JP2011230611A - Body frame of motorcycle and method for manufacturing the body frame of motorcycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide techniques of enhancing the appearance of a vehicle and reducing the cost of welding.SOLUTION: The body frame 11 of a motorcycle includes a head pipe 12, a main frame 41 extending from the head pipe 12 to the rear side of the vehicle, and a down frame 44 extended backward from the head pipe 12, wherein the down frame 44 is a hollow frame formed by folding a metal plate having a left flange 63 at one end and a right flange 64 at the other end into a cylindrical shape and welding the left and right flanges 63, 64 together, and is arranged so that the left and right flanges 64, 63 face the rear side of the vehicle.

Description

  The present invention relates to a technique for improving a body frame of a motorcycle.

  A head pipe, a main frame extending from the head pipe to the rear of the vehicle, and a down frame extending obliquely downward from the head pipe are provided. Each of the main frame and the down frame is a press-molded metal plate. 2. Description of the Related Art A body frame of a motorcycle having a structure in which press-formed metal plates are integrated by welding is known (see, for example, Patent Document 1 (FIG. 11)).

  As shown in FIG. 11 of Patent Document 1, the down frame (41) as a component of the vehicle body frame (21) (the numbers in parentheses indicate the symbols described in Patent Document 1. The same shall apply hereinafter) It is a member formed by butting members (41, 41) and welding these butted portions.

  The front part of the down frame (41) is overlapped front and back, the overlapped outer edge is welded (h), and the rear part of the down frame (41) is a flange part (41e, 41e). The flange portions (41e, 41e) are abutted and spot welding (k) is performed.

  However, the front part of the down frame (41) of Patent Document 1 is overlapped in the front-rear direction, and welding (h) is applied to the overlapped outer edge, so that the welded part is exposed to the front part of the vehicle. However, there was room for improvement in terms of appearance. In addition, since the left and right members (41, 41) are respectively welded at the front part and the rear part, the welding length is increased and the welding cost is increased. Any technique that can reduce welding costs while improving the appearance of the vehicle is suitable.

Japanese Patent No. 4153104

  This invention makes it a subject to provide the technique which can reduce welding cost, improving the external appearance property of a vehicle.

  According to a first aspect of the present invention, there is provided a motorcycle body frame including a head pipe, a main frame extending rearward from the head pipe, and a down frame extending rearward from the head pipe. Is a cylindrical frame in which a metal plate having a left flange portion and a right flange portion at the other end is bent into a cylindrical shape and the left and right flange portions are welded to each other, and the left and right flange portions are arranged to face the rear of the vehicle. It is characterized by that.

  In the invention according to claim 2, the down frame has a front surface portion extending in the vehicle width direction, a left side surface portion extending from one end of the front surface portion toward the rear of the vehicle, and a rear end of the left side surface portion from the rear end to the vehicle width center. A left rear surface portion extending from the left rear surface portion to the vehicle rear side, a right side surface portion extending from the other end of the front surface portion to the vehicle rear side, and a right rear surface portion extending from the rear end of the right side surface portion to the vehicle width center. This is a cylindrical frame having a substantially rectangular cross section, which is composed of a right flange portion extending from the right rear surface portion toward the rear of the vehicle.

  The invention according to claim 3 is characterized in that a fold line appearing at a portion where the front portion and the left and right side portions intersect is a substantially straight line.

  In the invention according to claim 4, the main frame is a cylindrical frame formed by combining the left half body and the right half body, and the left half body includes a left U-shaped cross section and an upper and lower sides from the left U-shaped cross section. Is a metal plate press-molded product having an upper left flange portion and a lower left flange portion. The right half has a right U-shaped cross section, and an upper right flange portion and a lower right flange extending vertically from the right U cross section. The left and right upper flanges are welded to each other, the left and right lower flanges are welded to each other, the down frame is opened upward, and the left tip and right tip at the top The left tip is applied to the outer surface of the left U-shaped cross section, the right tip is applied to the outer surface of the right U-shaped cross section, and the left tip is welded to the left U-shaped cross section. , The right tip is welded to the right U Frame is characterized in that it is connected.

  In the invention which concerns on Claim 5, the left-right front-end | tip part is welded by the lower corner part vicinity of the left-right U-shaped cross-section part, It is characterized by the above-mentioned.

  In the invention according to claim 6, the left and right U-shaped cross-sections are formed with bulging protrusions that protrude outward in the vehicle width direction, and the left and right tip portions have relief portions that avoid interference with the protrusions. It is formed.

  In the invention according to claim 7, one end of the front surface portion and the left side surface portion are connected via the front left slope portion, and the other end of the front surface portion and the right side surface portion are connected via the front right slope portion, The cylindrical frame has a substantially hexagonal cross section.

  In the invention according to claim 8, the left side surface portion and the left rear surface portion are connected via a rear left slope portion, the right side surface portion and the right rear surface portion are connected via a rear right left slope portion, and the down frame is approximately eight. It is a cylindrical frame with a square cross section.

  The invention according to claim 9 is characterized in that reinforcing protrusions extending substantially along the folding line are formed on the left and right side surfaces.

  The invention according to claim 10 is characterized in that the welding is spot welding.

  The invention according to claim 11 is a method for manufacturing a body frame of a motorcycle comprising a head pipe, a main frame extending rearward from the head pipe, and a down frame extending rearward from the head pipe. And a plastic working step of bending a metal plate having a left flange portion at one end and a right flange portion at the other end into a cylindrical shape, and a welding step of welding the left and right flange portions.

  The invention according to claim 12 is characterized in that the welding in the welding process is spot welding.

In the invention according to claim 1, the down frame is a hollow frame in which the left and right flange portions are welded to each other, and is arranged so that the left and right flange portions face the rear of the vehicle.
When the left and right flange portions of the down frame that is the welded portion are arranged facing the front of the vehicle, the welded portion is conspicuous, and thus the appearance of the vehicle may be impaired. Since the welded portion becomes invisible, the appearance of the vehicle can be improved.

