Title of Invention

BODY FRAME OF MOTORCYCLE

Abstract

A body frame of a motorcycle includes a main frame that extends downwardly and rearwardly from a head pipe. The main frame is formed by bonding plural frame constituents formed by press-molding a metal plate material, and has an elliptic cross-section in which the vertical direction is defined as a major axis direction. The main frame is configured to be vertically divided into two half-bodies: an upper frame half-body, having a substantially U-shaped cross-section that is open downwardly and has upper flanges at both sides of the lower end, and a lower frame half-body, having a U-shaped cross-section that is open upwardly. Lower flanges bonded to the upper flanges at both sides of the upper end. The resulting configuration provides sufficient strength while not increasing the weight of a main frame by decreasing the plate thickness of the main frame, while reducing the number of components and processing man-hours.

Full Text

BODY FRAME OF MOTORCYCLE CROSS-REFERENCE TO RELATED APPLICATION [0001] The present application claims priority to Japanese Patent Application Nos. 2006-356762 and 2006-356763, both of which were filed December 29, 2006, the entire contents of which are hereby incorporated by reference. BACKGROUND OF THE INVENTION Field of the Invention [0002] The present invention relates to a body frame of a motorcycle that is provided with a head pipe steerably joumaling a front fork that journals a front wheel, and a main frame extending downwardly and rearwardly from the head pipe, wherein plural frame constituents made by press-molding a metal plate material are bonded to compose the main frame. Description of Background Art [0003] It has conventionally been done in general that plural pipe materials are welded to constitute a body frame of a motorcycle, and plural frames made by press-molding a metal plate material are welded and bonded to constitute a body frame from the view point of a complicated frame structure or manufacturing cost (e.g., JP-A No. [0004] In the body frame disclosed in JP-Anon. 2000-095170, two frames made by press-molding a metal plate material are brought into contact face to face with each other and flange sections of both frames are welded to constitute the main frame. [0005] Meanwhile, the main frame needs sufficient strength, since many stresses are applied thereto. Since both frames have a flat shape in the vertical direction in the body frame disclosed in the JP-Anon. 2000-095170, the plate thickness has to be increased in order to enhance the strength in the vertical direction, which leads to the increase in the weight of the main frame and the increase in the weight of the motorcycle. [0006] In addition, a process for welding afterward an engine hanger for supporting an engine or front member is necessary, with the result that the number of components is increased and the processing time is increased. [0007] The present invention is accomplished in view of the foregoing circumstance, and aims to provide a body frame of a motorcycle that can secure the sufficient strength while avoiding the increase in the weight of the main frame by decreasing the plate thickness. In addition, the present invention aims to provide a body frame of a motorcycle that can reduce the number of components and processing man-hours. SUMMARY AND OBJECTS OF THE INVENTION [0008] According to an embodiment of the present invention, a body frame of a motorcycle includes a head pipe steerably joumaling a front fork that journals a front wheel and a main frame that extends downwardly and rearwardly from the head pipe, in which the main frame is composed by bonding plural frame constituents formed by press-molding a metal plate material. The main frame having an elliptic cross section in which the vertical direction is defined as a major axis direction is configured so as to be vertically divided into two, an upper frame half-body, which has a substantially U-shaped cross-section that is open downwardly and has upper flanges at both sides of the lower end, and a lower frame half-body, which has a substantially U-shaped cross-section that is open upwardly and has lower flanges bonded to the upper flanges at both sides of the upper end. According to an embodiment of the present invention, the bonded surface of the upper frame half-body and the lower frame half body is arranged at the position offset downwardly from the center of the section of the main frame. [0009] According to an embodiment of the present invention, a pivot that pivotably journals the front end of a swing arm, which journals a rear wheel, is provided at the bonded portion of the upper frame half body and the lower frame half-body, and arranged at the rear end of the main frame. [0010] According to an embodiment of the present invention, a body frame of a motorcycle includes a head pipe steerably joumaling a front fork that journals a front wheel and a main frame that extends downwardly and rearwardly from the head pipe, in which the main frame is composed by bonding plural frame constituents formed by press-molding a metal plate material. The main frame is configured so as to be