Method for manufacturing a frame unit for a bicycle

Abstract

A method of manufacturing a frame unit for a bicycle, comprising: Compression molding a left frame body (23) on which a part of an adjusting section (40), a part of a seat tube (5), a part of a frame (7) and a left strut (11) are integrally formed; Compression molding a right frame body (25) on which a part of the adjusting section (40), a part of the seat tube (5), a part of the frame (7) and a right strut (11a) are integrally formed; Adjusting a length (L) of the adjusting section (40); and Coupling the left frame body (23) and the right frame body (25), wherein after adjusting the length (L) of the adjusting portion (40), a head tube (3) is formed by bending a portion of the adjusting portion (40) and then the left frame body (23) and the right frame body (25) are coupled.

Description

[0001] The present invention relates to a method of manufacturing a frame unit for a bicycle, and more particularly to a method of manufacturing a frame unit for a bicycle, which frame unit comprises a head tube, a seat tube, a frame, and left and right stays.

[0002] In general, a bicycle frame unit is an assembly that forms an overall structure of a bicycle and is made by joining components such as a head tube, a seat tube, a frame, and left and right stays together.

[0003] Regarding the frame unit for a bicycle, ensuring differentiation in design and strength for safety are core factors, and for this purpose, respective manufacturers actively conduct research on the development of technologies, machining methods, materials and the like.

[0004] Recently, in order to ensure differentiation in design and strength for safety, materials such as aluminum, chromium molybdenum steel, carbon and titanium are used instead of high-strength steel material that is generally used.

[0005] Fig. 1 is a configuration diagram of a frame unit for a bicycle according to the related art.

[0006] With reference to Fig. 1, a frame unit 100 for a bicycle according to the related art includes a head tube 101, a seat tube 103, an upper frame 105, a lower frame 107, and upper and lower stays 109 and 111 arranged on both sides.

[0007] A steering tube to which a handlebar is connected is installed on the head tube 101, and a seat tube connected to a seat is installed on the seat tube 103.

[0008] The upper and lower frames 105 and 107 connect and support the head tube 101 and the seat tube 103 on the front and rear sides thereof.

[0009] Rear ends of the two upper and lower struts 109 and 111 are connected to each other in such a way that they form a rotary body fork 113 on which a rear wheel is mounted.

[0010] A front end of the lower stay 111 is connected to a pedal assembly 115 configured at a lower end of the seat tube 103.

[0011] Meanwhile, the frame unit 100 for a bicycle mainly includes both the upper frame 105 and the lower frame 107, but in some cases, only a single frame, that is, only the upper frame 105 between the head tube 101 and the seat tube 103 may be used.

[0012] However, according to the frame unit 100 for a bicycle of the related art having the above-mentioned configuration, when the head tube 101 is joined to the upper frame 105 or front ends of the upper and lower frames 105 and 107 by a welding process, residual stress due to welding heat is distributed to the joint portions, and in particular, impact loads are directly applied when the bicycle is running, thereby causing a serious problem in terms of safety such as breakage or damage occurring at the periphery of the joint portions.

[0013] In addition, since the process of welding the joint sections is carried out manually, a substandard rate is high because there is a difference in welding quality according to the skill of workers and the working environment, and thus there are disadvantages in that excessive working time is required and productivity deteriorates.

[0014] In addition, since the frame unit 100 for a bicycle according to the related art is manufactured in different sizes for each specification, a mold corresponding to the respective size range must be manufactured separately for each specification, and thus there are disadvantages in that the manufacturing cost is increased and productivity deteriorates.

[0015] The information disclosed in this Background of the Invention section is provided merely to enhance the understanding of the general background of the invention and should not be considered as an admission or any form of suggestion that this information constitutes prior art already known to a technically skilled person.

[0016] CN 202 508 232 U describes a frame unit for a bicycle, comprising a left frame body on which a part of a seat tube, a part of a frame and a left stay are formed integrally, and a right frame body on which a part of the seat tube, a part of the frame and a right stay are formed integrally, wherein the seat tube and the frame are formed integrally, and then the left frame body and the right frame body are coupled integrally.

[0017] Further frame units for a bicycle are known from US 4 613 146 A and US 5 215 322 A.

[0018] The object of the invention is to provide a method for manufacturing a frame unit for a bicycle having the advantages of improving productivity and reducing manufacturing costs by manufacturing the frame unit in different sizes for each specification using a single mold.

[0019] The object is achieved according to the invention by a method for producing a frame unit for a bicycle according to the features of claim 1. Advantageous further developments are described in the subclaims.

