V-shape as viewed from the side, which requires portions with different cross-sectional shapes and sizes, it is difficult to ensure the required precision when it is formed by drawing and bending a metal tube, which causes problems such as a low yield rate. Also, when it is formed by casting a metal material, another problem occurs in that the manufacturing cost becomes very high.

[0007] The present invention has been proposed in light of the above-mentioned problems, and has as its object to provide a bicycle frame structure having a down tube that is bent in an L-shape when viewed from the side and in which an electric unit is installed, which ensures the necessary product precision, ensures high yields, and reduces manufacturing costs, as well as a moped equipped with this bicycle frame structure. [Means for solving the problem]

[0008] The bicycle frame structure of the present invention has a down tube that is bent in an L-shape when viewed from the side, with an upward extension portion extending diagonally upward toward the head pipe, and a horizontal portion extending approximately horizontally rearward from a bent portion located near the position of the rider's feet, the down tube being composed of a single frame formed by joining a pair of left and right halves to each other in the width direction, an engagement and retention stay for an electric unit to be installed inside the down tube is provided inside the upward extension portion, and an opening is provided in the upward extension portion for installing the electric unit. According to this, by forming the down tube by joining the pair of left and right halves together in the width direction, it is possible to ensure the necessary product precision, ensure a high yield, and reduce manufacturing costs when manufacturing a bicycle frame structure having a down tube that is bent in a V-shape when viewed from the side and in which an electric unit is installed. Also, by extending the down tube substantially horizontally rearward from the bent portion located near the rider's feet and extending the length of the down tube in the fore-aft direction, it is possible to further increase the strength of the down tube. Also, by making the down tube a single frame, it is possible to ensure that the rider can easily place his / her feet on the ground.

[0009] The bicycle frame structure of the present invention is characterized in that the engagement and retention stay is fixed to one of the halves, the engagement and retention stay engages and retains the electric unit at a position close to the one of the halves, and the opening is formed in the other half. According to this, the engaging and retaining stay engages and retains the electric unit at a position close to one half, which creates more space inside the other half, and by changing the engaging and retaining stay according to the size and shape of the electric unit, electric units of various sizes and shapes can be engaged and retained inside the down tube. In other words, the degree of freedom in the size and shape of the electric unit that can be installed inside the down tube can be increased. Also, by forming an opening in the other half for installing the electric unit, it is possible to easily attach the electric unit to the engaging and retaining stay fixed to one half.

[0010] The bicycle frame structure of the present invention is characterized in that the electric unit is engaged and held by the engaging and holding stay, into which the electric unit can be engaged from above, and the inner peripheral surface of the one half. According to this, the electrical unit can be inserted into the down tube through the opening in the other half, slid along the inner surface of one of the halves, and engaged and held in place by engaging it from above into the engaging and retaining stay, greatly enhancing the convenience of the electrical unit installation work.

[0011] The bicycle frame structure of the present invention is characterized in that a tube cover which is roughly C-shaped in cross section is arranged so as to straddle the one half and the other half, stacked from the upper side to the side of the upward extension portion, the side wall portion of the upward extension portion in the arrangement area of ​​the tube cover is formed close to the inside of the down tube, both side walls of the tube cover are respectively fixed removably to the one half and the other half, and the opening is covered by the tube cover. According to this, the tube cover having a generally U-shaped cross section is arranged so as to straddle one half and the other half, and the side walls on both sides of the tube cover are detachably fixed to the one half and the other half, respectively, thereby increasing the fixing strength and integrity of the one half and the other half joined together in the width direction, and facilitating the maintenance of the electric unit. Also, by overlapping the tube cover having a generally U-shaped cross section covering the opening from the upper side to the side of the upper extension, the thickness of the down tube can be increased in the area where the tube cover overlaps other than the opening, and the strength and rigidity of the down tube can be further increased. Also, by forming the side wall of the upper extension in the area where the tube cover is arranged closer to the inside of the down tube, the protrusion of the tube cover from the down tube can be eliminated or reduced, and the design of the down tube can be improved.

[0012] The bicycle frame structure of the present invention is characterized in that a reinforcing member that partially increases the plate thickness is joined to the front end of the down tube adjacent to the head pipe. With this, by partially increasing the thickness of the reinforcing member at the front end of the down tube, the strength and rigidity of the down tube can be increased when a large load is applied from the front of the bicycle, such as in a head-on collision.