vertically divided into two in such a manner that an upper frame half-body having a substantially U-shaped cross-section that is open downwardly and a lower frame half- Body having a substantially U-shaped cross-section that is open upwardly are welded to each other, upper flanges, which protrude to both left and right sides, have consecutive surfaces along the longitudinal direction of the main frame and are arranged so as to be symmetric, are integrally and consecutively provided at both sides of the lower end of the upper frame half-body, lower flanges, which are bonded to both of the upper flanges, are integrally and consecutively provided at both sides of the upper end of the lower frame half body so as to protrude to both right and left sides, and engine mounting sections are formed at plural sections of support plates that extend downwardly from at least a part of the outer ends of both of the lower flanges integrally and consecutively, [0011] Further, according to an embodiment of the invention of the present invention, the lower frame half-body composed of a front lower frame member welded to the front portion of the upper frame half-body and a rear lower frame member that has the engine mounting sections and is welded to be bonded to the rear portion of the upper frame half-body, and the thickness of the rear lower frame member is set so as to be greater than the thickness of the front lower frame member. [0012] Still farther, according to an embodiment of the present invention, the lower frame half-body is welded consecutively to the upper frame half-body from its front end to its rear end. [0013] Still further, according to an embodiment of the present invention, regulating plate portions, which are outwardly opposite to and in contact with the outer ends of the upper flanges are integrally and consecutively provided at the outer ends of the lower flanges included in the front lower frame member so as to extend upwardly, and concave portions to which the upper flanges are fitted from above are formed at the upper surfaces of the lower flanges included in the rear lower frame member. [0014] Effects of the invention include the following: [0015] Since the main frame is composed by bonding the upper flanges of the upper frame half-body and the lower flanges of the lower frame half-body, and the upper flanges and the lower flanges protrude to the side from both sides of the main frame, strength sufficient for stress applied from a side-to-side direction to the main frame can be provided to the main frame, and since the main frame has an elliptic cross-section in which the vertical direction is defined as a major axis direction, strength sufficient for stress applied vertically to the main frame can be provided to the main frame, whereby, even if the plate thickness is decreased, sufficient strength can be provided to the main frame, which contributes to the reduction in the weight of the main frame 14A, i.e., to the reduction in the weight of the motorcycle. Further, since the main frame extending downwardly and rearwardly from the head pipe has a structure vertically divided into two, the amount of broken materials can be reduced upon the press molding of the metal plate material. [0016] Since the bonded surface of the upper frame half-body and the lower frame half-body is offset downwardly from the center of the section of the main frame, the amount of the metal plate material necessary for the lower frame half-body can be reduced, and since the arc portion at the lower part of the main frame becomes small, the main frame and the engine arranged below the main frame are arranged in a compact form, which contributes to downsizing of the motorcycle. [0017] Also, since the pivot having high stress load is provided at the bonded portion of the upper and lower flanges having high rigidity, the rigidity of the body frame can be secured. [0018] Since plural engine mounting sections are provided at the support plates integrally included in the lower frame half-body, the number of components can be reduced, and further, the formation of the engine mounting sections as post-processing becomes uimecessary, whereby processing man-hours can be reduced. Further, the engine mounting sections are formed upon the press molding, whereby the relative position among the engine mounting sections is determined without being affected by the bonding of the upper frame half-body and the lower frame half-body, resulting in that the mounting precision of the engine can be enhanced. Furthermore, the main frame extending downwardly and rearwardly from the head pipe is configured to have a structure vertically divided into two parts, whereby an amount of broken materials can be reduced upon the press molding of the metal plate material. Since the upper right and left flanges of the upper frame half-body have the surfaces consecutive along the longitudinal direction of the main frame and are arranged so as to be symmetric, the right and left upper flanges and right and left lower flanges can be simultaneously welded, thereby being capable of enhancing productivity. [0019] Since the lower frame half-body is composed of the front lower