JP6016841B2 - Manufacturing method of body frame - Google Patents

Description

  The present invention relates to a method for manufacturing a body frame.

  2. Description of the Related Art Conventionally, there is known a vehicle body frame that is an elliptical pipe member having a width direction as a major axis direction and is provided with a bent portion in a vertical direction (see, for example, Patent Document 1).

JP 09-95279 A

By the way, when manufacturing an elliptical frame, it may be possible to bend an elliptical pipe formed in advance, but to bend the elliptical pipe, it is necessary to put a core in the pipe and bend it. There was a problem of taking time and effort.
The present invention has been made in view of the above-described circumstances, and an object of the present invention is to make it possible to easily manufacture an elliptical frame.

In order to achieve the above object, according to the present invention, there is provided a method of manufacturing a vehicle body frame having an elliptical shape and a frame (17) which is bent at a necessary portion, wherein the frame (17) is a circular pipe. After the material is bent, it is processed into an elliptical pipe by a press machine (121), and the press machine (121) includes two molds, one side mold (123) and the other side mold (124). The one-side mold (123) and the other-side mold (124) have different R shapes on the machining surface so that the shape of the molded product is different between the one side and the other side, and the pipe material is laid out as a product. songs wants bent portion inwardly in the width direction upon (21a, 21b) and provided at a predetermined position, the elliptical pipe, upper R-shaped portion of the upper end (111), a lower R-shaped portion of the lower end (112 ) And the inner side surface in the width direction An inner R-shaped portion (113), in the an outer R-shaped portion (114) constituting the width direction of the outer side surface, the bent portions (21a, 21b) the one side type on the outside of the (123) the radius of curvature of the R-shaped (125) of the part forming the outer R-shaped portion (114), said parts forming the said inner R-shaped portion in the other side mold (124) (113) R-shaped (126 ) Is smaller than the radius of curvature.
According to the present invention, after bending a circular pipe material without using a core material, it is possible to obtain a bent elliptic pipe by processing with a press machine. Can be manufactured. Further, the R shape of the processed surface can be made different according to the bending direction, and the stress concentration at the bending portion can be effectively suppressed. The outer portion of the bent portion is likely to be distorted because it is compressed and deformed when being processed into an elliptical pipe. However, since the radius of curvature of the one-sided R-shape coming outside the bent portion is reduced, The stress concentration in the portion can be reduced, and a good molded product can be obtained.

Further, according to the present invention, the circular pipe material is a pipe material made of a single plate material, and includes a welded portion (116) on an outer peripheral surface, and the welded portion (116) is between end portions of the pipe material. The receiving surface (127) for receiving the welded portion (116) is formed in advance on the one-side mold (123) or the other-side mold (124). To do.
According to the present invention, the deformation generated in the welded portion can be controlled by the surface.
Further, according to the present invention, the receiving surface (127) is provided in the R shape (126) portion of the other side mold (124), and the R shape of the receiving surface (127) is the same as that of the pipe material. It is characterized by being adapted to an R shape.
ADVANTAGE OF THE INVENTION According to this invention, the deformation amount of a welding part can be made small and it can prevent that an excessive load arises in a welding part .

In the vehicle body frame manufacturing method according to the present invention, an elliptical frame to which bending is applied can be easily manufactured.
Further, the R shape of the processed surface can be made different according to the bending direction, and the stress concentration at the bending portion can be effectively suppressed.
Furthermore, the stress concentration in the portion outside the bent portion can be reduced, and a good molded product can be obtained.
Moreover, it can control by the surface which receives the deformation | transformation which arises in a welding part.
Moreover, it can prevent that an excessive load arises in a welding part.

1 is a left side view of a motorcycle including a body frame manufactured by a manufacturing method of the present invention. 1 is a right side view of a motorcycle. Fig. 2 is a plan view of the rear part of the motorcycle. 2 is a left side view of a vehicle body frame 11. FIG. It is the top view which looked at the body frame 11 from the upper part. It is VI-VI sectional drawing of FIG. It is VII-VII sectional drawing of FIG. It is a figure which shows the manufacturing process of a seat frame. It is a figure which shows the metal mold | die which manufactures a seat frame. It is a left view of the peripheral part of a luggage box. It is a top view of the peripheral part of a luggage box. It is a top view of the peripheral part of a lower case. It is a top view of the peripheral part of a luggage box. It is a left view of the peripheral part of the luggage box in a modification.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the description, descriptions of directions such as front and rear, right and left and up and down are the same as directions with respect to the vehicle body unless otherwise specified. Also, in each figure, the symbol FR indicates the front of the vehicle body, the symbol UP indicates the upper side of the vehicle body, and the symbol L indicates the left side of the vehicle body.

FIG. 1 is a left side view of a motorcycle having a body frame manufactured by the manufacturing method of the present invention. FIG. 2 is a right side view of the motorcycle.
In the motorcycle 10, an engine 12 is supported on a body frame 11, a pair of left and right front forks 13 that support a front wheel 2 is supported on a front end of the body frame 11, and a swing arm 14 that supports a rear wheel 3 is provided on a vehicle body. The vehicle is provided on the rear side of the frame 11. The motorcycle 10 is a saddle-ride type vehicle in which a seat 15 on which a driver (occupant) sits is supported on an upper portion of a rear portion of a vehicle body frame 11.
The motorcycle 10 includes a resin body cover (not shown) that covers the body frame 11 and the like.

FIG. 2 is a plan view of the rear portion of the motorcycle 10 with the seat 15 removed. FIG. 3 is a plan view of the rear part of the motorcycle 10. FIG. 3 shows a state in which the seat 15, a fuel tank, a rear fender, and the like, which will be described later, are removed.
1 to 3, the vehicle body frame 11 includes a front end head pipe 16 that pivotally supports a front fork 13 and a pair of left and right main pipes that extend rearward from the upper portion of the head pipe 16 with a downward slope. Frames 17 and 17, a pivot frame 18 that extends downward from the rear ends of the main frames 17 and 17, a pair of left and right down frames 19 and 19 that extend rearwardly from the lower part of the head pipe 16, and a down frame 19 , 19 and a pair of left and right gusset frames 20, 20 (gussets) that connect the main frames 17, 17.

The vehicle body frame 11 includes a pair of left and right seat frames 21, 21 extending from the rear of the main frames 17, 17 to the rear of the vehicle, and a rear frame extending rearward from the rear ends of the main frames 17, 17. 21 and 21 are provided with a pair of left and right seat frame support frames 22, 22 connected to the front and rear intermediate portions.
Further, a pair of left and right engine hangers 23, 23 are connected to the gusset frames 20, 20 so as to overlap the extended lines of the down frames 19, 19.

The left and right front forks 13 and 13 are connected to the left and right by bridges 25 at the upper ends. A steering shaft (not shown) that is pivotally supported by the head pipe 16 is provided at the center of the bridge 25. The steering handle 26 is connected to the upper end of the steering shaft.
The swing arm 14 includes a pair of left and right arm portions 14a and 14a, and the rear wheel 3 is pivotally supported by an axle 27 that connects the rear ends of the arm portions 14a and 14a.
The pivot frame 18 is provided with a pivot shaft 28 that penetrates the pivot frame 18 in the vehicle width direction. The swing arm 14 is pivotally supported by a pivot shaft 28 at the front end, and can swing up and down around the pivot shaft 28.
The pair of left and right rear cushions 29, 29 are stretched between the rear ends of the arm portions 14 a, 14 a and the rear portions of the seat frames 21, 21.

The engine 12 is a four-cycle single cylinder engine. The engine 12 includes a crankcase 30 that houses a crankshaft (not shown) that extends substantially horizontally in the vehicle width direction, and a cylinder portion 31 that extends obliquely forward and upward from the upper surface of the front portion of the crankcase 30. The cylinder portion 31 includes a cylinder 32 coupled to the upper surface of the crankcase 30, a cylinder head 33 coupled to the upper surface of the cylinder 32, and a head cover 34 that closes the upper surface of the cylinder head 33. The cylinder axis 31a of the cylinder part 31 extends vertically in a forward inclined posture.
A transmission (not shown) is integrally provided in the rear portion of the crankcase 30. A drive sprocket 35 is provided on the output shaft of the transmission protruding outward from the rear side surface of the crankcase 30, and the output of the engine 12 is driven across the drive sprocket 35 and the driven sprocket 38 of the rear wheel 3. It is transmitted to the rear wheel 3 through the chain 39.

The engine 12 includes fixed portions 40 a, 40 b, and 40 c that are connected to the body frame 11 side at the upper portion of the crankcase 30, the lower portion of the rear portion of the crankcase 30, and the lower portion of the front portion of the crankcase 30. The engine 12 is disposed below the rear portions of the main frames 17 and 17 and in front of the pivot frame 18 and is suspended from the vehicle body frame 11.
The exhaust pipe 41 of the engine 12 is drawn from the front surface of the cylinder head 33, extends rearward through the lower side of the engine 12, and is connected to a muffler 42 disposed on the side of the right arm portion 14a.

The intake device of the engine 12 includes an air cleaner box 44 that purifies the intake air, a throttle body (not shown), and a connecting tube (not shown) that connects the air cleaner box 44 and the throttle body.
The air cleaner box 44 is disposed between the left and right main frames 17 and 17 and between the left and right down frames 19 and 19, and is positioned above the cylinder portion 31. The throttle body is disposed in the vicinity of the air cleaner box 44 and connected to an intake port on the rear surface of the cylinder head 33.

