JP5991819B2 - Bicycle frame manufacturing method and bicycle frame - Google Patents

Description

  The present invention relates to a method for manufacturing a bicycle frame and a bicycle frame.

  In Patent Document 1 below, as a method of manufacturing a frame having a closed cross section of a bicycle, two half-frame bodies having an open cross section are bonded, welded, fastened by screws, or joined by a coupling method such as ultrasonic waves, A technique for making a frame is disclosed.

Registered Utility Model No. 3004828

  However, in the configuration described in Patent Document 1, for example, when two half-frame bodies are formed of resin and joined by a bonding method such as adhesion or ultrasonic waves to form a closed cross-section frame, the strength and rigidity of the frame In particular, there is a possibility that the strength and rigidity of the connecting pipe arranged in the direction crossing the axial direction of the bicycle seat pipe may be insufficient.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a bicycle frame manufacturing method and a bicycle frame capable of obtaining a resin bicycle frame having sufficient strength and rigidity.

In order to solve the above-mentioned problem, a manufacturing method of a bicycle frame according to claim 1 includes a half-cut head pipe having an open cross section to which a handle is attached and a half cut having an open cross section to which a seat post of a saddle is attached. Two half-cut bicycle frame members having an open cross section integrally formed with at least one of a seat pipe and an open cross-section half connecting member connected to at least one of the half head pipe and the half seat pipe A method of manufacturing a bicycle frame that is overlapped and joined by welding to form a bicycle frame having a closed cross section, wherein the half connecting member has at least a direction along an axial direction of the half seat pipe or the half head pipe. The width of one welding surface is set so that the bicycle frame is assembled with the axial direction of the half seat pipe or the half head pipe as the vertical direction. It is larger than the thickness of the side part of the half connection member when standing, and the half connection member is a curved surface in which the outer surface and the inner surface of the connection member formed by joining the half connection members are continuous. The welding is vibration welding that vibrates along the axial direction of the half head pipe or the half seat pipe, and the axial direction of the half connecting member intersects the vibration direction. Are arranged as follows .

In the invention according to claim 1, the connecting member connected to at least one of the head pipe and the seat pipe is caused by a load acting in a substantially axial direction of the seat pipe or the head pipe (vertical direction when the bicycle is formed). Bending stress acts. For this reason, it is effective to increase the wall thickness on the side on which the tensile force and the compressive force act. Therefore, by increasing at least one of the widths of the welded surfaces where the half connecting members are overlapped and joined, the thickness on the side on which the tensile force and the compressive force act is increased, and the member rigidity is increased.
Further, the half-bicycle frame member is joined by vibration welding that vibrates along the axial direction of the half-head pipe or the half-seat pipe to form a bicycle frame having a closed cross section. At that time, vibration welding along the axial direction of the half head pipe or the half seat pipe suppresses the head pipe or the seat pipe from being displaced, and the strength and dimensional accuracy of the head pipe or the seat pipe ( Inner diameter roundness, straightness) can be ensured. In addition, even if the halved connecting member is arranged so that the axial direction intersects the vibration direction, the welded surface of the halved connecting member has a large width, so the displacement of the welded surface is absorbed and the deterioration of the weldability is suppressed. can do.

  The invention according to claim 2 is the bicycle frame manufacturing method according to claim 1, wherein the half frame when the bicycle frame is assembled with the axial direction of the half seat pipe or the half head pipe as the vertical direction. The width of the upper and lower welding surfaces of the connecting member is larger than the thickness of the side portion of the half connecting member.

  In the invention according to claim 2, when the bicycle frame is assembled with the axial direction of the half seat pipe or the half head pipe as the vertical direction, the width of the upper and lower welding surfaces of the half connection member is set to By making it larger than the thickness of the side portion, the thickness of the side on which the tensile force and the compressive force are easily applied is increased, and the member rigidity is increased.

  According to a third aspect of the present invention, in the method for manufacturing a bicycle frame according to the first or second aspect, the half connecting member has a vertically long cross section perpendicular to the axial direction of the half connecting member.

  In the invention according to claim 3, the cross section orthogonal to the axial direction of the connecting member of the connecting member joined with the half connecting member is vertically long. Thereby, when a bending stress acts on a connection member, it can suppress that a connection member deform | transforms into the vertical surface side, ie, the substantially up-down side when it becomes a bicycle.

According to a fourth aspect of the present invention , there is provided a bicycle frame manufacturing method comprising: at least one of an open-section halved head pipe to which a handle is mounted and an open-section halved seat pipe to which a saddle seat post is mounted; Two half-cut bicycle frame members having an open cross-section integrally formed with at least one of the half-head pipe and the half-split seat pipe are joined together by welding. A method of manufacturing a bicycle frame as a bicycle frame having a closed cross section, wherein a width of at least one welding surface in a direction along an axial direction of the half seat pipe or the half head pipe of the half connecting member is When the bicycle frame is assembled with the axial direction of the half seat pipe or the half head pipe as the vertical direction, And larger than the thickness of the side members, the-half connecting member, which outer cross-sectional shape perpendicular to the axial direction of the half-split connecting member is oval and half shape, said ovoid Is formed such that the outer width in the direction perpendicular to the axial direction on the lower side is larger than the outer width in the direction perpendicular to the axial direction on the upper side, and the thickness on the lower side is thicker than the thickness on the upper side. Has been.

  In the invention described in claim 4, the connecting member obtained by joining the half connecting members has an oval shape in which the lower side is formed thicker than the upper side in a cross section orthogonal to the axial direction. Thereby, when bending stress acts on a connection member, it can control that a connection member changes below.

According to a fifth aspect of the present invention , there is provided a bicycle frame manufacturing method comprising: at least one of an open-section halved head pipe to which a handle is mounted and an open-section halved seat pipe to which a saddle seat post is mounted; Two half-cut bicycle frame members having an open cross-section integrally formed with at least one of the half-head pipe and the half-split seat pipe are joined together by welding. A method of manufacturing a bicycle frame as a bicycle frame having a closed cross section, wherein a width of at least one welding surface in a direction along an axial direction of the half seat pipe or the half head pipe of the half connecting member is When the bicycle frame is assembled with the axial direction of the half seat pipe or the half head pipe as the vertical direction, And larger than the thickness of the side members, the-half coupling member is vertically are disposed two on the lower side of the half-split connecting member, the axial direction of the lower side of the half-split connecting member The cross section orthogonal to the oval is a half-shaped oval shape, the lower side is formed thicker than the upper side, and the upper half connecting member is orthogonal to the axial direction of the upper half connecting member An oval shape with a reverse cross section is formed in a half shape, and the upper side is formed thicker than the lower side.
According to a sixth aspect of the present invention, there is provided a bicycle frame manufacturing method comprising: at least one of an open-section halved head pipe to which a handle is mounted and an open-section halved seat pipe to which a saddle seat post is mounted; Two half-cut bicycle frame members having an open cross-section integrally formed with at least one of the half-head pipe and the half-split seat pipe are joined together by welding. A method of manufacturing a bicycle frame as a bicycle frame having a closed cross section, wherein the half seat pipe or the half split when the bicycle frame is assembled with the axial direction of the half seat pipe or the half head pipe as the vertical direction. The width of the upper and lower welding surfaces of the half connecting member in the direction along the axial direction of the head pipe is set to the side of the half connecting member. The two half-split connecting members are arranged vertically, and the lower half-split connecting member is a cross section perpendicular to the axial direction of the bottom half-split connecting member. Is a half-shaped oval shape, the lower side is formed thicker than the upper side, and the upper half connecting member has an inverted cross section perpendicular to the axial direction of the upper half connecting member. The oval shape is a halved shape, with the upper side being thicker than the lower side.