frame member and the rear lower frame member, and the thickness of the rear lower frame member is set to be greater than the thickness of the front lower frame, only the thickness of the rear lower frame member, of the lower frame half-body, to which the engine mounting sections are mounted and that requires strength, is increased to thereby reduce the weight of the main frame. [0020] In addition, the strength of the main frame is stabilized by the consecutive welding of the upper frame half-body and the lower frame half-body, and further, three components are consecutively welded, whereby productivity can be enhanced. [0021] Further, the relative position of the upper frame half-body and the lower frame half-body can easily be determined upon welding the upper frame half-body and the lower frame half-body to each other. [0022] Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. BRIEF DESCRIPTION OF THE DRAWINGS [0023] The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: [0024] Fig. 1 is a side view of a motorcycle according to a first embodiment. [0025] Fig. 2 is a side view of a body frame and an engine; [0026] Fig. 3 is an exploded perspective view of a head pipe and a main frame; [0027] Fig. 4 is an enlarged sectional view of 4-4 line in Fig. 2; [0028] Fig. 5 is an enlarged sectional view of 5-5 line in Fig. 2; [0029] Fig. 6 is an enlarged sectional view of 6-6 line in Fig. 2; [0030] Fig. 7 is a sectional view of a second embodiment corresponding to Fig. 4 of the first embodiment; and [0031] Fig. 8 is a sectional view of the second embodiment corresponding to Fig. 5 of the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0032] Figs. 1 to 6 illustrate a first embodiment of the present invention, wherein Fig. 1 is a side view of a motorcycle. Fig. 2 is a side view of a body frame and an engine, Fig. 3 is an exploded perspective view of a head pipe and a main frame. Fig. 4 is an enlarged sectional view at 4-4 line in Fig. 2, Fig. 5 is an enlarged sectional view at 5-5 line in Fig. 2, and Fig. 6 is an enlarged sectional view at 6-6 line in Fig. 2. [0033] It is to be noted that the terms front-to-rear and side-to-side are defined with respect to the advancing direction of a scooter-type motorcycle. [0034] Firstly in Figs. 1 and 2, a body frame FA of this motorcycle has a head pipe 13 that supports a front fork 11, which joumals a front wheel WF, and steerably supports a steering handlebar 12, a main frame 14A that extends downwardly and rearwardly from the head pipe 13, and a left-right pair of seat rails 15 whose front end is bonded to the rearward middle part of the main frame 14A and that step wisely extends upwardly and rearwardly, wherein a four-cycle engine E that provides power for driving a rear wheel WR jumbled to the rear part of a swing arm 16, which is movably supported by the body frame FA so as to be vertically pivotable, is supported at the main frame 14A, and the power from the engine E is transmitted to the rear wheel WR through a chain transmitting means 17. A rear cushion 18 is provided between the swing arm 16 and the seat rail 15. [0035] An air intake system 20 connected to the upper side face of a cylinder head 19 provided at the engine E includes an air cleaner 21 arranged above the engine E in the frontward direction, a throttle body 22 whose upstream end is connected to the air cleaner 21, and an intake pipe 23 that links the throttle body 22 and the cylinder head 19. An exhaust system 24 is connected to the lower side face of the cylinder head 19, and an exhaust muffler 25 at the downstream end of the exhaust system 24 is arranged at the right side of the rear wheel WR. [0036] A fuel tank 26 is arranged above the engine E in the rearward direction. The body frame FA, a part of the engine E, and the field tank 26 are covered by a body cover 28, and a riding seat 29 supported by the seat rails 15 is arranged above the field tank 26 and on the body cover 28. [0037] With reference to Figs. 4 to 6 together, the main frame 14A is configured such that an upper frame half-body 31 with a substantially U-shaped cross-section that is open downward and a lower frame half-body 32A with a substantially U-shaped cross-section that is open upward are bonded to each other so as to be vertically divided into two, wherein the upper frame half-body 31 and the lower frame half-body 32A are welded to each other in this embodiment. [0038] Further, the lower frame half-body 32A is composed of a front lower frame member 33 A welded to the front portion of the upper frame half-body 31 and a rear lower frame member 34A welded to the rear portion of the upper frame half-body 31, wherein the upper frame half-body 31, front lower frame member 33A and rear lower frame member 34A are formed by a press molding of a metal plate member. [0039] Moreover, the thickness of the rear lower frame member 34A is set so as to be greater than the thickness of the front lower frame member 33A, e.g., when the thickness of the front lower frame member 33A is 2.3 mm, the thickness of the rear lower frame member 34A is set to be 2.8 mm, and the thickness of the upper frame half-body 31 is set so as to be smaller than the thickness