Title of Invention

A VEHICLE BODY FRAME

Abstract

A seat rail formed from a circular pipe extends substantially horizontally rearward from an upper part of a rear end of a main frame. From a position closer to a lower part of the rear end, a backstay formed from a square pipe extends obliquely upward toward the rear side. At a rear end of the backstay, formed is a bent part so as to face the seat rail in the longitudinal direction. In the facing part, an upper surface of the backstay undergoes a concave process to form a drain at the center part thereof by a pressing operation so that projecting parts would be relatively formed on the both sides of a concave groove. The projecting parts are offset inward or outward in the width direction with respect to a center line C of the seat rail and the backstay. This allows the both of the seat rail and the backstay to be easily welded.

Full Text

BODY FRAME This application claims priority from Japanese Patent Application No. 2007-025123 filed on February 5, 2007. BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a body frame of a straddle-type vehicle such as a motorcycle, for example. 2. Description of the Related Art As a rear frame of a motorcycle, there has been proposed a structure in which a seat rail extends substantially horizontally from an upper part of a rear end of a main frame toward the rear side, and a backstay extends from a lower part of the rear end of the main frame toward the rear side obliquely upward. In this structure, an upper end of the backstay is faced to a part closer to a rear end of the seat rail to carry out welding at the part. Such a structure is disclosed in JP-A-05-262269. It is effective to make an area of welding of the backstay and the seat rail large in order to improve strength in connection therebetween. As means for the above, it has been considered that predetermined areas of the backstay and the seat rail are faced to each other along the longitudinal direction to carry out welding for the facing areas. The 1 backstay 100 and the seat rail 101 both have been formed from circular pipes. Accordingly, an angle of opening sideward between the both of the above has been large, so that a torch for welding has comparatively easily entered a close part of the center of the facing areas, as shown in Fig. 7. In the case, however, that a square pipe is to be used for any one of the backstay 100 and the seat rail 101 in accordance with a request in designing, for example, the angle of opening sideward between the both of the above becomes small, as shown in Fig. 8, so that a torch for welding is difficult to enter. This causes the related connection form not to be capable of easily satisfying such a request in design. SUMMARY OF THE INVENTION The invention is completed in view of the above situation. An object of the invention is to provide a body frame formed from pipes, which are faced to each other along the longitudinal direction to be easily welded. In order to achieve the above object, according to a first aspect of the invention, there is provided a vehicle body frame including: a first pipe extending along an axial direction and including a curved surface part having an arc-shaped cross section in a direction crossing at right angles with the axial direction; a second pipe extending along the axial direction, faced to the curved surface part along a longitudinal direction 2 and including a projecting part projectingly provided along the longitudinal direction at a position offset outward in a width direction with respect to a center line extending downward from the curved surface part along the facing direction; and a welding part for welding outer surfaces of the curved surface part and the projecting part. According to a second aspect of the invention, wherein: the first pipe is a circular pipe; the second pipe is formed from a base material formed from a square pipe having the width substantially equal to an outer diameter of the first pipe, the second pipe having a concave groove formed on a surface facing the first pipe along the longitudinal direction so as to include a center part in the width direction; and the projecting part is formed at a position offset in the width direction with respect to the center of the concave groove. According to a third aspect of the invention,, the projecting part is formed into a pair on the both sides of the concave groove in the width direction. According to a fourth aspect of the invention, the concave groove is formed so as to be able to hold a space for draining between the concave groove and an outer surface of the first pipe. According to a fifth aspect of the invention, wherein: the first and second pipes are provided into a pair on the both sides in a width direction of a vehicle body along the 3 longitudinal direction so that the pair would be formed from the first and second pipes; and one of both of the first and second pipes is a seat rail for supporting a seat. According to a sixth aspect of the invention, wherein: the first pipe is a seat rail having one end connected to a part close to an upper end of a rear part of a main frame for a motorcycle and the other end extending substantially horizontally rearward; the second pipe is a backstay having one end connected to a part close to a lower part of the rear part of the main frame and the other end extending obliquely upward toward a rear side; a bent part is formed at the other end of the second pipe, the bent part being faced to the other end of the first pipe along the longitudinal direction; and the welding part is provided between the projecting part formed in the bent part and an outer surface on the other end side of the first pipe. According to a seventh aspect of the invention, a glove bar is bridged over the both rear ends of a pair of the seat rails. According to an eight aspect of the invention, wherein: a support bracket for mounting the glove bar is provided at the rear end of the seat rail; and the support bracket is arranged so that at least a part thereof would overlap in the longitudinal