A luggage box 47 that can store articles such as a helmet is provided between the left and right seat frames 21 and 21 above the rear portion of the engine 12. A fuel tank 48 is provided behind the luggage box 47 between the left and right seat frames 21 and 21.
The seat 15 is disposed so as to cover the luggage box 47 and the fuel tank 48 from above. Specifically, the seat 15 is integrally provided with a driver's front seat 15a and a passenger's rear seat 15b that is one step higher than the front seat 15a. The seat 15 is connected to the front portion of the luggage box 47 via a hinge 49 provided at the front end, and the seat 15 is opened by turning the seat 15 upward about the hinge 49, and the luggage box 47 and the fuel tank 48 are exposed to the outside.

The passenger tandem step 50 is supported by a stay 51 extending downward from the seat frame support frames 22, 22. A grab rail 52 that can be gripped by the passenger is provided on the left and right sides of the rear portion of the rear seat 15b.
A pair of left and right steps 53, 53 for the driver are supported at both ends of a step stay 54 that extends outward from the lower surface of the rear portion of the crankcase 30 in the vehicle width direction.
A seesaw-type shift pedal 55 is provided in front of the left step 53. A side stand 56 is provided below the left step 53. A main stand 57 is provided behind the side stand 56.
A brake pedal 58 for operating the brake of the rear wheel 3 is provided in the vicinity of the step 53 on the right side.
A rear fender 59 is provided above the rear wheel 3 so as to cover the fuel tank 48 from below.

FIG. 4 is a left side view of the vehicle body frame 11. FIG. 5 is a plan view of the vehicle body frame 11 as viewed from above. 6 is a sectional view taken along line VI-VI in FIG.
Next, the vehicle body frame 11 will be described in more detail. Since the body frame 11 is formed symmetrically, the same reference numerals are given to the left and right, and in the following description, only one reference is shown unless particularly required.
The body frame 11 is integrally formed by joining together a pipe material and a plate material made of a metal material such as a steel material by welding.
The head pipe 16 is disposed so as to be inclined rearward according to the caster angle.

The main frame 17 includes an upper pipe portion 61 that extends downward from the rear surface of the upper portion of the head pipe 16 toward the upper side of the crankcase 30 and is coupled to the gusset frame 20, and a bent portion at the rear end portion of the upper pipe portion 61. And a rear pipe portion 63 that is bent at 62 and extends rearwardly downward at a gentler angle than the upper pipe portion 61. The main frame 17 is a relatively long single pipe in which the upper pipe portion 61 and the rear pipe portion 63 extend continuously in the axial direction without welding seams.
Specifically, the upper pipe portion 61 is bent at the rear end of the upper pipe front portion 64 and the upper pipe front portion 64 extending rearward while extending in the vehicle width direction so that the distance between the left and right upper pipe portions 61 is increased. And an upper pipe extending portion 65 extending rearward substantially parallel to the center line M in the vehicle width direction and coupled to the gusset frame 20 at the rear end. The front end of the upper pipe front portion 64 is coupled to the head pipe 16 at a position closer to the intermediate position than the upper and lower intermediate positions of the head pipe 16.

  The rear pipe portion 63 is continuous with the upper pipe extension portion 65 and extends rearward while spreading in the vehicle width direction, and the rear pipe front portion 66 is bent inward in the vehicle width direction at the rear end of the rear pipe front portion 66 and rearward. A rear pipe intermediate portion 67 having a smaller left-right spacing toward the side, and a rear pipe rear portion 68 that is bent at the rear end of the rear pipe intermediate portion 67 and extends rearward substantially parallel to the center line M. A plate-like upper engine hanger 69 is provided on the lower surface of the rear pipe front portion 66, and the fixed portion 40 b of the engine 12 is connected to the upper engine hanger 69.

  The down frame 19 extends downward from the rear surface of the lower portion of the head pipe 16 to the vicinity of the cylinder portion 31 and is connected to the gusset frame 20. The down frame 19 includes a lower pipe front portion 70 that extends in the vehicle width direction so as to increase the distance between the front end portions of the left and right down frames 19 and a rear end of the lower pipe front portion 70 in a plan view. A lower pipe rear portion 71 that is bent and extends rearward substantially parallel to the center line M in the vehicle width direction and is coupled to the gusset frame 20 is provided. The front end of the lower pipe front portion 70 is coupled to the head pipe 16 at a position closer to the lower end position of the head pipe 16 below the upper and lower intermediate positions of the head pipe 16.

The down frame 19 extends rearward and downward with a larger lower gradient than the upper pipe portion 61, and the vertical distance between the down frame 19 and the upper pipe portion 61 is larger toward the rear side. The lower pipe rear portion 71 is disposed on the outer side in the vehicle width direction with respect to the upper pipe extending portion 65 and extends substantially parallel to the upper pipe extending portion 65.
The vehicle body frame 11 includes a pair of reinforcing plates 72 that vertically connect the lower pipe front portion 70 and the upper pipe front portion 64.

  The gusset frame 20 is a plate material that is formed in a substantially rectangular shape in a side view, and connects the rear end of the down frame 19 and the intermediate portions before and after the main frame 17. The gusset frame 20 includes an upper edge portion 74 extending so as to connect the down frame 19 and the upper pipe portion 61, a lower edge portion 75 extending so as to connect the engine hanger 23 and the rear pipe portion 63, It has a rear edge 76 coupled to the frame 17 and a front edge 77 coupled to the engine hanger 23. The gusset frame 20 has a lightening hole 78 in the center.

The gusset frame 20 is disposed so as to cover the lower end of the down frame 19 from the outside, and the front portion of the upper edge portion 74 is coupled to the rear end of the lower pipe rear portion 71. The engine hanger 23 is overlapped and fixed to the lower portion of the front edge 77 of the gusset frame 20 from the outside.
The rear edge 76 of the gusset frame 20 is coupled to the outer surface of the main frame 17 by a weld bead 79 along the rear edge 76. The weld bead 79 is an attachment position between the main frame 17 and the gusset frame 20. In addition, this attachment position should just be a position where the main frame 17 and the gusset frame 20 contacted and couple | bonded, and is not limited to a welding bead.

The rear end 79 a of the weld bead 79 is located behind the bent portion 62, and the front end 79 b of the weld bead 79 is located ahead of the bent portion 62. The position of the rear end 79 a substantially matches the position of the rear end of the gusset frame 20 on the main frame 17, and the position of the front end 79 b substantially matches the position of the front end of the gusset frame 20 on the main frame 17.
The rear edge portion 76 of the gusset frame 20 has a front portion coupled to the rear end portion of the upper pipe portion 61 and a rear portion coupled to the front end portion of the rear pipe portion 63. That is, the gusset frame 20 is coupled to the main frame 17 by the weld beads 79 that extend across the bent portion 62.

  The pivot frame 18 is disposed at the center in the vehicle width direction so as to overlap the center line M. The pivot frame 18 includes a pair of left and right plate portions 80 and a connecting plate 81 that connects the left and right plate portions 80 in the vehicle width direction. The connecting plate 81 is provided along the upper edge portion and the rear edge portion of the plate portion 80. The upper part of the connecting plate 81 constitutes an upper surface part 18a of the pivot frame 18 that inclines backward. A cutout portion 82 having a shape along the rear ends of the left and right rear pipe portions 63 is formed on the upper surface portion 18a, and the rear ends of the rear pipe portions 63 are fitted into the cutout portions 82, respectively. The pivot frame 18 is coupled to the rear end of the rear pipe portion 63 by a weld portion formed along the upper edge portion of the plate portion 80 and the inner edge portion of the notch portion 82.

A cylindrical pivot support cylinder 83 is spanned between the upper portions of the left and right plate portions 80, and the pivot shaft 28 is inserted through the pivot support cylinder 83.
An engine suspension portion 84 to which the fixed portion 40 b of the engine 12 is connected is provided below the pivot support cylinder 83 in the plate portion 80.
A main stand connecting portion 85 to which the main stand 57 is connected is provided at the lower portion of the plate portion 80.

  The seat frame 21 extends rearwardly from the upper surface of the front portion of the rear pipe portion 63 of the main frame 17 and rises rearward from the rear end portion of the frame front portion 86 with a larger inclination than the frame front portion 86. A frame intermediate portion 87 that extends and a frame rear portion 88 that extends rearwardly from the rear end portion of the frame intermediate portion 87 to the rear portion of the vehicle with substantially the same inclination as the frame front portion 86 are provided. The frame front portion 86 is continuous with the rear pipe front portion 66 of the main frame 17 and extends so as to expand in the vehicle width direction toward the rear side. The frame middle portion 87 and the frame rear portion 88 extend rearward substantially parallel to the center line M in plan view. A rear end bent portion 88a (FIG. 3) is formed at the rear end of the frame rear portion 88.

A coupling surface 89 is formed at the front end of the frame front portion 86 of the seat frame 21 so as to be obliquely cut so that the top surface is the tip. The seat frame 21 is a welded portion along the peripheral edge of the coupling surface 89. Is welded to the upper surface of the main frame 17. The coupling surface 89 is a mounting position of the seat frame 21 with respect to the main frame 17. The joining surface 89 of the seat frame 21 is welded to a position near the rear end of the gusset frame 20 behind the gusset frame 20. In addition, this attachment position should just be a position where the seat frame 21 and the main frame 17 contact and couple | bond, and is not limited to a welding part.
Specifically, in the front-rear direction, the rear end 79a of the weld bead 79 of the gusset frame 20 and the front end 89a of the welded portion of the coupling surface 89 overlap. Further, the rear end 89 b of the welded portion of the coupling surface 89 is positioned behind the rear end 79 a of the weld bead 79 and above the rear end of the upper engine hanger 69.
The upper engine hanger 69 is provided below the coupling surface 89 behind the gusset frame 20.
On the lower surface of the rear portion of the seat frame 21, a plate-like cushion upper end support portion 90 provided across the rear end of the frame intermediate portion 87 and the front end of the frame rear portion 88 is provided.

