CN113044149A - Bicycle frame manufacturing method and bicycle frame - Google Patents

Abstract

The invention discloses a bicycle frame and a manufacturing method thereof.A front beam tube and a rear fork tube of the bicycle frame are respectively spliced by at least two split parts, and after the split parts are disassembled, the inner cavities of the front beam tube and the rear fork tube can be exposed from one side; when preparing the bicycle frame, the method comprises the following steps: 1) designing the shape of the split part, and designing the shape of the split part according to the shape of the bicycle frame; 2) forming parts, namely respectively opening the molds according to the shapes of the designed split parts; then adding the given alloy raw materials into a corresponding die according to the proportion to prepare all the split parts; 3) splicing, namely assembling and molding the assembled split parts by using strong glue, and then fastening the two assembled split parts together by using bolts or screws; 4) and (5) curing, namely curing and molding the super glue. The invention has the characteristics of simpler process and higher overall strength of the frame.

Description

Bicycle frame manufacturing method and bicycle frame

Technical Field

The invention relates to the technical field of bicycle manufacturing, in particular to a bicycle frame and a manufacturing process thereof.

Background

The bicycle is a green vehicle and also a sports fitness device, which applies relevant principles of ergonomics and aerodynamics, and has a plurality of parts, such as a frame, a fork frame, a handle, a rim, a chain and the like. The bicycle frame is used as a key part of the bicycle, plays a role in connecting and supporting all parts, and generally needs to meet the requirements of light weight and high strength.

In the prior art, the processing and manufacturing of bicycle frames generally include two processes, namely welding process and die-casting forming process. The welding process generally adopts aluminum profiles or iron profiles for welding manufacture, and the appearance cannot be made too complicated due to the process; in addition, for welding, the structure of a heat affected zone of a welding joint is very uneven and is easy to become a failure source of the whole frame, the fatigue damage resistance is reduced, the welding joints can be damaged in advance in subsequent quality tests and use, the service life is shortened, and potential safety hazards are brought to riders. Although the whole frame can be obtained by one-time die casting, the die casting process is limited by a die stripping mode, and a high-strength frame cannot be manufactured. The original magnesium alloy die-casting is divided into two types, one type is used for manufacturing children bicycles, the strength of the die-out mode is very poor, glue at certain positions cannot be pulled out, the weight is heavier or workpieces with complex shapes cannot be manufactured, and the detection of the upper detection table loaded with 70 kg and vibrated for 10 ten thousand times cannot be achieved. In addition, the process for manufacturing the frame by die casting of the magnesium alloy also adopts a piece disassembling mode to manufacture the foldable electric bicycle, the frame is disassembled into 4 pieces or 6 pieces, and then the foldable electric bicycle is manufactured in a bolt connection mode, the mode has large investment of dies and heavy weight, a plurality of seams influence the appearance, and the requirement on machining precision is high, so that the cost is low. In addition, the existing processes have the problems of poor appearance and low performance of connection positions, and joints such as bolt connection structures and welding seams are very obvious, so that the overall appearance of the bicycle is influenced.

The Chinese patent application with the publication number of CN106114734A discloses an alloy integrated die-casting frame, which comprises a first frame pressing piece, a second frame pressing piece, a first rear beam pressing piece and a second rear beam pressing piece, wherein the first frame pressing piece and the second frame pressing piece respectively comprise a front shaft pressing part, a front beam pressing part, a saddle pressing part, a lower beam pressing part and a rear beam pressing part, and the front shaft pressing part, the front beam pressing part, the saddle pressing part and the lower beam pressing part in the first frame pressing piece are respectively in corresponding pressing molding with the front shaft pressing part, the front beam pressing part, the saddle pressing part and the lower beam pressing part in the second frame pressing piece. The method specifically comprises the following steps: s1, 3D design: drawing the shapes and the sizes of each part of a first frame pressing piece, a second frame pressing piece, a first rear beam pressing piece and a second rear beam pressing piece according to the requirements of a frame, and designing the specific positions of reinforcing ribs, reinforcing connecting plates and reinforcing connecting pipes in each part; s2, opening the mould: according to the drawing drawn in the step S1, respectively forming independent forming dies for the first frame pressing piece, the second frame pressing piece, the first back beam pressing piece, and the second back beam pressing piece; simultaneously opening a mold closing mold for the whole frame according to the whole frame diagram in the step S1; s3, smelting: respectively conveying the alloy ingredients, namely Mg15, Mn 0.6, Cr 0.02, La 0.2, Ce 0.3, Pr 0.08, Y0.2, Zn 0.3, Sr 0.8 and Cu 0.06 and the balance of Al ingredients, into independent forming molds respectively arranged in the step S2 for smelting into alloys, and manufacturing independent pressing parts which are a first frame pressing part, a second frame pressing part, a first back beam pressing part and a second back beam pressing part; s4, mold closing: respectively placing the first frame pressing piece, the second frame pressing piece, the first rear beam pressing piece, the second rear beam pressing piece, the front shaft supporting tube and the saddle supporting tube which are smelted in the step S3 into the integral frame die-closing die in the step S2; s5, gluing: smearing infiltration glue for preventing micro-pores of the alloy part from leaking on the pressed end faces of the first frame pressing part, the second frame pressing part, the first rear beam pressing part, the second rear beam pressing part, the front shaft supporting tube and the saddle supporting tube; s6, pressing: and pressing each pressing piece coated with the impregnating adhesive in an integral frame die assembly mould at the temperature of 550 ℃ and under the pressure of 90 MPa.