In the invention according to claim 5 or 6 , the lower connecting member joined to the lower half connecting member is an oval shape in which the lower side is formed thicker than the upper side in a cross section orthogonal to the axial direction. It becomes. The upper connecting member obtained by joining the upper half connecting members has an inverted oval shape in which the upper side is formed thicker than the lower side in a cross section orthogonal to the axial direction. Thereby, when a bending stress acts on the upper and lower connecting members, it is possible to suppress the upper connecting member from being deformed upward and the lower connecting member from being deformed downward.

According to a seventh aspect of the present invention, there is provided a bicycle frame manufacturing method comprising: at least one of an open-section halved head pipe to which a handle is mounted and an open-section halved seat pipe to which a saddle seat post is mounted; Two half-cut bicycle frame members having an open cross-section integrally formed with at least one of the half-head pipe and the half-split seat pipe are joined together by welding. A bicycle frame manufacturing method for a bicycle frame having a closed cross section, wherein the half connecting member has a width that is greater than a width of a welding surface in a direction along an axial direction of the half seat pipe or the half head pipe. Side part of the half connecting member when the bicycle frame is assembled with the axial direction of the split seat pipe or the half head pipe as the vertical direction The wall thickness is larger.

In the invention according to claim 7 , the axial direction of the half seat pipe or the half head pipe is larger than the width of the welding surface in the direction along the axial direction of the half seat pipe or the half head pipe of the half connecting member. By increasing the thickness of the side portion of the half connecting member when the bicycle frame is assembled in the vertical direction, the strength and rigidity of the connecting member joined to the half connecting member can be increased.

The invention according to claim 8 is the bicycle frame manufacturing method according to any one of claims 4 to 7, wherein the welding is performed in an axial direction of the half head pipe or the half seat pipe. And is arranged so that the axial direction of the half connecting member intersects the vibration direction.

In the invention according to claim 8 , the half-bicycle frame member is joined by vibration welding to vibrate along the axial direction of the half-head pipe or the half-seat pipe to form a closed cross-section bicycle frame. At that time, vibration welding along the axial direction of the half head pipe or the half seat pipe suppresses the head pipe or the seat pipe from being displaced, and the strength and dimensional accuracy of the head pipe or the seat pipe ( Inner diameter roundness, straightness) can be ensured. In addition, even if the halved connecting member is arranged so that the axial direction intersects the vibration direction, the welded surface of the halved connecting member has a large width, so the displacement of the welded surface is absorbed and the deterioration of the weldability is suppressed. can do.

The bicycle frame according to claim 9 is provided with at least one of an open-section halved head pipe to which a handle is mounted and an open-section halved seat pipe to which a saddle seat post is mounted, and the halved head. A pipe and a half connecting member having an open cross-section connected to at least one of the half seat pipes are formed by overlapping two integrally-formed half-cut bicycle frame members having an open cross-section and joining them by welding. A bicycle frame having a closed cross section, wherein a thickness of at least one of the connecting members in a direction along an axial direction of the seat pipe or the head pipe is defined with an axial direction of the seat pipe or the head pipe as a vertical direction. Larger than the thickness of the side of the connecting member when assembled, and the connecting member is axially connected to the connecting member. The outer width in the direction orthogonal to the lower axial direction is larger than the outer width in the direction orthogonal to the upper axial direction, and the lower side thickness is the upper side It is formed thicker.

In the invention according to claim 9 , the connecting member is an oval shape in which the thickness on the lower side is formed thicker than the upper side in a cross section orthogonal to the axial direction, and when bending stress acts on the connecting member, It is possible to suppress the connecting member from being deformed downward.

A bicycle frame according to claim 10 is provided with at least one of an open-section halved head pipe to which a handle is mounted and an open-section halved seat pipe to which a saddle seat post is mounted, and the halved head. A pipe and a half connecting member having an open cross-section connected to at least one of the half seat pipes are formed by overlapping two integrally-formed half-cut bicycle frame members having an open cross-section and joining them by welding. A bicycle frame having a closed cross section, wherein a thickness of at least one of the connecting members in a direction along an axial direction of the seat pipe or the head pipe is defined with an axial direction of the seat pipe or the head pipe as a vertical direction. Is larger than the thickness of the side part of the connecting member when assembled, and the two connecting members are arranged vertically. The lower connecting member has an oval shape in which the thickness of the lower side is formed thicker than the upper side in a cross section orthogonal to the axial direction of the lower connecting member, and the upper connecting member is In the cross section orthogonal to the axial direction of the connecting member, the upper side is thicker than the lower side.
A bicycle frame according to an eleventh aspect of the present invention is directed to at least one of an open-section halved head pipe to which a handle is mounted and an open-section halved seat pipe to which a saddle seat post is mounted, and the halved head. A pipe and a half connecting member having an open cross-section connected to at least one of the half seat pipes are formed by overlapping two integrally-formed half-cut bicycle frame members having an open cross-section and joining them by welding. A bicycle frame having a closed cross section, wherein the upper and lower sides of the connecting member in the direction along the axial direction of the seat pipe or the head pipe when the bicycle frame is assembled with the axial direction of the seat pipe or the head pipe as the vertical direction The thickness of the connecting member is larger than the thickness of the side portion of the connecting member, and two connecting members are arranged on the upper and lower sides. The connecting member on the side is an oval shape in which the thickness on the lower side is formed thicker than the upper side in the cross section orthogonal to the axial direction of the lower connecting member, and the upper connecting member is the upper connecting member In the cross-section orthogonal to the axial direction of the connecting member, it is an inverted oval shape in which the thickness on the upper side is formed thicker than that on the lower side.

In the invention according to claim 10 or claim 11 , the lower connecting member has an oval shape in which the thickness on the lower side is formed thicker than the upper side in a cross section orthogonal to the axial direction, and the upper connecting member Is an inverted oval shape in which the upper side is thicker than the lower side in a cross section perpendicular to the axial direction. Thereby, when a bending stress acts on the upper and lower connecting members, it is possible to suppress the upper connecting member from being deformed upward and the lower connecting member from being deformed downward.