The seat frame support frame 22 extends rearward and rearwardly from the upper surface of the rear end of the rear pipe portion 63 of the main frame 17 with a larger upward gradient than the frame intermediate portion 87, and the lower surface of the front end of the frame rear portion 88 of the seat frame 21. Combined with The upper end of the seat frame support frame 22 is also welded to the inner surface of the cushion upper end support portion 90. A stay 51 is provided on the upper portion of the seat frame support frame 22.
The seat frame support frame 22 is continuous with the rear pipe portion 63 and extends substantially straight rearward in a plan view, and the seat frame support frame 22 is bent at the rear end of the support frame front portion 91 and extends in the vehicle width direction. And a support frame rear portion 92 extending rearward. The upper end of the support frame rear portion 92 is coupled to the frame rear portion 88.

The vehicle body frame 11 includes a plurality of cross members that connect the left and right frames in the vehicle width direction. A front cross member 93 that connects the left and right rear pipe front portions 66 and 66 is provided at the front and rear intermediate portions of the main frame 17.
A plate-like first intermediate cross member 94 that connects the left and right rear pipe intermediate portions 67 and 67 is provided at the rear portion of the main frame 17.
A plate-like second intermediate cross member 95 that connects the left and right support frame front portions 91 and 91 is provided at the front portion of the seat frame support frame 22. The front edge of the second intermediate cross member 95 is welded to the rear surface of the connecting plate 81 of the pivot frame 18.
A plate-like rear cross member 96 that connects the rear ends of the left and right frame intermediate portions 87 and 87 is provided at the front and rear intermediate portions of the seat frame 21.
A rear end cross member 97 that connects the rear ends of the left and right rear end bent portions 88a and 88a is provided at the rear end of the seat frame 21.

The front cross member 93 is disposed behind the bent portion 62 of the main frame 17 and in front of the front end 89 a of the coupling surface 89 of the seat frame 21 and the upper engine hanger 69. The front cross member 93 is formed in a plate shape and is disposed substantially horizontally. A pair of front support holes 98 and 98 for supporting the front end of the luggage box 47 are provided on both ends of the front cross member 93 in the vehicle width direction.
The rear cross member 96 is formed in a plate shape that is disposed substantially horizontally, and a rear support hole 99 that supports the rear end of the luggage box 47 is provided at both ends of the rear cross member 96 in the vehicle width direction. A pair of 99 is provided.

  As shown in FIGS. 1 and 4, the vehicle body frame 11 has a seat frame 21 that extends rearward with an upper gradient and a middle portion of a main frame 17 that extends rearward with a lower gradient. In addition, a valley-like valley portion 100 is provided in a side view. The trough 100 forms a straddling space S that is recessed downward in a side view between the luggage box 47 and the main frame 17 at the front lower side of the seat 15. The driver can straddle the seat 15 through the legs in the straddling space S when getting on and off the motorcycle 10.

Since the valley part 100 is located in the middle part before and after the body frame 11, the load from the front wheel 2 side, the load from the seat 15 side, and the load from the rear wheel 3 side tend to concentrate on the valley part 100 side. . The engine 12 is suspended below the trough 100. For this reason, stress tends to concentrate on the valley portion 100.
In the present embodiment, the front cross member 93 that connects the left and right main frames 17, 17 is connected to the front end 79 b of the weld bead 79 of the gusset frame 20 and the seat frame 21 that are coupled to the main frame 17 below the trough 100. The coupling surface 89 is provided at a position between the front end 89a of the welded portion. For this reason, the load concerning the trough part 100 can be received effectively by the front cross member 93, and the rigidity of the vehicle body frame 11 can be improved.
Further, since the front cross member 93 is disposed between the engine hanger 23 and the engine suspension portion 84 of the pivot frame 18, the load of the engine 12 acting on the main frame 17 is effectively reduced by the front cross member 93. Can receive.

The front cross member 93 is disposed between the front end 79b and the rear end 79a of the weld bead 79 of the gusset frame 20, and the front and rear positions overlap the gusset frame 20 in a side view. For this reason, the load which acts on the gusset frame 20 can be shared and received by the front cross member 93, and the stress concentration in the vicinity of the valley 100 can be effectively suppressed.
4 and 5, the rear end 79a of the weld bead 79 of the gusset frame 20 and the front end 89a of the welded portion of the coupling surface 89 of the seat frame 21 overlap in plan view and side view. Therefore, the stress acting on the coupling surface 89 can be effectively received by the peripheral structure of the gusset frame 20 including the front cross member 93, and the rigidity and strength of the vehicle body frame 11 can be improved.

Next, the main frames 17 and 17 will be described in detail.
With reference to FIGS. 4 to 6, the main frame 17 includes a vertically long oval portion 101 having the vertical direction of the motorcycle 10 as a major axis direction. An elliptical long axis Y1 of the elliptical part 101 extends in a substantially vertical direction. The oval part 101 is provided continuously in a section from the front end of the upper pipe front part 64 of the upper pipe part 61 to the rear part of the upper pipe extension part 65. An elliptical portion rear end 101a at which the section of the elliptical portion 101 ends is provided in front of the front end 79b of the weld bead 79 of the gusset frame 20 and at a position close to the front end 79b.

  The main frame 17 changes to a perfect circle part 102 having a substantially perfect cross section behind the ellipse rear end 101a. The perfect circle portion 102 is continuously formed from a position in front of the gusset frame 20 to the rear end of the main frame 17. The perfect circle front end 102 a where the perfect circle 102 starts is located between the ellipse rear end 101 a and the front end 79 b of the weld bead 79 of the gusset frame 20. The perfect circle part 102 extends from the rear part of the upper pipe extension part 65 to the rear end of the rear pipe rear part 68, and the gusset frames 20, 20 are provided in the perfect circle part 102.

That is, the main frame 17 has an elliptical shape with the vertical direction as the major axis direction between the head pipe 16 and the weld bead 79 where the gusset frame 20 and the main frame 17 are attached. The cross-sectional shape changes to a substantially perfect circle after a predetermined position ahead of 79b. That is, the cross-sectional shape of the main frame 17 changes to a substantially perfect circle at least after the position of the weld bead 79.
Between the ellipse rear end 101a and the perfect circle front end 102a, the cross section of the main frame 17 continuously changes from an ellipse to a substantially perfect circle as it goes rearward.

  The down frame 19 is a round pipe having a substantially circular cross section throughout its length. The lower pipe rear portion 71 of the down frame 19 extends rearward substantially parallel to the elliptical portion 101 in a plan view from above at a position below the elliptical portion 101 of the main frame 17 and outside in the vehicle width direction. Further, the lower pipe rear portion 71 extends rearward with a lower slope than the ellipse portion 101 in a side view, and the vertical distance between the ellipse portion 101 and the lower pipe rear portion 71 is larger toward the rear side. Therefore, the space between the left and right ellipsoidal portions 101, 101 can be increased, and a large space can be ensured between the ellipsoidal portion 101 and the down frame 19, and other components such as an intake device can be efficiently arranged in this space. Furthermore, since the elliptical portion 101 is vertically long, the space between the elliptical portions 101 and 101 can be increased, and components can be easily placed in this space.

  The main frame 17 and the down frame 19 are manufactured from the same substantially circular pipe material. That is, the diameter and material of these pipe materials are the same. When forming the main frame 17, first, the pipe material is bent by a pipe bender or the like at a predetermined bending position such as a bent portion between the upper pipe front portion 64 and the upper pipe extension portion 65. Done. Subsequently, the elliptical part 101 is formed by compressing the substantially perfect pipe material after the bending process by press working using a metal mold. The down frame 19 is formed in a predetermined shape by bending the pipe material at a predetermined bending position. Thus, since the main frame 17 and the down frame 19 are manufactured from the same substantially circular pipe material, the vertical dimension of the oval part 101 is larger than the vertical dimension of the down frame 19, and The width dimension is smaller than the width dimension of the down frame 19. That is, the elliptical portion 101 is larger in the vertical direction than the down frame 19, and the horizontal stiffness is larger in the down frame 19 than the elliptical portion 101.

  A load from the road surface input to the front wheel 2 side is transmitted to the main frame 17 and the down frame 19 via the head pipe 16. Since the load in the vertical direction transmitted to the main frame 17 and the down frame 19 is effectively received by the main frame 17 having the elliptical portion 101 having high vertical rigidity, the vertical load at the front portion of the vehicle body frame 11 is Stiffness can be improved. Further, when a lateral load acts on the front portion of the vehicle body frame 11, the elliptical portion 101 having a relatively small lateral stiffness can be positively bent, so that the lateral load can be effectively released. .

Further, the down frame 19 has a substantially perfect circle, and the lateral rigidity is higher than that of the ellipse 101. Therefore, when a lateral load is applied, the front part of the body frame 11 has a fulcrum on the down frame 19 side. The main frame 17 closer to the upper end side of the head pipe 16 is swung so as to be twisted. For this reason, the driver can accurately grasp the traveling state of the motorcycle 10 through this deflection (twist).
Further, since the front end of the down frame 19 is coupled closer to the lower end position of the head pipe 16 and the upper end of the main frame 17 is coupled above the upper and lower intermediate positions of the head pipe 16, Can be. For this reason, the driver can easily grasp the traveling state of the motorcycle 10.
Further, the vertical and horizontal loads from the seat 15 side transmitted to the main frame 17 via the seat frame 21 are received substantially uniformly by the perfect circle portion 102. For this reason, the behavior of the bending of the rear portion of the main frame 17 with respect to the load becomes natural.