[0020] An exemplary embodiment of the present invention provides a method for manufacturing a frame unit for a bicycle, comprising compression molding a left frame body on which a part of an adjusting portion, a part of a seat tube, a part of a frame, and a left stay are integrally formed, compression molding a right frame body on which a part of the adjusting portion, a part of the seat tube, a part of the frame, and a right stay are integrally formed, adjusting a length of the adjusting portion, and coupling the left frame body and the right frame body.

[0021] After adjusting the length of the adjusting section, a head tube is formed by bending the adjusting section, and the left frame body and the right frame body are coupled.

[0022] A support ring can be inserted into the head tube and coupled to it.

[0023] The compression molding may further form a plurality of reinforcing ribs on the adjusting portion.

[0024] Reinforcing panels can be installed on the inside of the left and right frame bodies, and the reinforcing panels can be connected together with the left and right frame bodies along edges thereof.

[0025] The reinforcement panels can be installed between the head tube and the frame, between the seat tube and the frame, at a portion of the two stays where a rear wheel is installed, and at the inside of a pedal assembly where a pedal is installed, and then connected together with the left and right frame bodies.

[0026] The reinforcement panels can be connected together with the left and right frame bodies in a state in which the reinforcement panels are attached to or temporarily connected to the left and right frame bodies.

[0027] The reinforcement panels can be formed together with reinforcing ribs that protrude so that they cross each other inside and out.

[0028] According to the exemplary embodiment of the present invention, by adjusting a length of the adjusting portion, the bicycles can be easily manufactured to correspond to a size for each specification, and thereby a process of re-manufacturing a mold manufactured for each specification can be eliminated.

[0029] In addition, the frame unit for a bicycle is manufactured using a single mold, which improves productivity and reduces manufacturing costs.

[0030] In addition, the left and right frame bodies, which form the frame and the left and right struts, are integrally molded and coupled, which facilitates a manufacturing process.

[0031] In particular, the rigidity and durability between the head tube and the frame are stably maintained with respect to a shock load transmitted from a road surface and a fatigue load of the frame unit itself, thereby preventing damage such as breakage and ensuring safety.

[0032] In addition, the seat tube, frame, and left and right stays, which form the left and right frame bodies, are integrally molded, making the overall external appearance of the frame unit for a bicycle aesthetically attractive.

[0033] Furthermore, a welding process is performed along the edges of the left and right frame bodies when the left and right frame bodies are joined, so that the welding processes can be easily automated, the working hours can be reduced as a result of automation, and the quality and productivity of welding can be improved.

[0034] The methods and apparatus of the present invention have other features and advantages which will be apparent from, or set forth in more detail in, the accompanying drawings incorporated herein and the following detailed description, which together serve to explain certain principles of the present invention. Fig. 1 is a configuration diagram of a frame unit for a bicycle according to the related art. Fig. 2 is an exploded perspective view of a frame unit for a bicycle manufactured by a method according to the present invention. Fig. 3 is a side view of the frame unit for a bicycle manufactured by the method according to the present invention. Fig. 4 is an enlarged view illustrating an adjusting portion of the frame unit for a bicycle manufactured according to the invention. Fig. 5 is an enlarged view illustrating a state in which a length of the adjusting portion of the frame unit for a bicycle manufactured according to the invention is adjusted. Fig. 6 is an enlarged perspective view illustrating a partial configuration in a state in which a reinforcing panel is installed on the frame unit for a bicycle manufactured according to the invention. Fig. 7 is an enlarged perspective view illustrating a state in which rigid ribs are formed on a frame portion adjacent to a head tube of the frame unit for a bicycle manufactured according to the invention.

[0035] It should be understood that the attached drawings are not necessarily to scale and present a somewhat simplified representation of various features illustrating the basic principles of the invention. The specific design features of the present invention, including, for example, specific dimensions, orientations, positions, and shapes disclosed herein, will be determined in part by the particular intended application and usage environment.

[0036] In the figures, reference numerals refer to the same or equivalent parts of the present invention throughout the individual figures of the drawing.

[0037] Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) have been described in connection with exemplary embodiments, it is to be understood that the present description is not intended to limit the invention(s) to these exemplary embodiments. On the contrary, the invention(s) are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents, and other embodiments which may be included within the spirit and scope of the invention as defined by the appended claims.

[0038] The present invention will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. As those skilled in the art would appreciate, the described embodiments could be modified in various other ways without departing from the spirit or scope of the present invention.

[0039] A part irrelevant to the description is omitted in order to clearly describe the present invention, and the same or similar elements are denoted by the same reference numerals throughout the description.

[0040] The size and thickness of each component shown in the drawings are shown arbitrarily for clarity and ease of description, but the present invention is not limited thereto. The thicknesses of the various sections and regions are exaggerated for clarity.