Further, since the down frame is formed by bending a metal plate having left and right flange portions into a cylindrical shape, the number of parts can be reduced as compared with the case where the down frame is configured with the left member and the right member as separate members. In addition, since the left and right flange portions are simply welded after bending one metal plate, the welding length is shortened and the welding cost can be reduced.
Therefore, according to the present invention, there is provided a body frame of a motorcycle that can improve the appearance of the vehicle, reduce the number of parts, and reduce the welding cost.

In the invention according to claim 2, the down frame is a hollow frame having a substantially rectangular cross section when viewed in cross section. If the down frame has a cross-sectional view other than a rectangle, for example, an octagonal cross section, the shape of the mold forming surface may be more complicated than that of the rectangular cross section, which may increase the cost of the mold.
In this regard, in the present invention, the down frame is a hollow frame having a substantially rectangular cross section in a cross-sectional view. Therefore, the shape of the molding surface is simplified, and the mold cost can be kept low.

  In the invention according to claim 3, since the folding line is formed so as to be substantially straight when viewed from the side of the vehicle, the shape of the molding surface is simplified and the cost of the molding can be reduced.

  In the invention according to claim 4, since the left and right tip portions of the down frame are fixed to the outer surfaces of the left and right U-shaped cross sections of the main frame, the left and right tip portions of the down frame are fixed to the left and right lower flanges. Compared with the case where it is, it becomes possible to make the space | interval between right-and-left front-end | tip parts long, and if the space | interval between right-and-left front-end | tip parts becomes long, the torsional rigidity of a connection part can be improved.

  In the invention according to claim 5, since the left and right upper end portions of the down frame are welded in the vicinity of the lower corner portion, which is a highly rigid portion, in the main frame, the mounting rigidity of the down frame can be further increased.

  In the invention which concerns on Claim 6, since the escape part is formed in the right-and-left upper end part of a down frame, even if it is a case where a convex part is formed in the main frame, sufficient weld length is ensured. The For this reason, even if the convex part is formed, there is no concern that the mounting rigidity of the down frame is lowered.

  In the invention according to claim 7, the down frame is a hollow frame having a substantially hexagonal cross section having left and right front slope portions. With such a hollow frame, the traveling wind can flow smoothly to the left and right of the down frame when the traveling wind hits the down frame, compared to a hollow frame having a substantially rectangular cross section. Therefore, the aerodynamic performance of the vehicle can be improved.

  In the invention according to claim 8, the down frame is a hollow frame having a substantially octagonal cross section having left and right rear slopes. With such a hollow frame, compared to a hollow frame with a substantially hexagonal cross section, the traveling wind hits the down frame, the traveling wind flows to the side, and it is difficult for vortex to occur behind the down frame, and the traveling wind It can flow smoothly backwards. Therefore, the aerodynamic performance of the vehicle can be further improved.

  In the invention which concerns on Claim 9, since the reinforcement protrusion part is formed in the right-and-left side part of a down frame, the rigidity of a down frame can be improved compared with the case where the reinforcement protrusion part is not formed.

  In the invention which concerns on Claim 10, since welding is spot welding, compared with MIG welding etc., welding time is shortened and welding cost can be reduced.

  In the invention according to claim 11, in the plastic working process, the down frame is a member obtained by bending one metal plate into a cylindrical shape, so that productivity is improved as compared with the case of processing two metal plates. easy. In addition, in the welding process, since the down frame is formed by simply welding the left and right flange portions, the welding cost can be reduced.

  In the invention according to claim 12, since the welding is spot welding, the welding time is shortened as compared with MIG welding or the like. Since the welding time is shortened, welding costs can be reduced.

1 is a left side view of a motorcycle according to the present invention. 1 is a perspective view of a body frame of a motorcycle. Fig. 3 is a left side view of a body frame of the motorcycle. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. It is a figure explaining the manufacturing method of the down frame concerning the present invention. FIG. 6 is a sectional view taken along line 6-6 of FIG. It is a figure explaining a seat rail and its manufacturing process. It is a figure explaining inserting the seat rail of FIG. 7 in the opening part of a main frame. It is a figure explaining the state which inserted and fixed the seat rail of FIG. 7 in the opening part of the main frame. FIG. 10 is a cross-sectional view taken along line 10-10 in FIG. 3. FIG. 11 is a sectional view taken along line 11-11 in FIG. 3. FIG. 12 is a sectional view taken along line 12-12 of FIG. FIG. 13 is a cross-sectional view taken along line 13-13 in FIG. 3. FIG. 14 is a cross-sectional view taken along line 14-14 of FIG. It is a figure explaining the modification of FIG. It is a figure explaining the state which inserted the seat rail of FIG. 15 in the opening part of the main frame, and was fixed after insertion. It is a figure explaining another Example of FIG. It is a figure explaining the state which inserted the seat rail of FIG. 17 in the opening part of the main frame, and was fixed after insertion. It is a figure explaining the 1st modification of FIG. It is a figure explaining the 2nd modification of FIG. It is a figure explaining the 3rd modification of FIG. 1 is an exploded perspective view of a vehicle body frame according to the present invention and an exploded perspective view of a vehicle body frame according to a comparative example.

  Hereinafter, embodiments of the present invention will be described in detail. In the drawings and examples, “up”, “down”, “front”, “rear”, “left”, and “right” respectively indicate directions viewed from the driver who rides the motorcycle. The drawings are viewed in the direction of the reference numerals.

Embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, a motorcycle 10 is provided with a body frame 11 and a front fork 13 slidably attached to a head pipe 12 attached to a front end portion of the body frame 11, and the front fork 13. A front wheel 14 attached to the lower end, a handle 15 attached to the upper part of the front fork 13, a fuel tank 16 attached to the front upper part of the vehicle body frame 11, an engine 17 and a transmission 18 disposed below the fuel tank 16. And a power unit 21 having.

  Further, a seat 22 attached to the upper part of the rear part of the body frame 11, a swing arm 23 attached to the lower part of the body frame 11 so as to be swingable, and a rear wheel 24 attached to the rear end of the swing arm 23. The rear cushion unit 25 is provided between the rear part of the swing arm 23 and the rear part of the body frame 11.