Next, the seat frames 21 and 21 will be described in detail. 7 is a cross-sectional view taken along the line VII-VII in FIG. In FIG. 7, a cross section of the left seat frame 21 is shown.
Referring to FIGS. 4 to 7, the seat frame 21 is a single relatively long pipe that extends continuously over the entire length of the main frame 17 without any welding seam connecting in the axial direction. The seat frame 21 includes an elliptical portion 110 having the longitudinal direction of the motorcycle 10 as a major axis direction. The oval part 110 is provided over the entire length of the seat frame 21.
The seat frame 21 includes inner-direction bent portions 21a and 21b between the frame front portion 86 and the frame intermediate portion 87, and between the frame rear portion 88 and the rear end bent portion 88a. The inwardly bent portions 21a and 21b are bent portions that bend inward in the vehicle width direction. Between the frame middle portion 87 and the frame rear portion 88, an upper and lower bent portion 21c that is bent in the vertical direction is provided.

The elliptical part 110 is formed in a vertically long elliptical shape, and the major axis Y2 of the elliptical part 110 is longer than the minor axis X2. The ellipse part 110 is provided in a direction in which the long axis Y2 faces the substantially vertical direction.
The oval part 110 includes an upper R-shaped part 111 at the upper end, a lower R-shaped part 112 at the lower end, an inner R-shaped part 113 that constitutes the inner side surface of the seat frame 21 in the vehicle width direction, and the vehicle width of the seat frame 21. And an outer R-shaped portion 114 constituting the side surface on the outer side in the direction. Here, the R shape means an arcuate curved surface shape.

The curvature radius of the upper R-shaped portion 111 and the curvature radius of the lower R-shaped portion 112 are substantially equal.
The inner R-shaped portion 113 is a curved surface that does not have a flat portion and is entirely curved and protrudes inward in the vehicle width direction. The outer R-shaped portion 114 is a curved surface that does not have a flat portion and is entirely curved and protrudes outward in the vehicle width direction. The radius of curvature of the inner R-shaped portion 113 is larger than the radius of curvature of the outer R-shaped portion 114. For this reason, the protrusion amount P1 in the vehicle width direction of the inner R-shaped portion 113 from the long axis Y2 is smaller than the protrusion amount P2 in the vehicle width direction of the outer R-shaped portion 114 from the long axis Y2. Accordingly, a large space can be secured between the inner R-shaped portions 113, 113 of the left and right seat frames 21, 21, and a large luggage box 47 and a fuel tank 48 can be disposed in this space in the vehicle width direction.

The inner R-shaped portion 113 includes an R-shaped protruding portion 115 that protrudes inward in the vehicle width direction at an intermediate portion in the vertical direction. The R-shaped protrusion 115 is an arcuate curved surface, and the radius of curvature of the R-shaped protrusion 115 is smaller than the radius of curvature of the inner R-shaped portion 113 and the radius of curvature of the outer R-shaped portion 114.
The seat frame 21 is a pipe formed by rolling plate materials into a pipe shape and joining the seam with a weld bead 116 extending in the axial direction. For example, the seat frame 21 is an electric resistance welded steel pipe. The weld bead 116 is formed over the entire length at the upper and lower intermediate portions of the inner R-shaped portion 113, more specifically, at the apex portion of the R-shaped protruding portion 115. That is, since the weld bead 116 is located on the inner side in the vehicle width direction and hidden from the outer side, the appearance of the seat frame 21 is good.

Since the seat frame 21 supporting the luggage box 47 and the cushion upper end support portion 90 is formed into a vertically long elliptical portion 110, the load transmitted to the seat frame 21 from the seat 15 and rear cushion 29 side is effected by the seat frame 21 having high rigidity in the vertical direction. Can be received.
Further, since the inner R-shaped portion 113 includes the R-shaped projecting portion 115, the section modulus of the elliptical portion 110 increases, so that the strength of the elliptical portion 110 can be improved.

Here, a method for manufacturing the seat frame 21 will be described.
FIG. 8 is a diagram illustrating a manufacturing process of the seat frame 21. FIG. 9 is a view showing a mold for manufacturing the seat frame 21.
The manufacturing process of the seat frame 21 includes a bending process in which a straight pipe material (not shown) having a substantially circular cross section is bent at a necessary portion, and a pipe material 130 that is bent in the bending process is compressed by a press machine 121. And an oval pressing process.
In the bending process, a straight pipe member having a substantially circular cross section is bent by a pipe bender or the like, so that the inner-direction bent portions 21a and 21b and the upper and lower bent portions 21c are formed. In this bending step, a straight pipe material having a substantially circular cross section is bent, so that it is possible to obtain the inner bent portions 21a and 21b and the upper and lower bent portions 21c having good shapes without inserting a core material into the pipe material. Can do.

The press machine 121 includes a mold 122 that forms an elliptical part 110, and the mold 122 includes a one-side mold 123 that forms an outer R-shaped part 114 and an other-side mold 124 that forms an inner R-shaped part 113. Prepare.
The one-side mold 123 includes a concave portion 123a, and includes an outer R-shaped processed surface 125 formed along the shape of the outer R-shaped portion 114 at the bottom of the concave portion 123a.
The other-side mold 124 includes a convex portion 124a that enters the concave portion 123a, and an inner R-shaped processed surface 126 that is formed along the shape of the inner R-shaped portion 113 on the tip surface of the convex portion 124a. At the center of the inner R-shaped processed surface 126, an R-shaped protruding portion processed surface 127 formed so as to follow the shape of the R-shaped protruding portion 115 is provided. The radius of curvature of the processed surface 127 of the R-shaped protruding portion is provided approximately equal to the radius of curvature of the outer peripheral surface of the straight pipe member having a substantially circular cross section before the bending process.

In the pressing step, first, the pipe material 130 after the bending step is set in the mold 122 so that the weld bead 116 is positioned in the R-shaped protruding portion 115 when pressing. The curvature radius of the outer peripheral surface 130a of the pipe member 130 after the bending process is the same as the curvature radius before the bending process.
Next, by pressing so that the mating surfaces 123b and 124b of the one-side mold 123 and the other-side mold 124 are aligned with each other, the pipe material having a substantially circular cross section becomes the outer R-shaped processed surface 125 and the inner R-shaped processed surface. The ellipse 110 is formed by being compressed and deformed along the shape of 126. The interval between the mating surfaces 123b and 124b is adjusted by sandwiching the shim 128 therebetween. The R-shaped protrusion processing surface 127 is a receiving surface that receives the weld bead 116 in the pressing process.

The radius of curvature of the outer R-shaped portion 114 is smaller than the radius of curvature of the inner R-shaped portion 113, and the curvature of the outer peripheral surface of the pipe material having a substantially circular cross section before the pressing process as compared with the radius of curvature of the inner R-shaped portion 113. Near the radius. The radius of curvature of the R-shaped protruding portion 115 is substantially equal to the radius of curvature of the outer peripheral surface 130a of the pipe member having a substantially circular cross section, and is smaller than the radius of curvature of the outer R-shaped portion 114. The R-shaped protrusion 115 is hardly deformed in the pressing process.
That is, in the pressing step, the degree of processing of the outer R-shaped portion 114 is smaller than the degree of processing of the inner R-shaped portion 113, and the degree of processing of the R-shaped protruding portion 115 is smaller than the degree of processing of the outer R-shaped portion 114. In the present embodiment, since the weld bead 116 is provided on the R-shaped protrusion 115 having a small degree of processing in the pressing process, it is possible to prevent the load of the press processing from being excessively applied to the weld bead 116.

  Further, the inner R-shaped portion 113 of the inner-direction bent portions 21a and 21b is a portion that is displaced outward in the vehicle width direction and is extended in the axial direction of the pipe material when compressed by the pressing process. On the other hand, the outer R-shaped portion 114 of the inner-direction bent portions 21a and 21b is a portion that is displaced inward in the vehicle width direction and compressed in the axial direction of the pipe material when compressed by the pressing process. That is, the outer R-shaped portion 114 of the inner-direction bent portions 21a and 21b is a portion where compression distortion tends to concentrate. In the present embodiment, the radius of curvature of the outer R-shaped portion 114 is made smaller than the radius of curvature of the inner R-shaped portion 113, and the degree of processing of the outer R-shaped portion 114 with respect to the pipe material before processing is processed by the inner R-shaped portion 113. Therefore, the concentration of strain of the outer R-shaped portion 114 at the inner bent portions 21a and 21b can be reduced. For this reason, even if it is the manufacturing method which forms in the ellipse by a press process after forming inner side bending part 21a, 21b, the seat frame 21 of a favorable shape can be obtained.

  Further, the ellipse portion 110 does not have a parallel portion such as a so-called racetrack-shaped ellipse on the side surface, and the outer R-shaped portion 114 and the inner R-shaped portion 113 are entirely curved and project outward in the radial direction. Therefore, a good product shape can be obtained without putting a core material in the pipe in the pressing process. When the racetrack-shaped elliptical parallel part is formed by pressing, the parallel part is recessed radially inward unless a core material is put in the pipe, and it is difficult to obtain a good shape.