direction with an area of connection of the seat rail and the bent part. 4 According to the first aspect of the invention, plural pipes are faced to each other over a predetermined length for welding. Accordingly, sufficient connection strength can be achieved even when no bracket for connection or the like is provided unlike a case of connecting an end of a pipe. Further, in the case that a circular pipe or a square pipe, for example, is faced to a pipe having a curved surface part like the first pipe along the longitudinal direction, a connection part of the both pipes is at a position just under a center axis of the first pipe, so that a welding device cannot easily reach the connection part even when it approaches from a side of the pipe. In accordance with the invention, however, the projecting part is provided at a position offset in the width direction with respect to the center axis of the curved surface part of the second pipe. This causes the connection part of the both pipes to be located closely to: the outer side, and thereby, a welding device can approach the connection part. This allows a stable welding state to be achieved. In accordance with the second aspect of the invention, the body frame can be formed by connection of pipe materials having different cross sections. Further, performing a pressing operation so that the center part of the square pipe would be included allows a part offset in position in the width direction with respect to the concave groove to be relatively projected to form a projecting part. Accordingly, the 5 projecting part can be formed in a simple process. In accordance with the third aspect of the invention, there are two welding parts inside and outside the concave groove. This allows the connection strength to be improved. In accordance with the fourth aspect of the invention, the concave groove can be used as a space for drain as it is. Accordingly, the rinse liquid or the like, for example, can be prevented from remaining between the both pipes. In accordance with the fifth aspect of the invention, two of the first and second pipes can be stably welded. This allows sufficient supporting strength to be secured for the seat. In accordance with the sixth aspect of the invention, a bent part is formed to be welded being faced to the first pipe along the longitudinal direction in connecting an end of the seat rail extending, substantially horizontally rearward from the upper part of the main frame and an end of the backstay extending obliquely upward toward the rear side from the lower part of the main frame, differently from a usual case in which a bracket for connection is provided at an end of the backstay to carry out connection with the seat rail. Accordingly, sufficient connection strength can be achieved without using a bracket. In accordance with the seventh aspect of the invention, the glove bar can be mounted in the vicinity of the connection 6 part of the pipes. This allows force operated on the glove bar to be certainly received. In accordance with the eighth aspect of the invention, a support bracket for mounting the glove bar is provided so as to overlap in the longitudinal direction with an area of connection of the seat rail and the backstay. Accordingly, it is possible to surely resist an external force from a fellow passenger holding the glove bar even when the external force operates. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a side view of a whole motorcycle in accordance with Embodiment 1; Fig. 2 is a perspective view showing the periphery of a connection part of a seat rail and a backstay; Fig. 3 is a sectional view of the connection part in Fig. 2; Fig. 4 is a sectional view showing a state of connection in another arrangement; Fig. 5 is a sectional view showing a state of connection in further another arrangement; Fig. 6 is a sectional view showing a state of connection in further another arrangement; Fig. 7 is a sectional view showing a problem of a related art; and 7 Fig. 8 is a sectional view showing a problem of a related art. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 of the invention will be described, with reference to Figs. 1 to 3. Fig. 1 shows a whole motorcycle to which the invention is applied. A body frame of the motorcycle includes a head pipe 1 and a pair of right and left main frames 2 for supporting an engine. A pair of right and left seat rails 3 extends rearward from upper ends of rear parts of the main frames 2, respectively. A bracket 15 for connection is provided between a front end of the seat rail 3 and the main frame 2. Both of the seat rail 3 and the main frame 2 are fixed to each other by welding via the bracket 15. The seat rail 3 (corresponding to a first pipe in the invention) is formed from a circular pipe, which is used as a base material. The seat rail 3 extends substantially horizontally from a place of the above-mentioned connection with the main frame 2, and then, bends slightly obliquely upward from a middle part thereof. On a side closer to the front ends of the both seat rails 3, projectingly formed are front side seat brackets 5 for fixing a front part of a seat 4. Further, a rear side seat bracket 6 for fixing a rear part of the seat 4 is bridged over rear ends of the both seat rails 3. 