JP5944523B2 - Frame structure of saddle-ride type vehicle - Google Patents

Description

  The present invention relates to a frame structure of a saddle-ride type vehicle including a head pipe, a down frame extending downward from a rear portion of the head pipe, and a lower frame extending rearward from a lower portion of the down frame.

  2. Description of the Related Art Conventionally, a frame structure of a saddle-ride type vehicle is known in which a frame constituted by a leg shield, a lower frame, or the like that supports a head pipe is formed by combining a plurality of plate materials (see, for example, Patent Document 1). ).

JP-A 61-287883

By the way, in the frame structure of the above conventional saddle-ride type vehicle, the frame which becomes the vehicle body skeleton is composed entirely of plate material, and generally used pipe material is not used. In the frame structure of a saddle-ride type vehicle, the required characteristics differ depending on the part. Therefore, by making the frame structure taking advantage of the plate material and pipe material, weight reduction is achieved while improving the function of the frame. It is desirable.
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 reduce the weight while improving the function of the frame in the frame structure of the saddle-ride type vehicle.

In order to achieve the above object, the present invention comprises a head pipe (11) for pivotally supporting a front wheel (2), a down frame (12) extending downward from a rear portion of the head pipe (11), In the frame structure of a saddle-ride type vehicle having a lower frame (13) extending rearward from the lower part of the down frame (12), the down frame (12) is made of a pipe material, and the lower frame ( 13) are provided in a pair of left and right, and each has a closed cross section made of a plate material having a vertically divided structure, and the lower frame (13) extends in the vehicle width direction from the connecting portion with the down frame (12). to have a bent portion that is bent (64) backwards after the lower frame (13), it has an upper lower upper frame (70) and a lower lower-down frame (71) 2 minutes Is a structure, deformation of the lower frame (13), the lower upper frame (70) is characterized that you have been formed so as to be larger than the lower-down frame (71).
According to the present invention, the down frame is composed of a pipe material, so that the rigidity and strength required for the down frame can be secured while reducing the number of connecting portions of the down frame, and the lower frame is a closed cross section made of a plate material having an upper and lower split structure. Therefore, the cross-sectional area and shape of the bent portion can be optimized to distribute the stress acting on the bent portion, and the weight can be reduced. For this reason, weight reduction can be achieved, ensuring the strength and rigidity required for the frame. In addition, since the shape change of the lower frame is formed so that the lower upper frame is larger than the lower down frame, the input load from the lower frame can be transmitted gently through the lower upper frame, By avoiding stress concentration, the strength and rigidity can be optimized.

Also, the present invention has an upper surface of said lower upper frame (70), characterized in that it is formed so as to be positioned gradually upward by the down frame (12) side.
According to the present invention, when the lower down frame is viewed as a fulcrum for supporting the down frame, the lower upper frame is connected at a position close to the head pipe, which is the load input point, and the lower upper frame has a gently cross-sectional shape. It will change, and it can control that stress concentration arises by the input load from a head pipe. For this reason, a load can be disperse | distributed also to the rear part side of a lower frame, and weight reduction can be achieved.

Further, according to the present invention, the lower frame (13) includes a straight portion (65) extending in the front-rear direction behind the bent portion (64), and the bent portion (64), the straight portion (65), and The cross-sectional area is minimized at the boundary position (X).
According to the present invention, the rigidity does not suddenly increase at the boundary position between the straight portion and the bent portion having high rigidity, the rigidity characteristic of the lower frame as a whole can be moderated, and the weight can be further reduced. .
Further, the present invention is characterized in that the lower upper frame (70) has a height (H1) behind the bent portion (64) smaller than a height (H2) of the lower down frame.
According to the present invention, even in a lower upper frame having a large shape change, moldability can be ensured and productivity can be improved.

Further, according to the present invention, the lower upper frame (70) is overlapped with the lower down frame (71) from the outside and is mutually connected to the lower down frame (71) at a lower edge of the lower upper frame (70). fixed by welding, characterized in Tei Rukoto.
According to the present invention, the stress concentration applied to the welded portion can be suppressed by providing the welded portion at the intermediate portion in the height direction of the lower frame. For this reason, further weight reduction can be achieved.

Further, the present invention is the pair of left and right lower frames (13), the lower the are respectively so as to surround the semicircular weld when viewed Tei Rutotomoni of the down frame (12), the down frame (12) in the front and rear, front coupling portion at the front end of the pair of left and right lower frames (13) (82) and the rear coupling section (83) is welded in contact respectively, characterized in Tei Rukoto.
According to the present invention, the welding length can be increased by surrounding the lower portion of the down frame in a semicircular shape, and the welding strength can be improved by welding the front connecting portion and the rear connecting portion. Moreover, the rigidity of the lower part of a down frame can be improved by enclosing the lower part of a down frame with a lower frame.

Further, according to the present invention, a notch (a predetermined size) is provided between the abutting portions of the pair of left and right lower frames (13) of the front connecting portion (82) and / or the rear connecting portion (83). 75) is provided, wherein the lower frame through the cutout (75) (13), characterized in Tei Rukoto welded to the down frame (12).
According to the present invention, the left and right lower frames and the down frame can be welded through the notches, and the joint strength can be improved.

With the frame structure of the saddle-ride type vehicle according to the present invention, it is possible to reduce the weight while securing the strength and rigidity necessary for the frame.
In addition, the input load from the down frame can be gently transmitted via the lower upper frame, so that stress concentration can be avoided and optimization of strength and rigidity can be achieved.
Further, it is possible to suppress the concentration of stress due to the input load from the head pipe, and it is possible to reduce the weight because the load can be distributed to the rear side of the lower frame.
Further, the rigidity does not suddenly increase at the boundary position between the straight portion and the bent portion having high rigidity, the rigidity characteristic of the lower frame as a whole can be moderated, and the weight can be further reduced.

Further, even in the case of a lower upper frame having a large shape change, the moldability can be secured and the productivity can be improved.
Further, the welded portion can be provided in the intermediate portion in the height direction of the lower frame to suppress stress concentration applied to the welded portion, and further weight reduction can be achieved.
Further, the welding length can be increased by surrounding the lower portion of the down frame in a semicircular shape, and the welding strength can be improved by welding the front connecting portion and the rear connecting portion. Moreover, the rigidity of the lower part of a down frame can be improved.
Furthermore, the left and right lower frames and the down frame can be welded through the notches, and the joint strength can be improved.

1 is a left side view of a motorcycle according to a first embodiment of the present invention. It is a left view of a vehicle body frame. It is a perspective view of a body frame. It is the top view which looked at the front part of the body frame from the upper part. It is the figure which looked at the lower part of the body frame from the front. It is VI-VI sectional drawing of FIG. It is a perspective view of a lower upper frame. It is the perspective view which looked at the suspension part vicinity from the back side. It is the figure which looked at the suspension part from back. It is the side view which looked at the suspension part of the left side from the vehicle width direction outer side. It is the side view which looked at the suspension part of the left side from the vehicle width direction inner side. It is a left view of an upper half. It is a left view of a lower inner member. It is sectional drawing in the case of seeing a suspension part vicinity from the side. It is XV-XV sectional drawing of FIG. It is a left view of the vehicle body frame in 2nd Embodiment.

  Hereinafter, a motorcycle having a frame structure according to 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. Further, 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 LE indicates the left side of the vehicle body.