Next, the configuration of the luggage box 47 will be described.
FIG. 10 is a left side view of the periphery of the luggage box 47. FIG. 11 is a plan view of the periphery of the luggage box 47. In FIG. 11, the lid 150 of the luggage box 47 is removed.
The luggage box 47 is formed in a box shape having an upper opening 140 whose upper surface is substantially entirely open, and the upper opening 140 is closed by a plate-shaped lid 150. The front end of the lid 150 is pivotally supported coaxially with the seat 15 by a hinge 49. The upper opening 140 is opened and closed by the lid 150 pivoting up and down around the hinge 49.
The luggage box 47 includes a bottom surface portion 141 disposed above the pivot frame 18 and a peripheral wall portion 142 extending upward from the peripheral edge of the bottom surface portion 141. The upper edge portion 142a of the peripheral wall portion 142 receives the seat 15, An upper opening 140 is formed. Specifically, the lower surface of the peripheral portion of the lid 150 is received by the upper edge portion 142 a of the luggage box 47, and the sheet bottom plate on the lower surface of the front portion of the seat 15 is received by the upper surface of the peripheral portion of the lid 150.
The peripheral wall portion 142 includes a rear wall portion 142b that extends upward from the rear edge of the bottom surface portion 141, a front wall portion 142c that faces the rear wall portion 142b, and a left and right connecting the front wall portion 142c and the rear wall portion 142b in the front-rear direction. Side wall parts 142d and 142d are provided.
The luggage box 47 includes a front bulging portion 143 that bulges forward from the lower portion of the front wall portion 142c.

The luggage box 47 is divided into two parts in the vertical direction, and includes a lower case 144 having the bottom surface portion 141 and an upper case 145 connected to the upper surface of the lower case 144.
The lower case 144 and the upper case 145 respectively include a lower case side mating surface 146 (mating surface) and an upper case side mating surface 147 (mating surface) extending rearwardly along the upper surface 21d of the seat frame 21 in a side view, The lower case side mating surface 146 and the upper case side mating surface 147 are joined together. That is, the dividing surface of the upper case 145 and the lower case 144 extends rearward with an upward gradient along the upper surface 21 d of the seat frame 21. The lower case side mating surface 146 and the upper case side mating surface 147 are formed in a substantially rectangular frame shape in plan view.
The upper case side mating surface 147 defines a lower opening 155 (opening connected to the lower luggage) that allows the upper case 145 to communicate with the lower case 144. The lower case side mating surface 146 defines an opening 156 (opening connected to the upper luggage) that allows the lower case 144 to communicate with the upper case 145.

  The upper case 145 includes an upper case peripheral wall portion 148 that extends downward from the entire periphery of the upper opening portion 140 and connects the upper opening portion 140 and the upper case side mating surface 147. In the upper case 145, the upper opening 140 is substantially horizontal, whereas the upper case side mating surface 147 has an upward slope, so that the height of the wall is smaller toward the rear side.

  The upper case peripheral wall portion 148 includes an upper case front wall 148a extending downward in a posture slightly tilted rearward from the front edge of the upper opening 140, and a frame front portion 86 of the seat frame 21 from the lower edge of the upper case front wall 148a. A bulging portion upper wall portion 149 extending forward and downward along the upper edge, left and right upper case side walls 148b and 148b, and an upper case rear wall 148c are provided. The peripheral edge portion of the lower surface of the bulging portion upper wall portion 149 constitutes the front end portion of the upper case side mating surface 147. The hinge 49 is provided on the upper part of the upper case front wall 148a.

The upper case 145 includes an upper flange portion 151 that protrudes from the upper case side mating surface 147 to the outside of the luggage box 47. The upper flange portion 151 is provided over the entire circumference of the upper case side mating surface 147.
The upper case 145 includes an upper plate portion 152 that extends forward from the front edge of the upper flange portion 151 and a pair of upper plate portions 153 and 153 that extend rearward from left and right ends of the rear edge of the upper flange portion 151. Further, the upper case 145 includes a plurality of upper width direction protrusions 154 that protrude outward in the vehicle width direction from the upper flange portions 151 on the upper case side walls 148b and 148b.

FIG. 12 is a plan view of the periphery of the lower case 144. FIG. 12 shows a state where the upper case 145 is removed.
As shown in FIGS. 10 and 12, the lower case 144 includes a bottom surface portion 141 and a lower case peripheral wall portion 160 that extends upward from the periphery of the bottom surface portion 141 and connects the bottom surface portion 141 and the lower case side mating surface 146. . The lower case 144 is formed in a bowl shape that widens in the front-rear and left-right directions toward the upper side.
The lower case peripheral wall portion 160 includes a lower case side bulging portion 160a that bulges forward from the upper case front wall 148a, left and right lower case side walls 160b and 160b that are positioned behind the lower case side bulging portion 160a, A lower case rear wall 160c.

The lower case-side bulging portion 160a extends upward from the bulging portion bottom surface portion 161 that extends upward along the upper edge of the rear pipe portion 63 of the main frame 17 and the left and right edges of the bulging portion bottom surface portion 161. The bulging part side wall 162,162 is provided. The upper edges of the bulging portion side walls 162, 162 extend forward and downward along the upper edge of the frame front portion 86, and join the tip of the bulging portion bottom surface portion 161 that rises forward. That is, the lower case side bulging portion 160a is formed to taper toward the front end side in a side view.
The upper edge of the lower case side bulging portion 160a forms a front end portion of the lower case side mating surface 146 and also forms a bulging portion opening portion 163 that opens upward. The bulging portion opening 163 is defined by the front edge of the bulging portion bottom surface portion 161 and the upper edges of the left and right bulging portion side walls 162 and 162. When the upper case 145 is attached, the bulging portion opening 163 is blocked by the bulging portion upper wall portion 149, thereby forming the front bulging portion 143.

The lower case 144 includes a lower flange portion 164 that protrudes from the lower case side mating surface 146 to the outside of the luggage box 47. The lower flange portion 164 is provided over the entire circumference of the lower case side mating surface 146.
The lower case 144 includes a lower plate portion 165 extending forward from the front edge of the lower flange portion 164 and a pair of lower plate portions 166 and 166 extending rearward from left and right ends of the rear edge of the lower flange portion 164. The lower case 144 includes a plurality of lower width direction protrusions 167 that protrude outward in the vehicle width direction from the upper flange portion 151 on the lower case side walls 160b and 160b.

The upper case 145 and the lower case 144 are engaged with the upper case side mating surface 147 and the lower case side mating surface 146 together, and the upper flange portion 151 and the lower flange portion 164 are in contact with each other. Can be adjusted up and down. The upper flange portion 151 and the lower flange portion 164 are vertically joined to form a flange portion 168 that protrudes outward from the joint portion between the upper case 145 and the lower case 144.
The flange portion 168 is formed over the entire circumference of the peripheral wall portion 142 of the luggage box 47, and includes a front flange portion 169 at the front edge, a rear flange portion 170 at the rear edge, and width direction flange portions 171 and 171 at the left and right side surfaces. With.

  When the upper case 145 and the lower case 144 are combined, the upper plate portions 152, 153, 153 and the lower plate portions 165, 166, 166 are combined vertically, and the front side and the rear end of the luggage box 47 are joined to the plate-shaped front side. A box mounting portion 172 (FIG. 11) and rear box mounting portions 173 and 173 are formed. The front box mounting portion 172 is provided in the front flange portion 169 and extends forward to above the front cross member 93. The rear box attaching portions 173 and 173 are provided in the rear flange portion 170 and extend rearward to above the rear cross member 96.

  Further, when the upper case 145 and the lower case 144 are combined, the plurality of upper width direction protrusions 154 and the lower width direction protrusion 167 are vertically combined, and the case connecting portion 174 is formed on the left and right sides of the luggage box 47. A plurality of are formed. The width direction flange portions 171 and 171 include a case connecting portion 174, and the case connecting portion 174 extends outward in the vehicle width direction. That is, the flange portion 168 integrally includes a front box mounting portion 172, a rear box mounting portion 173, 173, and a plurality of case connecting portions 174.

The case connecting portions 174 are provided in a pair of left and right above an intermediate portion before and after the frame front portion 86 of the seat frame 21, and are also provided in a pair of left and right above the front portion of the frame intermediate portion 87. In the present embodiment, the case connecting portions 174 are provided at two positions on the front and rear on the left and right width direction flange portions 171 and 171. Each case connecting portion 174 includes a frame grounding portion 175 extending downward from the lower width direction protruding portion 167. The frame grounding portion 175 extends below the lower case side mating surface 146. By providing the frame grounding portion 175, the case connecting portion 174 has a large plate thickness.
In addition, a plurality of locking pieces 159 protruding upward from the upper flange portion 151 are formed in the left-side width direction flange portion 171 in the front-rear direction. Hose and cables extending forward and backward along the luggage box 47 are locked to the locking piece 159.

The upper case 145 and the lower case 144 are coupled by case coupling bolts 176 that are inserted into the respective case coupling portions 174 from above and fastened to the lower width direction projecting portions 167.
Further, a case connecting bolt 176a is also provided at the center of the front box mounting portion 172, and the upper plate portion 152 and the lower plate portion 165 are coupled by the case connecting bolt 176a. Further, the case connecting bolt (not shown) is also fastened to a case connecting portion (not shown) provided at the rear end portion of the luggage box 47.

FIG. 13 is a plan view of the periphery of the luggage box 47.
10 to 13, the luggage box 47 is disposed in a space between the left and right seat frames 21 and 21 between the front cross member 93 and the rear cross member 96. The luggage box 47 has the front box mounting portion 172 placed on the front cross member 93 and the rear box mounting portions 173 and 173 placed on the rear cross member 96, thereby Supported from below.