A bicycle frame according to claim 12 is provided with at least one of an open-section halved head pipe to which a handle is mounted and an open-section halved seat pipe to which a saddle seat post is mounted, and the halved head. A pipe and a half connecting member having an open cross-section connected to at least one of the half seat pipes are formed by overlapping two integrally-formed half-cut bicycle frame members having an open cross-section and joining them by welding. A bicycle frame having a closed cross section, wherein the bicycle frame is assembled with the axial direction of the seat pipe or the head pipe as the vertical direction rather than the thickness of the connecting member in the axial direction of the seat pipe or the head pipe. The thickness of the side portion of the connecting member is large.

In the invention according to claim 12 , the connecting member when the bicycle frame is assembled with the axial direction of the seat pipe or head pipe as the vertical direction rather than the thickness of the connecting member in the axial direction of the seat pipe or head pipe. Since the thickness of the side portion is large, the strength and rigidity of the connecting member can be increased.

  According to the present invention, it is possible to obtain a resin-made bicycle frame having a high weld strength at the welded portion (surface) and sufficient strength and rigidity.

It is a perspective view which shows the resin-made half bicycle frame members applied to the bicycle frame of 1st Embodiment. It is a perspective view which shows the bicycle frame which welded and integrated the half-bicycle frame member shown in FIG. It is a side view which shows the vibration direction at the time of carrying out the vibration welding of the welding surface of the half-bicycle frame member shown in FIG. (A) is sectional drawing along the up-down direction orthogonal to the axial direction of a half connection member, (B) is the up-down direction orthogonal to the axial direction of the connection member which welded and integrated the half connection member. FIG. It is a perspective view which shows the apparatus which carries out the vibration welding of a pair of right and left half bicycle frame members. (A) is sectional drawing which shows the state before welding of the apparatus which carries out vibration welding of the half connection member, (B) is sectional drawing which shows the state after welding of the apparatus which carries out vibration welding of a half connection member. It is a 1st modification of a half connection member, Comprising: (A) is sectional drawing along the up-down direction orthogonal to the axial direction of a half connection member, (B) welds a half connection member and is integrated. It is sectional drawing along the up-down direction orthogonal to the axial direction of the made connection member. It is a 2nd modification of a half connection member, Comprising: (A) is sectional drawing along the up-down direction orthogonal to the axial direction of the upper and lower half connection members, (B) is a half connection member. It is sectional drawing along the up-down direction orthogonal to the axial direction of the upper and lower connection members which welded and integrated. It is sectional drawing along the up-down direction orthogonal to the axial direction which shows the 3rd modification of a half connection member. It is sectional drawing along the up-down direction orthogonal to the axial direction which shows the comparative example of a half connection member. It is a perspective view which shows the bicycle frame of 2nd Embodiment. FIG. 11 is a half connecting member used in the bicycle frame shown in FIG. 11, (A) is a cross-sectional view along the vertical direction orthogonal to the axial direction of the half connecting member, and (B) is a half connecting member. It is sectional drawing along the up-down direction orthogonal to the axial direction of the connection member welded and integrated. It is sectional drawing along the up-down direction orthogonal to the axial direction which shows the 4th modification of a half connection member. It is sectional drawing along the up-down direction orthogonal to the axial direction which shows the 5th modification of a half connection member.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In these drawings, an arrow FR appropriately shown indicates the front side of the bicycle, and an arrow UP indicates the upper side of the bicycle.

  FIG. 1 shows a pair of left and right halved bicycle frame members 10 and 20 used in the bicycle frame manufacturing method according to the first embodiment of the present invention. FIG. 2 shows a bicycle frame 40 manufactured by the bicycle frame manufacturing method according to the first embodiment of the present invention. As shown in FIG. 1, a pair of left and right open-section halved bicycle frame members 10, 20 arranged on the left side and the right side in a rear view of the bicycle are arranged in a substantially half-open section. The split head pipes 12 and 22; the half head pipes 12 and 22 having an open cross-section disposed along the up and down direction at an interval from the half head pipes 12 and 22; The upper half-split connecting members 16, 26 and the lower side of the open cross section that are arranged to intersect the seat pipes 14, 24 and connect between the half-head pipes 12, 22 and the half-split seat pipes 14, 24 And half-split connecting members 18 and 28. Further, the half-bicycle frame members 10 and 20 include chain stays 32 and 34 extending rearward from the lower ends of the half-seat pipes 14 and 24, and upper ends of the half-seat pipes 14 and 24 and the chain stay 32, 34, and back hawks 36 and 38 that connect the rear end portions of 34.

  The half bicycle frame member 10 includes a half head pipe 12, a half seat pipe 14, an upper half connection member 16, a lower half connection member 18, a chain stay 32, and a back fork 36. Is integrally formed of resin. Further, the half bicycle frame member 20 includes a half head pipe 22, a half seat pipe 24, an upper half connection member 26, a lower half connection member 28, a chain stay 34, a backhawk. 38 are integrally formed of resin.

  As shown in FIG. 3, the left half bicycle frame member 10 has welding surfaces 12A and 12B formed in the front and rear ends of the half head pipe 12 along the vertical direction. Welding surfaces 14 </ b> A and 14 </ b> B are formed on the front end portion and the rear end portion of the seat pipe 14 along the vertical direction. The half-head pipe 12 and the half-sheet pipe 14 are formed in a substantially semicircular cross section along the lateral direction, and are formed with a substantially uniform thickness along the circumferential direction. Although not shown, the right half bicycle frame member 20 is bilaterally symmetric with the left half bicycle frame member 10, and a welding surface is similarly formed on the half head pipe 22 and the half seat pipe 24. Yes.

  The left half-bicycle frame member 10 is formed with welding surfaces 16A and 16B at the upper end and the lower end of the upper half connecting member 16, and the upper half connecting member 18 has an upper end and a lower end. Welding surfaces 18A and 18B are formed at the lower end.

  As shown in FIG. 4A, the pair of left and right upper half connecting members 16 and 26 are welded at the upper end welding surfaces 16A and 26A and at the lower end in a vertical cross section perpendicular to the axial direction. The widths of the surfaces 16B and 26B (the width in the axial direction of the half seat pipes 14 and 24) are formed to be thicker than the thicknesses (thicknesses) of the side portions 16C and 26C of the half connection members 16 and 26. ing. Although not shown in the drawings, the widths of the upper and lower welding surfaces 18A and 18B in the same manner are also applied to the lower pair of left and right lower half connecting members 18 and 28 (in the axial direction of the half seat pipes 14 and 24). The width in the along direction) is formed to be thicker than the thickness of the side portions of the half connecting members 18 and 28.