[First Embodiment]
FIG. 1 is a left side view of a motorcycle according to a first embodiment of the present invention.
The motorcycle 1 (saddle-ride type vehicle) is a scooter type vehicle having a low floor step floor 52 on which a rider seated on a seat 10 places his / her foot, and has a front wheel 2 in front of a body frame F, A certain rear wheel 3 is pivotally supported by a unit swing engine U (unit swing power unit) disposed at the rear of the vehicle. The vehicle body frame F is covered with a resin vehicle body cover C.

FIG. 2 is a left side view of the vehicle body frame F. FIG. FIG. 3 is a perspective view of the vehicle body frame F. FIG. FIG. 4 is a plan view of the front portion of the vehicle body frame F as viewed from above.
As shown in FIGS. 1 to 4, the vehicle body frame F is formed by joining a plurality of metal pipes and plate materials by welding, and includes a head pipe 11 provided at the front part and a rear part from the rear part of the head pipe 11. Down frame 12 extending downward, a pair of left and right lower frames 13 and 13 extending in the vehicle width direction from the lower part of down frame 12 and then bending and extending rearward, and the rear ends of lower frames 13 and 13 A pair of left and right suspension parts 14, 14 connected to each other and a pair of left and right rear frames 15, 15 extending from the rear end of the suspension parts 14, 14 rearward and upward to the rear of the vehicle are provided.

The body frame F is a cross frame that connects the left and right frames, and a cross member 16 that connects the rear portions of the lower frames 13 and 13 and a front portion of the rear frames 15 and 15 that is above the cross member 16. An intermediate cross member 17, a rear cross member 18 that connects the front and rear intermediate portions of the rear frames 15, 15, and a rear end cross member 19 that connects the rear ends of the rear frames 15, 15 are provided.
The head pipe 11 is reinforced by the reinforcing plate 20 with the lower part of the rear part connected to the upper part of the down frame 12.
In the rear frames 15, 15, a pair of left and right step stays 21, 21 extending rearward and downward are provided behind the intermediate cross member 17.
Stays 22 and 22 are provided at the front and rear portions of the upper surfaces of the lower frames 13 and 13 so as to protrude upward in the vehicle width direction. Above the lower frames 13, 13, a pipe-like step frame (not shown) is disposed between the front and rear stays 22, 22.
A side stand 39 is attached to the rear portion of the left lower frame 13.

  As shown in FIG. 1, the steering system for steering the front wheels 2 includes a steering shaft (not shown) pivotally supported by the head pipe 11, a handle 25 coupled to the upper portion of the steering shaft, A pair of left and right front forks 26, 26 are connected to the lower end of the steering shaft. The front wheel 2 is pivotally supported at the lower ends of the front forks 26 and 26 and is steered by an operation with the handle 25.

The unit swing engine U is a unit swing type in which an engine E and a transmission case M in which a belt-type continuously variable transmission mechanism (not shown) is accommodated, and is used as a swing arm that supports the rear wheel 3. It also has a function. The unit swing engine U is indirectly connected to the suspension parts 14 and 14 via a link member 27 connected to the front part thereof, and swings up and down around a pivot shaft 28 provided on the link member 27. It is free.
The engine E is a water-cooled four-cycle single-cylinder engine, and is arranged so that the cylinder axis 29 extends substantially horizontally forward. The engine E is configured by connecting a cylinder 31 and a cylinder head 32 to the front surface of a crankcase 30 disposed at the front of the unit swing engine U.

The transmission case M extends rearward from the rear portion of the crankcase 30 through the left side of the rear wheel 3. The rear wheel 3 is supported by an axle 3 a provided at the rear part of the transmission case M. The output of the engine E is transmitted to the rear wheel 3 through the continuously variable transmission mechanism.
A rear cushion member 33 is disposed between the rear end of the transmission case M and the left rear frame 15 so as to be inclined forward.

On the upper surface of the transmission case M, an air cleaner box 34 for sucking outside air is provided. The air cleaner box 34 is connected to a throttle body 35 connected to an intake port on the upper surface of the cylinder head 32.
An exhaust pipe 36 connected to an exhaust port on the lower surface of the cylinder head 32 extends rearward under the engine E and is connected to a muffler 37 provided on the right side of the rear wheel 3.
A fuel tank 40 that stores fuel for the engine E is disposed between the lower frames 13 and 13 and in front of the cross member 16 at the rear of the down frame 12. The fuel tank 40 is disposed such that the front surface is along the down frame 12 and the bottom surface is along the lower frames 13 and 13, and the rear surface is inclined forward.

A storage box 41 for storing articles is disposed between the rear frames 15 and 15 and extends from the vicinity of the rear portion of the fuel tank 40 to above the transmission case M. The storage box 41 is connected to the intermediate cross member 17, the rear cross member 18, and a plurality of stays 38 provided on the upper surfaces of the rear frames 15 and 15. The upper surface of the storage box 41 is opened above the rear frames 15, 15 over the entire length thereof, and the opening is closed by an occupant seat 10 so as to be freely opened and closed. The seat 10 includes a front seat 10a on which a driver is seated and a rear seat 10b that is formed one step higher than the front seat 10a and on which a passenger sits.
A grab rail 42 is fixed to the rear of the rear frames 15 and 15 behind the storage box 41.

  The vehicle body cover C is continuously provided on the front cover 45 that covers the head pipe 11 and the down frame 12 from the front and side, the upper inner cover 46 that covers the head pipe 11 from the rear, and the lower part of the upper inner cover 46. A lower inner cover 47 that covers the fuel tank 40 from above, a rear cover 48 that covers the storage box 41 and the rear frames 15 and 15 from the side, and a front cover 45 and a rear cover 48 are arranged continuously below the fuel tank 40 and A middle cover 49 that covers the front portions of the rear frames 15 and 15 from the side and a lower cover 50 that covers the lower portion of the vehicle body frame F from below and from the sides are provided. A screen 44 extending rearward and upward is provided on the upper portion of the front cover 45.

The lower inner cover 47, the rear part of the front cover 45, and the middle cover 49 form a center tunnel part 51 that bulges upward between both feet of the driver seated on the seat 10, and the lower edge of the center tunnel part 51 The driver places his / her feet on a pair of left and right step floors 52 extending outward in the vehicle width direction. The step floor 52 is supported from below by the step frame. The step floor 52 extends rearward to the vicinity of the unit swing engine U, and a tandem step 52a on which a passenger puts his / her foot is provided at the rear end of the step floor 52. Each tandem step 52a is supported by step stays 21, 21 (FIG. 2).
The front wheel 2 is covered from above by a front fender 53. The rear wheel 3 is covered from above by the rear fender 54.

Hereinafter, the frame structure of the motorcycle 1 will be described in detail.
As shown in FIGS. 2 to 4, the down frame 12 is a pipe-shaped frame, and is connected to the head pipe 11 and has an upper pipe portion 60 that extends downward to an upper and lower middle portion with a substantially constant diameter, and an upper pipe. A tapered portion 61 that extends downward from the portion 60 and has a large diameter portion 62 that is formed to have a larger diameter than the upper pipe portion 60 and extends from the tapered portion 61 to the lower end of the down frame 12 with substantially the same diameter. ing.

The large-diameter portion 62 has an oval cross-sectional shape that is long in the vehicle width direction, and an outer peripheral portion thereof includes a pair of left and right curved surface portions 62a and 62a having a semicircular cross section and curved surface portions 62a and 62a. Are flat surfaces 62b, 62b that connect the left and right sides on the front side and the rear side.
Since the down frame 12 is linear, it can be easily formed by processing the pipe material even if it has a cross-sectional change such as the tapered portion 61 and the large-diameter portion 62, and the desired strength can be obtained by changing the cross-section. And rigidity can be obtained. That is, the lower part of the down frame 12 to which the lower frames 13, 13 are coupled has a large diameter part 62 to ensure strength and rigidity.