[0041] Furthermore, in the following detailed description, names of components which are in the same relationship are classified into “the first”, “the second” and the like, but the present invention is not limited to the order in the following description.

[0042] Throughout the specification and claims, unless expressly stated to the contrary, the word "comprise" and variations such as "comprises" or "having" are intended to include stated elements but not to exclude any other elements.

[0043] In addition, “unit,” “means,” “part,” “element,” or the like described in the specification means a unit of a comprehensive configuration that performs at least one function or activity.

[0044] Fig. Figure 2 is an exploded perspective view of a frame unit for a bicycle made according to the invention, and Fig. 3 is a side view of the frame unit for a bicycle made according to the invention.

[0045] With reference to the Fig. 2 and Fig. 3, a frame unit 1 for a bicycle manufactured according to the invention comprises a head tube 3, a seat tube 5, a frame 7, a pedal assembly 9 and left and right stays 11 and 11a.

[0046] That is, a steering tube on which a handlebar is mounted is installed on the head tube 3, and a front wheel is installed on a fork configured on a lower side of the steering tube.

[0047] A saddle is installed on the seat tube 5 by means of a seat tube 13.

[0048] The frame 7 integrally connects the head tube 3 and the seat tube 5 and integrally connects the pedal assembly 9 to a lower extension frame 15, thereby forming a body of a bicycle.

[0049] Here, one frame can be formed between the head tube 3 and the seat tube 5.

[0050] The left and right stays 11 and 11a have an upper stay 17 and a lower stay 19, respectively, rear ends of the upper stay 17 and the lower stay 19 are connected to each other to form a rotary fork 21 on which a rear wheel is mounted, and front ends of the respective upper stay 17 are connected to the seat tube 5.

[0051] Here, the front end of the lower stay 19 may be connected to the pedal assembly 9 configured on a lower side of the seat tube 5.

[0052] The pedal assembly 9 may be formed to protrude downward, and a pedal connected to the rear wheel via a chain is installed on the pedal assembly 9.

[0053] Here, the head tube 3, the seat tube 5, the frame 7, the pedal assembly 9 and the left and right stays 11 and 11a are formed on a left frame body 23 and a right frame body 25, which are integrally molded.

[0054] Further, the left and right frame bodies 23 and 25 are connected along the edges thereof so as to form an overall configuration of the frame unit 1 for a bicycle.

[0055] The left and right frame bodies 23 and 25 are joined to each other by a welding method, and in this case, the welding method may be an arc welding method or the like.

[0056] Fig. 4 is an enlarged view illustrating an adjusting portion of the frame unit for a bicycle manufactured according to the invention.

[0057] With reference to Fig. 4, an adjusting portion 40 for adjusting a position of the head tube 3 with respect to the frame 7 for each specification is integrally formed at one end of the frame 7.

[0058] Fig. 5 is an enlarged view illustrating a state in which a length of the adjusting portion of the frame unit for a bicycle manufactured according to the invention is changed.

[0059] With reference to Fig. 5, the adjusting portion 40 is provided to meet a size for each specification of the bicycle, and the head tube 3 is formed by machining the adjusting portion 40, or a part of the adjusting portion 40 is cut off, and then the head tube 3 is coupled to the cut end.

[0060] That is, the adjusting portion 40 may be processed by bending the adjusting portion 40 into a tubular shape to form the head tube 3, or the head tube 3 having a tubular shape may be coupled to the adjusting portion 40 after adjusting a length L of the adjusting portion 40.

[0061] Here, as the length of the adjusting portion 40 becomes shorter, an overall size of the frame unit 1 for a bicycle is reduced.

[0062] Further, when the adjusting portion 40 is shortened, an overall size of the bicycle is adjusted by attaching the seat tube 13 which is coupled to the seat tube 5 and has a relatively short length.

[0063] That is, the length of the seat tube 13 is determined by changing a position of the head tube 3, and the overall size of the bicycle is made small by making the seat tube 13 relatively short in length when the adjusting portion 40 is shortened, and making the seat tube 13 relatively long in length when the adjusting portion 40 is shortened in a manner as shown in Fig. 4. The overall size of the bicycle can be adjusted by coupling the seat tube 13, which has a predetermined length corresponding to a predetermined length L of the adjusting portion 40. In addition, the seat tube 13 has a predetermined length, and an insertion depth of the seat tube 13 can be adjusted.

[0064] As in Fig. 5, the overall size of the bicycle can be minimized by minimizing (completely removing) the adjusting section 40, and as shown in Fig. 4, the head tube 3 can be formed without adjusting the length of the adjusting portion 40. Furthermore, it is possible to manufacture bicycles of different sizes by adjusting the length of the adjusting portion 40 differently.