  As shown in FIGS. 1 and 2, etc., the pair of left and right half bicycle frame members 10, 20 includes a half head pipe 12, 22, a half seat pipe 14, 24, and an upper half connecting member 16. , 26 and the lower half connecting members 18, 28 are overlapped and welded by a predetermined welding method so that the pair of left and right half bicycle frame members 10, 20 are integrated. A cross-sectional bicycle frame 40 is formed. In this embodiment, vibration welding is used as the welding method. As shown in FIG. 3, in vibration welding, the axial direction of the half head pipe 12 and the half seat pipe 14 (the longitudinal direction of the half head pipe 12 and the half seat pipe 14, that is, the arrow A direction and the arrow B direction). ). That is, the welding surfaces 12A and 12B of the half-head pipe 12 and the welding surfaces 14A and 14B of the half-sheet pipe 14 are arranged substantially in parallel with the vibration direction, and the welding surfaces along the axial direction of the upper half connecting member 16 are arranged. 16A, 16B and welding surfaces 18A, 18B along the axial direction of the lower half connecting member 18 are arranged so as to intersect the vibration direction.

  The pair of left and right halved bicycle frame members 10 and 20 are divided into half head pipes 12 and 22, half seat pipes 14 and 24, upper half connection members 16 and 26, and lower half connection member 18. , 28 are overlapped and vibration welded, so that the weld surfaces are melted and joined by frictional heat generated by pressure and reciprocating motion. Accordingly, as shown in FIG. 2, the closed section head pipe 42, the closed section seat pipe 44, the upper section connecting member 46 that connects the head pipe 42 and the seat pipe 44, and the lower section connection are connected. A bicycle frame 40 having a member 48 is formed. At that time, since the vibration direction is set in the axial direction (longitudinal direction) of the half head pipes 12 and 22 and the half seat pipes 14 and 24, the half head pipes 12 and 22 at the time of vibration welding, The displacement of the welding surface with the split sheet pipes 14 and 24 is suppressed, and the strength and dimensional accuracy of the head pipe 42 and the seat pipe 44 after welding can be ensured.

  On the other hand, since the welding surface of the half connecting member is arranged in a direction intersecting with the vibration direction, there is a possibility that the weldability may be deteriorated due to deviation of the facing welding surface. On the other hand, in this embodiment, as shown in FIG. 4A, the pair of left and right upper half connecting members 16 and 26 have upper end welding surfaces 16A and 26A and lower end welding surfaces 16B. , 26B is formed to be thicker than the thickness of the side portions 16C, 26C of the halved connecting members 16, 26, so that the welding surfaces 16A, 26A at the time of vibration welding and the welding surface The deviation from 16B and 26B is absorbed, and a decrease in weldability can be suppressed. Further, as shown in FIG. 4B, the connecting member 46 after welding is connected when the bicycle using the bicycle frame 40 is run because the thickness of the upper part 46A and the lower part 46B is larger than the thickness of the side part 46C. Even if bending stress acts on the member 46, the vertical deformation of the connecting member 46 is suppressed.

  Similarly, the width of the welding surface 18A at the upper end portion and the welding surface 18B at the lower end portion (length in the vertical direction) of the lower half connecting members 18 and 28 on the left and right pairs is also divided into the half connecting members 18 and 28. By being formed thicker than the thickness of the side portion, the displacement of the welding surface at the time of vibration welding is absorbed, and a decrease in weldability can be suppressed. In addition, since the thickness of the upper and lower portions of the connecting member 48 after welding is thicker than the thickness of the side portions, even when bending stress acts on the connecting member 48, deformation of the connecting member 48 in the vertical direction is suppressed. . Thereby, the welding strength of the welding surface of the bicycle frame 40 is high, and the strength and rigidity of the bicycle frame 40 can be improved.

  Next, the manufacturing method of the bicycle frame 40 of this embodiment is demonstrated.

  As shown in FIG. 5, the vibration welding device 60 for manufacturing the bicycle frame 40 includes a substantially rectangular welding jig 62 having a recess 62 </ b> A into which the half-bicycle frame member 10 is fitted on one side surface, A substantially rectangular welding jig 64 having a concave portion 64A into which the half-bicycle frame member 20 is fitted on a surface facing the concave portion 62A. In this vibration welding apparatus 60, a welding jig 62 is disposed on the upper side in the vertical direction of the apparatus shown in FIG. 5, and a welding jig 64 is disposed on the lower side. In the vibration welding apparatus 60, the welding surfaces of the half-bicycle frame member 10 of the welding jig 62 are loaded on the welding surfaces of the half-bicycle frame member 20 of the welding jig 64 with the welding jig 64 fixed. , And are caused to vibrate in the axial direction (substantially up and down direction) of the half head pipe 12 and the half seat pipe 14, so that each welding surface of the half bicycle frame member 10 and each half bicycle frame member 20 are The welding surface is joined by vibration welding.

  6A and 6B are partial cross-sectional views showing a process of vibrating and welding the welding surface of the pair of left and right upper half connecting members 16 and the welding surface of the upper half connecting member 26. ing. As shown in FIG. 6 (A), the upper half connecting member 16 is fitted into the recess 62A of the welding jig 62, and the upper side of the welding jig 64 is fitted into the concave part 64A of the welding jig 64. The welding surfaces 26 </ b> A and 26 </ b> B of the half connection member 26 are disposed to face each other. 6B, with the welding jig 64 fixed, the welding surfaces 16A and 16B of the half connecting member 16 of the welding jig 62 are welded to the half connecting member 26 of the welding jig 64. As shown in FIG. A load is applied to the surfaces 26A and 26B by a pressing means (not shown) in the direction of arrow C, and the surface is vibrated in a substantially vertical direction (arrow A direction) by the vibration device 66. As a result, the welding surfaces 16A and 16B of the half connection member 16 and the welding surfaces 26A and 26B of the half connection member 26 are melted and bonded by pressure and frictional heat due to reciprocating motion, thereby connecting the closed cross section. A member 46 is formed.

  In such a manufacturing method of the bicycle frame 40, the welding surfaces 12A, 12B of the half head pipe 12 and the welding surfaces 14A, 14B of the half seat pipe 14 are arranged substantially parallel to the vibration direction, so that at the time of vibration welding. The deviation of the welding surface between the half-split head pipes 12 and 22 and the half-split sheet pipes 14 and 24 is suppressed, and the strength and dimensional accuracy of the welded head pipe 42 and seat pipe 44 can be ensured.

  Also, as shown in FIG. 6A, the pair of left and right upper half linking members 16 and 26 are formed of the widths (vertical direction) of the welding surfaces 16A and 26A at the upper end and the welding surfaces 16B and 26B at the lower end. (Length) is formed to be thicker than the thickness of the side portions 16C and 26C of the half connecting members 16 and 26, so that it vibrates in a direction crossing the axial direction (longitudinal direction) of the half connecting members 16 and 26. However, the gap between the welding surfaces 16A and 26A and the welding surfaces 16B and 26B is absorbed, and a decrease in weldability can be suppressed.