Although the frame manufactured by the patent has the defects of reducing the weight of the frame and avoiding the strength reduction and the influence of welding lines on the appearance caused by the traditional welding process; but the pressing process is difficult to control, and the aluminum alloy die casting is generally not suitable for heat treatment due to the existence of subcutaneous air holes; the high temperature in the pressing process can not only damage the performance of the first frame pressing piece and the second frame pressing piece, but also easily cause the deformation of the first frame pressing piece and the second frame pressing piece.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a method for manufacturing a bicycle frame, which has simpler process and higher overall strength.

In order to achieve the purpose, the invention adopts the following technical scheme.

A method for manufacturing a bicycle frame is characterized in that a front beam tube and a rear fork tube of the bicycle frame are respectively formed by splicing at least two split parts, and after the split parts are disassembled, inner cavities of the front beam tube and the rear fork tube can be exposed from one side.

When the bicycle frame is prepared, the method comprises the following steps: 1) and designing the shape of the split part, and designing the shape of the split part according to the shape of the bicycle frame.

2) Forming parts, namely respectively opening the molds according to the shapes of the designed split parts; and then adding the determined alloy raw materials into the corresponding die according to the proportion to prepare all the split parts.

3) Splicing, namely firstly assembling and molding the corresponding split parts by using strong glue, and then fastening the two split parts which are assembled with each other by using bolts or screws.

4) And curing, namely drying after all the split parts are assembled into the bicycle frame through the bolts or the screws, and further curing and molding the super glue.

More preferably, each of the separate parts is provided with a corresponding connecting hole, and during splicing, the bolt or the screw fastens two separate parts assembled with each other through the corresponding connecting hole.

More preferably, the connecting hole is integrally cast and formed by the mold in the part forming process, or the connecting hole is additionally machined after the split part is cast and formed.

More preferably, the connecting hole is a counter bore, and the bolt or the screw is a countersunk bolt or a countersunk screw; after the two assembled split parts are fastened through the bolts or the screws, two ends of each bolt or each screw are hidden in the counter bores; and filling filler for shielding the bolt or the screw into the counter bore.

More preferably, a corresponding glue groove is arranged on each split part, and the powerful glue is filled in the glue grooves during splicing; the glue groove is integrally cast and formed by the die in the part forming process, or the glue groove is additionally processed after the split part is cast and formed.

More preferably, the bicycle frame is composed of a left split part and a right split part which are symmetrical with each other, and a front pipe part, a front beam pipe part, a middle pipe part and a rear fork pipe part which are molded together are respectively arranged on each split part; the rear fork tube part on the split part on the left side is a complete left rear fork tube part, and the rear fork tube part on the split part on the right side is a complete right rear fork tube part.

More preferably, the bicycle frame is composed of a frame body including a front tube part, a front beam tube part, a middle tube part, a left rear fork tube part and a right rear fork tube part which are molded together, and a plurality of tube covers, each of which corresponds to the front beam tube part, the left rear fork tube part and the right rear fork tube part, respectively.

More preferably, the front beam tube part comprises an upper tube part and a lower tube part, the upper tube part, the lower tube part and the middle tube part form a triangular or quadrilateral structure with a narrow front part and a wide rear part, and the left rear fork tube part and the right rear insertion tube part are triangular or quadrilateral structures with a wide front part and a narrow rear part.