Each lower frame 13 includes a front end coupling portion 63 coupled to the large-diameter portion 62 of the down frame 12, a bent portion 64 that bends rearward after extending outward in the vehicle width direction from the front end coupling portion 63, and a bent portion. A straight portion 65 linearly extending in the front-rear direction substantially horizontally from 64 to the rear end of the lower frame 13, and a rear end coupling portion 66 coupled to the suspension portion 14 at the rear end of the straight portion 65.
The suspension portion 14 is coupled to the rear end coupling portion 66, the rear frame 15 is coupled to the rear end of the suspension portion 14, and the rear frame 15 is fixed by the suspension portion 14 in a direction directed rearward and upward. Extends upward. When the lower frame 13, the suspension portion 14, and the rear frame 15 are viewed as an integral frame, the frame is bent rearward and upward at the suspension portion 14. That is, the suspension part 14 is a bent part that bends the vehicle body frame F. Here, although the suspension portion 14 is provided between the lower frame 13 and the rear frame 15, it can be said that the suspension portion 14 is provided at the rear end of the lower frame 13.
A mounting portion 15 b to which the upper end of the rear cushion member 33 is connected is provided at the rear portion of the left (one side) rear frame 15. No rear cushion member is arranged on the right side (the other side).

FIG. 5 is a view of the lower part of the body frame F as viewed from the front. 6 is a sectional view taken along line VI-VI in FIG.
The lower frames 13 and 13 are divided into two parts in the vertical direction, and are formed by connecting a lower upper frame 70 constituting the upper half and a lower down frame 71 constituting the lower half. The lower upper frame 70 is formed in a bowl shape that opens downward, and the lower down frame 71 is formed in a bowl shape that opens upward. By connecting the lower upper frame 70 and the lower down frame 71, each lower frame 13 is formed in a hollow pipe shape. Since the lower upper frame 70 and the lower down frame 71 are manufactured by forming a plate material by press working using a mold, the degree of freedom of the shape is high compared with the case of forming a pipe material, and the lower upper frame 70 and the lower down frame 71 are pressed. By connecting the lower upper frame 70 and the lower down frame 71, a pipe shape having a continuously changing cross-sectional shape can be easily formed even if the shape has the bent portion 64.

FIG. 7 is a perspective view of the lower upper frame 70.
As shown in FIGS. 4 and 7, the bent portion 64 of the lower frame 13 is formed by continuously changing its shape so as to become wider as it approaches the large diameter portion 62 of the down frame 12. That is, the lower upper frame 70 and the lower down frame 71 are formed so as to be wider toward the front end coupling portion 63 side.
As shown in FIGS. 4 to 7, the upper surface of the lower upper frame 70 has a bulging portion 72 that gradually increases from the outside in the vehicle width direction toward the large diameter portion 62 side. Furthermore, a mountain-shaped bulging portion 72 a is formed at the end of the bulging portion 72 on the large-diameter portion 62 side so that the central portion in the width direction of the lower upper frame 70 bulges upward.
On the other hand, the bottom side of the lower down frame 71 does not have a complicated shape such as a gradual change in height, and extends substantially flat toward the large diameter portion 62. That is, the processing degree on the upper surface side of the lower upper frame 70 is higher than the processing degree on the bottom surface side of the lower down frame 71.

  FIG. 6 is a cross section at the boundary position X between the bent portion 64 and the straight portion 65. In the portion rearward of the boundary position X, the height H1 (depth of pressing) of the lower upper frame 70 is lower. The down frame 71 is formed lower than the height H2 (depth of press work). In addition, the height H <b> 1 of the lower upper frame 70 is lower than the height H <b> 2 of the lower down frame 71 also in a portion ahead of the boundary position X. That is, the lower upper frame 70 is set to be shallower than the lower down frame 71 in the press molding. In this way, by reducing the depth of the lower upper frame 70, even the lower upper frame 70 having the bulging portion 72 and the ridge-shaped bulging portion 72a and having a high degree of shape change is subjected to press molding. The moldability can be improved, and the productivity can be improved.

As shown in FIG. 6, engagement step portions 73, 73 are formed on the inner sides of the left and right lower edge portions of the bowl shape of the lower upper frame 70, with the lower edge portion bulging outward. The engagement step portions 73 and 73 are provided over the entire length of the lower upper frame 70 excluding the front end coupling portion 63 and the rear end coupling portion 66.
The lower upper frame 70 is provided so that the engagement step portions 73 and 73 are engaged with the left and right upper edge portions of the lower down frame 71 from the outside, and in this state, the front end portions of the engagement step portions 73 and 73 are arranged. The lower upper frame 70 and the lower down frame 71 are joined by fillet welding to the lower down frame 71 by the weld bead 74 formed along the engagement step portion 73. Thereby, the pipe-like lower frame 13 which has a closed cross section is formed, respectively.
In this way, the lower upper frame 70 having a lower height is pressed in order to overlap the lower upper frame 70 having a lower height on the lower down frame 71 from the outside and weld it at the lower edge of the lower upper frame 70. However, the weld bead 74 can be moved downward and provided closer to the center of the lower frame 13 in the vertical direction, and stress concentration applied to the weld bead 74 can be suppressed.

As shown in FIGS. 5 and 6, the front end coupling portion 63 of the lower frame 13 is an open end, and the open end of this pipe-shaped member is fitted to the large diameter portion 62 and welded, The lower frame 13 is fixed to the down frame 12.
Specifically, the front end coupling portion 63 is formed by being cut out in a semicircular shape when viewed from above (FIG. 4) along the outer peripheral portion of the large diameter portion 62, and is formed along the curved surface portion 62 a. An upper contact portion 80 and a lower contact portion 81, a front connection portion 82 extending along the curved surface portion 62a of the large diameter portion 62 and the flat surface 62b on the front surface side, and the curved surface portion 62a. And a rear connecting portion 83 extending along the flat surface 62b on the rear surface side.
The upper abutting portion 80 is formed at the front bulged portion 72 a of the lower upper frame 70, and the lower abutting portion 81 is formed at the front end of the lower down frame 71. The front connecting portion 82 and the rear connecting portion 83 are formed by joining the tongue portions 70a and 71a formed at the front ends of the lower upper frame 70 and the lower down frame 71, respectively. The tongue portions 70 a and 71 a are joined by a weld bead 74.

  Each lower frame 13 has an upper edge and a lower edge of the mountain-shaped bulging portion 72a, the lower abutting portion 81, and the front connecting portion 82 in a state where the front end coupling portion 63 is fitted to the large diameter portion 62 from the side. And welded to the down frame 12 by a weld bead 84 (FIG. 5). Thus, since welding is performed along the chevron bulge 72a, the weld bead 84 can be lengthened, and the joint strength can be improved.

  As shown in FIGS. 5 and 6, the front connecting portions 82 and the rear connecting portions 83 of the left and right lower frames 13, 13 contact each other at a position overlapping the axis L of the down frame 12 in the front view and the rear view. They are welded by welding beads 85 (FIG. 5) formed on the contact surfaces 82a and 82a at the front ends and the contact surfaces 83a and 83a. The rear connection part 83 on the rear surface side is provided to be offset upward from the front connection part 82 on the front surface side. Since the contact surfaces 82a and 82a and the contact surfaces 83a and 83a are contacted and welded, the strength and rigidity in the vicinity of the front end coupling portion 63 can be improved. Further, since the large diameter portion 62 is surrounded by the front end coupling portion 63 from the entire circumference, the strength and rigidity of the large diameter portion 62 can be improved.