  When the bicycle frame 40 is used for a bicycle, a handle (not shown) is attached to the head pipe 42, and a saddle seat post (not shown) is attached to the seat pipe 44. Bending stress is applied to the connecting members 46 and 48 connecting the head pipe 42 and the seat pipe 44 by a load acting in the axial direction of the seat pipe 44. For this reason, it is effective to increase the thickness of the connecting members 46 and 48 on the side on which the tensile force and the compressive force act. In this embodiment, as shown in FIG. 4 (B), the connecting member 46 after welding has a tensile force and a compressive force by making the thickness of the upper part 46A and the lower part 46B larger than the thickness of the side part 46C. The thickness of the acting side is increased to increase the member rigidity. The same applies to the connecting member 48. For this reason, the vertical deformation of the connecting members 46 and 48 can be suppressed, and the strength and rigidity of the bicycle frame 40 can be improved.

  Next, a bicycle frame connecting member according to a first modification of the present invention will be described. In addition, the same code | symbol is attached | subjected to the member same as 1st Embodiment, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 7 (A), a pair of left and right open half-section connecting members 72, 74 that connect the half head pipe (see FIG. 1) and the half seat pipe (see FIG. 1) are vertically arranged. The section along the section (the section along the axial direction of the half-seat pipe) is vertically long. Further, the half connecting members 72 and 74 have the width (length in the vertical direction) of the welding surfaces 72A and 74A at the upper end portion and the welding surfaces 72B and 74B at the lower end portion as side portions 72C of the half connecting members 72 and 74, respectively. It is formed thicker than 74C. As shown in FIG. 7 (B), the welded surfaces 72A and 74A at the upper end portions of the half-split connecting members 72 and 74 and the weld surfaces 72B and 74B at the lower end portions are fused and joined by vibration welding. A connecting member 76 in which the members 72 and 74 are integrated is formed. The upper and lower connecting members 76 have substantially the same cross section along the vertical direction.

  In such a half connecting member 72, 74, even if the half connecting member 72, 74 is arranged in a direction crossing the vibration direction, the upper end weld surface 72A, 74A and the lower end weld surface 72B, 74B. Is formed to be thicker than the thickness of the side portions 72C and 74C of the half connecting members 72 and 74, so that the misalignment between the welding surfaces 72A and 74A and the welding surfaces 72B and 74B is absorbed. Thus, a decrease in weldability can be suppressed. Further, as shown in FIG. 7B, the welded connecting member 76 has a vertically long cross section in the vertical direction, and the thickness (thickness) of the upper portion 76A and the lower portion 76B is larger than the thickness of the side portion 76C. Therefore, even when bending stress is applied to the connecting member 76, deformation of the connecting member 76 in the vertical direction can be suppressed.

  Next, a bicycle frame connecting member according to a second modification of the present invention will be described. In addition, the same code | symbol is attached | subjected to the member same as 1st Embodiment and a 1st modification, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 8 (A), the upper half connecting members 82 and 84 of the left and right pair of open cross sections connecting the half head pipe (see FIG. 1) and the half seat pipe (see FIG. 1) An oval shape whose cross section along the direction (cross section along the axial direction of the half-seat pipe) is reversed is formed into half. Further, the upper half connecting members 82 and 84 are formed such that the widths (vertical lengths) of the welding surfaces 82A and 84A at the upper ends are larger than the widths of the welding surfaces 82B and 84B at the lower ends. The widths of the weld surfaces 82B and 84B of the part are formed to be larger than the thicknesses of the side parts 82C and 84C. Further, the lower half connecting members 86 and 88 for connecting the half head pipe (see FIG. 1) and the half seat pipe (see FIG. 1) on the lower side of the pair of left and right open sections have a cross section in the vertical direction. The shape is halved. Further, the lower half connecting members 86 and 88 are formed such that the widths of the welding surfaces 86B and 88B at the lower end are larger than the widths of the welding surfaces 86A and 88A at the upper end, and the welding surfaces 86A and 86A at the upper end. The width of 88A is formed larger than the thickness of the side portions 86C and 88C.

  The welded surfaces 82A and 84A at the upper ends of the half-split connecting members 82 and 84 and the welded surfaces 82B and 84B at the bottom end are melt-bonded by vibration welding that vibrates along a substantially vertical direction, respectively. The welding surfaces 86A and 88A at the upper end of 88 and the welding surfaces 86B and 88B at the lower end are melt-bonded by vibration welding, respectively. As a result, as shown in FIG. 8B, the upper connection member 90 of the closed cross section in which the half connection members 82 and 84 are integrated and the closed cross section in which the half connection members 86 and 88 are integrated. A lower connecting member 92 is formed. The upper connecting member 90 has an oval shape opposite to the cross section along the vertical direction (the cross section along the axial direction of the half-seat pipe), and the lower connecting member 92 is vertically symmetrical with the connecting member 90. It is oval.

  As shown in FIG. 8A, the pair of left and right halves of the connecting members 82 and 84 have a thickness in the vicinity of the welding surfaces 82A and 84A at the upper end portion that is long from the peripheral surfaces of the side portions 82C and 84C. By making it thicker than the thickness in the vicinity of the welding surfaces 82B and 84B at the lower end portion where the distance from the peripheral surfaces of the side portions 82C and 84C is short, it is vibrated in a direction (substantially up and down direction) intersecting the half connecting members 82 and 84. Even in this case, it is possible to suppress the collapse deformation in the vicinity of the welding surfaces 82A and 84A at the upper end. Similarly, the pair of left and right halves of the connecting members 86 and 88 has a thickness in the vicinity of the welding surfaces 86B and 88B at the lower end that has a long distance from the peripheral surfaces of the side portions 86C and 88C, from the peripheral surfaces of the side portions 86C and 88C. Even if it is made to vibrate in the direction (substantially up and down direction) intersecting with the half connecting members 86, 88 by making it thicker than the thickness near the welding surfaces 86A, 88A at the upper end where the distance is short, the welding surface 86B, Falling deformation near 88B can be suppressed.

  Further, as shown in FIG. 8B, the upper connecting member 90 after welding has an inverted oval shape, and the lower connecting member 92 after welding has an oval shape symmetrical to the connecting member 90. The thickness (thickness) of the upper portion 90A of the connecting member 90 is thicker than the thickness of the side portion 90C and the lower portion 90B, and the thickness (thickness) of the lower portion 92B of the connecting member 92 is larger than the thickness of the side portion 92C and the upper portion 92A. Since it is thick, when bending stress acts on the connecting members 90 and 92, it is possible to more reliably suppress the connecting member 90 and the connecting member 92 from being bent and deformed in the vertical direction.