More preferably, reinforcing ribs are arranged in the inner cavities of the front beam tube part, the left rear fork tube part and/or the right rear fork tube part, and the reinforcing ribs are distributed in a strip shape or a grid shape.

A bicycle frame, characterized in that it is made by a method of manufacturing a bicycle frame as described above, which bicycle frame acts as an electric bicycle frame or a pedal bicycle frame.

The invention has the beneficial effects that: compared with the prior art, the invention adopts the bolt fixing and gluing process, effectively avoids the material performance damage caused by high-temperature pressing, has no deformation problem during pressing, has high product yield and ensures that the frame strength meets the relevant standard; no additional front axle support tube, seat support tube, etc. need be provided. Through practical tests, the bicycle frame manufactured by the method can load 70 kilograms, passes 10 ten thousand vibration tests, 10 ten thousand pedal force tests and 10 ten thousand vertical force tests at one time, and completely meets the use requirements of adult frames. Besides, the frame manufactured by the invention has no process limitation on appearance, can be manufactured in any appearance, and can weigh about 2 kilograms.

Drawings

FIG. 1 is a process flow diagram of a method of manufacturing a bicycle frame according to the present invention.

FIG. 2 is a schematic view of a bicycle frame made in accordance with one embodiment of the present invention.

Fig. 3 shows a side view of fig. 2.

Figure 4 is a schematic view of the structure of one piece of the frame member of figure 2.

Fig. 5 is a schematic structural view of another frame part of fig. 2.

FIG. 6 is a schematic view of a bicycle frame made in accordance with another embodiment of the present invention.

Fig. 7 is a schematic structural view of the front beam tube portion of fig. 6 with the tube cover removed.

FIG. 8 is a schematic view of the breech tube section of FIG. 6 with the tube cover removed.

Reference numerals indicate the same.

1: bicycle frame, 1-1: left split part, 1-2: right split part, 1-3: front duct portion, 1-4: front beam tube part, 1-5: middle tube part, 1-6: left rear fork tube part, 1-7: the right rear fork tube portion.

2: bicycle frame, 2-1: frame main body, 2-2: and (7) covering the tube.

Detailed Description

In the description of the present invention, it should be noted that, for the terms of orientation, such as "central", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., it indicates that the orientation and positional relationship shown in the drawings are based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, but does not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated without limiting the specific scope of protection of the present invention.

Furthermore, if the terms "first" and "second" are used for descriptive purposes only, they are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features. Thus, a definition of "a first" or "a second" feature may explicitly or implicitly include one or more of the feature, and in the description of the invention, "at least" means one or more unless specifically defined otherwise.

In the present invention, unless otherwise expressly specified or limited, the terms "assembled", "connected", and "connected" are to be construed broadly, e.g., as meaning fixedly connected, detachably connected, or integrally connected; or may be a mechanical connection; the two elements can be directly connected or connected through an intermediate medium, and the two elements can be communicated with each other. The specific meanings of the above terms in the present invention can be understood by those of ordinary skill in the art according to specific situations.

In the present invention, unless otherwise specified and limited, "above" or "below" a first feature may include the first and second features being in direct contact, and may also include the first and second features not being in direct contact but being in contact with each other through another feature therebetween. Also, the first feature being "above," "below," and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply an elevation which indicates a level of the first feature being higher than an elevation of the second feature. The first feature being "above", "below" and "beneath" the second feature includes the first feature being directly below or obliquely below the second feature, or merely means that the first feature is at a lower level than the second feature.

The following describes the embodiments of the present invention with reference to the drawings of the specification, so that the technical solutions and the advantages thereof are more clear and clear. The embodiments described below are exemplary and are intended to be illustrative of the invention, but are not to be construed as limiting the invention.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

A method for manufacturing a bicycle frame is characterized in that a front beam tube and a rear fork tube of the bicycle frame are respectively formed by splicing at least two split parts, and after the split parts are disassembled, inner cavities of the front beam tube and the rear fork tube can be exposed from one side.

As shown in fig. 1, the preparation of the bicycle frame includes the following steps.

1) And designing the shape of the split part, and designing the shape of the split part according to the shape of the bicycle frame. In designing the shape of the separate component, it is also possible to consider that a separate structure is provided for the front beam pipe and the rear fork pipe, and that a separate structure is provided for other pipe bodies than the front beam pipe and the rear fork pipe, such as the front pipe and the center pipe. But the split part design of the front beam pipe and the rear fork pipe is the most basic requirement.