  A headlamp 27 is disposed in front of the head pipe 12, and a front fender 28 that covers the upper portion of the front wheel 14 and is attached to the front fork 13 is provided on the front fork 13. A throttle body 31 is provided at the upper rear portion of the engine 17. A tail lamp 32 is disposed behind the seat 22, and a rear fender 33 that covers the upper portion of the rear wheel 24 is provided below the tail lamp 32. The throttle body 31 may be a carburetor.

Next, the structure of the body frame will be described.
As shown in FIG. 2, the body frame 11 of the motorcycle includes a head pipe 12, a main frame 41 that extends downward from the head pipe 12 and then extends downward, and a lower end portion of the main frame 41. A pivot plate 43 provided with a pivot shaft 42 and having a substantially U-shaped cross-sectional view, and a down frame 44 extending obliquely from the head pipe 12 to the rear and downward of the vehicle.

  A seat rail 46 that supports the seat (FIG. 1, reference numeral 22) extends from the main frame 41, and a support frame 47 is passed between the seat rail 46 and the pivot plate 43. The seat rail 46 and the support frame 47 exhibit a substantially Y shape in a side view of the vehicle. Each component of the body frame 11 is made of a press-molded metal plate and is a hollow frame.

The seat rail 46 includes a left rail member 46L and a right rail member 46R. A cross member 50 is provided between the left rail member 46L and the right rail member 46R to connect the left rail member 46L and the right rail member 46R.
The cross member 50 includes first to fourth cross members 51 to 54 that extend in the vehicle width direction from the front to the rear of the vehicle, respectively.

  Returning to FIG. 1, the down frame 44 is a member extending obliquely rearward from the lower end of the main frame 41 and the head pipe 12, and an engine hanger 49 for attaching the engine 17 is attached to the lower end portion of the down frame 44. ing.

As shown in FIG. 3, the main frame 41 includes a main frame front half 55 that extends rearward from the head pipe 12 and a main frame rear half 56 that extends downward from the main frame front half 55. A convex portion 57 having a bolt that bulges outward in the vehicle width direction and holds the fuel tank 16 is integrally provided in the main frame front half portion 55.
The pipe positioning part 61 is provided in the main frame front half part 55 and the down frame 44. The detailed structure will be described later.

Next, the cross-sectional structure of the down frame will be described.
As shown in FIG. 4, the down frame 44 is formed by bending a metal plate having a left flange portion 63 at one end and a right flange portion 64 at the other end into a cylindrical shape, and the left and right flange portions 63 and 64 are welded together. The left and right flange portions 63 and 64 are arranged so as to face the rear of the vehicle.

Next, a method for manufacturing the down frame will be described.
As shown to Fig.5 (a), the metal plate 66 called a blank material is prepared.
5 (b) to 5 (c) show the plastic working process.
As shown in FIG. 5 (b), the metal plate 66 is cut into a predetermined shape, shaped so as to form a small convex portion 67, and then the edge is cut (first forming step, trimming step). ).

As shown in FIG. 5 (c), the metal plate 66 processed in FIG. 5 (b) is set in a mold 68 and bent into a cylindrical shape in the directions of arrows c and c (second forming step).
As shown in FIG. 5D, the left and right flange portions 63, 64 of the metal plate 66 processed in FIG. 5C are welded (welding process). Spot welding is suitable for welding in the welding process.

Next, the structure of the main frame will be described.
As shown in FIG. 6, the main frame 41 is a hollow frame formed by combining a left half 71 and a right half 81, and the left half 71 is a left U-shaped cross section in which the vehicle body center side is opened. This is a press-formed product of a metal plate having a portion 72 and an upper left flange portion 73 and a lower left flange portion 74 extending vertically from the left U-shaped cross section 72. Similarly, the right half 81 is a metal plate having a right U-shaped cross-sectional portion 82 that is open on the vehicle body center side, and an upper right flange portion 83 and a lower right flange portion 84 that extend vertically from the right U-shaped cross-sectional portion 82. It is a press-formed product. The left and right upper flange portions 73 and 83 are welded together, and the left and right lower flange portions 74 and 84 are welded together.
In the figure, G is the tip of the welding gun, and E is the ground.

Next, the structure and the like of the seat rail will be described in detail.
As shown in FIG. 7A, the right rail member 46R constituting the right side of the seat rail 46 includes a right U-shaped cross-section rail portion 101 that opens to the vehicle body center side, and the right U-shaped cross-section rail portion 101 on the vehicle body center side. It is a hollow cross-section member which consists of the right lid member 102 contacted and welded. The right lid member 102 is spot welded to the right U-shaped cross-section rail portion 101 as shown in FIG. 7A to obtain the right rail member 46R shown in FIG. 7B.

  As with the right rail member 46R, the left rail member 46L includes a left U-shaped cross-section rail portion 91 that opens toward the vehicle body center side, and a left lid member 92 that is welded to the left U-shaped cross-section rail portion 91 from the vehicle body center side. This is a hollow cross-sectional member. The manufacturing method of the left rail member 46L is the same as that of the right rail member, and a description thereof will be omitted.

  As shown in FIG. 7C, the front portion of the left rail member 46L is aligned with the front portion of the right rail member 46R as shown by the arrow c in the figure.

As shown in FIG. 8A, an opening 111 is provided in the main frame 41, and the left and right lid members 102L are aligned with the ends of the left rail member 46L and the right end of the left rail member 46L. The tip of the rail member 46R is configured to be insertable.
FIG. 8B is a cross-sectional view taken along line 8 (b) -8 (b) of FIG. 8A, and shows a cross section of the main frame 41. FIG.

  As shown in FIG. 9, the front end of the left rail member 46L and the front end of the right rail member 46R are inserted so that the front ends of the left and right lid members 102 are aligned with each other, and the main frame 41 and the front end of the left and right rail members 46R are welded together. By doing so, the seat rail 46 is coupled to the main frame 41.