of the lower frame half-body 32A, e.g., 2.0 mm. [0040] Upper flanges 35, 35 that extend to both right and left sides and have continuous surfaces along the longitudinal direction of the main frame 14A are arranged at both sides of the lower end of the upper frame half-body 31 so as to be generally symmetric and to be integrally provided consecutively. Further, lower flanges 36, 36 welded to both of the upper flanges 35 respectively are integrally provided consecutively, as extending to both right and left sides, at both sides of the upper end of the front lower frame member 33A of the lower frame half-body 32A, and lower flanges 37, 37 welded to both of the upper flanges 35 respectively are integrally provided consecutively, as extending to both right and left sides, at both sides of the upper end of the rear lower frame member 34A at the lower frame half-body 32A. [0041] Thus, the lower flanges 36 of the front lower frame member 33A and the lower flanges 37 of the rear lower frame member 34A at the lower frame half-body 32A are consecutively welded to the upper flanges 35 of the upper frame half-body 31 so as to be consecutive from its front end to its rear end by, for example, a seam welding or laser welding. [0042] As described above, the upper frame half-body 31 and the lower frame half-body 32A composed of the front lower frame member 33A and the rear front frame member 34A are bonded to compose the main frame 14A. The sectional shape of the main frame 14A is formed into an ellipse in which its vertical direction is defined as a major axis, and the bonded surface 30 of the upper frame half-body 31 and the lower frame half-body 32A is arranged at the position offset downwardly from the center C of the section of the main frame 14 A. [0043] Moreover, the lower flanges 37 of the rear lower frame member 34A at the lower frame half-body 32A are formed so as to protrude more outwardly than the upper flanges 35 of the upper frame half-body 31. Furthermore, support plates 38, 38 extending downwardly are provided consecutively on at least a part of the lower flanges 36 and 37 at the lower frame half-body 32A, i.e., at the outer ends of the lower flanges 37 in this embodiment, so as to be integral therewith and perpendicular thereto, and engine mounting sections 39, 40, and 41 for mounting the engine E are formed at plural portions, e.g., three portions, of both support plates 38. [0044] On the other hand, brackets 43, 44, and 45 that are in contact with the engine mounting sections 39, 40, and 41 from the inside are provided at a crankcase 42 in the engine E, wherein the bracket 43 is fastened to the engine mounting section 39 with a bolt 46 and a nut (not shown), the bracket 44 is fastened to the engine mounting section 40 with a bolt 47 and a nut 52 (see Fig. 5), and the bracket 45 is fastened to the engine mounting section 40 with a bolt 48 and a nut (not shown). [0045] A gusset 49 is provided between the lower part of the front end of the main frame 14A, i.e., the front lower frame member 33A at the lower frame half-body 32A, and the head pipe 13. Further, the air cleaner 21 at the air intake system 20 is supported by the front end of the main frame 14A. Mounting plate portions 21a, 21a arranged at both sides of the upper part of the front end of the main frame 14A, i.e., at both sides of the front end of the upper frame half-body 31, are disposed so as to extend upwardly. These mounting plate portions 21a are attached to the front end of the main frame 14A in such a manner that bolts 51,51 inserted into the mounting plate portions 21a and the upper frame half-body 31 are screwed and fastened to weld nuts 50, 50 fixed to the inner surface of the front end of the upper frame half-body 31. [0046] On the other hand, the front portion of the swing arm 16 is pivotably joumaled to a pivot 54 arranged at the rear end of the main frame 14A. This pivot 54 is fixed to the bonded portion of the upper frame half-body 31 and the lower frame half-body 32A so as to be sandwiched between the bonded surface of the upper frame half-body 31 and the rear lower frame member 34A of the lower frame half-body 3 2 A. Support pipes 55 are provided between the pivot 54 and the middle part of both of the seat rails 15. [0047] Next, the operation of the first embodiment will be explained. Since the main frame 14A extending downwardly and rearwardly from the head pipe 13 is composed so as to be vertically divided into two parts in such a manner that the upper frame half-body 31 with the substantially U-shaped cross-section that is open dowoiwardly and the lower frame half-body 32 A with the substantially U-shaped cross-section that is open upwardly are bonded to each other, the amount of broken materials upon the press molding of the metal plate member can be reduced. Further, since the main frame 14A is constituted by bonding the upper flanges 35 of the upper frame half-body 31 and the lower flanges 36 and 37 of the lower frame half-body 32A to each other, and the upper flanges 35 and lower flanges 36 and 37 are protruded to the side from both sides of the main frame 14A, strength sufficient for the stress applied to the main frame 14A from