2) Forming parts, namely respectively opening the molds according to the shapes of the designed split parts; and then adding the determined alloy raw materials into the corresponding die according to the proportion to prepare all the split parts. When the parts are formed, according to different specific requirements, the corresponding connecting holes can be formed on the split parts at the same time, so that the subsequent splicing operation is facilitated. Of course, according to different actual needs, a person skilled in the art can also additionally machine the connecting hole after the split part is cast, and only one additional step of opening the connecting hole is added, so that the technical problem is not affected.

3) Splicing, namely firstly assembling and molding the split parts assembled with each other by using strong glue, and then fastening the two split parts assembled with each other by using bolts or screws. During splicing, in order to conveniently glue the high-power glue, a corresponding glue groove is preferably arranged on each split part, and the high-power glue is filled in the glue grooves during splicing. In this embodiment, the glue tank is integrally cast and molded by the mold in the part molding process; obviously, according to different actual needs, a person skilled in the art may additionally process the glue tank to be an upper part after the casting of the split component, and is not limited to the embodiment.

4) And curing, namely drying after all the split parts are assembled into the bicycle frame through the bolts or the screws, and further curing and molding the super glue. In this step, the curing process flow is specifically: firstly, the frame is solidified for 1h at room temperature, then enters an oven to be heated for 45 min at 180 +/-10 ℃, and finally is naturally cooled. Obviously, the curing is only for the purpose of fast setting and forming the super glue, and those skilled in the art can perform curing of the super glue by using various other curing processes that are currently available or can be realized in the future according to different actual needs (different glue types), and the curing process is not limited to the embodiment.

Wherein, in the step 2) of part forming step2, each of the separate parts is manufactured by a die casting process. That is, the casting liquid is filled into the corresponding mold under high pressure and high speed, and is molded and solidified under high pressure. Here, the die-casting process is adopted to prepare the left and right frame parts, and the advantages are that: the forming speed is high, and the casting liquid can be ensured to fill the whole cavity of the die. Of course, in the step2 of step 2), the corresponding split parts can be made by casting process or other casting process according to the shape difference or casting difficulty of the specific split parts. For example, the casting liquid with the liquidus temperature of more than 150 ℃ is poured from the top to the bottom of the mould, and after the casting liquid is filled in the whole cavity of the mould, the casting liquid is cooled, solidified and shelled. The temperature of the casting liquid is set to be more than 150 ℃ of the liquidus temperature, so that the casting liquid can be ensured to fill the whole cavity of the die, and the die is particularly suitable for processing some frame parts with complex shapes.

It should be noted that, in this embodiment, the connecting hole is a counterbore, and the bolt or the screw is a countersunk head bolt or a countersunk head screw. The purpose of this is: after the assembled split parts are fastened through bolts or screws, two ends of each bolt or screw can be hidden in the counter bores. In the actual preparation process, the counter bore can be filled with filler for covering the bolt. Thus, after the surface is polished, the frame with beautiful appearance, high strength and light weight can be obtained, and the surface of the frame has almost no splicing trace. In this embodiment, the filler is preferably a metal filler, such as an aluminum alloy, a magnesium alloy, or a stainless steel filler. The filler is a resin filler or a filler made of other materials according to different actual needs, and is not limited to this embodiment.

As an alternative embodiment, a corresponding connecting column is formed corresponding to the counter bore, and threads can be machined on the connecting column. In this way, the connection and fixation of the split parts assembled with each other can be realized through the screws; besides, the connecting column can play a role in supporting and strengthening besides serving as a connecting function, and can play a role in assembling and positioning through the groove positions corresponding to the connecting column.

In addition, a corresponding glue groove is formed on the split parts which are assembled with each other. And during splicing, the strong glue is filled in the glue groove. Therefore, after the mutually assembled split parts are pressed, enough glue is left between the mutually assembled split parts, and the bonding strength and the sealing property are ensured. In this embodiment, the glue groove is preferably continuously arranged along the splicing periphery of each frame part, and here, during the bonding, uniform stress can be ensured at the splicing part of the split parts assembled with each other, thereby ensuring the connection strength.