[0013] The bicycle frame structure of the present invention is characterized in that the electrical unit is an ECU, and a wire guide for bundling the wiring of the ECU is provided above the installation area of ​​the ECU in the upward extension portion. According to this, when the ECU, which is connected to various components and numerous wiring, is installed inside the down tube as an electrical unit, bundling the wiring with a wire guide prevents the numerous wiring from becoming twisted or tangled, thereby improving manufacturing efficiency when manufacturing the bicycle and improving maintainability during maintenance.

[0014] The motorized bicycle of the present invention is characterized in that it travels at a low speed of 20 km / h or less and is equipped with the bicycle frame structure of the present invention. This makes it possible to provide a bicycle frame structure with sufficient strength for a motorized bicycle traveling at low speeds of 20 km / h or less, while also ensuring that the rider can easily place their feet on the ground. Effect of the Invention

[0015] According to the present invention, in a bicycle frame structure having a down tube that is bent into an L-shape when viewed from the side and in which an electric unit is mounted, it is possible to ensure the necessary product precision, ensure high yields, and reduce manufacturing costs. [Brief description of the drawings]

[0016] [Figure 1] 1 is a side view of a motorized bicycle equipped with a bicycle frame structure according to an embodiment of the present invention; [Diagram 2]2 is a side view of a down tube and a tube cover in the bicycle frame structure according to the embodiment. FIG. [Diagram 3] FIG. 2 is a plan view of a down tube and a tube cover in the bicycle frame structure according to the embodiment. [Figure 4] 2, (a) is an enlarged cross-sectional view taken along the line AA in FIG. 2, and (b) is an enlarged plan view of a portion of the front end of the down tube in FIG. [Diagram 5] 4A is an enlarged plan view of one half that constitutes the down tube in the embodiment, and FIG. 4B is an enlarged plan view of the other half that constitutes the down tube in the embodiment. [Figure 6] 2 is a partial cross-sectional view showing one half, an engagement retention stay, and an ECU in the bicycle frame structure according to the embodiment. FIG. [Figure 7] 7A is an enlarged cross-sectional view taken along line BB in FIG. 6, FIG. 7B is an enlarged cross-sectional view taken along line CC in FIG. 6, and FIG. 7C is an enlarged cross-sectional view of the ECU area in FIG. 6 as viewed from the bottom side. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] [Vehicle body frame structure and motorized bicycle according to the embodiment] 1 to 4, the bicycle frame structure for the motorized bicycle 1 includes a head pipe 2, a down tube 3 formed of a single tube and extending obliquely downward from the head pipe 2, a pair of left and right rear stays 4,4 fixed to the rear end of the down tube 3, a bottom bridge 5 that is substantially cylindrical and V-shaped in side view and fixed by welding or the like to the rear ends of the rear stays 4, a pair of left and right cylindrical seat stays 6,6 that are fixed by welding or the like to the upper ends of the bottom bridges 5 and extend obliquely upward toward the front, a top bridge 7 that is cylindrical and V-shaped in side view and fixed by welding or the like to the upper ends of the seat stays 6, and a cylindrical seat rail 8 that is fixed by welding or the like to the rear ends of the parts of the top bridges 7 that extend rearward. Each frame that constitutes the bicycle frame structure of this embodiment is preferably made of, for example, stainless steel, aluminum alloy, aluminum, steel, etc.

[0018] The down tube 3 is formed with an upward extension portion 31 that extends obliquely upward toward the head pipe 2, a bent portion 32 that bends from the lower end of the upward extension portion 31 and is located near the foot position of the rider 100, and a horizontal portion 33 that extends approximately horizontally rearward from the bent portion 32, and is configured as a cylindrical single frame that is bent in an L-shape when viewed from the side. The upper end portion of the upward extension portion 31 is fixed to the head pipe 2 by welding or the like. The rear end portion of the down tube 3 is gradually changed so that the size of the opening of the tube is reduced.

[0019] In order to improve manufacturing efficiency, etc., the down tube 3 is formed by joining a pair of left and right halves 34, 35 aligned in the width direction, one half 34 located on the right side facing forward, and the other half 35 located on the left side facing forward, to each other by welding or the like, and in this embodiment is composed of a square cylindrical single frame (see Figures 3 to 6).

[0020] A tube cover 36 having a generally U-shaped cross section is disposed on the down tube 3, overlapping from the upper side to the side of the upward extension portion 31, and spanning one half 34 and the other half 35. Side wall portions 342, 352 which are parts of the side walls 341, 351 of the upward extension portion 31 in the region where the tube cover 36 is disposed are formed in positions closer to the inside of the down tube 3 than the other parts of the side walls 341, 351, respectively, and preferably in a position closer to the inside by the plate thickness of the side wall 361 of the tube cover 36, and the tube cover 36 is disposed so as to cover the upper surface of the upward extension portion 31 and the side wall portions 342, 352 (see FIG. 4).