  As shown in FIG. 10, the left and right rail members 46L and 46R are inserted into the opening 111 opened in the main frame 41, and the front end portions of the left and right upper sub-flanges 93 and 103 and the front end portions of the left and right lower sub-flanges 94 and 104 are It faces the opening 111.

  As shown in FIG. 11, the seat rail 46 inside the opening 111 is inserted. Unlike FIG. 10, the left and right upper sub-flanges 93 and 103 and the left and right lower sub-flanges 94 and 104 are disposed inside the opening 111. Is not inserted.

  7-9, the left U-shaped cross-section rail portion 91 has left upper and lower sub-flange portions 93, 94 extending vertically at a portion excluding the front end, and the right U-shaped cross-section rail portion 101 has a front end. The upper and lower sub-flange portions 103 and 104 extending vertically are provided at portions excluding the upper left sub-flange portion 93 and the front end of the upper left sub-flange portion 93 and the front end of the upper right sub-flange portion 103 are the edge 111f of the opening portion or the left and right upper and lower flange portions 73 and 83 , 74 and 84 are in contact with the rear ends.

  Next, on the basis of FIGS. 12 to 13, the structure and the like of the pipe as a vibration isolating member that is passed between the main frame and the down frame, respectively, between the opposing wall surfaces of the hollow frame, and the like will be described.

  As shown in FIG. 12, the main frame 41 is a hollow frame formed by combining a left half 71 and a right half 81, and the left half 71 includes a left U-shaped cross-section 72 that is open on the vehicle body center side. This is a metal plate press product having an upper left flange portion 73 and a lower left flange portion 74 extending up and down from the left U-shaped cross section 72, and the right half 81 has a right U-shaped cross section 82 opened at the vehicle body center side. And a press product of a metal plate having an upper right flange portion 83 and a lower right flange portion 84 extending vertically from the right U-shaped cross-section portion 82, the left and right upper flange portions 83 are welded together, and the left and right lower flange portions 84 are Are welded.

The left half body 71 and the right half body 81 are formed with a pair of pipe positioning portions 61 at opposing positions, and the pipe positioning portion 61 has a diameter corresponding to the outer diameter (Da) of the pipe 113 and the vehicle width direction outer side. It is the convex parts 123 and 123 which protrude to.
The pipe 113 is joined to the left half 71 and the right half 81 constituting the hollow frame by the spot welded portion 117.

  As shown in FIG. 13, the down frame 44 as a component of the vehicle body frame 11 includes a front surface portion 131 that extends in the vehicle width direction and a left side surface portion that extends from one end of the front surface portion 131 toward the rear of the vehicle. 132, the left rear surface portion 133 extending from the rear end of the left side surface portion 132 toward the vehicle width center, the left flange portion 63 extending from the left rear surface portion 133 toward the rear of the vehicle, and the other end of the front surface portion 131 extending toward the rear of the vehicle. It is a hollow frame having a substantially rectangular cross section comprising a right side surface portion 142, a right rear surface portion 143 extending from the rear end of the right side surface portion 142 toward the vehicle width center, and the right flange portion 64 extending from the right rear surface portion 143 toward the rear of the vehicle. .

  A pair of pipe positioning portions 61 are formed at opposite positions on the left side surface portion 132 and the right side surface portion 142, and the pipe positioning portion 61 has a diameter corresponding to the inner diameter (Db) of the pipe 113 and protrudes toward the vehicle width center side. Concave portions 124 and 124. The pipe 113 is joined to the left side surface part 132 and the right side surface part 142 constituting the hollow frame by spot welds 118, 118. The longitudinal direction of the pipe 114 and the pressurizing direction when joining the left and right flange portions 63 and 64 are made to coincide.

  That is, the pipe 114 is passed inside the down frame 44 as a hollow frame, and a pipe positioning portion 61 that positions the pipe 114 in the direction perpendicular to the axis is provided on the down frame 44 at a portion where both ends of the pipe 114 contact. It has been.

Next, the member to which the upper end portion of the rear cushion unit is attached will be described.
As shown in FIG. 14, between the left and right rail members 46L, 46R, a second cross member 52 as a component of the cross member is passed, and the second cross member 52 includes the left and right rail members 46L, 46R has protrusions 151 and 151 protruding left and right in the vehicle width direction, and these protrusions 151 and 151 are rear cushion stays to which a rear cushion unit (FIG. 1, reference numeral 25) (rear cushion 25) can be connected. Also serves as 152.
The left and right rail members 46L and 46R are provided with rib portions 159L and 159R, respectively. Compared with the case where the rib portions 159L and 159R are not formed, the left and right rail members 46L and 46R are more rigid. The deformation of 46R is suppressed.

Next, the structure of the rail member according to the modification will be described.
As shown in FIG. 15, the right rail member 46 </ b> R constituting the right side of the seat rail 46 includes a right U-shaped cross-section rail portion 101 that opens toward the vehicle body center side, and the right U-shaped cross-section rail portion 101. It is a hollow cross-section member which consists of the right lid member 102 contacted and welded. The right lid member 102 is aligned with the right U-shaped cross-section rail portion 101 as shown in the arrow a and resistance welding (spot welding) is performed to obtain the right rail member 46R shown in FIG.

  The right lid member 102 is largely different from FIG. 7 in that the right lid member 102 is applied to the right upper and lower sub-flange portions 103 and 104 from the rear to the front, and the front end portion 102a is bent outward in the vehicle width direction. The point is that it is fixed to the inner side surface 101u of the portion 101 at a plurality of welding points 168, and there is no other significant difference.

As with the right rail member 46R, the left rail member 46L includes a left U-shaped cross-section rail portion 91 that opens toward the vehicle body center side, and a left lid member 92 that is welded to the left U-shaped cross-section rail portion 91 from the vehicle body center side. This is a hollow cross-sectional member. The structure and manufacturing method of the left rail member 46L are the same as those of the right rail member, and a description thereof will be omitted.
As shown in FIG. 15 (c), the front portion of the left rail member 46L is aligned with the front portion of the right rail member 46R as shown by the arrow c in the figure.