In this embodiment, the alloy raw material is preferably a magnesium alloy raw material, and the magnesium alloy raw material includes the following specific components: comprises the following components in percentage by weight: 3-10% of Al, and the balance of Mg and trace impurities. Magnesium alloys are the most widely used alloys in modern industrial engineering with the lightest mass, high specific strength and high specific stiffness. Compared with aluminum alloy, the magnesium alloy has lower price, and the specific gravity of the magnesium alloy is two thirds of that of the aluminum alloy; therefore, the price is much lower than that of aluminum alloy according to the volume calculation, and the magnesium alloy product has noble and elegant silver color, fine texture, elegant appearance and high-grade feeling, and is more suitable for manufacturing the vehicle frame. Obviously, the specific components of the alloy raw materials are not limited to the above examples, and those skilled in the art can appropriately adjust the mixture ratio of the above alloy raw materials according to different actual needs, for example, the alloy raw materials comprise, by weight: al 3-10%, Zn 0.5-1%, Mg and trace impurities; or comprises the following components in percentage by weight: 3-10% of Al, 0.2-1% of Mn, and the balance of Mg and trace impurities; or comprises the following components in percentage by weight: 1-6% of Zn, 0.1-1% of Zr, and the balance of Mg and trace impurities.

As a variation, the magnesium alloy raw material may be replaced by an aluminum alloy raw material, and the magnesium alloy raw material may specifically include: comprises the following components in percentage by weight: 5-15% of Mg, and the balance of Al and trace impurities; or comprises the following components in percentage by weight: 5-15% of Mg, 0.4-0.8% of Mn, and the balance of Al and trace impurities such as magnesium aluminum series and the like.

In the step 3) of splicing step3, the strong glue is a metal bonding glue with ultrahigh viscosity, so that the bonding strength of the split parts assembled with each other can be ensured. As for the selection of the specific type of the super glue, various existing or future realizable super glues such as German Hangao Letai 9432N A, Letai DP460, Hua Qishi metal super glue QIS-5011, Hua Qishi metal super adhesive QIS-3008 and the like can be selected.

In order to make the skilled person better understand the principle of the above-mentioned split part design, the following is a detailed description through two different split part design structures.

As shown in figures 2-5, a bicycle frame 1 manufactured by the manufacturing method comprises a left split part 1-1 and a right split part 1-2 which are symmetrical to each other and are arranged at the left and the right, and a front pipe part 1-3, a front beam pipe part 1-4, a middle pipe part 1-5 and a rear fork pipe part which are formed together are respectively arranged on the left split part 1-1 and the right split part 1-2; the rear fork tube part positioned on the left split part 1-1 is a complete left rear fork tube part 1-6, and the rear fork tube part positioned on the right split part 1-2 is a complete right rear fork tube part 1-7.

It should be noted that. The front beam portion 1-4 and the middle tube portion 1-5 form a triangular structure with a narrow front and a wide rear (of course, a quadrangular structure with a narrow front and a wide rear is also possible, and the shape can be adjusted appropriately, but not limited to the shape shown in the drawing), and the left rear fork portion 1-6 and the right rear fork portion 1-7 are each a quadrangular fork with a wide front and a narrow rear (of course, a triangular structure with a narrow front and a wide rear is also possible, and the shape can be adjusted appropriately, but not limited to the shape shown in the drawing). Here, providing the front beam sections 1 to 4 in a triangular or quadrangular structure with narrow front and wide rear can improve the strength of the entire vehicle frame.

In addition, in this structure, the connection holes 1 to 8 may be provided along the front beam portions 1 to 4, and the connection structure is simple.

As shown in fig. 6 to 8, another bicycle frame 2 manufactured by the above manufacturing method is composed of a frame body 2-1 and a plurality of tube caps 2-2, the frame body 2-1 includes a front tube portion, a front beam tube portion, a center tube portion, a left rear fork tube portion and a right rear fork tube portion which are molded together, and the tube caps 2-2 correspond to the front beam tube portion, the left rear fork tube portion and the right rear fork tube portion, respectively.

Similarly, the front beam tube part comprises an upper tube part and a lower tube part, the upper tube part, the lower tube part and the middle tube part form a triangular or quadrilateral structure with a narrow front part and a wide rear part, and the left rear fork tube part and the right rear insertion tube part are both triangular or quadrilateral structures with a wide front part and a narrow rear part. Obviously, the person skilled in the art may omit the lower pipe portion according to different actual needs, and is not limited to this embodiment.

Compared with the bicycle frame 1, the bicycle frame 2 has higher strength on the premise of not influencing casting because the whole frame main body 2-1 is cast together.

Further preferably, reinforcing ribs 2-3 are arranged in the inner cavities of the front beam tube part, the left rear fork tube part and/or the right rear fork tube part, and the reinforcing ribs are distributed in a strip shape or a grid shape. Thus, the strength of the entire bicycle frame can be further improved.