[0021] The side walls 361, 361 on both sides of the tube cover 36 are respectively detachably fixed to one half 34 and the other half 35 constituting the down tube 3, and in this embodiment, as shown in Figures 1 to 4, they are fixed by bolt tightening with bolts and nuts at predetermined locations in the area where the left side wall 361 of the tube cover 36 overlaps with the side wall portion 342 of the down tube 3, and at predetermined locations in the area where the right side wall 361 of the tube cover 36 overlaps with the side wall portion 352 of the down tube 3.

[0022] An opening 353 is provided in the side wall 352 of the other half 35 constituting the down tube 3 for mounting an ECU (Electronic Control Unit) 9, which corresponds to the electric unit in this embodiment, in the upward extension portion 31, and the opening 353 is covered and closed by the tube cover 36 (see Figs. 2 and 6). Also, the overlapping region between the tube cover 36 and the upper surface of the upward extension portion 31, the overlapping region between the tube cover 36 and the side wall 342, and the overlapping region between the tube cover 36 and the side wall 352 other than the portion where the opening 353 is formed are reinforced regions that are thicker than the other upward extension portions 31 by the plate thickness of the tube cover 36.

[0023] Reinforcing members 343, 354 for partially thickening the plate thickness are joined to the front end of the down tube 3 adjacent to the head pipe 2. In this embodiment, as shown in Figs. 3 to 6, a substantially C-shaped reinforcing member 343 is provided along the inner circumference of the front end of one half 34 and is joined to the one half 34 by welding at a predetermined location, and a substantially C-shaped reinforcing member 354 is provided along the inner circumference of the front end of the other half 35 and is joined to the other half 35 by welding at a predetermined location. Furthermore, a welded portion 373 is formed so as to fill a slit 371 formed on the upper surface of the front end of the down tube 3 and a slit 372 formed on the lower surface of the front end of the down tube 3, and the reinforcing member 343, the reinforcing member 354, the one half 34, and the other half 35 are joined together.

[0024] An engagement and retention stay 38 that engages and retains the ECU 9 mounted inside the down tube 3 is provided inside the upward extension portion 31 of the down tube 3. In this embodiment, as shown in Figs. 5 to 7, the engagement and retention stay 38 is fixed to one half 34 by welding or the like, and the engagement and retention stay 38 engages and retains the ECU 9 at a position closer to one half 34.

[0025] Furthermore, the engagement retaining stay 38 in this embodiment is an integrally formed member having a plate-shaped fixing portion 381 fixed to one of the half bodies 34 by welding or the like, a rear lower retaining plate 382 that holds the approximately rectangular parallelepiped ECU 9 from the rear lower side which is fitted inside so as to approximately follow the upward extension portion 31, a front lower retaining plate 383 that holds the ECU 9 from the front lower side, and a side retaining plate 384 that holds the ECU 9 from the other half body 35 side.

[0026] The ECU 9 inserted through the opening 353 is inserted from above into a region surrounded by the front lower holding plate 383, the side holding plate 384, and the inner peripheral side surface of the one half 34 so as to slide along the inner peripheral side surface of the one half 34 until it abuts against the rear lower holding plate 382, ​​and is engaged and held by the front lower holding plate 383, the side holding plate 384, the inner peripheral surface of the one half 34, and the rear lower holding plate 382. In the illustrated example, the engaging and holding stay 38 has engaging portions 385, 386 formed on the rear lower holding plate 382 with which the protruding portion of the ECU 9 engages, and the protruding portion of the ECU 9 is engaged and locked in the concave engaging portions 385, 386.

[0027] A wire guide 344 that bundles multiple wirings 91 extending from the ECU 9 is provided above the installation area of ​​the ECU 9 in the upward extension portion 31 of the down tube 3, and in this embodiment, the wire guide 344 is fixed to one of the halves 34 by welding or the like.

[0028] In the motorized bicycle 1 of this embodiment, the seat rail 8 is formed in a generally U-shape in plan view, with one end of the seat rail 8 fixed to the left top bridge 7 by welding or the like, and the other end of the seat rail 8 fixed to the right top bridge 7 by welding or the like. A seat 10, which is generally L-shaped in side view, is attached to the upper side of the seat rail 8 so as to be placed thereon.