  Next, a bicycle frame connecting member according to a third modification of the present invention will be described. In addition, the same code | symbol is attached | subjected to the member same as 1st Embodiment, a 1st modification, and a 2nd modification, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 9, the pair of left and right open half-section connecting members 102 and 104 that connect the half head pipe (see FIG. 1) and the half seat pipe (see FIG. 1) extend in the vertical direction. The cross section (the cross section along the axial direction of the halved sheet pipe) is symmetrical and substantially U-shaped, and the widths of the welding surfaces 102A and 104A at the upper end and the welding surfaces 102B and 104B at the lower end (in the vertical direction) The length) is formed to be thicker than the thickness of the side portions 102C and 104C of the half connecting members 102 and 104. Also, the welding surfaces 102A and 104A at the upper end and the welding surfaces 102B and 104B at the lower end are formed so as to protrude from the side portions 102C and 104C in a direction close to each other with substantially the same thickness (width in the vertical direction). .

  In such a half connecting member 102, 104, the half connecting member 102A, 104A is melt-bonded by vibration welding that vibrates the welding surfaces 102B, 104B at the upper end portion and the welding surfaces 102B, 104B at the lower end portion in a substantially vertical direction. A connecting member (not shown) having a closed cross section in which 102 and 104 are integrated is formed. At that time, the welded surfaces 102A and 104A at the upper end and the welded surfaces 102B and 104B at the lower end protrude from the side portions 102C and 104C so as to be close to each other with substantially the same thickness (width in the vertical direction). Sometimes, it is possible to suppress the falling deformation of the welding surfaces 102A and 104A at the upper end and the welding surfaces 102B and 104B at the lower end.

  FIG. 10 shows a half frame connecting member of a bicycle frame according to a comparative example. As shown in FIG. 10, the pair of left and right open-section halves of the connecting members 202 and 204 have a substantially C-shaped cross section that is symmetrical in the vertical direction. Welded portions 203 and 205 protruding so as to be close to each other in the vertical direction are formed.

The width of the welding surfaces 203A and 203B of the welding portion 203 (length in the vertical direction) and the width of the welding surfaces 205A and 205B of the welding portion 205 (length in the vertical direction) are the side portions of the half connecting members 202 and 204. It is formed thicker than the thicknesses of 202C and 204C.

  Such half-split connecting members 202, 204 are provided with welded portions 203, 205 protruding at the upper end portion and the lower end portion so as to be close to each other in the vertical direction. When the welded surface 205A, the welded surface 203B, and the welded surface 205B are vibration welded, there is a possibility that the welded portions 203 and 205 may fall down with respect to the side portions 202C and 204C.

  On the other hand, in the pair of left and right halves of the first embodiment, the first modification to the third modification, the welded portion does not protrude to the adjacent side in the vertical direction, and the width of the welded surface (vertical direction) The length of the welding surface is made larger than that of the side portion, so that the welding surface can be more reliably restrained from falling down when being welded by vibrating substantially vertically.

  Next, a bicycle frame connecting member according to a second embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the member same as 1st Embodiment and a 1st modification-a 3rd modification, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 11, the bicycle frame 130 having a closed cross section is disposed along the substantially vertical direction with a gap between the head pipe 132 and the head pipe 132 having a closed cross section disposed along the vertical direction. A closed cross-section seat pipe 134, and a head pipe 132 and a single closed cross-section connecting member 136 that are arranged to intersect the seat pipe 134 and connect the head pipe 132 and the seat pipe 134. Yes. Further, the bicycle frame 130 includes chain stays 32, 34 extending rearward from the lower end portion of the seat pipe 134, and back forks 36, 38 connecting the upper end portion of the seat pipe 134 and the rear end portions of the chain stays 32, 34. And.

  The bicycle frame 130 includes a pair of left and right open-section halved bicycle frame members 140 and 144, open-section halved head pipes 12 and 22, open-section halved seat pipes 14 and 24, and open-section halved connections. The weld surfaces of the members 142 and 146 are overlapped and welded by vibration welding, thereby being melt bonded.

  As shown in FIG. 12 (A), the half connecting members 142 and 146 in the cross section along the vertical direction (the cross section along the axial direction of the half seat pipe) are the welding surfaces 142B and 146B at the lower end. The width (length in the vertical direction) is formed larger than the width of the welding surfaces 142A and 146A at the upper end, and the width of the welding surfaces 142A and 146A at the upper end is greater than the thickness (thickness) of the side portions 142C and 146C. Is also formed large.

  12B by melting and joining the welding surfaces 142A, 146A at the upper ends of the half-split connecting members 142, 146 and the welding surfaces 142B, 146B at the lower ends by vibrating in a substantially vertical direction. As shown in the drawing, a connection member 136 having a closed cross section is formed by integrating the half connection members 142 and 146.

  Further, as shown in FIG. 12B, since the thickness (thickness) of the lower portion 136B of the connecting member 136 is thicker than the thickness (thickness) of the side portion 136C and the upper portion 136A, bending stress is applied to the connecting member 136. When it acts, it can suppress more reliably that the connection member 136 carries out bending deformation in the up-down direction, especially downward.

  Next, a bicycle frame connecting member according to a fourth modification of the present invention will be described. In addition, the same code | symbol is attached | subjected to the member same as 1st and 2nd embodiment and the 1st-3rd modification, and the duplicate description is abbreviate | omitted.

  As shown in FIG. 13, a pair of left and right open half-section connecting members 150 and 152 that connect the half-head pipe and the half-seat pipe have a lower end in a cross section along the vertical direction perpendicular to the axial direction. The widths (vertical lengths) of the welding surfaces 150B and 152B of the portion are formed to be larger than the widths (lengths of the vertical direction) of the welding surfaces 150A and 152A of the upper end portion and the thicknesses of the side portions 150C and 152C. The width (length in the vertical direction) of the welding surfaces 150A and 152A at the upper end and the thickness of the side portions 150C and 152C are formed with substantially the same dimensions. The welded surfaces 150A and 152A at the upper ends of the half-split connecting members 150 and 152 and the welded surfaces 150B and 152B at the bottom end are melt-bonded by vibration welding, respectively, so that the half-split connecting members 150 and 152 are integrated. A cross-section connecting member (not shown) is formed. A closed cross-section connecting member (not shown) in which the half connecting members 150 and 152 are integrated is applied to either the connecting member of the bicycle frame 40 shown in FIG. 2 or the connecting member of the bicycle frame 130 shown in FIG. Also good.

  The connecting member (not shown) in which the half connecting members 150 and 152 are integrated has a lower thickness (thickness) thicker than the upper and side thicknesses, so even if bending stress acts on the connecting member, Deformation of the connecting member in the vertical direction can be suppressed.