  As shown in FIG. 16A, an opening 111 is provided in the main frame 41, and the ends of the left rail member 46L are aligned with the ends of the left and right lid members 92, 102 in the opening 111. And the front-end | tip of the right rail member 46R is comprised so that insertion is possible.

  As shown in FIG. 16B, the front end of the left rail member 46L and the front end of the right rail member 46R are inserted so that the front ends of the left and right lid members 92 and 102 are aligned with each other. The seat rail 46 is connected to the main frame 41 by welding the tip of the rail member 46R.

Next, the structure of the rail member which concerns on another Example is demonstrated.
As shown in FIG. 17A, the right rail member 46 </ b> R is a hollow cross-section member that includes a right U-shaped cross-section rail portion 101 that opens toward the center of the vehicle body and a right lid member 102.

As shown in FIG. 17B, the right lid member 102 is applied to the right U-shaped cross-section rail portion 101 from the vehicle body center side and welded. The structure of the left rail member 46L and the manufacturing method thereof are the same as those of the right rail member, and the description thereof is omitted.
As shown in FIG. 17C, the front portion of the left rail member 46L is aligned with the front portion of the right rail member 46R as shown by the arrow c in the figure.

  18A, the front end 46La of the left rail member 46L and the front end 46Ra of the right rail member 46R are bent so as to follow the outer side surface 82s of the left and right U-shaped cross section 82 of the main frame 41. The leading ends of the left rail member 46L and the right rail member 46R are applied to the outer surface 82s of the left and right U-shaped cross section 82 of the main frame 41 and welded at a plurality of welding points 169.

  The left and right upper flange portions 83 and the lower and lower flange portions 84 are bent and formed at the ends of the left rail member 46L and the right rail member 46R, and the left and right flange portions 154 are formed on the left and right sides of the main frame. The upper flange portions 73 and 83 are engaged.

Next, a modified example of the down frame having a substantially octagonal cross section will be described.
As shown in FIG. 19, the reinforcing protrusions 156 and 156 indicated by the folding line 155 at the reference numeral 155 in FIG. 3 are formed on the left and right side surfaces 132 and 142.

  One end of the front surface portion 131 and the left side surface portion 132 are connected via a front left slope portion 135, and the other end of the front surface portion 131 and the right side surface portion 142 are connected via a front right slope portion 145, and The rear surface portion 133 is connected through a rear left slope portion 136, and the right side surface portion 142 and the right rear surface portion 143 are connected to each other through a rear right left slope portion 146.

  Returning to FIG. 3, the reinforcing protrusions 156 and 156 (only the reference numeral 156 on the left side of the drawing) intersect with the front part 131 and the left and right side surface parts 132 and 142 (only the reference numeral 132 on the left side of the drawing). Are shown as fold lines 155 and 155 (only the reference numeral 155 on the left side of the drawing is shown), and these fold lines 155 and 155 are substantially straight lines when viewed from the side of the vehicle.

Next, a modified example of the down frame having a substantially rectangular cross section will be described.
As shown in FIG. 20, the down frame 44 includes a front surface portion 131 that extends in the vehicle width direction, a left side surface portion 132 that extends from one end of the front surface portion 131 toward the rear of the vehicle, and the left side surface portion 132. A left rear surface portion 133 extending from the rear end to the vehicle width center, the left flange portion 63 extending from the left rear surface portion 133 to the vehicle rear side, a right side surface portion 142 extending from the other end of the front surface portion 131 to the vehicle rear side, and the right side This is a hollow frame having a substantially rectangular cross section, which includes a right rear surface portion 143 extending from the rear end of the surface portion 142 to the vehicle width center and the right flange portion 64 extending from the right rear surface portion 143 toward the rear of the vehicle.

Next, a modified example of the down frame having a substantially hexagonal cross section will be described.
As shown in FIG. 21, in the down frame, one end of the front surface portion 131 having a small length in the vehicle width direction and the left side surface portion 132 are connected via a front left slope portion 135 (left front slope portion 135). The other end and the right side surface portion are connected via a front right slope portion 145 (right front slope portion 145), and the down frame 44 is a hollow frame having a substantially hexagonal cross section.
Note that the cross-sectional shape of the down frame 44 may be any shape. For example, a pentagon, a heptagon, and a nine-sided shape may be used.

  In the embodiment shown in FIG. 22A, the main frame 41 is a hollow frame formed by combining a left half 71 and a right half 81, and the seat rail 46 includes a left rail member 46L and a right rail. It consists of member 46R. The left rail member 46L is composed of a left U-shaped cross-section rail portion 91 and a left lid member 92, and the right rail member 46R is composed of a right U-shaped cross-section rail portion 101 and a right lid member 102. An opening 111 is provided in the main frame 41, and the ends of the left rail member 46L and the right rail member 46R are indicated by an arrow α so that the ends of the left and right lid members 92 and 102 are aligned with each other. The seat rail 46 was connected to the main frame 41 by inserting in the direction and welding the main frame 41 and the tip of the left and right rail members 46R.

  In the comparative example shown in FIG. 22B, the main frame 41M is a hollow frame formed by combining an upper half body 161 and a lower half body 162, and the main frame 41 extends to the rear of the vehicle and is a seat. Also serves as a rail.

Next, the operation of the frame structure of the motorcycle having the above configuration will be described.
First, as shown in FIG. 4, the down frame 44 is a hollow frame in which the left and right flange portions 63 and 64 are welded to each other, and the left and right flange portions 63 and 64 are arranged to face the rear of the vehicle.

  When the left and right flange portions of the down frame that is the welded portion are arranged facing the front of the vehicle, the welded portion is conspicuous, and thus the appearance of the vehicle may be impaired. Since the welded portion becomes invisible, the appearance of the vehicle can be improved.

Further, since the down frame 44 is formed by bending a metal plate having left and right flange portions 63 and 64 into a cylindrical shape, the number of parts is reduced compared to a case where the left frame and the right member are separate members and the down frame is configured. be able to. In addition, since the left and right flange portions 63 and 64 are simply welded after bending one metal plate, the welding length is shortened and the welding cost can be reduced.
Therefore, according to the present invention, there is provided a body frame 11 of a motorcycle that can improve the appearance of a vehicle, reduce the number of parts, and reduce the welding cost.