The front box mounting portion 172 is fastened and fixed to the front cross member 93 by a pair of box fixing bolts 178 and 178 inserted through the front box mounting portion 172 from above. The rear box mounting portions 173 and 173 are fastened and fixed to the rear cross member 96 by box fixing bolts 179 and 179 inserted through the rear box mounting portions 173 and 173 from above. That is, the luggage box 47 is supported by the vehicle body frame 11 via the front box mounting portion 172 and the rear box mounting portions 173 and 173 of the flange portion 168.
Further, the upper case 145 and the lower case 144 are more firmly coupled by the fastening force of the box fixing bolts 178, 178, 179, 179.
Further, the fuel tank 48 (FIG. 2) is disposed in a space between the seat frames 21 and 21 behind the luggage box 47 and the rear cross member 96. The front end portion of the fuel tank 48 is fastened to a tank fixing portion 158 provided on the seat frames 21 and 21 behind the rear cross member 96.

As shown in FIGS. 10 and 13, when the luggage box 47 is attached to the vehicle body frame 11, the width-direction flange portions 171 and 171 are spaced apart from the upper surfaces 21 d of the left and right seat frames 21 and 21 by a predetermined distance. In the above position, it extends rearward with an upward gradient along the upper surface 21d of the seat frames 21, 21. That is, the seat frames 21 and 21 extend rearward and upward through the outer side of the upper portion of the lower case 144.
Further, the width-direction flange portions 171 and 171 overlap the inner side surface portion of the seat frames 21 and 21 in the vehicle width direction from above in a plan view from above. Further, the four case connecting portions 174 also overlap the seat frames 21 and 21 from above in a plan view from above. The frame grounding portion 175 on the lower surface of the case connecting portion 174 extends into a space between the lower case side mating surface 146 and the upper surface 21d of the seat frames 21 and 21.

Each frame grounding portion 175 is not grounded to the upper surface 21 d of the seat frames 21, 21 in a state where no occupant is seated on the seat 15, and has a predetermined distance from the upper surface 21 d of the seat frames 21, 21. Have. If a load of a predetermined value or more acts on the luggage box 47 due to a driver sitting on the seat 15, a heavy object stored in the luggage box 47, or a shock from the road surface, the luggage box 47 47 is bent downward, and each frame grounding portion 175 is grounded to the upper surface 21d of the seat frames 21 and 21. For this reason, when a predetermined load or more is applied to the luggage box 47, this load can be received by the seat frames 21 and 21 via the frame ground contact portion 175.
Further, since the width direction flange portions 171 and 171 are provided before and after the frame grounding portion 175, the strength and rigidity of the frame grounding portion 175 and the width direction flange portions 171 and 171 can be enhanced. For this reason, a load can be effectively received by the frame grounding portion 175.

  As shown in FIGS. 10, 11, and 12, the lower case 144 is formed to be longer forward than the upper case 145 by the amount provided with the lower case side bulging portion 160 a. A partition wall 180 that partitions the space in the lower case 144 forward and backward is provided at the front portion in the lower case 144. The partition wall 180 includes a vertical wall portion 181 that extends vertically and an upper wall portion 182 that extends forward from the upper edge of the vertical wall portion 181. The upper wall part 182 continues to the rear part of the bulging part upper wall part 149. The partition wall 180 is detachably provided on the lower case 144 via a fixture such as a bolt.

By providing the partition wall 180, a rear storage portion 183 behind the partition wall 180 and a front storage portion 184 provided between the front bulge portion 143 and the partition wall 180 are formed in the lower case 144. The rear storage unit 183 is combined with the storage space in the upper case 145 to form a main storage unit 185 (storage space) that can store a large article such as a full-face helmet.
Electrical components such as a battery 186 and a fuse box (not shown) are disposed in the front storage portion 184. The battery 186 is disposed at the rear portion of the front storage portion 184 at a position close to the front surface of the partition wall 180 and below the hinge 49. A fuse box that is smaller than the battery 186 is disposed in front of the battery 186 and in front of the front storage portion 184.
By providing the partition wall 180, it is possible to prevent unexpected access to the electrical component from the rear storage unit 183 side.

The upper case 145 and the lower case 144 are resin molded products. The upper case 145, the lower case 144, and the resin molded product are divided into two parts, and the large luggage box 47 can be easily formed by connecting the upper case 145 and the lower case 144 with the case connecting bolt 176. .
The driver or the like can access the main storage portion 185 including the rear storage portion 183 from the upper opening 140 of the upper case 145 by opening the lid 150 after the seat 15 is rotated upward and opened. .

  In the present embodiment, in the configuration in which the luggage box 47 is formed by combining the upper case 145 and the lower case 144, the rear storage unit 183 can be accessed from the upper opening 140 of the upper case 145. Without opening the upper case 145, the state in the rear storage portion 183 can be easily grasped from the upper opening 140, and the rear storage portion 183 can be easily accessed. Further, the luggage box 47 is connected via the front box mounting portion 172 and the rear box mounting portions 173 and 173 of the flange portion 168 extending from the lower case side mating surface 146 and the upper case side mating surface 147 to the outside of the luggage box 47. Since it is supported by the body frame 11, the luggage box 47 can be supported with a simple structure.

Further, since the lower case side mating surface 146 and the upper case side mating surface 147 are positioned above the seat frames 21, 21, the seat frames 21, 21 are disposed on the lower case side mating surface 146 and the upper case side mating surface 147. Does not get in the way. For this reason, the luggage box 47 can be enlarged in the vehicle width direction.
In addition, the upper case 145 and the lower case 144 are divided and formed, and the lower case 144 is provided with a lower case side bulging portion 160a that extends forward from the upper case 145. By changing the shape of the part, the straddling property of the straddling space S and the capacity of the luggage box 47 can be easily changed. That is, as shown in FIG. 10, the upper case front wall 148a of the upper case 145 is provided behind the lower case side bulging portion 160a, and the lower case side bulging portion 160a is closed by the bulging portion upper wall portion 149. Thus, the straddling space S can be increased to improve the straddling property. Further, when the upper case 145 has a bulging portion that bulges forward corresponding to the lower case side bulging portion 160a, the capacity of the main storage portion 185 can be increased.

  As described above, according to the embodiment to which the present invention is applied, the luggage box structure of the motorcycle 10 is composed of the upper and lower divided structures of the upper case 145 and the lower case 144 to form the main storage portion 185. A luggage box 47 and a seat 15 supported swingably on the luggage box 47 are provided. The luggage box 47 is disposed below the seat 15, and the lower case 144 has an opening 156 connected to the upper case 145 at the upper part. The upper case 145 includes a lower opening 155 that communicates with the lower case 144 in the lower portion, an upper opening 140 that communicates with the storage space, and the seat 15 includes an upper opening. 140 is supported by the upper case 145 so as to be openable and closable, and the upper case 145 and the lower case 144 are joined together. A flange portion 168 that is fixed by the side mating surface 147 and the lower case side mating surface 146 and extends from the upper case side mating surface 147 and the lower case side mating surface 146 is provided on the vehicle body frame 11 via the flange portion 168. Supported. As a result, the upper case 145 and the lower case 144 are fixed by the upper case side mating surface 147 and the lower case side mating surface 146, so that the main storage portion 185 can be opened between the upper case 145 and the lower case 144. Instead, by opening the seat 15, the state inside the main storage portion 185 can be easily grasped from the upper opening 140 of the upper case 145, and the main storage portion 185 can be easily accessed. Further, since the main storage portion 185 is supported by the vehicle body frame 11 via the flange portion 168 extending from the upper case side mating surface 147 and the lower case side mating surface 146, the load acting on the luggage box 47 from the seat 15 is It can be received with a simple and strong structure.

Further, since the upper case side mating surface 147 and the lower case side mating surface 146 of the upper case 145 and the lower case 144 extend along the pair of seat frames 21, 21, the presence of the flange portion 168 The influence on the arrangement of exterior parts and body components can be minimized, and the degree of freedom in design can be improved.
Further, the luggage box 47 is disposed between the pair of seat frames 21 and 21, and the rear part connecting the pair of seat frames 21 and 21 and the pair of main frames 17 and 17 before and after the storage unit. A cross member 96 and a front cross member 93 are provided, and the luggage box 47 is supported by the rear cross member 96 and the front cross member 93. Therefore, the luggage box 47 can be firmly supported by the rear cross member 96 and the front cross member 93 which are strength members of the vehicle body frame 11.

  Further, the flange portion 168 includes a front flange portion 169, a rear flange portion 170, and width direction flange portions 171 and 171. The front flange portion 169 and the rear flange portion 170 include the front and rear front cross members 93 and the rear portion. The width direction flange portions 171 and 171 are respectively connected to the cross member 96 and are arranged so as to overlap the vehicle body frame 11 in plan view. Therefore, the luggage box 47 can be firmly supported by the front cross member 93 and the rear cross member 96 via the front flange portion 169 and the rear flange portion 170, and the width direction flange portions 171 and 171 are used for the exterior parts of the vehicle body and the vehicle body. The influence on the arrangement of components can be minimized.

Further, since the lower case 144 includes a frame grounding part 175 that extends into the space between the lower case side mating surface 146 and the seat frames 21 and 21, the load of the luggage box 47 is loaded via the frame grounding part 175. It can be received by the frames 21 and 21.
Further, since the frame grounding portion 175 is disposed so as not to contact the seat frames 21 and 21 when no occupant is on the seat 15, this load is applied when a load exceeding a predetermined value acts on the luggage box 47. Can be received by the seat frames 21 and 21 via the frame grounding portion 175.