  Next, a bicycle frame connecting member according to a fifth modification of the present invention will be described. In addition, the same code | symbol is attached | subjected to the member same as 1st and 2nd embodiment and the 1st-4th modification, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 14, a pair of left and right open half-section connecting members 160 and 162 connecting the half-head pipe and the half-seat pipe have upper end portions in a cross section along the vertical direction perpendicular to the axial direction. The side portions 160C and 162C of the half connecting members 160 and 162 are formed thicker than the width (vertical length) of the welding surfaces 160A and 162A and the welding surfaces 160B and 162B at the lower end. By closing the welded surfaces 160A and 162A at the upper end of the half-split connecting members 160 and 162 and the welded surfaces 160B and 162B at the lower end by vibration welding, the half-split connecting members 160 and 162 are integrally closed. A cross-section connecting member (not shown) is formed. A closed cross-section connecting member (not shown) in which the half connecting members 160 and 162 are integrated is applied to either the connecting member of the bicycle frame 40 shown in FIG. 2 or the connecting member of the bicycle frame 130 shown in FIG. Also good.

  In such a half connecting member 160, 162, even if the axial direction of the half connecting member 160, 162 is arranged in a direction crossing the vibration direction, the welding surfaces 160A, 162A at the upper end and the welding surface at the lower end. Since the thickness of the side portions 160C and 162C is thicker than the width (length in the vertical direction) of 160B and 162B, the upper end welding surfaces 160A and 162A and the lower end welding surfaces 160B and 162B are collapsed. It is suppressed. Further, the connecting member (not shown) having a closed cross section in which the half connecting members 160 and 162 are integrated is thicker than the thickness of the side portion C than the thickness (thickness) of the upper portion and the lower portion. Even if stress acts, the connecting member is difficult to bend and deform.

  In the first embodiment, the second embodiment, and the first to fifth modifications, the welding surfaces of the pair of left and right halved bicycle frame members are joined by vibration welding, but other welding methods, for example, You may join by heat welding or laser welding. Hereinafter, thermal welding and laser welding will be described.

  Thermal welding includes hot plate welding and hot air welding. There are two types of hot plate welding: contact type and non-contact type. In the case of contact type, each welding surface (joint surface) of the half-cut bicycle frame member with an open cross section is heated by heat conduction. The radiant heat heats each welding surface of the half-cut bicycle frame member having an open cross section. The hot plate heating method includes heater heating and electromagnetic induction heating. In hot plate welding, the welding conditions are set by the temperature of the hot plate, the heating time of the welding surface, and the contact pressure. Hot air welding is a method in which high-temperature air is blown to each welding surface (joining surface) of a half-bicycle frame member having an open cross section to melt a resin and perform pressure joining. Further, an infrared sealing method in which infrared rays are applied to the welding surface (joint surface) is also used.

  Laser welding is a method in which laser beam energy is converted into thermal energy on the surface of the laser absorber and welded. In laser welding, a material that transmits laser light and a material that absorbs laser light are combined. For example, the laser light irradiated from above passes through the material that transmits the upper laser light, and the lower laser light. Is absorbed by the material that absorbs the heat, heat is generated between the joint surfaces of the two materials (welding surface of the half-bicycle frame member), the resin is melted, and the joint surfaces are welded. . This laser welding has the advantage that it has less physical stress compared to vibration welding and the like, and because it is non-contact welding, the surface is hardly affected by heat, scratches or deformation, and burrs are hardly generated.

  In the first embodiment, the second embodiment, and the first to fifth modifications, the half head pipe, the half seat pipe, and the half head pipe connecting the half head pipe and the half seat pipe. Although the half bicycle frame member integrally formed with the connecting member is used, the present invention is not limited to this. For example, a half bicycle frame member in which a half seat pipe and a half joint member connected to the half seat pipe are integrally formed, or a half head pipe and a half joint connected to the half head pipe. A half bicycle frame member integrally formed with the connecting member may be used.

10, 20 Half-divided bicycle frame member 12, 22 Half-split head pipe 12A Welding surface 14, 24 Half-split seat pipe 14A Welding surface 16, 26 Half-split connecting member 16A, 26A Welding surface 16B, 26B Welding surface 16C, 26C Side 18, 28 Split connection member 18A Welding surface 18B Welding surface 40 Bicycle frame 42 Head pipe 44 Seat pipe 46 Connection member 46A Upper part 46B Lower part 46C Side part 48 Connection member 72, 74 Half connection member 72A, 74A Welding surface 72B, 74B Welding surfaces 72C, 74C Side part 76 Connecting member 76A Upper part 76B Lower part 76C Side part 82, 84 Half-split connecting member 82A, 84A Welding face 82B, 84B Welding face 82C, 84C Side part 86, 88 Half-split connecting member 86A, 88A Welding Surface 86B, 88B Welding surface 86C, 88C Side 90 series Connecting member 90A Upper part 90B Lower part 90C Side part 92 Connecting member 92A Upper part 92B Lower part 92C Side part 102, 104 Split connection member 102A, 104A Welding face 102B, 104B Welding face 102C, 104C Side part 130 Bicycle frame 132 Head pipe 134 Seat pipe 136 Connecting member 136A Upper part 136B Lower part 136C Side part 140, 144 Half-split bicycle frame member 142, 146 Connecting member 142A, 146A Welding face 142B, 146B Welding face 142C, 146C Side part 150, 152 Half-split connecting member 150A, 152A Welding face 150B, 152B Welding surfaces 150C, 152C Side portions 160, 162 Half split connecting members 160A, 162A Welding surfaces 160B, 162B Welding surfaces 160C, 162C Side portions

Claims (12)