Secondly, as shown in FIG. 20, the down frame 44 is a hollow frame having a substantially rectangular cross section in a cross-sectional view.
If the down frame has a cross-sectional view other than a rectangle, for example, an octagonal cross section, the shape of the mold forming surface may be more complicated than that of the rectangular cross section, which may increase the cost of the mold.
In this regard, in the present invention, the down frame 44 is a hollow frame having a substantially rectangular cross section in a cross-sectional view, so that the shape of the molding surface is simplified, and the mold cost can be kept low.

  Third, as shown in FIG. 3, the fold line 153 is formed so as to be substantially straight when viewed from the side of the vehicle. Therefore, the shape of the mold forming surface is simplified and the mold cost can be reduced.

  Fourth, as shown in FIG. 6, the left and right tip portions of the down frame 44 are fixed to the outer surfaces of the left and right U-shaped cross-sections of the main frame 41, so the left and right tip portions of the down frame 44 are Compared to the case where it is fixed to the left and right lower flanges, the distance between the left and right tip portions can be increased, and if the distance between the left and right tip portions is increased, the torsional rigidity of the connecting portion can be increased. .

  Fifth, as shown in FIG. 6, in the main frame 41, the left and right upper end portions 139 and 149 of the down frame are welded in the vicinity of the lower corner portion, which is a highly rigid portion. Can be further enhanced.

  Sixth, as shown in FIG. 2, relief portions 164, 164 are formed at the left and right upper end portions 139, 149 of the down frame 44, so that the projection 57 is formed on the main frame 41. Even if it exists, sufficient welding length is ensured. For this reason, even if the convex part 57 is formed, there is no fear that the attachment rigidity of the down frame 44 will fall.

  Seventh, as shown in FIG. 21, the down frame 44 is a hollow frame having a substantially hexagonal cross section. If the hollow frame has a substantially hexagonal cross section, the traveling wind can flow smoothly to the left and right of the down frame 44 when the traveling wind hits the down frame 44 as compared to the hollow frame having a substantially rectangular cross section. Therefore, the aerodynamic performance of the vehicle can be improved.

  Eighth, as shown in FIG. 4, the down frame 44 is a hollow frame having a substantially octagonal cross section. If the hollow frame has a substantially octagonal cross section, the traveling wind hits the down frame compared to the hollow frame having a substantially hexagonal cross section, the traveling wind flows to the side, and vortices are less likely to occur behind the down frame 44. The running wind can flow smoothly backwards. Therefore, the aerodynamic performance of the vehicle can be further improved.

  Ninth, as shown in FIGS. 3 and 19, since the reinforcing protrusions 156 are formed on the left and right side surfaces 132, 142 of the down frame, compared with the case where the reinforcing protrusions 156 are not formed. Thus, the rigidity of the down frame 44 can be increased.

  10thly, since welding is spot welding, compared with MIG welding etc., welding time is shortened and welding cost can be reduced.

  Eleventhly, as shown in FIG. 5, in the plastic working process, the down frame 44 is a member obtained by bending a single metal plate into a cylindrical shape. Therefore, as compared with the case of processing two metal plates, Easy to increase productivity. In addition, in the welding process, the down frame 44 is formed simply by welding the left and right flange portions 63 and 64 together, so that the welding cost can be reduced.

  12thly, as shown in FIG. 5, since welding was spot welding, welding time was shortened compared with MIG welding etc. FIG. Since the welding time is shortened, welding costs can be reduced.

  13thly, as shown in FIGS. 7-9, the main frame 41 is a hollow frame formed by combining the left half 71 and the right half 81, and the seat rail 46 includes the left rail member 46L and the right rail member. 46R. The left rail member 46L is composed of a left U-shaped cross-section rail portion 91 and a left lid member 92, and the right rail member 46R is composed of a right U-shaped cross-section rail portion 101 and a right lid member 102.

  Then, an opening 111 is provided in the main frame 41, and the tip of the left rail member 46L and the tip of the right rail member 46R are inserted into the opening 111 so that the tips of the left and right lid members 92, 102 are aligned. The seat rail 46 was connected to the main frame 41 by welding the main frame 41 and the front ends of the left and right rail members 46R.

  Conventionally, when a body frame is formed of a metal press-molded product, for example, in a main frame that is joined after a U-shaped member is abutted so as to face the center in the vehicle width direction, it is adjusted to a portion with a large load load. The cross-sectional structure was set. For this reason, although the rigidity of the main frame is sufficiently ensured, there has been a problem that the weight of the body frame tends to increase.

  In this respect, in the present invention, the main frame 41 and the left and right seat rails 46 are hollow cross-section members each formed of separate members. In the case of the main frame 41 and the left and right seat rails 46, the weight of the body frame 11 can be reduced by increasing the cross section of the portion where the load is large and reducing the cross section of the portion where the load is small. it can.

Further, the front ends of the left and right rail members 46L and 46R are inserted and welded into the opening 111 opened in the main frame 41. Since the left and right seat rails 46 are welded along the wall portion of the opening 111 of the main frame 41, the welding length can be shortened, and a predetermined rigidity is provided to the connecting portion between the main frame 41 and the seat rail 46. Can be granted.
Therefore, according to the present invention, the body frame 11 can be reduced in weight.

14thly, as shown in FIGS. 8-9, the left-and-right sub-flange part 93,103,94,104 is not provided in the front-end | tip of the left-right U-shaped cross-section rail part.
When the left and right rail members 46L and 46R are inserted into the opening 111 of the main frame 41, the ends of the left and right U-shaped cross-section rail portions 91 and 92 are located in the main frame 41, and the left and right upper sub-flange portions 93, Since the front end of 103 is brought into contact with the edge 111f of the opening or the rear end of the left and right upper and lower flange portions 73, 83, 74, 84, positioning work can be easily performed when the seat rail 46 is inserted into the main frame 41. it can.