  A notch 75 of a predetermined size is formed in each of the upper and lower intermediate portions of the contact surfaces 82a and 82a and the contact surfaces 83a and 83a. The notch 75 is provided with a filler (not shown) such as a filler wire, and the front connecting part 82 and the rear connecting part 83 are welded together by a weld bead 86 provided in the notch 75 together with the filler. And is also welded to the front surface of the down frame 12. For this reason, joint strength can be improved. The predetermined size of the notch 75 is set to such a size that the filler can be provided and sufficient welding strength can be obtained.

When the down frame 12 and the lower frame 13 are assembled, first, the lower frames 13 and 13 are formed by welding the lower upper frame 70 and the lower down frame 71 with the weld beads 74. Next, the lower frames 13 and 13 are fitted to the down frame 12, the weld beads 84 formed respectively on the upper and lower sides are welded, the weld bead 85 is welded, and finally the notch 75 together with the filler is formed. Welded by a weld bead 86.
Each stay 22 is welded after press molding of the lower upper frame 70.

  During traveling of the motorcycle 1, a force R (FIG. 2) directed in the axial direction of the head pipe 11 is greatly exerted on the front wheel 2 side due to the unevenness of the road surface and acceleration / deceleration, while the force acting in the vehicle width direction is It tends to be smaller than the force R. Since the down frame 12 is provided at the center in the vehicle width direction and is connected to the front wheel 2 side, the down frame 12 is set to receive the force R more efficiently than the force acting in the vehicle width direction. Specifically, since the down frame 12 is supported by the front end coupling parts 63 and 63 of the lower frames 13 and 13 at the fulcrum, it is effective to increase the strength and rigidity of the lower part near the fulcrum. In the embodiment, strength and rigidity are ensured by providing the tapered portion 61 and the large diameter portion 62. The down frame 12 only needs to be able to receive force in the vertical and longitudinal directions due to the force R, so that the required strength and rigidity can be obtained by making it simple such as the tapered portion 61 and the large diameter portion 62. can get. For this reason, the optimal shape which satisfy | fills a required characteristic can be obtained only by shaping | molding a pipe material.

  Since the bent portion 64 of the lower frame 13 is located outside in the vehicle width direction and is a bent portion, the direction in which the force acts is complicated. For this reason, the optimum shape of the cross section that can obtain the strength and rigidity required in the bent portion 64 becomes complicated, and when the pipe material is processed to obtain the same characteristics as the optimum shape, the plate thickness is It becomes thick and the weight increases.

In the first embodiment, the lower frame 13 has a vertically divided structure, and the lower upper frame 70 and the lower down frame 71 having a shape in which the cross-sectional area and shape of the bent portion 64 are optimized are individually formed by press work, Then, since it was welded and formed into a pipe shape with a closed cross section, the optimally shaped lower frame 13 can be easily formed. By adopting the optimal shape, strength and rigidity can be ensured even with a small plate thickness, so that weight reduction can be achieved. By adopting a configuration in which the lower frames 13 and 13 and the down frame 12 are coupled, an optimally shaped frame structure can be easily formed.
Further, the upper surface of the lower upper frame 70 has a bulging portion 72 that gradually increases as it approaches the large diameter portion 62 side, and the bulging portion 72 joins the lower upper frame 70 to the down frame 12. The position can be increased to improve the support strength of the down frame 12, and the input load from the down frame 12 can be transmitted gently. For this reason, stress concentration can be avoided and optimization of strength and rigidity can be achieved.

Moreover, as shown in FIG. 6, the cross-sectional shape of the linear part 65 of the lower frame 13 is formed in an ellipse long vertically. For this reason, the rigidity with respect to the force R is high, and the ride comfort is good.
Further, the cross-sectional area of the lower frame 13 is the smallest at the boundary position X (FIG. 4) between the bent portion 64 and the straight portion 65, and gradually increases toward the rear side. For this reason, the rigidity does not suddenly increase at the boundary position X between the straight portion 65 and the bent portion 64 having high rigidity, and the rigidity characteristics of the lower frame 13 as a whole can be moderated.

Next, the configuration near the suspension parts 14 and 14 will be described.
FIG. 8 is a perspective view of the vicinity of the suspension portions 14 and 14 as viewed from the rear side. Here, in FIG. 8, illustration of a weld bead described later is omitted.
As shown in FIG. 8, plate-like extension portions 90, 90 extending rearward and downward are formed on the rear surfaces of the suspension portions 14, 14, and the link member 27 includes left and right extension portions 90. , 90.
The link member 27 includes a connecting shaft 91 that is provided between the extending portions 90 and 90 and extends in the vehicle width direction, a pair of arm portions 92 and 92 that extend rearward from the rear surface of the connecting shaft 91, and arm portions 92 and 92. A pivot support portion 93 that is fixed to the rear end and extends parallel to the connecting shaft 91 and a stopper 94 that extends forward from the front surface of the connecting shaft 91 are provided.

The extension portions 90, 90 are provided with shafts (not shown) penetrating the extension portions 90, 90 in the vehicle width direction, and the link member 27 is supported by the connection shaft 91 being pivotally supported by the shaft. It is supported so as to be swingable about an axis. The stopper 94 extends to above the cross member 16 and abuts on the upper surface of the cross member 16 via an elastic member (not shown) provided on the lower surface of the stopper 94. That is, the rotation of the link member 27 is regulated by the stopper 94, and the link member 27 can be slightly rotated by the amount of elastic deformation of the elastic member.
The unit swing engine U is supported by a pivot shaft 28 (FIG. 1) inserted through the pivot support portion 93 and can swing around the pivot shaft 28.

FIG. 9 is a view of the suspension portions 14 as viewed from the rear. FIG. 10 is a side view of the left suspension 14 as viewed from the outside in the vehicle width direction. FIG. 11 is a side view of the left suspension 14 as viewed from the inside in the vehicle width direction. Since the left and right suspension parts 14 are formed substantially symmetrically, the description will be made mainly with reference to the left suspension part 14 here.
As shown in FIGS. 8 to 11, the suspension part 14 is bent to a front part coupling part 95 coupled to the rear end coupling part 66 of the lower frame 13, and after extending rearward from the front coupling part 95. A suspension bending portion 96 extending rearward and upward, a rear coupling portion 97 coupled to the front end 15a of the rear frame 15, and the extending portion 90 are provided.

  A pipe fitting portion 98 that opens in a semicircular shape when viewed from the side is formed at the front end of the front coupling portion 95. The pipe fitting portion 98 is fitted to the cross member 16 by welding to the rear half portion of the cross member 16 from the rear. Further, a pipe fitting portion 67 that opens in a semicircular shape in a side view is formed at the rear end of the rear end coupling portion 66 of the lower frame 13, and the front half of the cross member 16 is a pipe fitting portion 67. Are welded and fixed to the pipe fitting portion 67.

A pipe support hole 99 that penetrates the suspension part bending part 96 in the vehicle width direction is formed in the suspension part bending part 96. A cylindrical collar 100a (cross member) into which a bolt (not shown) for fixing the side stand 39 to the vehicle body frame F is inserted is fixed to the pipe support hole 99 by welding. In addition, a pipe support hole 101 that penetrates the lower frame 13 in the vehicle width direction is formed in the rear portion of the left lower frame 13, and the collar 100b extends in the vehicle width direction in the pipe support hole 101. It is welded and fixed in the penetrating state. The side stand 39 is fixed by the bolt inserted through the pair of collars 100a and 100b. Since the collars 100a and 100b act as cross members that connect the left and right wall portions of the suspension bending portion 96 and the lower frame 13, respectively, the strength and rigidity of the suspension bending portion 96 and the lower frame 13 can be improved.
Cutout portions 102, 102 extending in the vertical direction are formed at the front and rear central portions of the rear coupling portion 97. The notches 102 are provided on the outer surface side and the inner surface side in the vehicle width direction.