Further, the strength of the luggage box 47 can be improved while the strength of each other can be enhanced by the frame grounding portion 175 and the widthwise flange portions 171 and 171 of the frame grounding portion 175.
The storage space of the lower case 144 is longer forward than the storage space of the upper case 145, and the lower case 144 is partitioned into a front storage portion 184 and a rear storage portion 183 by a partition wall 180. The rear storage portion 183 can be accessed from the upper opening 140 of the case 145. Therefore, the storage space of the lower case 144 can be widely used, and the storage space can be functionally partitioned by the partition wall 180.
In addition, electrical components such as a battery 186 are disposed in the front storage portion 184 of the lower case 144, and frequently accessed items such as a helmet can be stored in the rear storage portion 183. Easy access to frequently accessed items.

  Further, according to the embodiment to which the present invention is applied, the vehicle body frame structure includes main frames 17 and 17 extending from the head pipe 16 and a pair of seat frames 21 and 21 extending from the main frames 17 and 17. Cushion upper end support for supporting the upper ends of the rear cushions 29 and 29 for suspending the rear wheel 3 is provided with a vehicle body frame 11 provided with down frames 19 and 19 extending from the head pipe 16 below the main frames 17 and 17. A portion 90 is provided on the seat frames 21, 21, and the main frames 17, 17 are a pair of frames that extend backward from the head pipe 16 with a downward slope, and at the ends of the down frames 19, 19, Gusset frames 20, 20 connected to the frames 17, 17 are provided, and the seat frames 21, 21 are The front cross member 93 that extends rearward from the position behind the front end 79 b of the frame 20, 20 with a higher slope than the main frames 17, 17 and connects between the pair of main frames 17, 17 is a gusset frame 20. , 20 at the rear of the front end 79 b and at the front of the rear end 89 b of the coupling surface 89, which is the mounting position of the seat frames 21, 21 with respect to the main frames 17, 17. Accordingly, the gussets formed by the main frames 17 and 17 extending rearward with a lower gradient and the seat frames 21 and 21 extending rearward with an upper gradient from a position behind the front ends 79b of the gusset frames 20 and 20 are formed. Although stress concentrates in the troughs 100 around the frames 20 and 20, the front cross behind the front ends 79 b of the gusset frames 20 and 20 and ahead of the rear ends 89 b of the coupling surfaces 89 of the seat frames 21 and 21. The member 93 can effectively receive stress. For this reason, the front cross member 93 can be compactly provided at an appropriate position as a strength member between the vehicle body frames.

Further, the front cross member 93 overlaps with the weld bead 79 that is a mounting position of the gusset frames 20 and 20 with respect to the main frames 17 and 17 in a side view, and the front cross member 93 is in the vicinity of a portion where stress is easily concentrated. Since 93 is located, the strength of the body frame 11 can be effectively improved. In the present embodiment, the front cross member 93 overlaps the weld bead 79 in a side view, but the front cross member 93 overlaps the gusset frames 20 and 20 in the front-rear direction in the side view. Just do it.
A pivot frame 18 is provided at the rear ends of the main frames 17, 17. The engine 12 is supported by the pivot frame 18 and the gusset frames 20, 20, and the front cross member 93 is pivoted with the gusset frames 20, 20. Located between the frame 18. Therefore, the front cross member 93 can effectively improve the rigidity and strength of the portion that supports the engine 12.

Further, the gusset frames 20, 20 and the coupling surfaces 89 of the seat frames 21, 21 overlap with each other in plan view, and therefore stress acting on the coupling surfaces 89 of the seat frames 21, 21 is applied to the gusset frames including the front cross member 93. 20 and 20 can be effectively received by the peripheral structure, and the strength of the body frame 11 can be improved. Here, the gusset frames 20, 20 only have to overlap the coupling surface 89 in the front-rear direction position in plan view.
In addition, a luggage box 47 is disposed between the pair of seat frames 21 and 21, and the luggage box 47 is supported by the front cross member 93, so that the number of parts can be reduced and the luggage box 47 can be appropriately disposed. I can support it.
Further, there are provided seat frame support frames 22, 22 extending from the rear ends of the main frames 17, 17 and connected to the seat frames 21, 21, and the connection between the seat frame support frames 22, 22 and the seat frames 21, 21 is provided. Since the cushion upper end support portion 90 is provided at a location, the upper ends of the rear cushions 29 and 29 can be supported at a portion having high strength.

  Further, according to the embodiment to which the present invention is applied, the vehicle body frame structure includes main frames 17 and 17 extending from the head pipe 16 and a pair of seat frames 21 and 21 extending from the main frames 17 and 17. Down frames 19 and 19 extending from the head pipe 16 below the main frames 17 and 17, and the main frames 17 and 17 are a pair of frames and extend rearward from the head pipe 16 with a downward slope. The gusset frames 20, 20 connected to the main frames 17, 17 are provided at the ends of the down frames 19, 19. The seat frames 21, 21 are located behind the front ends 79 b of the gusset frames 20, 20. From the position, it extends rearward with a higher slope than the main frames 17 and 17, and the main frames 17 and 17 An elliptical shape with the vertical direction as the major axis direction is formed between the weld 16 and the weld bead 79 where the gusset frames 20 and 20 and the main frames 17 and 17 are attached. The shape has changed. Accordingly, the vertical rigidity of the main frames 17 and 17 supporting the head pipe 16 can be increased by an elliptical shape that is vertically long, and the lateral rigidity of the main frames 17 and 17 can be appropriately reduced. For this reason, the main frame 17 and 17 can effectively receive the thrust load from the head pipe 16 side, and the lateral load is actively released by elastic deformation (bending) of the main frames 17 and 17. be able to. Further, on the gusset frames 20 and 20 side, the main frames 17 and 17 change from an elliptical shape that is long in the vertical direction, so that rigidity according to required characteristics on the seat frames 21 and 21 side can be obtained. Therefore, the rigidity and strength of the body frame 11 can be obtained in accordance with the part of the body frame 11. Here, it is sufficient that the main frames 17 and 17 are changed in cross-sectional shape at least after the position of the weld bead 79, and at the position closer to the head pipe 16 than the weld bead 79 as in the present embodiment. Of course, the cross-sectional shape may be changed.

Further, since the down frames 19 and 19 have a circular cross section, the rigidity of the down frames 19 and 19 is substantially uniform vertically and horizontally, and the lateral rigidity is larger than that of the main frames 17 and 17. For this reason, the front part of the vehicle body frame 11 can be swung at a lower fulcrum with the down frame 19, 19 side as a fulcrum, and the driver can accurately feel the running state of the motorcycle 10 through this swing. it can.
The main frames 17 and 17 are attached closer to the intermediate position of the head pipe 16 above the intermediate position of the head pipe 16, and the down frames 19 and 19 are lower than the intermediate position of the head pipe 16. 16 is attached near the lower end position. For this reason, the front part of the vehicle body frame 11 can be swung at a lower fulcrum with the down frame 19, 19 side as a fulcrum, and the driver can accurately feel the running state of the motorcycle 10 through this swing. it can.

Further, cushion upper end support portions 90, 90 for supporting the upper ends of the rear cushions 29, 29 for suspending the rear wheel 3 are provided on the seat frames 21, 21, and the seat frames 21, 21 have the longitudinal direction as the major axis direction. Because of the elliptical shape, the load transmitted from the cushion upper end support portions 90, 90 to the seat frames 21, 21 can be effectively received by the elliptical seat frames 21, 21 having high rigidity in the vertical direction.
Further, since the main frames 17 and 17 have a circular cross section after the position of the weld bead 79 of the gusset frames 20 and 20, the vertical and horizontal loads on the side of the seat frames 21 and 21 are applied to the main frames 17 and 17, respectively. It can be received uniformly by the perfect circle portion 102.

  The pair of main frames 17 and 17 extend from the head pipe 16 toward the rear in the width direction in plan view, and the pair of main frames 17 and 17 are located at positions of the weld beads 79 of the gusset frames 20 and 20. In the section from the front to the weld bead 79, they extend backward in parallel with each other. For this reason, a space between the pair of main frames 17 and 17 can be enlarged, and vehicle body components such as an intake device can be arranged in this space.

The down frames 19, 19 are a pair of frames that extend outward from the head pipe 16 in the width direction and are provided with a lower slope than the main frames 17, 17. It extends to the outside in the width direction. Therefore, a large space between the down frames 19 and 19 and the main frames 17 and 17 and a space between the pair of down frames 19 and 19 can be secured, and vehicle body components such as an intake device are arranged in this space. it can.
Further, the front cross member 93 that connects the pair of vertically long elliptical main frames 17 and 17 is behind the front ends of the gusset frames 20 and 20 and from the rear end of the seat frame mounting position with respect to the main frame. Is also located forward. For this reason, the front cross member 93 effectively receives the load at the location where the stress is concentrated between the rear end 89b of the gusset frames 20 and 20 and the rear end 89b of the coupling surface 89 of the seat frames 21 and 21. be able to.