the side-to-side direction can be provided to the main frame 14A. Moreover, since the cross-sectional shape of the main frame 14A is an ellipse in which its vertical direction is defined as a major axis, strength sufficient for the stress applied to the main frame 14A from the vertical direction can be provided to the main frame 14A. Specifically, even if the thickness is reduced, sufficient strength can be provided to the main frame 14A, which contributes to the reduction in the weight of the main frame 14A, i.e., to the reduction in the weight of the motorcycle. [0048] Since the engine mounting sections 39, 40, and 41 are provided at plural portions (three in the first embodiment) of the support plates 38 that droop from the outer ends of the lower flanges 37 of the rear lower frame member 34A at the lower frame half-body 32A, the number of components can be reduced, and the formation of the engine mounting sections as post-processing becomes unnecessary to thereby be capable of reducing the processing man-hours. Since the engine mounting sections 39, 40, and 41 are formed during the press molding, the relative position of the engine mounting sections 39, 40, and 41 is determined without being affected by the bonding of the upper frame half-body 31 and the lower frame half-body 32A, whereby the mounting precision of the engine E can be enhanced. [0049] Further, the lower frame half-body 32A is composed of the front lower frame member 33A welded to the front portion of the upper frame half-body 31 and the rear lower frame member 34A welded to the rear portion of the upper frame half- body 31, and the thickness of the rear lower frame member 34A is set so as to be greater than the thickness of the front lower frame member 33 A, whereby the weight of the main frame 14A can be reduced by increasing only the thickness of the rear lower frame member 34A of the lower frame half-body 32A to which the engine mounting sections 39, 40, and 41 are formed and that requires the strength. [0050] Moreover, since the lower frame half-body 32A is welded consecutively to the upper frame half-body 31 from its front end to its rear end, the strength of the main frame 14A is stabilized by the consecutive welding of the upper frame half-body 31 and the lower frame half-body 32A, and productivity can be enhanced by consecutively welding three components 31, 33A and 34A, [0051] Since the bonded surface 30 of the upper frame half-body 31 and the lower frame half-body 32A is arranged at the position offset downwardly from the center C of the section of the main frame 14A, the amount of the metal plate material necessary for the lower frame half-body 32A can be reduced, and since the arc portion at the lower part of the main frame 14A becomes small, the main frame 14A and the engine E arranged below the main frame 14A are arranged in a compact form, which contributes to downsizing of the motorcycle. [0052] Further, since the pivot 54 that pivotably journals the front end of the swing arm 16 is provided at the bonded portion of the upper frame half-body 31 and the lower frame half-body 32A and arranged at the rear end of the main frame 14A, and the pivot 54 having high stress load is provided at the bonded portion of the upper and lower flanges 35 and 37 having high rigidity, the rigidity of the body frame FA can be secured. [0053] Figs. 7 and 8 illustrate a second embodiment of the present invention, wherein Fig. 7 is a sectional view corresponding to Fig. 4 of the first embodiment, and Fig. 8 is a sectional view corresponding to Fig. 5 of the first embodiment. [0054] It is to be noted the components corresponding to the first embodiment are only illustrated with the same reference numerals, and the detailed explanation thereof will be omitted. [0055] A main frame 14B constituting a part of a body frame FB is configured to be vertically divided into two in such a manner that an upper frame half-body 31 with a substantially U-shaped cross-section that is open downwardly and a lower frame half-body 32B with a substantially U-shaped cross-section that is open upwardly are welded to each other. [0056] Further, the lower frame half-body 32B is composed of a front lower frame member 33B welded to the front portion of the upper frame half-body 31 and a rear lower frame member 34A that is formed to have a thickness greater than that of the front lower frame member 33B and welded to the rear portion of the upper frame half-body 31, wherein the upper frame half-body 31, front lower frame member 33B and rear lower frame member 34B are formed respectively by a press molding of a metal plate material [0057] Upper flanges 35, 35 that extend to both right and left sides and have continuous surfaces along the longitudinal direction of the main frame 14B are arranged at both sides of the lower end of the upper frame half-body 31 so as to be generally symmetric and to be integrally provided consecutively. Further, lower flanges 36, 36 welded to both of the upper flanges 35 respectively are integrally provided consecutively, as extending to both right and left sides, at both sides of the upper end of the front lower frame member 33B at the lower frame half-body 