[0065] Fig. 6 is an enlarged perspective view illustrating a partial configuration in a state in which a reinforcing panel is installed on the frame unit for a bicycle manufactured according to the invention.

[0066] With reference to Fig. 6, the left and right frame bodies 23 and 25 are connected in a state in which a reinforcing panel 27 is locally installed on the inside of the left and right frame bodies 23 and 25, so that an overall configuration of the frame unit 1 for a bicycle can be formed.

[0067] That is, the reinforcement panel 27 can be installed at a section where rigidity is required, that is, as in Fig. 6, between the head tube 3 and the frame 7, and the reinforcement panels 27 may also be installed between the seat tube 5 and the frame 7 at a portion of the rotary body fork 21 of the two stays 11 where the rear wheel is installed, and on the inside of the pedal assembly 9.

[0068] Further, the reinforcement panels 27 are connected to each other in a state in which the reinforcement panels 27 are attached to both inner sides of the left and right frame bodies 23 and 25, respectively, or in a state in which the reinforcement panels 27 are attached to the inner sides of the left and right frame bodies 23 and 25 and then temporarily connected thereto, when the left and right frame bodies 23 and 25 are connected to each other.

[0069] Here, grooves in which the reinforcement panels 27 are arranged may be formed on the two inner sides of the left and right frame bodies 23 and 25, and the reinforcement panels 27 may be mounted in the grooves or temporarily connected thereto.

[0070] Meanwhile, the reinforcement panel 27 has a plurality of reinforcement ribs 29 formed to protrude. The reinforcement ribs 29 protrude to cross inside and outside along an up-and-down direction of the reinforcement panel 27, thereby improving the rigidity of the reinforcement panel 27 itself.

[0071] Fig. 7 is an enlarged perspective view illustrating a state in which rigid ribs are formed on a frame portion adjacent to a head tube of the frame unit for a bicycle manufactured according to the invention.

[0072] With reference to Fig. 7, rigid ribs 31 are formed such that they protrude outwards between the head tube 3 and the frame 7 of the two left and right frame bodies 23 and 25.

[0073] The plurality of rigid ribs 31 are repeatedly formed at portions where the head tube 3 and the frame 7 are in contact with each other along a longitudinal direction or an up-and-down direction of the frame 7, thereby improving rigidity at a connecting portion between the head tube 3 and the frame 7.

[0074] Here, repeated profiles protrude outward when the rigid ribs 31 are formed on the frame 7, thereby improving both an overall design of the frame unit 1 for a bicycle and improving the rigidity of the frame 7.

[0075] While a configuration in which the rigid ribs 31 are formed at the portions where the head tube 3 and the frame 7 are in contact with each other has been described above, the rigid ribs 31 may also be formed at the adjusting portion 40.

[0076] A support ring 33 is inserted into the head tube 3 such that the steering tube, which is not shown, can be installed on the support ring 33, and the support ring 33 can reinforce the rigidity of the head tube 3.

[0077] According to the frame unit 1 for a bicycle manufactured according to the invention having the above-mentioned configuration, the head tube 3 is formed integrally with the main frame 7 without a connecting portion, so that residual stress due to welding heat at a connecting portion according to the related art can be prevented, and a factor causing deterioration of the connecting rigidity due to the residual stress can be eliminated.

[0078] In addition, an occurrence of a safety accident due to fractures and damages occurring in the connecting portion is reduced, and the rigidity and durability between the head tube 3 and the frame 7 with respect to an impact load transmitted from a road surface and a fatigue load of the frame unit itself are stably maintained.

[0079] Further, the left and right frame bodies 23 and 25 constituting the bicycle frame unit 1 are integrally formed, thereby making the overall external appearance of the bicycle frame unit 1 aesthetically attractive.

[0080] In addition, welding beads, which are formed when the left and right frame bodies 23 and 25 are joined, are not directly exposed on a surface, so that an influence on the design of the entire external appearance of the frame unit 1 for a bicycle is minimized.

[0081] In addition, welding is performed along edges of the left and right frame bodies 23 and 25 when the left and right frame bodies 23 and 25 are joined, so that the welding processes can be automated, the working hours can be reduced as a result of the automation, and the quality and productivity of welding can be improved.

[0082] In addition, since the length of the adjusting portion 40 formed between the head tube 3 and the frame 7 can be adjusted, bicycles of various sizes can be easily manufactured using a single mold, thereby reducing the number of molds manufactured for each specification (for each size).

[0083] Furthermore, since the size for each specification can be addressed with a single mold, overall productivity is improved.