  Fifteenthly, as shown in FIGS. 15 to 16, the left and right lid members 92 and 102 are respectively applied to the left and right upper and lower sub-flange portions 93, 103, 94, and 104, and the front ends are outside in the vehicle width direction. And is fixed to the inner side surfaces of the left and right U-shaped cross-section rail portions 101 and 101. Since the front end portions of the left and right lid members 92 and 102 are respectively fixed to the left and right U-shaped cross-section rail portions 91 and 101, the rigidity of the front portions of the left and right rail members 46L and 46R can be increased.

  Sixteenthly, as shown in FIGS. 17 to 18, the front end of the seat rail 46 composed of the left rail member 46 </ b> L and the right rail member 46 </ b> R is bent so as to be along the outer side surface of the left and right U-shaped cross section 82 of the main frame. The front end of the left rail member 46L and the right rail member 46R is applied and welded so as to be sandwiched between the outer side surfaces of the left and right U-shaped cross sections 72 and 82 of the main frame 41. Since welding is performed with the main frame 41 sandwiched from the rear of the vehicle at the front end of the seat rail 46, the welding length can be increased as compared with the case where the front end of the seat rail 46 is simply welded to the main frame. Since the welding length can be increased, the bonding strength between the seat rail 46 and the main frame 41 can be increased.

  Seventeenthly, as shown in FIG. 18, when the seat rail 46 is attached to the main frame 41, the flange storage portion 154 formed between the front end of the left rail member 46L and the front end of the right rail member 46R, The left and right upper flange portions 83 and the left and right lower flange portions 84 provided on the main frame 41 side are matched. Therefore, the operation of positioning the seat rail 46 on the main frame 41 can be easily performed.

  Eighteenthly, as shown in FIG. 2, since the cross member 50 is provided between the left rail member 46L and the right rail member 46R, the rigidity of the vehicle body frame 11 can be increased.

  Nineteenthly, as shown in FIG. 14, the cross member 50 also serves as the rear cushion stay 152, so the number of parts can be reduced.

20thly, as shown to FIGS. 12-13, the pipe 113 is passed inside the hollow frame (the main frame 41, the down frame 44). If the pipe 113 is made of a metal member, vibration generated in the hollow frame can be suppressed and the rigidity of the hollow frame can be increased while reducing the cost as compared with a rubber member that is normally used.
In addition, pipe positioning portions 61 and 61 are provided in a portion where both ends of the pipe 113 are in contact with the hollow frame.

  Conventionally, when a rubber-made anti-vibration block that suppresses vibration generated in the hollow frame is arranged in the hollow frame, a member that stops the anti-vibration block on the hollow frame has been used. This led to an increase in the cost of the body frame.

  In this respect, in the present invention, since the pipe positioning portion 61 is provided at a portion where both ends of the pipe 113 of the hollow frame are in contact, the positioning work of the pipe 113 can be easily performed. Workability can be improved.

21stly, as shown in FIG. 12, the pipe positioning part 61 is the convex parts 123 and 123 which protrude to the vehicle width direction outer side with the diameter corresponding to the outer diameter of a pipe.
Conventionally, when passing a pipe member to a hollow portion of a hollow frame, for example, a hole is formed in the hollow frame, the pipe member is inserted into the hole, and both ends of the pipe member are fixed to the hollow frame by MIG welding or the like. .

  In this respect, in the present invention, the hollow frame (main frame 41) is formed with convex portions 123 and 123 protruding outward in the vehicle width direction, and the pipe positioning is performed by setting the end face of the pipe 113 in these concave portions 123 and 123. Since the portion 61 is used, drilling work is not necessary, and processing costs are reduced. In addition, MIG welding and the like are unnecessary, and there are no weld marks on the surface, so that the appearance of the hollow frame can be improved.

22ndly, as shown in FIG. 13, the pipe positioning part 61 is the recessed parts 124 and 124 which protrude to the vehicle width center side.
Compared to the case where a hole is made in a conventional hollow frame, a pipe member is inserted into this hole, and both ends of the pipe member are fixed to the hollow frame by MIG welding or the like, MIG welding or the like is not necessary, so welding marks are formed on the surface. Will not remain. Since no weld marks remain on the surface, the appearance of the hollow frame can be enhanced.

  Twenty-third, as shown in FIG. 12, the main frame 41 is a hollow frame, and when the pipe 114 is passed to the hollow frame, one end of the pipe is inserted into the concave portion 124 formed on one of the left and right halves. Next, while aligning the other end of the pipe 113 with the recess 124 formed in the left and right half, the left and right half and the left and right half are brought into contact with each other. The flange portions 73 and 74 are welded together, and the left and right lower flange portions 83 and 84 are welded together. At this time, the other end of the pipe 113 is engaged with the recess 124 formed in the other half of the left and right, so that the positioning operation for aligning the left half 71 and the right half 81 is facilitated. The workability related to is improved.

  Twenty-fourth, as shown in FIG. 13, the down frame 44 is a hollow frame having a substantially rectangular cross section, and the longitudinal direction of the pipe 113 and the left and right flange portions 63, 64 passed to the hollow portion of the hollow frame are connected to each other. Since the pressurizing direction at the time of joining is made coincident, the operation of changing the direction of the welding gun becomes unnecessary, and the welding time can be shortened accordingly.

  25. As shown in FIGS. 3 and 12, a vibration-proof pipe is disposed in the main frame front half 55 having a flat surface that is more likely to generate vibration than the main frame rear half 56 that is less likely to generate vibration. A pipe positioning portion 61 is provided. Therefore, the main frame 41 is less likely to vibrate.

  26th, as shown in FIG. 3 and FIG. 13, the wide portion 166 of the down frame, which is formed narrower in a side view of the vehicle and is less susceptible to vibration than the lower portion of the down frame 44, is more susceptible to vibration. A pipe positioning part 61 is provided in which a vibration isolating pipe is located. Accordingly, the down frame 44 is less likely to vibrate.

  27thly, since the pipe 113 is joined to the hollow frame by spot welding, the welding time is shorter than that of MIG welding or the like. Since welding time is shortened, welding costs can be reduced.