8 On the other hand, respective one ends of the pair of right and left backstays 7 (corresponding to a second pipe in the invention) are connected to parts closer to the lower parts of the rear parts of the both main frames 2. The backstays 7 extend obliquely rearward from an end of the connection with the main frame 2. The backstay 7 is formed from a square pipe, which is used as a base material. A front end of the backstay 7 is fixed to the main frame 2 by welding. A rear end of the backstay 7 bends on the slightly rear side of the rear seat bracket 6 to form a bent part 8 facing the rear end of the seat rail 3 along the longitudinal direction. The backstay 7 is connected to the seat rail 3 at the bent part 8 as described below. In Fig. 3, the both of the above are enlarged at the connection part. As shown in Fig. 3, the seat rail 3 and the backstay 7 are formed into the substantially same size in outer width and faced to each other with the respective center positions being accorded with each other in a perpendicular direction (refer to a center line C with respect to the width directions of the seat rail 3 and the backstay 7, which is shown in Fig. 3). By the way, the connection between the seat rail 3 and the backstay 7 is a connection between two kinds of pipes having different cross sections such as a square pipe and a circular pipe. Accordingly, at a part where the both of the above are 9 faced, a circumferential surface of the seat rail 3 forms a curved surface R while that of the backstay 7 forms a flat part. It has been mentioned already, however, that an angle of opening sideward between the curved surface R and the flat part is narrow as shown in Fig. 8 and a welding torch is difficult to enter the center part of the facing part when the curved surface R is welded to the backstay 7 with the circumferential surface of the backstay 7 remaining to be a flat surface. Therefore, in Embodiment 1, a concave groove 9 is formed at a center part of the flat part in the width direction by press-processing along the longitudinal direction to make the both sides of the concave groove 9 in the width direction relatively project, and thus, a pair of projecting parts 10 are formed. This allows the seat rail 3 to be in contact with and supported on the both projecting parts 10 in the longitudinal direction at a place offset inward or outward in the width direction with respect to the center line C. Welding is performed at the contacted and supported part (a welding part 11) as described above, so that the connection between the seat rail 3 and the bent part 8 of the backstay 7 is made possible. On the other hand, the concave groove 9 is formed so that a bottom surface thereof would curve. A curvature of the concave groove is arranged to be larger than that of a curved surface part R of the seat rail 3. Accordingly, a gap is held along the longitudinal direction between the bottom surface 10 of the concave groove 9 and an outer surface of the curved surface part R of the seat rail 3. The gap is opened in the back-and-forth direction and functions as a drain for draining a rinse liquid when the whole body frame is rinsed before painting. The rear ends of the seat rails 3 project further rearward from the rear ends of the backstays 7 to form projections 12, respectively. A support bracket 14 is fixed to an upper surface of the seat rail 3 on a rear end. A glove bar 14 is mounted by means of the support bracket 14. The support bracket 14 is provided over the length to the projected part so as to overlap with the above-mentioned welding part 11 in the longitudinal direction. The rear ends of the backstays 7 and those of the seat rails 3 are not arranged in line and only the rear ends of the seat rails 3 project in Embodiment 1. This is because a space for providing components having the height equal to that of two pipes cannot be secured at a rear end of the motorcycle due to the structure thereof. Accordingly, it is possible, of course, to arrange the rear ends of the seat rails 3 and the backstays 7 in line in the case that a sufficient space can be secured. Now, concretely described will be an operation and an effect of Embodiment 1 having the structure described above. In forming the body frame, the front ends of the seat rails 11 3 and the backstays 7 are connected by welding or the like respectively to the upper and lower parts of the rear part of the main frame 2. When the rear end of the seat rail 3 is faced to the bent part 8 of the backstay 7 along the longitudinal direction so that the respective centers thereof would be in line in the perpendicular direction, the seat rail 3 is in contact with and supported on an inner surface of both of the projecting parts 10 of the backstay 7, the inner surface close to the tops of the projecting parts 10, in the longitudinal direction, as shown in Fig. 3. Under such a condition, an outer surface of the seat rail 3 is welded to an outer surface of the backstay 7 along a peripheral contact part of both of the above. At that time, the welding part 11 is located at a position offset inward or outward in the width direction with respect to the center line C of the seat rail 3 and the backstay 7, so that a welding, torch is not required to deeply enter between the seat rail 3 and the backstay 7. This allows a welding operation to be easily performed. Further, providing a pair of the projecting parts 10 on the both sides in the width direction allows the welding part 11 also to be arranged symmetrically with respect to the center line C. Accordingly, strength of connection between the seat rail 3 and the backstay 7 can be improved with a good balance. After completing a welding process as described above, the body frame is transmitted to a rinse process for removing 12 grease, and then, transmitted to a drying process. The rinse liquid poured in the rinse process is drained through the concave groove 9. This allows a residue of the rinse liquid to be prevented from remaining in a subsequent painting process. As described above, in accordance with Embodiment 1, a pair of projecting parts 10 are provided in the backstay 7 so as to be offset in the width direction with respect to the center line C in connecting the facing part of the seat rail 3 formed from a circular pipe and the backstay 7 formed from a square pipe. Accordingly, a welding operation can be easily carried out. Moreover, forming the bent part 8 in the backstay 7 so that a predetermined length of the bent part 8 would be faced to the seat rail 3 for welding allows a certain length of the welding part 11 to be secured to achieve predetermined strength of connection. Additionally, the rinse liquid can be drained, through the concave groove 9 provided at the center part of the backstay 7 in the longitudinal direction, so that no rinse liquid remains between the seat rail 3 and the