Compared with the prior art, this embodiment adopts bolt fastening and sticky bonding technology, effectively avoids the material properties destruction that the high temperature pressfitting brought, does not have the deformation problem when pressfitting, and not only the product yield is high, need not to set up structures such as extra front axle stay tube, saddle stay tube moreover and can ensure that frame strength accords with relevant standard. Through practical tests, the bicycle frame manufactured by the embodiment can load 70 kilograms, passes 10 ten thousand vibration tests, 10 ten thousand pedal force tests and 10 ten thousand vertical force tests at one time, and completely meets the use requirements of adult frames. In addition, the frame manufactured by the embodiment has no process limitation except the appearance, can be manufactured in any appearance, has the weight within 2 kilograms, and is very suitable for serving as an electric bicycle frame or a pedal bicycle frame.

It will be appreciated by those skilled in the art from the foregoing description of construction and principles that the invention is not limited to the specific embodiments described above, and that modifications and substitutions based on the teachings of the art may be made without departing from the scope of the invention as defined by the appended claims and their equivalents. The details not described in the detailed description are prior art or common general knowledge.

Claims (10)

1. A bicycle frame manufacturing method is used for preparing a frame of an electric bicycle or a pedal bicycle; the bicycle frame is characterized in that a front beam tube and a rear fork tube of the bicycle frame are respectively formed by splicing at least two split parts, and after the split parts are disassembled, inner cavities of the front beam tube and the rear fork tube can be exposed from one side;

when the bicycle frame is prepared, the method comprises the following steps:

1) designing the shape of the split part, and designing the shape of the split part according to the shape of the bicycle frame;

2) forming parts, namely respectively opening the molds according to the shapes of the designed split parts; then adding the given alloy raw materials into the corresponding die according to the proportion to prepare all the split parts;

3) splicing, namely assembling and molding the assembled split parts by using strong glue, and then fastening the two assembled split parts together by using bolts or screws;

4) and curing, namely drying after all the split parts are assembled into the bicycle frame through the bolts or the screws, and further curing and molding the super glue.

2. A method as claimed in claim 1, wherein each of said separate parts is provided with a corresponding attachment hole, and during assembly, said bolt or said screw fastens together two separate parts assembled with each other through said corresponding attachment holes.

3. The method of claim 2, wherein the attachment holes are integrally cast by the mold during the molding of the parts, or the attachment holes are machined separately from the separate parts after the molding.

4. The method of claim 1, wherein the attachment hole is a counterbore, and the bolt or screw is a countersunk bolt or a countersunk screw; after the two assembled split parts are fastened through the bolts or the screws, two ends of each bolt or each screw are hidden in the counter bores; and filling filler for shielding the bolt or the screw into the counter bore.

5. The method of claim 1, wherein a glue groove is provided on each of the separate parts, and the glue groove is filled with the super glue during the assembling process; the glue groove is integrally cast and formed by the die in the part forming process, or the glue groove is additionally processed after the split part is cast and formed.

6. A method for manufacturing a bicycle frame according to claim 1, wherein the bicycle frame is composed of a left and a right split parts which are symmetrical to each other, and a front tube part, a front beam tube part, a middle tube part and a rear fork tube part which are formed together are respectively provided on each split part; the rear fork tube part on the split part on the left side is a complete left rear fork tube part, and the rear fork tube part on the split part on the right side is a complete right rear fork tube part.

7. A method of manufacturing a bicycle frame as defined in claim 1, wherein said bicycle frame is made up of a frame body and a plurality of tube caps, said frame body including a front tube portion, a front beam tube portion, a center tube portion, a left rear fork tube portion and a right rear fork tube portion which are molded together, said tube caps respectively corresponding to said front beam tube portion, said left rear fork tube portion and said right rear fork tube portion.

8. The method of claim 6 or 7, wherein the front rail tube portion includes an upper tube portion and a lower tube portion, the upper tube portion, the lower tube portion and the middle tube portion form a triangular or quadrangular structure with a narrow front and a wide rear, and the left rear fork tube portion and the right rear fork tube portion each have a triangular or quadrangular structure with a wide front and a narrow rear.

9. A method as claimed in claim 1, wherein reinforcing ribs are provided in the inner cavities of said front and rear fork tube portions, said ribs being arranged in a strip or grid pattern.

10. A bicycle frame, characterized by being produced by a method of manufacturing a bicycle frame according to any of claims 1-9, which bicycle frame functions as an electric bicycle frame or a pedal bicycle frame.

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