  Although the present invention has been applied to motorcycles in the embodiment, it can also be applied to rough terrain vehicles (three-wheel buggy, four-wheel buggy) as saddle riding type vehicles, and is applicable to general vehicles. Is fine.

  The present invention is suitable for motorcycles.

  DESCRIPTION OF SYMBOLS 10 ... Motorcycle, 11 ... Body frame, 12 ... Head pipe, 25 ... Rear cushion, 41 ... Main frame, 44 ... Down frame (hollow frame), 46 ... Seat rail (hollow frame), 46L ... Left rail member (hollow Frame), 46R ... right rail member (hollow frame), 55 ... main frame first half, 56 ... main frame latter half, 61 ... pipe positioning part, 63 ... left flange, 64 ... right flange, 71 ... left half 72 ... Left U-shaped cross section, 73 ... Upper left flange, 74 ... Lower left flange, 81 ... Right half, 82 ... Right U-shaped cross section, 83 ... Upper right flange, 84 ... Lower right flange, 91 ... Left U-shaped cross-section rail, 92 ... Left lid member, 93 ... Upper left sub-flange, 94 ... Lower left sub-flange, 101 ... Right U-shaped cross-section rail, 102 ... Right lid member DESCRIPTION OF SYMBOLS 103 ... Upper right subflange part, 104 ... Right lower subflange part, 111 ... Opening part, 111f ... Edge of opening part, 113 ... Pipe, 114 ... Pipe, 123 ... Convex part, 124 ... Concave part, 131 ... Front part, 132 ... left side, 133 ... left rear surface, 139 ... upper left end, 142 ... right side, 143 ... right rear surface, 149 ... upper right end, 152 ... rear cushion stay, 153 ... folding line, 166 ... wide part.

Claims (12)

A vehicle body of a motorcycle provided with a head pipe (12), a main frame (41) extending rearward from the head pipe (12), and a down frame (44) extending rearward from the head pipe (12). In frame (11),
The down frame (44) is formed by bending a metal plate having a left flange portion (63) at one end and a right flange portion (64) at the other end into a cylindrical shape, and the left and right flange portions (63, 64) are welded together. A motorcycle body frame, wherein the left and right flange portions (63, 64) are arranged so as to face the rear of the vehicle.   The down frame (44) includes a front surface portion (131) extending in the vehicle width direction, a left side surface portion (132) extending from one end of the front surface portion (131) toward the rear of the vehicle, and the left side surface portion (132) in a cross-sectional view. A left rear surface portion (133) extending from the rear end to the vehicle width center, the left flange portion (63) extending from the left rear surface portion (133) to the rear of the vehicle, and the rear end of the front surface portion (131) from the rear of the vehicle A right side surface portion (142) extending to the vehicle width center from the rear end of the right side surface portion (142), and the right flange portion (64) extending from the right rear surface portion (143) to the rear of the vehicle. 2. The body frame of a motorcycle according to claim 1, wherein the frame is a hollow frame having a substantially rectangular cross section.   The body frame of a motorcycle according to claim 2, wherein the folding lines (153, 153) appearing at a portion where the front portion (131) and the left and right side portions (132, 142) intersect are substantially straight lines. . The main frame (41) is a hollow frame formed by combining a left half (71) and a right half (81),
The left half (71) has a left U-shaped cross section (72), and an upper left flange portion (73) and a lower left flange portion (74) extending vertically from the left U-shaped cross section (72). Is a press-molded product of
The right half (81) has a right U-shaped cross section (82), a right upper flange (83) and a lower right flange (84) extending vertically from the right U cross section (82). A press-molded product of a plate,
The left and right upper flange portions (73, 83) are welded together, and the left and right lower flange portions (74, 84) are welded together,
The down frame (44) is opened upward, and has an upper left end (139) and an upper right end (149) at the upper end.
The upper left end (139) is applied to the outer surface of the left U-shaped cross section (72), the upper right end (149) is applied to the outer surface of the right U-shaped cross section (82), and the upper left end is (139) is welded to the left U-shaped cross section (72), and the upper right end (149) is welded to the right U-shaped cross section (82).
The body frame of the motorcycle according to any one of claims 1 to 3, wherein the down frame (44) is connected to the main frame (41).   The body frame of the motorcycle according to claim 4, wherein the left and right upper end portions (139, 149) are welded in the vicinity of a lower corner portion of the left and right U-shaped cross section (82).   Convex portions (57, 57) projecting outward in the vehicle width direction are bulged and formed on the left and right U-shaped cross-sectional portions (72, 82), and the convex portions are formed on the left and right upper end portions (139, 149). The body frame of the motorcycle according to claim 4 or 5, wherein escape portions (164, 164) for avoiding interference with the portions (57, 57) are formed. One end of the front surface portion (131) and the left side surface portion (132) are connected via a front left slope portion (135), and the other end of the front surface portion (131) and the right side surface portion (142) are connected to a front right slope surface. Part (145),
The body frame of the motorcycle according to claim 2, wherein the down frame (44) is a hollow frame having a substantially hexagonal cross section. The left side surface portion (132) and the left rear surface portion (133) are connected via a rear left slope portion (136), and the right side surface portion (142) and the right rear surface portion (143) are connected to a rear right slope portion (146). )
The motorcycle body frame according to claim 7, wherein the down frame (44) is a hollow frame having a substantially octagonal cross section.   The motorcycle body according to claim 3, wherein reinforcing left and right side portions (132, 142) are formed with reinforcing protrusions (156, 156) extending substantially along the folding lines (153, 153). flame.   The motorcycle body frame according to any one of claims 1 to 9, wherein the welding is spot welding. A body frame (11) of a motorcycle comprising a head pipe (12), a main frame (41) extending rearward from the head pipe (12), and a down frame (44) extending rearward from the head pipe (12). ) Manufacturing method,
The down frame (44) includes a plastic working step of bending a metal plate having a left flange portion (63) at one end and a right flange portion (64) at the other end into a cylindrical shape,
And a welding step of welding the left and right flange portions (63, 64) to each other.   The method for manufacturing a body frame of a motorcycle according to claim 11, wherein the welding in the welding step is spot welding.

Images