[0029] The rear stays 4, seat stays 6, and seat rails 8 connected via the bottom bridge 5 and top bridge 7 form an inverted Z-shaped frame in side view, which is provided to protrude to the left and right. A bridge tube (not shown) is installed between the left seat stay 6 and the right seat stay 6 near the longitudinal middle of the seat stay 6, and both ends of the bridge tube are fixed to the left and right seat stays 6 by welding or the like.

[0030] A rear tube 11 extending diagonally upward toward the rear is provided between the horizontal portion 33 of the down tube 3 and the bridge tube, and the lower end of the rear tube 11 is fixed to the horizontal portion 33 by welding or the like, and the upper end of the rear tube 11 is fixed to the bridge tube near the midpoint of the bridge tube by welding or the like.

[0031] A cylindrical handle post 12 is fixed to the upper side of the head pipe 2, and a cylindrical operating handle 13 is provided at the upper end of the handle post 12. An operating unit 14 is provided at the grip portion at the tip of the operating handle 13, which allows the rider 100 to operate the motorized bicycle 1 to drive, stop, decelerate, accelerate, etc. A front fork 15 is fixed to the lower side of the head pipe 2, and a front wheel 16 is rotatably supported at the lower end of the front fork 15.

[0032] A rear wheel 17 is rotatably supported at a bent portion of the bottom bridge 5, and a motor device 18 is provided to control and operate the rear wheel 17, such as by driving, stopping, decelerating, and accelerating. The motor device 18 and the ECU 9, and the operation unit 14 and the ECU 9 are connected by wiring 91, respectively.

[0033] Foot rest portions 19, 19 that locally protrude to the left and right are attached to the down tube 3 in the range from the curved portion 32 to the front of the rear end of the horizontal portion 33. In the illustrated example, the foot rest portions 19, 19 that locally protrude to the left and right are attached to the horizontal portion 33 near the curved portion 32.

[0034] According to this embodiment, by forming the down tube 3 by joining a pair of left and right halves 34, 35 together in the width direction, it is possible to ensure the necessary product precision, ensure a high yield, and reduce manufacturing costs when manufacturing a bicycle frame structure having a down tube 3 that is bent in a V-shape when viewed from the side and in which an electric unit such as an ECU 9 is housed. Also, by extending the down tube 3 substantially horizontally rearward from the bent portion 32 located near the position of the rider's 100's feet, and by extending the length of the down tube 3 in the fore-aft direction, it is possible to further increase the strength of the down tube 3. Also, by making the down tube 3 a single frame, it is possible to ensure that the rider 100 can easily place his / her feet on the ground.

[0035] Furthermore, by the engagement and retention stay 38 engaging and retaining an electric unit such as the ECU 9 at a position closer to one half 34, a larger space is created inside the other half 35, and by changing the engagement and retention stay 38 according to the size and shape of the ECU 9, it is possible to engage and retain ECUs of various sizes and shapes inside the down tube 3. That is, it is possible to increase the degree of freedom in the size and shape of the electric unit such as the ECU 9 that can be housed inside the down tube 3. Furthermore, by forming an opening 353 in the other half 35 for housing an electric unit such as the ECU 9, it is possible to easily attach the electric unit such as the ECU 9 to the engagement and retention stay 38 fixed to the one half 34.

[0036] Furthermore, an electric unit such as ECU 9 can be inserted into the down tube 3 through the opening 353 of the other half 35, and the electric unit such as ECU 9 can be slid along the inner peripheral surface of one half 34 and engaged with the engaging and retaining stay 38 from above, thereby greatly enhancing the convenience of the installation work of an electric unit such as ECU 9.

[0037] In addition, by disposing the tube cover 36 having a generally U-shaped cross section so as to straddle the one half 34 and the other half 35, and by removably fixing the side walls 361, 361 on both sides of the tube cover 36 to the one half 34 and the other half 35, respectively, it is possible to increase the fixing strength and integrity of the one half 34 and the other half 35 joined together in the width direction, and to facilitate the maintenance of the ECU 9, etc. In addition, by overlapping the tube cover 36 having a generally U-shaped cross section covering the opening 353 from the upper side to the side of the upper extension 31, it is possible to increase the thickness of the down tube 3 in the area where the tube cover 38 overlaps other than the opening 353, and it is possible to further increase the strength and rigidity of the down tube 3. In addition, by forming the side walls 342, 352 of the upper extension 31 in the area where the tube cover 36 is disposed closer to the inside of the down tube, it is possible to eliminate or reduce the protrusion of the tube cover 36 from the down tube 3, and it is possible to improve the design of the down tube 3.