[0084] Hereinafter, a method of manufacturing the frame unit 1 for a bicycle according to the exemplary embodiment of the present invention described above will be described with reference to Fig. 2 to 7.

[0085] First, the adjusting portion 40, the seat tube 5, the frame 7, the pedal assembly 9, and the left and right stays 11 and 11a are integrally molded, and the left and right frame bodies 23 and 25, which are symmetrical to each other, are compression molded.

[0086] In this case, the adjusting portion 40 for adjusting a position of the head tube 3 with respect to the frame 7 is integrally molded at one end of the frame 7.

[0087] When the left and right frame bodies 23 and 25 are compression molded, the plurality of rigid ribs 31 projecting inward and outward as shown in Fig. 7, on the adjusting portion 40 and the frame 7 along a longitudinal direction or an up-and-down direction of the frame 7.

[0088] Further, the length L of the adjusting portion 40 is adjusted for each size, and then the head tube 3 is formed.

[0089] The head tube 3 is processed into a cylindrical shape by bending the adjusting section 40 with the adjusted length, or the head tube 3 with a cylindrical shape is coupled to the adjusting section 40.

[0090] Thereafter, the left and right frame bodies 23 and 25 formed by a press are joined together by welding along edges of the left and right frame bodies 23 and 25 and manufactured as the frame unit 1 for a bicycle as shown in Fig. 3 is shown.

[0091] Meanwhile, as in Fig.6, the reinforcement panels 27 are locally installed on the inside of the left and right frame bodies 23 and 25 before the left and right frame bodies 23 and 25 are joined, and thereafter, the left and right frame bodies 23 and 25 can be joined along the edges of the left and right frame bodies 23 and 25.

[0092] The reinforcement panels 27 are installed at portions where rigidity is required, that is, between the head tube 3 and the frame 7, between the seat tube 5 and the frame 7, at the portion of the rotary body fork of the two stays 11 where the rear wheel is installed, and at the inside of the pedal assembly 9, and thereafter, the reinforcement panels 27 are connected to each other when the left and right frame bodies 23 and 25 are connected.

[0093] In this case, in a state where the reinforcement panels 27 are attached to or temporarily connected to the left and right frame bodies 23 and 25, the reinforcement panels 27 may be connected together with the left and right frame bodies 23 and 25, and the plurality of reinforcement ribs 29 projecting so as to cross each other inside and outside may also be formed.

[0094] In addition, the support ring 33 is inserted into the head tube 3 so that the steering tube, which is not shown, can be installed on the support ring 33, and the support ring 33 can enhance the rigidity of the head tube 3.

[0095] For ease of explanation and precise definition in the appended claims, the terms "top," "bottom," "inside," and "outside" are used to describe features of the exemplary embodiments with reference to the positions of such features as shown in the figures.

Claims

[1] A method of manufacturing a frame unit for a bicycle, comprising: Compression molding a left frame body (23) on which a part of an adjusting section (40), a part of a seat tube (5), a part of a frame (7) and a left strut (11) are integrally formed; Compression molding a right frame body (25) on which a part of the adjusting section (40), a part of the seat tube (5), a part of the frame (7) and a right strut (11a) are integrally formed; Adjusting a length (L) of the adjusting section (40); and Coupling the left frame body (23) and the right frame body (25), wherein after adjusting the length (L) of the adjusting portion (40), a head tube (3) is formed by bending a portion of the adjusting portion (40) and then the left frame body (23) and the right frame body (25) are coupled. [2] Method according to claim 1, wherein a support ring (33) is inserted into the control tube (3) and coupled thereto. [3] The method of claim 1, wherein said compression molding further forms a plurality of reinforcing ribs (29) on said adjusting portion (40). [4] The method according to claim 1, wherein reinforcing panels (27) are installed on the inside of the left and right frame bodies (23, 25), and the reinforcing panels (27) are joined together with the left and right frame bodies (23, 25) along edges thereof. [5] The method according to claim 4, wherein the reinforcing panels (27) are installed between the head tube (3) and the frame (7), between the seat tube (5) and the frame (7), at a portion of the two stays (11, 11a) where a rear wheel is configured to be installed, and at the inside of a pedal assembly (9) on which a pedal is configured to be installed. [6] The method according to claim 4, wherein the reinforcing panels (27) are connected together with the left and right frame bodies (23, 25) in a state in which the reinforcing panels (27) are attached to or temporarily connected to the left and right frame bodies (23, 25). [7] A method according to claim 4, wherein the reinforcing panels (27) are formed together with reinforcing ribs (29) projecting so as to cross each other inside and outside.

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