Each of the extending portions 90 includes an extending portion upper portion 110 that is disposed substantially at the center in the vehicle width direction of the rear frame 15 at a position that overlaps the axis K (FIG. 9) of the rear frame 15 in the rear view, and an extending portion upper portion 110. The bent portion 111 is bent inward in the vehicle width direction from the lower end of the extended portion and extends downward in the vehicle width direction, and is located on the inner side of the extended portion bent portion 111 from the lower end of the extended portion bent portion 111 to the axis K. And an extending portion lower portion 112 extending along the same.
A support portion 112a (FIG. 11) that protrudes rearward in an arc shape is formed in the extended portion lower portion 112, and the bolt that supports the connecting shaft 91 of the link member 27 is inserted into the support portion 112a. A hole 90a is formed. The unit swing engine U is supported between the support portions 112 a and 112 a of the left and right extending portions 90 and 90 via the link member 27. The extended lower portions 112 and 112 extend below the cross member 16.

The suspension portion 14 is formed in a bent pipe shape, and is manufactured by combining plate members that are divided into three in the circumferential direction. Specifically, the suspension portion 14 constitutes the upper surface of the suspension portion 14 and opens to the lower side, and a lower outer member 104 that is divided in the vehicle width direction and constitutes the lower surface of the suspension portion 14. And the lower inner member 105.
Since the upper half body 103, the lower outer member 104, and the lower inner member 105 are manufactured by molding a plate material by press working using a mold, the degree of freedom of shape is higher than when a pipe material is molded. By joining the press products, even if the shape is provided with the suspended portion bending portion 96, a pipe-shaped member having a desired cross-sectional shape can be easily formed.

FIG. 12 is a left side view of the upper half 103. FIG. 13 is a left side view of the lower inner member 105. FIG. 14 is a cross-sectional view when the vicinity of the suspension 14 is viewed from the side.
Referring to FIGS. 8 to 14, the upper half 103 is formed in a bowl shape, and has a curved upper surface portion 103 a, and a pair of left and right outer wall portions 103 b and inner wall portion 103 c extending downward from the upper surface portion 103 a. And have. The upper half 103 is bent so as to warp opposite to the open side of the bowl shape in a side view. A front coupling portion 95 is formed at the front end of the upper half 103. The front coupling portion 95 is formed in a semicircular shape when viewed from the front, and has a front overlapping portion 95a (FIG. 14) that overlaps and fits on the outer peripheral surface of the upper portion of the rear end coupling portion 66 from the outside. Moreover, the upper half part of the pipe fitting part 98 is formed under the front part overlap part 95a.

At the upper end of the upper half 103, a rear overlapping portion 97 a that forms the front half of the rear coupling portion 97 is formed. The rear overlapping portion 97a overlaps the outer peripheral surface of the front surface of the front end 15a of the rear frame 15 from the outside. The rear overlapping portion 97a extends to a position where the upper end portion 97d located on the outer side in the vehicle width direction is higher than the inner portion. The notch 102 is formed by notching the rear edge of the rear overlapping portion 97a.
Engagement step portions 106 and 106 (FIG. 12) are formed on the lower edge portions of the outer wall portion 103b and the inner wall portion 103c of the upper half body 103, and the lower edge portion bulges outward. The engagement step portions 106 and 106 extend between the pipe fitting portion 98 and the notch portion 102.
The pipe support hole 99 is provided through the outer wall portion 103b and the inner wall portion 103c.

The lower inner member 105 (FIG. 13) includes an inner curved surface portion 115 that constitutes an inner portion in the vehicle width direction on the lower surface side of the pipe-like suspension portion 14, and an inner extension portion 116 that constitutes the inner surface of the extension portion 90. And have.
The cross-sectional shape of the suspension portion 14 in the inner curved surface portion 115 as viewed in the axial direction is formed in a curved surface shape so as to constitute a part of a substantially circular pipe shape. At the upper end of the inner curved surface portion 115, a rear overlapping portion 97b constituting the rear portion of the rear coupling portion 97 is formed. The lower inner member 105 has an upper extension portion 117 that extends upward from the rear overlapping portion 97b along the rear surface portion of the rear frame 15.
At the front edge of the inner curved surface portion 115, an engagement edge portion 115a that is engaged and welded to the engagement step portion 106 of the inner wall portion 103c of the upper half 103 is formed.

A pipe fitting portion 98 is formed at the front end of the lower inner member 105 so as to straddle the inner curved surface portion 115 and the inner extending portion 116. That is, the upper part of the pipe fitting part 98 on the inner side in the vehicle width direction is provided at the front end of the inner curved surface part 115, and the lower part of the pipe fitting part 98 is provided at the front end of the inner extension part 116.
A protruding piece 118 that protrudes rearward is formed at a portion corresponding to the extended portion bent portion 111 of the inner extended portion 116. A welding portion 119 welded to the lower outer member 104 is provided above the protruding piece 118 at the rear edge of the inner curved surface portion 115. In addition, a welding portion 120 welded to the lower outer member 104 is provided below the protruding piece 118 at the rear edge of the inner extension portion 116. On the other hand, the protruding piece 118 is not welded to the lower outer member 104, but is fixed by welding of adjacent welded portions 119 and 120.
Further, the welded portion 120 and the pipe fitting portion 98 at the rear and lower edges of the lower inner member 105 are also non-welded portions 121 (FIG. 11) that are not welded to the lower outer member 104.

The lower outer member 104 (FIG. 10) includes an outer curved surface portion 125 that constitutes an outer portion in the vehicle width direction on the lower surface side of the pipe-like suspension portion 14, and an outer extension portion 126 that constitutes an outer surface of the extension portion 90. And have.
The cross-sectional shape of the suspension portion 14 in the outer curved surface portion 125 as viewed in the axial direction is formed in a curved surface shape so as to constitute a part of a substantially circular pipe shape. A rear overlapping portion 97 c constituting the rear portion of the rear coupling portion 97 is formed at the upper end of the inner curved surface portion 115.
At the front edge of the outer curved surface portion 125, an engagement edge portion 125a that is engaged and welded to the engagement step portion 106 of the outer wall portion 103b of the upper half 103 is formed.

  The protruding piece 118 (FIG. 11) of the inner extension portion 116 is not welded to the outer extension portion 126. The extended portion bent portion 111 is a bent portion, and it is difficult to properly contact the inner extended portion 116 and the outer extended portion 126 depending on the accuracy of press molding. For this reason, in this 1st form, in the extension part bending part 111, it is set as the structure which provides the clearance gap between the inner side extension part 116 and the outer side extension part 126, and welds to this part. A protruding piece 118 is provided as a mark indicating a portion not to be used. For this reason, it is easy to perform welding work. The joint strength is sufficiently ensured by the welded portions 119 and 120.

A pipe fitting portion 98 (FIG. 10) is formed at the front end of the lower outer member 104 across the outer curved surface portion 125 and the outer extension portion 126. That is, the upper part of the pipe fitting part 98 on the outer side in the vehicle width direction is provided at the front end of the outer curved surface part 125, and the lower part of the pipe fitting part 98 is provided at the front end of the outer extension part 126.
The extension part 90 is formed by joining the outer extension part 126 and the inner extension part 116. The outer extension portion 126 is formed larger than the inner extension portion 116 as a whole in a side view, and covers the inner extension portion 116 from the outside.