Connected to at least one of an open-section half-head pipe to which a handle is attached and an open-section half-seat pipe to which a saddle seat post is attached, and at least one of the half-head pipe and the half-seat pipe A half-cycle connecting member having an open cross-section, and two half-section bicycle frame members having an open cross-section formed integrally, and joined by welding to form a bicycle frame having a closed cross-section,
The width of at least one welding surface in the direction along the axial direction of the half seat pipe or the half head pipe of the half connecting member is set so that the axial direction of the half seat pipe or the half head pipe is up and down. It is larger than the thickness of the side part of the half connecting member when the bicycle frame is assembled as a direction,
The half connecting member has a shape in which an outer surface and an inner surface of a connecting member formed by joining the half connecting members are continuously curved ,
The welding is vibration welding that vibrates along the axial direction of the half head pipe or the half seat pipe, and the bicycle frame is arranged so that the axial direction of the half connection member intersects the vibration direction. Manufacturing method.   The width of the upper and lower welding surfaces of the half connection member when the bicycle frame is assembled with the axial direction of the half seat pipe or the half head pipe as the vertical direction is the thickness of the side part of the half connection member. The method for manufacturing a bicycle frame according to claim 1, wherein the bicycle frame is made larger.   The method for manufacturing a bicycle frame according to claim 1 or 2, wherein the half connecting member has a vertically long cross section perpendicular to the axial direction of the half connecting member. Connected to at least one of an open-section half-head pipe to which a handle is attached and an open-section half-seat pipe to which a saddle seat post is attached, and at least one of the half-head pipe and the half-seat pipe A half-cycle connecting member having an open cross-section, and two half-section bicycle frame members having an open cross-section formed integrally, and joined by welding to form a bicycle frame having a closed cross-section,
The width of at least one welding surface in the direction along the axial direction of the half seat pipe or the half head pipe of the half connecting member is set so that the axial direction of the half seat pipe or the half head pipe is up and down. It is larger than the thickness of the side part of the half connecting member when the bicycle frame is assembled as a direction,
The half connecting member has an oval cross-sectional shape orthogonal to the axial direction of the half connecting member, and the oval has an outer shape in a direction orthogonal to the lower axial direction. A method for manufacturing a bicycle frame, wherein the width is formed larger than the outer width in the direction orthogonal to the axial direction on the upper side, and the thickness on the lower side is made larger than the thickness on the upper side. Connected to at least one of an open-section half-head pipe to which a handle is attached and an open-section half-seat pipe to which a saddle seat post is attached, and at least one of the half-head pipe and the half-seat pipe A half-cycle connecting member having an open cross-section, and two half-section bicycle frame members having an open cross-section formed integrally, and joined by welding to form a bicycle frame having a closed cross-section,
The width of at least one welding surface in the direction along the axial direction of the half seat pipe or the half head pipe of the half connecting member is set so that the axial direction of the half seat pipe or the half head pipe is up and down. It is larger than the thickness of the side part of the half connecting member when the bicycle frame is assembled as a direction,
Two of the half connecting members are arranged vertically,
The lower half linking member has a cross-section perpendicular to the axial direction of the lower half linking member having an oval half shape, and the lower side is formed thicker than the upper side,
The upper half-split connecting member has an oval shape whose cross section perpendicular to the axial direction of the upper half-split connecting member is a half-split shape, and the upper side is formed thicker than the lower side. Manufacturing method of the frame. Connected to at least one of an open-section half-head pipe to which a handle is attached and an open-section half-seat pipe to which a saddle seat post is attached, and at least one of the half-head pipe and the half-seat pipe A half-cycle connecting member having an open cross-section, and two half-section bicycle frame members having an open cross-section formed integrally, and joined by welding to form a bicycle frame having a closed cross-section,
The half connecting member in a direction along the axial direction of the half seat pipe or the half head pipe when the bicycle frame is assembled with the axial direction of the half seat pipe or the half head pipe as the vertical direction. The width of the upper and lower welded surfaces is larger than the thickness of the side part of the half connecting member,
Two of the half connecting members are arranged vertically,
The lower half linking member has a cross-section perpendicular to the axial direction of the lower half linking member having an oval half shape, and the lower side is formed thicker than the upper side,
The upper half-split connecting member has an oval shape whose cross section perpendicular to the axial direction of the upper half-split connecting member is a half-split shape, and the upper side is formed thicker than the lower side. Manufacturing method of the frame. Connected to at least one of an open-section half-head pipe to which a handle is attached and an open-section half-seat pipe to which a saddle seat post is attached, and at least one of the half-head pipe and the half-seat pipe A half-cycle connecting member having an open cross-section, and two half-section bicycle frame members having an open cross-section formed integrally, and joined by welding to form a bicycle frame having a closed cross-section,
The axial direction of the half-seat pipe or the half-head pipe is defined as the vertical direction rather than the width of the welding surface along the axial direction of the half-seat pipe or the half-head pipe of the half connecting member. A method of manufacturing a bicycle frame in which the thickness of the side portion of the half connecting member when the bicycle frame is assembled is increased. The welding is vibration welding that vibrates along an axial direction of the half head pipe or the half seat pipe, and is arranged so that an axial direction of the half connecting member intersects a vibration direction. The method for manufacturing a bicycle frame according to any one of claims 4 to 7. Connected to at least one of an open-section half-head pipe to which a handle is attached and an open-section half-seat pipe to which a saddle seat post is attached, and at least one of the half-head pipe and the half-seat pipe that the half coupling member in the open cross-section, but a bicycle frame of closed cross section are joined by welding surfaces are superimposed two half bicycle frame member opening cross section which is integrally molded,
The thickness of at least one of the connecting members in the direction along the axial direction of the seat pipe or the head pipe is that of the connecting member when the bicycle frame is assembled with the axial direction of the seat pipe or the head pipe as the vertical direction. Greater than the wall thickness of the side,
Further, the connecting member is an egg formed so that an outer width in a direction orthogonal to the lower axial direction is larger than an outer width in a direction orthogonal to the upper axial direction in a cross section orthogonal to the axial direction of the connecting member. A bicycle frame that is shaped and has a thickness on the lower side that is greater than that on the upper side . Connected to at least one of an open-section half-head pipe to which a handle is attached and an open-section half-seat pipe to which a saddle seat post is attached, and at least one of the half-head pipe and the half-seat pipe A closed-section bicycle frame in which two half-section bicycle frame members with an open section formed integrally with each other are joined together at a welding surface,
The thickness of at least one of the connecting members in the direction along the axial direction of the seat pipe or the head pipe is that of the connecting member when the bicycle frame is assembled with the axial direction of the seat pipe or the head pipe as the vertical direction. Greater than the wall thickness of the side,
Two of the connecting members are arranged up and down,
The lower connecting member has an oval shape in which the thickness on the lower side is formed thicker than the upper side in a cross section orthogonal to the axial direction of the lower connecting member,
The upper connecting member is a bicycle frame having an inverted oval shape in which the upper side is thicker than the lower side in a cross section orthogonal to the axial direction of the upper connecting member . Connected to at least one of an open-section half-head pipe to which a handle is attached and an open-section half-seat pipe to which a saddle seat post is attached, and at least one of the half-head pipe and the half-seat pipe A closed-section bicycle frame in which two half-section bicycle frame members with an open section formed integrally with each other are joined together at a welding surface,
The upper and lower thicknesses of the connecting member in the direction along the axial direction of the seat pipe or the head pipe when the bicycle frame is assembled with the axial direction of the seat pipe or the head pipe as the vertical direction is the side of the connecting member. It is larger than the wall thickness of the part,
Two of the connecting members are arranged up and down,
The lower connecting member has an oval shape in which the thickness on the lower side is formed thicker than the upper side in a cross section orthogonal to the axial direction of the lower connecting member,
The upper connecting member is a bicycle frame having an inverted oval shape in which the upper side is thicker than the lower side in a cross section orthogonal to the axial direction of the upper connecting member . Connected to at least one of an open-section half-head pipe to which a handle is attached and an open-section half-seat pipe to which a saddle seat post is attached, and at least one of the half-head pipe and the half-seat pipe that the half coupling member in the open cross-section, but a bicycle frame of closed cross section are joined by welding surfaces are superimposed two half bicycle frame member opening cross section which is integrally molded,
The side part of the connecting member when the bicycle frame is assembled with the axial direction of the seat pipe or the head pipe as the vertical direction rather than the thickness of the connecting member in the direction along the axial direction of the seat pipe or the head pipe Bicycle frame with large wall thickness .

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