backstay 7. Furthermore, the support bracket 14 for mounting the glove bar 13 is provided so that a part of the support bracket 14 would overlap in the longitudinal direction with a welding area, that is, a connection area between the seat rail 3 and the backstay 7. This allows the pulling force or pushing force operated on the glove bar 13 by a tandem rider to be received in a double 13 structural part. Therefore, achieved can be an effect of certainly resisting such a force. The invention is not limited to Embodiment 1 described in the above description and drawings. The following embodiments, for example, are also included in a technical range of the invention. Further, various modifications can be carried out within a range not deviating from the spirit of the invention other than the following description. (1) The number of the first and second pipes is not limited to the case of Embodiment 1. A mode in which second pipes P2 are connected on the both sides of a first pipe PI (refer to Fig. 4) and a mode in which the first pipes PI are connected on the both sides of the second pipe P2 contrary to the above (refer to Fig. 5) can be considered, for example. A structure in common with Embodiment 1 is marked with the same signs and references and the description is omitted. (2) Further, one pipe is not necessarily provided so as to sandwich the other pipe and may be provided at a position offset in a circumferential direction by a predetermined angle, for example (refer to Fig. 6) . (3) The projecting part 10 is only required to be offset to an outer side (or an inner side) in the width direction with respect to at least a center axis of the curved surface part. The projecting part 10 is not necessarily provided on the both 14 sides so as to form a pair, as in Embodiment 1. (4) The outer diameters of the first and second pipes are not limited. That is to say, in the case that the second pipe is a square pipe sufficiently wider than the first pipe, for example, it is possible to provide plural first pipes on a flat surface part of the second pipe in parallel to carry out welding. 15 WE CLAIM: 1. A vehicle body frame comprising: a first pipe extending along an axial direction and including a curved surface part having an arc-shaped cross section in a direction crossing at right angles with the axial direction; a second pipe extending along the axial direction, faced to the curved surface part along a longitudinal direction and including a projecting part projectingly provided along the longitudinal direction at a position offset outward in a width direction with respect to a center line extending downward from the curved surface part along the facing direction; and a welding part for welding outer surfaces of the curved surface part and the projecting part. 2. The vehicle body frame as claimed in Claim 1, wherein: the first pipe is a circular pipe; the second pipe is formed from a base material formed from a square pipe having the width substantially equal to an outer diameter of the first pipe, the second pipe having a concave groove formed on a surface facing the first pipe along the longitudinal direction so as to include a center part in the width direction; and the projecting part is formed at a position offset in 16 the width direction with respect to the center of the concave groove. 3. The vehicle body frame as claimed in Claim 2, wherein the projecting part is formed into a pair on the both sides of the concave groove in the width direction. 4. The vehicle body frame as claimed in Claim 3, wherein the concave groove is formed so as to be able to hold a space for draining between the concave groove and an outer surface of the first pipe. 5. The vehicle body frame as claimed in Claim 1, wherein: the first and second pipes are provided into a pair on the both sides in a width direction of a vehicle body along the longitudinal direction so that the pair would be formed from the first and second pipes; and one of both of the first and second pipes is a seat rail for supporting a seat. 6. The vehicle body frame as claimed in Claim 5, wherein: the first pipe is a seat rail having one end connected to a part close to an upper end of a rear part of a main frame 17 for a motorcycle and the other end extending substantially horizontally rearward; the second pipe is a backstay having one end connected to a part close to a lower part of the rear part of the main frame and the other end extending obliquely upward toward a rear side; a bent part is formed at the other end of the second pipe, the bent part being faced to the other end of the first pipe along the longitudinal direction; and the welding part is provided between the projecting part formed in the bent part and an outer surface of the other end of the first pipe. 7. The vehicle body frame as claimed in Claim 6, wherein a glove bar is bridged over the both rear ends of a pair of the seat rails. 8. The vehicle body frame as claimed in Claim 7, wherein: a support bracket for mounting the glove bar is provided at the rear end of the seat rail; and the support bracket is arranged so that at least a part thereof would overlap in the longitudinal direction with an area of connection of the seat rail and the bent part. 18 A seat rail formed from a circular pipe extends substantially horizontally rearward from an upper part of a rear end of a main frame. From a position closer to a lower part of the rear end, a backstay formed from a square pipe extends obliquely upward toward the rear side. At a rear end of the backstay, formed is a bent part so as to face the seat rail in the longitudinal direction. In the facing part, an upper surface of the backstay undergoes a concave process to form a drain at the center part thereof by a pressing operation so that projecting parts would be relatively formed on the both sides of a concave groove. The projecting parts are offset inward or outward in the width direction with respect to a center line C of the seat rail and the backstay. This allows the both of the seat rail and the backstay to be easily welded.