Each suspension portion 14 is formed along the engagement step portions 106 and 106 while joining the lower outer member 104 and the lower inner member 105 by weld beads 128 (FIG. 11) formed in the weld portions 119 and 120. By connecting the engagement edge portions 115a and 125a to the engagement step portions 106 and 106 by the weld beads 129 and 129, the pipe is formed.
Next, each suspension portion 14 is joined to the rear frame 15 by inserting the front end 15a of each rear frame 15 into the rear joint portion 97 and welding in this state. Specifically, the suspension portion 14 includes a weld bead 130 along the upper edge of the rear overlap portion 97 a of the upper half 103, and a weld bead 131 along the rear overlap portion 97 b and the upper extension portion 117 of the lower inner member 105. And a weld bead 132 (FIG. 10) along the edge of the rear overlapping portion 97 c of the lower outer member 104 and joined to the rear frame 15. Thereby, the small assembly 133 in which the suspension part 14 and the rear frame 15 are integrally joined is formed.
Here, it has been described that the suspension portion 14 is welded to the rear frame 15 after the suspension portion 14 is formed in a pipe shape. However, the present invention is not limited to this, and the upper half 103 so as to surround the front end 15 a of the rear frame 15. Alternatively, the weld bead 130, 131, 132 may be formed in the process of setting the lower outer member 104 and the lower inner member 105 and then forming the weld beads 129, 129.

  The weld beads 130, 131, 132 are also formed at the edges of the outer and inner cutouts 102, 102, and the weld length is longer than that of the configuration in which the cutouts 102, 102 are not provided. Yes. For this reason, joint strength can be improved. In addition, by providing the notches 102 and 102, it becomes easy to deform the portions in the vicinity of the weld beads 130, 131, and 132 along the weld, so that the adhesion of the weld can be improved and the joint strength is improved. it can.

The cross member 16 is joined to the pipe fitting portion 67 at the rear end of the lower frames 13 and 13 in advance by a weld bead 134 (FIG. 10).
The small assembly 133 is fitted to the rear end coupling portion 66 of the lower frame 13 so that the pipe fitting portion 98 at the front end of the suspension portion 14 is brought into contact with the cross member 16 from the rear, and the front edge of the front overlapping portion 95a is fitted. Are welded to the lower frames 13 and 13 and the cross member 16 by a weld bead 135 formed along the peripheral edge of the pipe fitting portion 98. In this way, by welding the suspension part 14 not only to the lower frame 13 but also to the cross member 16, the weld length can be increased and the joint strength can be improved. Furthermore, since a part of the weld bead 136 is provided at the front end of the inner curved surface portion 115 and extends in the vehicle width direction, the weld length can be increased and the joint strength can be improved. Moreover, since the welding position can be accurately positioned by applying the suspension portion 14 to the cross member 16, the assemblability is good.

As shown in FIGS. 10 and 15, in the rear portion of the lower frame 13, the engagement step portion 73 is not formed on the rear lower edge 76 of the lower upper frame 70, but the rear lower edge 76 is above the lower down frame 71. It abuts on the edge and is joined to the lower down frame 71 by a weld bead 74. The upper half 103 extends downward and covers the lower frame 13 across the rear lower edge 76 of the lower upper frame 70 at the front coupling portion 95. For this reason, the joint strength between the lower upper frame 70 and the lower down frame 71 can be improved.
In addition, when it is desired to make the body frame common to a plurality of different vehicle types, for example, the head pipe 11, the down frame 12, and the lower frames 13 and 13 are shared, and the shape of the frame of the portion of the small assembly 133 is matched to the vehicle type By changing, it is possible to easily construct frames of different vehicle types.

15 is a cross-sectional view taken along the line XV-XV in FIG.
As shown in FIGS. 14 and 15, the suspension portion 14 is a separate member from the lower frame 13 and the rear frame 15 and is formed in a pipe shape having a different closed cross-sectional structure, and the lower frame 13 and the rear frame 15 are connected. The suspension portion 14 overlaps the lower frame 13 from the outside at the front overlap portion 95a at the front end, overlaps the rear frame 15 from the outside at the rear overlap portions 97a, 97b, and 97c at the rear end, and extends from the front overlap portion 95a to the rear end. In the section between the rear overlapping portions 97a, 97b, and 97c, the lower frame 13 and the rear frame 15 are not overlapped. That is, the vehicle body frame F has a structure in which the lower frame 13 and the rear frame 15 do not pass through the suspension portion 14.

  The suspension part 14 is a bent connection part that connects the lower frame 13 and the rear frame 15 extending in a direction different from the lower frame 13, and smoothly transmits the load between the lower frame 13 and the rear frame 15. It must be strong and rigid. Moreover, since the suspension part 14 is a part which suspends the unit swing engine U via the link member 27, it needs to have the intensity | strength and rigidity which can support the unit swing engine U appropriately. That is, the suspension part 14 is required to have an optimum shape that satisfies the strength and rigidity from the viewpoints of both the connection part and the support part of the unit swing engine U.

In the first embodiment, the suspension portion 14 has a three-part structure, and the upper half body 103, the lower outer member 104, and the lower inner member 105, each having a cross-sectional area and shape optimized to satisfy the above requirements, are individually provided. And then welded to form a pipe with a closed cross section, and the suspension 14 is welded so that the lower frame 13 and the rear frame 15 do not pass through the suspension 14. The portion 14 can be easily provided, and the lower frame 13 and the lower frame 13 can be formed in an optimum shape without being influenced by the required characteristics of the suspension portion 14. For this reason, it is not necessary to increase the thickness of the vehicle body frame F, and the weight can be reduced.
Moreover, since the suspension part 14 is composed of one upper half body 103 on the front side and has a rib-like extension part 90 on the rear side, the suspension part 14 has high rigidity against the force R and can improve riding comfort.
Further, in the front overlapping portion 95a and the rear overlapping portions 97a, 97b, and 97c, the suspension portion 14 overlaps the lower frame 13 and the rear frame 15 to form a double pipe structure, so that the strength and rigidity are high.

As shown in FIG. 9, the extension portion upper portion 110 of the extension portions 90, 90 is provided at the center in the width direction of the rear frame 15 by overlapping with the axis K of the rear frame 15, so that the unit swing engine The load from the U side can be efficiently transmitted to the rear frame 15, and the load can be effectively received.
The extension part lower portions 112 and 112 of the extension parts 90 and 90 are provided closer to the inner side in the vehicle width direction than the axis K of the rear frame 15. Thereby, since the connection shaft 91 supported by the extension part lower parts 112 and 112 can be shortened and the rigidity of the connection shaft 91 can be improved, the support rigidity of the unit swing engine U can be improved. The extension part lower parts 112 and 112 are brought closer to the inner side than the axis K of the rear frame 15, but the extension part lower parts 112 and 112 have sufficient rigidity by the front end being coupled to the cross member 16. Has been.
Moreover, as shown in FIG. 11, since the non-welded part 121 is provided in a part around the support part 112a of the extension part 90, when assembling the connecting shaft 91 between the support parts 112a and 112a. , The weld bead does not get in the way. For this reason, it is easy to assemble.