[0038] In addition, by partially thickening the plate thickness at the front end of the down tube 3 using reinforcing members 343, 354 at the front end of the down tube 3, the strength and rigidity of the down tube 3 can be increased when a large load is applied from the front of the bicycle, such as in a head-on collision.

[0039] In addition, when the ECU 9, which is connected to various components and numerous wirings, is installed inside the down tube 3 as an electrical unit, bundling the multiple wirings 91 of the ECU 9 with wire guides 344 prevents the numerous wirings from becoming twisted or tangled, thereby improving manufacturing efficiency when manufacturing the bicycle and improving maintainability during maintenance.

[0040] Furthermore, in a motorized bicycle 1 traveling at a low speed of 20 km / h or less, a bicycle frame structure with sufficient strength can be provided, and ease of placement of the rider's 100 feet on the ground can be ensured.

[0041] [Scope of the invention disclosed herein] The inventions disclosed in this specification include, in addition to the inventions and embodiments listed as inventions, those specified by changing partial contents of these to other contents disclosed in this specification, those specified by adding other contents disclosed in this specification to these contents, or those specified by deleting partial contents of these to the extent that partial effects can be obtained, and specifying them as a higher-level concept. The inventions disclosed in this specification also include the following modified examples and added contents.

[0042] For example, the electrical unit installed in the down tube in the bicycle frame structure of the present invention is not limited to the ECU 9 of the above embodiment, and could be any type of electrical device, such as a battery, etc. Also, while the bicycle to which the bicycle frame structure of the present invention is applied is preferably a moped that travels at a low speed of 20 km / h or less, other types of bicycles are also possible, and it is also possible to apply the structure to mopeds that can travel at speeds above 20 km / h, electrically assisted bicycles, pedaled bicycles without electrically assisted bicycles, etc. [Industrial Applicability]

[0043] The present invention can be used, for example, as a bicycle frame structure for a motorized bicycle that travels at low speeds. [Explanation of symbols]

[0044] 1...motorcycle 2...head pipe 3...down tube 31...upward extension portion 32...bent portion 33...horizontal portion 34...one half 341...side wall 342...side wall portion 343...reinforcing member 344...wire guide 35...other half 351...side wall 352...side wall portion 353...opening 354...reinforcing member 36...tube cover 361...side wall 371, 372...slit 373...welded portion 38...engagement retaining stay 381...fixing portion 382...rear lower retaining plate 383...front lower retaining plate 384...side retaining plate 385, 386...engagement portion 4...rear stay 5...bottom bridge 6...seat stay 7...top bridge 8...seat rail 9...ECU 91...wiring 10...seat 11...rear tube 12...Handle post 13...Operating handle 14...Operating section 15...Front fork 16...Front wheel 17...Rear wheel 18...Motor device 19...Footrest 100...Driver

Claims

1. The down tube is bent in a V-shape in a side view, and includes an upward extension portion extending obliquely upward toward a head pipe, a horizontal portion extending rearward substantially horizontally from a bent portion located near a rider's feet that is bent from a lower end of the upward extension portion, and The down tube is composed of a single frame formed by joining a pair of left and right halves together in the width direction, an engagement and retention stay for an electric unit mounted inside the down tube is provided inside the upward extension portion, a bicycle frame structure including a frame member for mounting an electric unit to said bicycle;

2. The engagement retention stay is fixed to the one half, The engagement and retention stay engages and retains the electric unit at a position close to the one half, 2. A bicycle frame structure according to claim 1, wherein said opening is formed in said other half.

3. 3. The bicycle frame structure according to claim 2, wherein the electric unit is engaged and held by the engaging and holding stay, into which the electric unit can be engaged from above, and an inner peripheral surface of the one half.

4. A tube cover having a generally U-shaped cross section is disposed so as to overlap the upper side and the side of the upward extension portion and straddle the one half and the other half, A side wall portion of the upward extension portion in an arrangement area of ​​the tube cover is formed toward an inner side of the down tube, Both side walls of the tube cover are detachably fixed to the one half and the other half, respectively, and 3. The bicycle frame structure according to claim 2, wherein said opening is covered by said tube cover.

5. 5. A bicycle frame structure as claimed in any one of claims 1 to 4, characterized in that a reinforcing member for partially increasing the thickness of the down tube is joined to a front end portion of the down tube adjacent to the head pipe.

6. A bicycle frame structure as described in any one of claims 1 to 4, characterized in that the electrical unit is an ECU, and a wire guide for bundling the wiring of the ECU is provided above the installation area of ​​the ECU in the upward extension portion.

7. 7. A motorized bicycle which travels at a low speed of 20 km / h or less and which comprises the bicycle frame structure according to claim 6.

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