Furthermore, according to the embodiment to which the present invention is applied, the press machine 121 includes two molds, that is, the one-side mold 123 and the other-side mold 124, and the one-side mold 123 and the other-side mold 124 have an outer R shape. The R shape of the processed surface 125 and the inner R-shaped processed surface 126 are made different so that the shape of the seat frame 21 as a molded product is different on one side (outer side) and the other side (inner side). Thus, by making the R shape of the processed surface of the mold different according to the bending direction of the seat frame 21, the stress concentration of the inner-direction bent portions 21a and 21b can be effectively suppressed.
Furthermore, the pipe material has inner side bent portions 21a and 21b that bend only in one direction in the width direction when laid out as a product at a predetermined position, and the outside of the one-side mold 123 that comes outside the inner direction bent portions 21a and 21b. The radius of curvature of the R-shaped machining surface 125 is smaller than the radius of curvature of the inner R-shaped machining surface 126 of the other die 124. The outer side portions of the inner-direction bent portions 21a and 21b are likely to be distorted because they are compressed and deformed when processed into an elliptical pipe, but the one-side mold 123 that comes outside the inner-side bent portions 21a and 21b Since the radius of curvature of the outer R-shaped processed surface 125 is reduced, the degree of processing from the pipe material 130 before the pressing process can be reduced, and the stress concentration of the outer R-shaped portion 114 in the inner-side bent portions 21a and 21b can be reduced. A molded product can be obtained.

In addition, the circular pipe material before the bending process is a pipe material made of a single plate material, and is provided with a weld bead 116 on the outer peripheral surface, and the weld bead 116 is formed linearly across the ends of the pipe material. An R-shaped protrusion 115 that receives the weld bead 116 is formed in the other mold 124 in advance. For this reason, the deformation generated in the weld bead 116 can be controlled by the R-shaped protrusion 115.
In addition, the R-shaped protrusion processing surface 127 is provided on the inner R-shaped processing surface 126 of the other mold 124, and the R-shape of the R-shaped protrusion processing surface 127 matches the R shape of the pipe material before the bending process. It has been. For this reason, the deformation amount of the R-shaped protrusion 115 can be reduced, and an excessive load can be prevented from being generated on the weld bead 116.

  In addition, according to the embodiment to which the present invention is applied, the vehicle body frame structure includes the seat frames 21 and 21 that have an elliptical shape and are bent at necessary portions, and the seat frames 21 and 21 are a pair. It is provided and has an elliptical shape with the vertical direction as the major axis direction, and the radius of curvature of the inner R-shaped portion 113 located inside each seat frame 21, 21 is outside the seat frame 21, 21. The radius of curvature of the R-shaped portion 114 is larger. As a result, the inner R-shaped portion 113 positioned inside the seat frames 21 and 21 can be made flatter than the outer R-shaped portion 114, and a large space is secured between the seat frames 21 and 21, so that the luggage box 47 and the fuel tank can be secured. For example, body components such as 48 can be arranged. For this reason, it is possible to easily arrange the surrounding vehicle body components while making the seat frames 21 and 21 elliptical.

The pair of seat frames 21 and 21 are frames extending from the main frames 17 and 17, and a luggage box 47 is disposed between the pair of seat frames 21 and 21. For this reason, the large luggage box 47 can be arranged between the pair of seat frames 21 and 21 in the width direction.
The pair of seat frames 21, 21 is provided with a rear cross member 96 that connects the seat frames 21, 21, and the luggage box 47 is supported by the rear cross member 96. Therefore, the strength of the seat frames 21 and 21 can be improved by the rear cross member 96, and the luggage box 47 can be firmly supported by using the rear cross member 96.

Furthermore, since the fuel tank 48 is provided between the pair of seat frames 21 and 21 behind the luggage box 47, the large fuel tank 48 in the width direction can be provided between the pair of seat frames 21 and 21.
Further, the seat frames 21 and 21 are formed into an elliptical shape by pressing after bending, and the inner R-shaped portions 113 positioned inside the seat frames 21 and 21 are formed in the bent inner-direction bent portions 21a and 21b. Was made larger than the radius of curvature of the outer R-shaped portion 114 located outside. The outer R-shaped portion 114 of the inner-direction bent portions 21a and 21b is likely to be distorted because it is compressed and deformed when processed into an elliptical shape. However, the radius of curvature of the inner R-shaped portion 113 of the inner-direction bent portions 21a and 21b is increased. Since the radius of curvature of the outer R-shaped portion 114 is larger than that of the outer R-shaped portion 114, the stress concentration of the outer R-shaped portion 114 at the inner-side bent portions 21a and 21b can be reduced, and a good molded product can be obtained.

  The inner R-shaped portion 113 of the seat frames 21 and 21 is provided with an R-shaped protruding portion 115 having a smaller radius of curvature than the outer outer R-shaped portion 114 at the upper and lower intermediate portions. For this reason, the R-shaped protrusion 115 acts as a reinforcing rib, and the rigidity can be improved.

Further, the seat frames 21 and 21 are formed in an elliptical shape by compressing the pipe member 130 having a substantially circular cross section, and the curvature radius of the R-shaped protruding portion 115 is that of the pipe member 130 having a substantially circular cross section. It is almost equal to the radius of curvature. For this reason, the R-shaped protrusion 115 can be easily formed by leaving the shape of the pipe member 130 having a substantially circular cross section with almost no deformation.
The seat frames 21 and 21 are pipe frames in which plate members are formed in a pipe shape and the seam is welded in the axial direction. Since the weld bead 116 that is the seam is formed on the R-shaped projecting portion 115, the weld bead is formed. It can be avoided that a large stress is applied to 116.

[Modification]
Hereinafter, a modification of the present invention will be described with reference to FIG. In this modification, the same components as those in the above embodiment are denoted by the same reference numerals and description thereof is omitted.
This modification is different from the above-described embodiment in that a bulging portion that bulges forward corresponding to the lower case side bulging portion 160a is provided in the upper case 145.

FIG. 14 is a left side view of the peripheral portion of the luggage box 247 in the modified example.
The luggage box 247 includes a lower case 144 and an upper case 245. The upper case 245 includes an upper case side bulging portion 248a that bulges to the front edge of the lower case side bulging portion 160a beyond the position of the hinge 49.
The partition wall 280 includes a vertical wall portion 181 and an upper wall portion 282 extending forward from the upper edge of the vertical wall portion 181. The upper wall portion 282 extends to the front end portion of the lower case side bulging portion 160a and closes the upper surface of the front storage portion 184.
Thus, the capacity | capacitance of the main accommodating part 185 can be expanded by providing the upper case side swelling part 248a. Further, by extending the upper wall portion 282 of the partition wall 280 forward corresponding to the upper case side bulging portion 248a, the front storage portion 184 in which the electrical components are arranged can be isolated from the main storage portion 185.

In addition, the said embodiment shows the one aspect | mode which applied this invention, Comprising: This invention is not limited to the said embodiment.
In the above-described embodiment, the front cross member 93 has been described as overlapping with the weld bead 79 that is the attachment position of the gusset frames 20 and 20 to the main frames 17 and 17 in a side view, but the present invention is not limited thereto. Is not to be done. For example, the front cross member 93 is moved rearward, and the front cross member 93 is provided so as to overlap in the front-rear direction with the coupling surface 89 that is the mounting position of the seat frames 21, 21 with respect to the main frames 17, 17 in a side view. May be.
In the above embodiment, the R-shaped protrusion processing surface 127 has been described as being provided on the inner R-shaped processing surface 126 of the other die 124, but is not limited thereto, and the outer R-shape of the one-side die 123 is not limited thereto. The processing surface 125 may be provided with the R-shaped protruding portion processing surface 127, and the outer R-shaped portion 114 of the seat frame 21 may be provided with the R-shaped protruding portion 115.
In the above embodiment, the lid 150 covers the upper opening 140 of the luggage box 47, and the sheet 15 covers the lid 150 from above. The present invention is limited to this. It is not a thing. For example, without providing the lid 150, the seat 15 may cover the upper opening 140 of the luggage box 47 from above and directly close the upper opening 140.

11 Body frame 17 Main frame (frame)
21a, 21b Inner direction bent part (bent part)
116 Weld beads (welded part)
121 Press machine 123 One-side mold 124 Other-side mold 125 Outer R-shaped processed surface (R-shape of one-side mold)
126 Inside R-shaped machining surface (R shape of other side)
127 R-shaped protrusion processing surface (receiving surface)

Claims (3)

In the manufacturing method of the vehicle body frame provided with the frame (17) which has an elliptical shape and is bent at a necessary place,
The frame (17) is bent into a circular pipe material and then processed into an elliptical pipe by a press machine (121).
The press machine (121) includes two molds, a one-side mold (123) and an other-side mold (124), and the one-side mold (123) and the other-side mold (124) have a machining surface R. Make the shape different so that the shape of the molded product is different on one side and the other side,
The pipe member includes songs wants bent portion inwardly in the width direction when the layout as product (21a, 21b) at a predetermined location, wherein the elliptical pipe, upper R-shaped portion of the upper end (111), the lower end A lower R-shaped portion (112), an inner R-shaped portion (113) constituting the inner side surface in the width direction, and an outer R-shaped portion (114) constituting the outer side surface in the width direction. ,
The radius of curvature of the R shape (125) of the portion forming the outer R shape portion (114) in the one side die (123) coming outside the bent portion (21a, 21b) is the other side die (124). ) Is smaller than the radius of curvature of the R shape (126) of the portion forming the inner R shape portion (113) .   The circular pipe material is a pipe material made of a single plate material, and includes a welded portion (116) on the outer peripheral surface, and the welded portion (116) is linearly formed between the end portions of the pipe material. The receiving surface (127) that is formed and that receives the weld (116) is formed in advance in the one-side mold (123) or the other-side mold (124). A method for manufacturing a body frame.   The receiving surface (127) is provided in a portion of the R shape (126) of the other side mold (124), and the R shape of the receiving surface (127) is matched with the R shape of the pipe material. The method for manufacturing a vehicle body frame according to claim 2, wherein:

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