  As described above, according to the first embodiment to which the present invention is applied, the down frame 12 extending downward from the rear portion of the head pipe 11 is made of a pipe material, and the lower frames 13 and 13 are After being provided with a pair of left and right, each of which has a closed cross section made of a plate material of a vertically divided structure, the lower frames 13 and 13 extend from the front end coupling portion 63 which is a connecting portion with the down frame 12 in the vehicle width direction. It has a bent portion 64 that bends backward, and the down frame 12 is made of a pipe material, so that the rigidity and strength required for the down frame 12 can be secured while reducing the number of connecting portions of the down frame 12, and the lower frame 13 is configured by a plate material having a bifurcated structure of upper and lower parts, so that the cross section area and shape of the bent portion 64 are optimized and the stress acting on the bent portion 64 is dispersed. It is possible to achieve even lighter with the kill. For this reason, weight reduction can be achieved, ensuring the strength and rigidity required for the frame.

The lower frames 13 and 13 have an upper lower frame 70 and a lower lower frame 71 and are divided into two parts. The shape of the lower frames 13 and 13 is changed by the lower upper frame 70. Since it is formed so as to be larger than the down frame 71, the input load from the down frame 12 can be gently transmitted through the lower upper frame 70, avoiding stress concentration, and having strength and rigidity. Optimization can be achieved.
In addition, since the upper surface of the lower upper frame 70 has a bulging portion 72 formed so as to be gradually positioned on the down frame 12 side, when the lower down frame 71 is viewed as a fulcrum for supporting the down frame 12, The upper frame 70 is connected at a position close to the head pipe 11 that is an input point of the load, and the cross-sectional shape of the lower upper frame 70 changes gradually, and stress concentration occurs due to the input load from the head pipe 11. This can be suppressed. For this reason, the load can be distributed also to the rear side of the lower frames 13 and 13, and it is not necessary to increase the plate thickness.

  Further, the lower frames 13, 13 are provided with a straight portion 65 extending in the front-rear direction behind the bent portion 64, and are configured to have a minimum cross-sectional area at a boundary position X between the bent portion 64 and the straight portion 65. Therefore, the rigidity does not suddenly increase at the boundary position X between the straight portion 65 and the bent portion 64 having high rigidity, the rigidity characteristics of the lower frames 13 and 13 as a whole can be moderated, and the weight can be further reduced. Can do.

Further, since the lower upper frame 70 has a height behind the bent portion 64 that is smaller than the height of the lower down frame 71, even if the lower upper frame 70 has a large shape change, the formability during press molding is improved. Can be secured and productivity can be improved.
Further, the lower upper frame 70 has the engagement step portions 73 and 73 overlapped with the lower down frame 71 from the outside, and is welded and fixed to the lower down frame 71 at the lower edge of the lower upper frame 70. The stress concentration applied to the weld bead 74 can be suppressed by providing 74 near the intermediate portion in the height direction of the lower frames 13 and 13. For this reason, further weight reduction can be achieved.

Further, the front end coupling portions 63 of the pair of left and right lower frames 13 and 13 are respectively welded so as to surround the large-diameter portion 62 at the lower portion of the down frame 12 in a semicircular shape when viewed from above, and In the rear, the front connecting portion 82 and the rear connecting portion 83 at the front ends of the pair of left and right lower frames 13 and 13 are welded in contact with the left and right contact surfaces 82a and 83a, respectively. By encircling in the shape, the weld bead 84 can be increased in welding length, and the welding strength can be improved by welding the front connecting portion 82 and the rear connecting portion 83. Further, by surrounding the large diameter portion 62 with the front end coupling portion 63, the rigidity of the lower portion of the down frame 12 can be improved.
Further, a notch 75 having a predetermined size is provided between the contact surfaces 82a and 82a of the lower frames 13 and 13 of the front connection portion 82 and the rear connection portion 83 and between the contact surfaces 83a and 83a. Since the lower frames 13 and 13 are welded to the down frame 12 through the left and right, the left and right lower frames 13 and 13 and the down frame 12 can be welded through the notch 75, and the joint strength can be improved.

  In addition, according to the first embodiment to which the present invention is applied, the suspension portions 14 and 14 provided between the lower frames 13 and 13 and the rear frames 15 and 15 are provided on the lower frames 13 and 13 and the rear frame 15. , 15 is formed in a closed cross-sectional structure, and the lower frames 13, 13 and the rear frames 15, 15 do not pass through the suspension parts 14, 14. 95 and the rear coupling portion 97 are connected to the lower frames 13 and 13 and the rear frames 15 and 15, so that the suspension portions 14 and 14 can be provided by optimizing the strength and rigidity necessary for the suspension portions 14 and 14. At the same time, the lower frames 13 and 13 and the rear frames 15 and 15 can be formed in an optimum shape without being influenced by the required characteristics of the suspensions 14 and 14. 4, it is possible to mutually optimized strength and rigidity of the lower frame 13 and rear frame 15, 15, it is possible to reduce the weight.

In addition, the suspension parts 14 and 14 are provided between the lower frames 13 and 13 and the rear frames 15 and 15 and also form bent portions, so that the lower frames 13 and 13 and the rear frames 15 and 15 The optimum shape can be obtained according to the required characteristics, and the suspension parts 14 and 14 can ensure the strength and rigidity of load transmission as a frame for transmitting the load between the lower frames 13 and 13 and the rear frames 15 and 15. However, it is possible to realize an optimum shape that also takes into account the input of the load from the unit swing engine U, and to further reduce the weight.
Further, a cross member 16 for connecting the rear ends of the pair of left and right lower frames 13 and 13 is provided, and the suspension portions 14 and 14 are connected not only to the lower frames 13 and 13 but also to the cross member 16. Can be increased, and the bonding strength can be improved.

  The suspension parts 14 and 14 are divided into three parts, that is, an upper half body 103 that opens downward, and a lower outer member 104 and a lower inner member 105 that are connected to the lower side of the upper half body 103 and are divided in the vehicle width direction. A unit swing engine U is formed in an extended portion 90 that forms a closed section with a structure, and is formed by overlapping an outer extension portion 126 and an inner extension portion 116 that extend downward from each of the lower outer member 104 and the lower inner member 105. Since the support portion 112a is formed, the load applied to the suspension portions 14 and 14 can be effectively received by the upper half 103, and the extension portion in which the outer extension portion 126 and the inner extension portion 116 are overlapped with each other. By forming the support portion 112a at 90, the support rigidity and strength of the support portion 112a can be increased.

  Furthermore, the extension part 90 includes an extension part upper part 110 formed at a substantially center in the vehicle width direction of the rear frames 15 and 15, and an extension part lower part 112 provided on the inner side in the vehicle width direction from the extension part upper part 110. Since the support portion 112a of the unit swing engine U is provided at the extension portion lower portion 112, the load from the support portion 112a is evenly distributed at the approximate center in the width direction of the rear frames 15 and 15 by the extension portion upper portion 110. Can be transmitted to the rear frames 15 and 15 side, and the distance between the left and right extending portion lower portions 112 and 112 can be shortened to improve the strength and rigidity of the connecting shaft 91 provided at this distance. it can.

In addition, the peripheral edges of the outer extension portion 126 and the inner extension portion 116 are welded to each other, and the non-welded portion 121 is provided around a part of the support portion 112a. Therefore, the assembling property of the connecting shaft 91 can be improved.
In addition, since the notches 102 and 102 are provided on the suspension parts 14 and 14 side at the joints between the suspension parts 14 and 14 and the rear frames 15 and 15, the suspension parts 14 and 14 and the rear frames 15 and 15 are provided. In addition, the weld strength can be increased and the weld strength can be increased.

  The left rear frame 15 is provided with a mounting portion 15b for the rear cushion member 33 that supports the unit swing engine U, and the suspension portion 14 on the side where the mounting portion 15b is provided penetrates the closed section of the suspension portion 14. Since the collar 100a is arranged and the rigidity of the suspension part 14 on the side where the attachment part 15b is provided can be improved by the collar 100a, the rigidity of the load transmission path can be increased and the riding comfort can be improved.