Documents:

00010-kol-2008-abstract.pdf

00010-kol-2008-claims.pdf

00010-kol-2008-correspondence others.pdf

00010-kol-2008-description complete.pdf

00010-kol-2008-drawings.pdf

00010-kol-2008-form 1.pdf

00010-kol-2008-form 2.pdf

00010-kol-2008-form 3.pdf

00010-kol-2008-form 5.pdf

10-KOL-2008-(06-12-2012)-ANNEXURE TO FORM 3.pdf

10-KOL-2008-(06-12-2012)-CLAIMS.pdf

10-KOL-2008-(06-12-2012)-CORRESPONDENCE.pdf

10-KOL-2008-(10-09-2013)-CORRESPONDENCE.pdf

10-KOL-2008-(10-09-2013)-OTHERS.pdf

10-KOL-2008-(18-12-2012)-CLAIMS.pdf

10-KOL-2008-(18-12-2012)-CORRESPONDENCE.pdf

10-KOL-2008-(23-05-2012)-ABSTRACT.pdf

10-KOL-2008-(23-05-2012)-AMANDED CLAIMS.pdf

10-KOL-2008-(23-05-2012)-DESCRIPTION (COMPLETE).pdf

10-KOL-2008-(23-05-2012)-DRAWINGS.pdf

10-KOL-2008-(23-05-2012)-EXAMINATION REPORT REPLY RECIEVED.PDF

10-KOL-2008-(23-05-2012)-FORM-1.pdf

10-KOL-2008-(23-05-2012)-FORM-2.pdf

10-KOL-2008-(23-05-2012)-FORM-3.pdf

10-KOL-2008-(23-05-2012)-OTHERS.pdf

10-KOL-2008-(23-05-2012)-PA-CERTIFIED COPIES.pdf

10-KOL-2008-(23-05-2012)-PETITION UNDER RULE 137.pdf

10-KOL-2008-CORRESPONDENCE OTHERS 1.1.pdf

10-KOL-2008-CORRESPONDENCE OTHERS 1.2.pdf

10-KOL-2008-OTHERS.pdf

10-KOL-2008-PRIORITY DOCUMENT.pdf

10-KOL-2008-TRANSLATED COPY OF PRIORITY DOCUMENT.pdf

50-KOL-2008-(19-11-2012)-ABSTRACT.pdf

50-KOL-2008-(19-11-2012)-AMANDED PAGES OF SPECIFICATION.pdf

50-KOL-2008-(19-11-2012)-CLAIMS.pdf

50-KOL-2008-(19-11-2012)-CORRESPONDENCE.pdf

50-KOL-2008-(19-11-2012)-DRAWINGS.pdf

50-KOL-2008-(19-11-2012)-FORM-3.pdf

50-KOL-2008-(19-11-2012)-FORM-5.pdf

50-KOL-2008-(19-11-2012)-PA.pdf

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