32B, and lower flanges 37, 37 welded to both of the upper flanges 35 respectively are integrally provided consecutively, as extending to both right and left sides, at both sides of the upper end of the rear lower frame member 34B at the lower frame half-body 32B. [0058] Regulating plate portions 56, 56 that are outwardly opposite to and in contact with the outer ends of the upper flanges 35 are integrally and consecutively provided at the outer ends of the lower flanges 36 of the front lower frame member 33B at the lower frame half-body 32B as extending upwardly, and concave portions 58, 58 to which the upper flanges 35 are fitted from above are formed at the upper surfaces of the lower flanges 57 of the rear lower frame member 34B at the lower frame half-body 32B. [0059] Further, the lower flanges 57 of the rear lower frame member 34B at the lower frame half-body 32B are formed so as to protrude more outwardly than the upper flanges 35 of the upper frame half-body 31. Support plates 38, 38 extending downwardly are provided consecutively at the outer ends of the lower flanges 57... so as to be integral therewith and perpendicular thereto, and engine mounting sections 39, 40, and 41 for mounting the engine E are formed at plural portions, e.g., three portions, of both support plates 38. [0060] According to this second embodiment, the effect same as that in the first embodiment can be provided, and further, the relative position of the upper frame half- body 31 and the lower frame half-body 32B can easily be determined upon welding the upper frame half-body 31 and the lower frame half-body 32B to each other. [0061] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. WHAT IS CLAIMED IS: 1. A body frame of a motorcycle comprising: a head pipe steer ably jumbling a front fork that jumble a front wheel; and a main frame that extends downwardly and rearward from the head pipe, in which the main frame is composed by bonding a plurality of frame constituents formed by press-molding a metal plate material, wherein the main frame includes an elliptic cross-section in which a vertical direction is defined as a major axis direction is configured so as to be vertically divided into an upper frame half-body and a lower half-body, the upper frame half-body having a substantially U-shaped cross-section that is open dovmwardly and has upper flanges at both sides of a lower end, and the lower frame half-body having a substantially U-shaped cross-section that is open upwardly and has lower flanges bonded to the upper flanges at both sides of an upper end. 2. The body frame of a motorcycle according to Claim 1, wherein a bonded surface of the upper frame half-body and the lower frame half- body is arranged at a position offset downwardly from a center of a section of the main frame. 3. The body frame of a motorcycle according to Claim 1, further comprising a pivot that pivotally jumbles a front end of a swing arm, which jumbles a rear wheel. wherein the pivot is provided at a bonded portion of the upper frame half body and the lower frame half-body, and is arranged at the rear end of the main frame. 4. The body frame of a motorcycle according to Claim 2, fritter comprising a pivot that pivotally journals a front end of a swing arm, which journals a rear wheel, wherein the pivot being is provided at a bonded portion of the upper frame half body and the lower frame half-body, and is arranged at the rear end of the main frame. 5. The body frame of a motorcycle according to Claim 1, flirter comprising engine mounting sections formed at a plurality of sections of support plates that extend downwardly from at least a part of outer ends of both of the lower flanges integrally and consecutively. 6. The body frame of a motorcycle according to Claim 5, wherein the lower frame half-body is composed of a front lower frame member welded to the front portion of the upper frame half-body and a rear lower frame member that has the engine mounting sections and is welded to be bonded to the rear portion of the upper frame half-body, and a thickness of the rear lower frame member is set so as to be greater than a thickness of the front lower frame member. 7. The body frame of a motorcycle according to Claim 6, wherein the lower frame half-body is welded consecutively to the upper frame half-body from its front end to its rear end. 8. The body frame of a motorcycle according to Claim 6, wherein regulating plate portions, which are outwardly opposite to and in contact with outer ends of the upper flanges are integrally and consecutively provided at outer ends of the lower flanges included in the front lower frame member so as to extend upwardly, and concave portions to which the upper flanges are fitted from above are formed at the upper surfaces of the lower flanges included in the rear lower frame member. 