In addition, the said 1st Embodiment shows the one aspect | mode which applied this invention, Comprising: This invention is not limited to the said 1st Embodiment.
In the first embodiment, the notch 75 is described as being provided in the front connecting part 82 and the rear connecting part 83. However, the notch 75 is provided only in one of the front connecting part 82 and the rear connecting part 83. It is good also as a structure provided in. That is, the cutout 75 may be provided in the front connection portion 82 and / or the rear connection portion 83.
In the first embodiment, the unit swing engine U is described as being indirectly connected to the suspension parts 14 and 14 via the link member 27 connected to the front part thereof. Not limited to this, the unit swing engine U may be directly supported by the extending portions 90 and 90 without using the link member 27.

[Second Embodiment]
Hereinafter, a second embodiment to which the present invention is applied will be described with reference to FIG. In the second embodiment, parts that are configured in the same manner as in the first embodiment are given the same reference numerals, and descriptions thereof are omitted.
In the first embodiment, the suspension portion 14 has been described as being provided between the lower frame 13 and the rear frame 15. However, in the second embodiment, the suspension portion 214 has a rear frame. The point provided in the middle of 215 is different from the first embodiment.

FIG. 16 is a left side view of the vehicle body frame F1 according to the second embodiment.
The motorcycle 1 includes a body frame F1. The body frame F1 extends in the vehicle width direction from the head pipe 11, the down frame 12, and the lower portion of the down frame 12, and then bends and extends rearward. A lower frame 213, 213, a center cross frame 216 provided at the rear of the lower frames 213, 213, and connecting the left and right lower frames 213, 213, and a pair of left and right extending from the center cross frame 216 to the rear upper part to the rear of the vehicle Rear frames 215 and 215, and suspension portions 214 and 214 provided in the middle of the rear frames 215 and 215. The lower frames 213 and 213 and the rear frames 215 and 215 are pipe-shaped frames.
The vehicle body frame F1 includes a center cross frame 216 as a cross frame that connects the left and right frames, an intermediate cross member 217 that connects the front portions of the rear frames 215 and 15 above the center cross frame 216, and a rear frame 215. , 215, and a rear cross member (not shown) for connecting the front and rear intermediate portions, and a rear end cross member 219 for connecting the rear ends of the rear frames 215 and 215.

Each rear frame 215 includes a front rear frame 215a coupled to the rear portion of the center cross frame 216, and a rear rear frame 215b coupled to the front rear frame 215a via the suspension portion 214.
Each suspension part 214 is formed in a pipe shape, and is divided into three in the circumferential direction as in the first embodiment. Specifically, the suspension part 214 includes a bowl-shaped upper half 203 that opens downward, a lower outer member 204 and a lower inner member (not shown) that are divided in the vehicle width direction and constitute the lower surface of the suspension part 214. Have A plate-like extension portion 290 that extends rearward and downward is provided on the lower surface of each suspension portion 214. The upper half 203, the lower outer member 204, and the lower inner member are individually formed by press molding.

The suspension parts 214 and 214 suspend the unit swing engine U via a link mechanism (not shown) connected to the extension parts 290 and 290. The unit swing engine U may be directly supported by the extending portions 290 and 290 without using the link mechanism.
The suspension 214 is a separate member from the front rear frame 215a and the rear rear frame 215b, and is formed in a pipe shape having a closed cross-sectional structure different from that of the rear frame 215, and the front rear frame 215a and the rear rear frame 215a. The frame 215b is connected.
The suspension 214 overlaps from the outside to the rear end of the front rear frame 215a in the front overlap portion 214a at the front end, and overlaps from the outside to the front end of the rear rear frame 215b in the rear overlap portion 214b at the rear end. And the rear overlapping portion 214b do not overlap the rear frame 215. That is, the body frame F1 has a structure in which the rear frame 215 does not pass through the suspension portion 214.

  The suspension portions 214 and 214 provided in the middle of the rear frames 215 and 215 are formed with a closed cross-sectional structure different from that of the rear frames 215 and 215, and the rear frames 215 and 215 do not pass through the suspension portions 214 and 214. Since the structure is connected to the rear frames 215 and 215 at the front overlap portion 214a and the rear overlap portion 214b of the suspension portions 214 and 214, the strength and rigidity necessary for the suspension portions 214 and 214 are optimized and the suspension portion 214 and 214 can be provided, and the rear frames 215 and 215 can also have an optimum shape regardless of the required characteristics of the suspension portions 214 and 214, and the suspension frames 214 and 214 and the rear frames 215 and 215 can be formed. Since the strength and rigidity can be mutually optimized, the weight can be reduced.

1 Motorcycle (saddle-ride type vehicle)
2 Front wheel 11 Head pipe 12 Down frame 13, 13 Lower frame 64 Bent part 65 Straight part 70 Lower upper frame 71 Lower down frame 75 Notch 82 Front connecting part 83 Rear connecting part H1 Height H2 Height X Boundary position

Claims (7)

A head pipe (11) for pivotally supporting the front wheel (2), a down frame (12) extending downward from the rear part of the head pipe (11), and a rear part from the lower part of the down frame (12) In the frame structure of a saddle-ride type vehicle provided with an extended lower frame (13),
The down frame (12) is made of a pipe material,
The lower frame (13) is provided as a pair on the left and right sides, and each of the lower frame (13) has a closed cross section made of a plate material having a vertically divided structure, and the lower frame (13) is connected to the down frame (12) from the connecting portion. bent portion that is bent rearward after extending in a direction (64) possess,
The lower frame (13) has an upper lower upper frame (70) and a lower lower frame (71) to form a two-part structure, and the shape change of the lower frame (13) frame structure for a saddle type vehicle is characterized that you have been formed so as to be larger than the upper frame (70) is the lower-down frame (71). Top surface, the down frame (12) frame of the saddle-ride type vehicle according to claim 1, characterized in that it is formed gradually so as to be positioned above at side structure of the lower upper frame (70). The lower frame (13) includes a linear portion (65) extending in the front-rear direction behind the bent portion (64), and a boundary position (X) between the bent portion (64) and the linear portion (65). The frame structure of the saddle-ride type vehicle according to claim 1 or 2 , wherein the cross-sectional area is configured to be minimum. The lower upper frame (70), the height at the rear of the bent portion (64) (H1), any of claims 1 to 3, wherein the height of the lower down frames (H2) less than A frame structure of a saddle-ride type vehicle according to claim 1. The lower upper frame (70) is superimposed on said externally lower down frame (71), Tei Rukoto fixed by welding the mutually the lower down frame (71) at the lower edge of the lower upper frame (70) The frame structure of a saddle-ride type vehicle according to claim 4 . Pair of left and right lower frames (13), said are respectively welded to enclose the semicircular at the bottom of the down frame (12) in top view Tei Rutotomoni, at the front and rear of the down frame (12), left and right saddle according to any one of claims 1 to 5 the front connecting portion (82) and the rear coupling section (83) is welded in contact respectively, characterized in Tei Rukoto at the front end of the pair of the lower frame (13) Frame structure for riding type vehicles. A notch (75) having a predetermined size is provided between the abutting portions of the pair of left and right lower frames (13) of the front connecting portion (82) and / or the rear connecting portion (83), notches (75) the lower frame via (13) is a frame structure for a saddle type vehicle according to claim 6, wherein Tei Rukoto welded to the down frame (12).

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