9. A body frame of a motorcycle comprising a head pipe steer ably jumbling a front fork that journals a front wheel and a main frame that extends downwardly and rearward from the head pipe, in which the main frame is composed by bonding a plurality of frame constituents formed by press-molding a metal plate material, wherein the main frame is configured so as to be vertically divided into an upper frame half-body and a lower frame half-body, the upper frame half-body having a substantially U-shaped cross-section that is open downwardly, the lower frame half-body having a substantially U-shaped cross-section that is open upwardly are welded to each other, upper flanges, which protrude to both left and right sides, have consecutive surfaces along the longitudinal direction of the main frame and are arranged so as to be symmetric, are integrally and consecutively provided at both sides of the lower end of the upper frame half-body, lower flanges, which are bonded to both of the upper flanges, are integrally and consecutively provided at both sides of the upper end of the lower frame half body so as to protrude to both right and left sides, and engine mounting sections are formed at a plurality of sections of support plates that extend downwardly from at least a part of the outer ends of both of the lower flanges integrally and consecutively. 10. The body frame of a motorcycle according to Claim 9, wherein the lower frame half-body is composed of a front lower frame member welded to the front portion of the upper frame half-body and a rear lower frame member that has the engine mounting sections and is welded to be bonded to the rear portion of the upper frame half-body, and a thickness of the rear lower frame member is set so as to be greater than a thickness of the front lower frame member. 11. The body frame of a motorcycle according to Claim 10, wherein the lower frame half-body is welded consecutively to the upper frame half-body from its front end to its rear end. 12. The body frame of a motorcycle according to Claim 10, wherein regulating plate portions, which are outwardly opposite to and in contact with outer ends of the upper flanges are integrally and consecutively provided at outer ends of the lower flanges included in the front lower frame member so as to extend upwardly, and concave portions to which the upper flanges are fitted from above are formed at the upper surfaces of the lower flanges included in the rear lower frame member. 13. The body frame of a motorcycle according to Claim 12, wherein a bonded surface of the upper frame half-body and the lower frame half- body is arranged at a position offset downwardly from a center of a section of the main frame. 14. The body frame of a motorcycle according to Claim 12, further comprising a pivot that pivotally journals a front end of a swing arm, which journals a rear wheel, wherein the pivot is provided at a bonded portion of the upper frame half body and the lower frame half-body, and is arranged at the rear end of the main frame. 15. A main frame of a vehicle having a head pipe steer ably jumbling a front fork that journals a front wheel, wherein the main frame that extends downwardly and rearward from the head pipe, and is formed by bonding a plurality of frame constituents formed by press-molding a metal plate material, the main frame comprising: an elliptic cross-section in which the vertical direction is defined as a major axis direction is configured so as to be vertically divided into an upper frame half-body and a lower half body, the upper frame half-body having a substantially U-shaped cross-section that is open downwardly and has upper flanges at both sides of the lower end, and the lower frame half-body having a substantially U-shaped cross-section that is open upwardly and has lower flanges bonded to the upper flanges at both sides of the upper end. 16. The main frame of a vehicle according to Claim 15, wherein a bonded surface of the upper frame half-body and the lower frame half body is arranged at a position offset downwardly from the center of the section of the main frame. 17. The main frame of a vehicle according to Claim 15, further comprising a pivot that pivotably joumals a front end of a swing arm, which journals a rear wheel, wherein the pivot is provided at a bonded portion of the upper frame half body and the lower frame half-body, and is arranged at the rear end of the main frame. 18. The main frame of a vehicle according to Claim 16, further comprising a pivot that pivotably joumals a front end of a swing arm, which joumals a rear wheel, wherein the pivot is provided at a bonded portion of the upper frame half body and the lower frame half-body, and is arranged at the rear end of the main frame. 19. The main frame of a vehicle according to Claim 15, further comprising engine mounting sections formed at a plurality of sections of support plates that extend downwardly from at least a part of outer ends of both of the lower flanges integrally

Documents:

3021-CHE-2007 AMENDED CLAIMS 10-02-2012.pdf

3021-CHE-2007 FORM-3 10-02-2012.pdf

3021-CHE-2007 OTHER PATENT DOCUMENT 10-02-2012.pdf

3021-CHE-2007 EXAMINATION REPORT REPLY RECEIVED 10-02-2012.pdf

3021-che-2007-abstract.pdf

3021-che-2007-claims.pdf

3021-che-2007-correspondnece-others.pdf

3021-che-2007-description(complete).pdf

3021-che-2007-drawings.pdf

3021-che-2007-form 1.pdf

3021-che-2007-form 18.pdf

3021-che-2007-form 26.pdf

3021-che-2007-form 3.pdf

3021-che-2007-form 5.pdf

3021-che-2007-other documents.pdf