JP2000095171A - Frame structure of motorcycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of components, the number of man-hours, weight and cost by joining a sub-frame member having a U-shape in cross section so as to suspend the sub-frame member downward from a main frame extending from a head pipe, and integrally providing a component attachment portion to the sub-frame member. SOLUTION: A main frame 30, comprising an upper member 31 having an inverted-U shape in cross section, and a lower member 32 having a U shape in cross section, has a vertically symmetric shape. An arc-shaped recess 31a in which a rear part of the upper portion of a head pipe 22 is fitted is formed in the front end. The upper member 31 and the lower member 32 are molded by pressing. Flange portions 31c, 32c which are bent to protrude outward are integrally provided at opposing ends of right and left sidewall portions 31b, 32b of the upper member 31 and the lower member 32, respectively. Thus, the number of components of a sub-frame member, and the number of ma-hours of assembling, welding the components, or the like is reduced, whereby reduction in weight of the frame and cost can be achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motorcycle frame structure, and more particularly to a frame structure for mounting and supporting an engine.

[0002]

2. Description of the Related Art As a vehicle body frame of a motorcycle, for example, Japanese Patent Laid-Open No. 9-95279 is disclosed. The technology disclosed herein is to make the main frame a flat pipe material, bend the rear part downward, attach the upper part of the engine rear to the rear part, and join the hanger to support as a separate member,
It is an integrated structure, and a bracket for attaching and supporting the lower part of the rear part of the engine is provided as a separate member and joined and integrated below the upper hanger. Not limited to this example, a conventional engine hanger in a motorcycle includes a frame member that supports an engine and a rear swing arm with a main frame as a separate member, and a hanger formed separately from the frame member. Brackets are joined, and the hanger and brackets are used to mount and support the engine.

[0003]

In the above prior art, the engine mounting and support members such as hangers and brackets are formed separately from the frame components, and are joined to the frame components by welding or screwing. Because of the integrated structure, the number of parts increases, the number of man-hours required for welding etc. increases, the frame structure becomes complicated, the number of man-hours required for manufacturing increases, and this tends to increase the weight. Since the engine mounting and support members such as are separately provided, there are disadvantages in that it is disadvantageous in terms of cost when manufacturing the frame, and it is not preferable in reducing the cost of the motorcycle as a whole.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a simple structure in which a frame including an engine mounting and a support portion is manufactured with a simple structure.
It is another object of the present invention to provide a motorcycle frame structure that can be obtained at a low cost and that can obtain a lightweight frame while securing high rigidity and strength.

[0005]

In order to solve the above-mentioned problems, a first aspect of the present invention is to press-form a metal plate having a U-shaped cross section from a main frame extending rearward from a head pipe toward a lower side of the main frame. The assembled sub-frame members were joined and hung down, and the sub-frame members were integrally provided with component mounting portions by press working.

According to the first aspect of the present invention, since the component mounting portion is provided integrally with the sub-frame member, the component mounting portion is formed as a separate member.
There is no need to weld or screw this, and it is possible to reduce the number of parts, reduce man-hours, reduce weight, and reduce costs. Also, since the sub-frame member has a U-shape in cross section, it is easy to perform welding, etc. when joining to the main frame by welding, etc., and it is easy to gain a joint area such as a welding area, and the sub-frame member to the high rigidity and strength main frame. Can be easily joined.

According to a second aspect, in the first aspect, the component mounting portion is an engine hanger portion. It is not necessary to weld the upper and lower engine hangers and brackets as separate members to the sub-frame members provided on the main frame, as in the conventional case. This simplifies the structure of the frame, simplifies manufacturing, reduces costs and reduces weight. I can do it.

According to a third aspect of the present invention, in the first aspect, a reinforcing member having a U-shaped cross section is disposed inside the sub-frame member, and the sub-frame member and the reinforcing member are joined.
Integrated. According to the third aspect of the present invention, since the sub-frame member and the reinforcing member are joined to each other, the structure becomes a closed-section structure, and high rigidity and strength can be obtained in a component mounting portion such as an engine mounting portion and a support portion. Since a U-shaped reinforcing member is fitted into the joints and joined by welding or the like, manufacture is easy.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings should be viewed in the direction of reference numerals. FIG. 1 is an external side view showing an example of a motorcycle employing a frame structure according to the present invention, and FIG. 2 is a plan view of FIG. The outline of the motorcycle will be described with reference to FIGS. 1 and 2. The motorcycle 1 is supported by a front fork 3 so as to be steerable by a front fork 3 via a head pipe 22 at a front end of a frame 21 which will be described in detail later. . A rear wheel 5 is supported via a swing arm 4 extending rearward from a lower portion of a middle portion of the frame 21, and a rear cushion unit 6, 6 for rear wheel suspension is provided between a rear portion of the swing arm 4 and the frame 21. Are interposed on the left and right.

A fuel tank 7 is installed on the front of the frame 21, an occupant seat 8 is installed on the rear of the frame 30, and an engine 9 is mounted on the frame 30 below the fuel tank 7. A drive sprocket 10a is arranged on one side of a transmission case 10 at a lower rear portion of the engine 9, and is connected to a driven sprocket 5a provided on the same side of the rear wheel 5 by a chain 10, thereby driving the rear wheel 5. I do. A headlight 12 is installed above the front of the front fork 3, and a bar-type handle 13 is installed immediately above the headlight 12 on the top bridge at the upper end of the front fork 3. Is provided with a meter unit 14.

Side cowls 15, 15 are disposed on the left and right below the front portion of the seat 7 to cover the side portions of this portion, and the side portions of the middle portion of the seat 7 in the front-rear direction to the rear portion are rear cowls. Cover with 16, 16 and rear cowl 16, 16
The rear fender 17 is installed at the rear of the vehicle so as to be inclined downward and rearward. The upper half of the front wheel 2 is the front fender 2
Cover with a. The seat 8 is a tandem type that is long in the front and rear directions. Rear grips 18 are provided on the left and right lower portions of the rear portion of the seat to hold rear passengers and to provide clues when the main stand of the motorcycle stands.
The rear grip 18 is substantially U-shaped in plan view as clearly shown in FIG. The carburetor 19 disposed behind the cylinder of the engine 9 is connected to an air cleaner (not shown) disposed in a space behind the side cover 15 hidden behind. In FIG. 2, reference numeral 20 denotes a muffler extending rearward on one side of the rear part of the motorcycle 1 and extending outward.

FIG. 3 is an external side view of the frame according to the present invention. The frame 21 has a length substantially the entire length of the motorcycle, a long front and rear main frame 30, and a front member 40 that is welded to both sides of a front end to a middle portion of the front end of the main frame 30 so as to tilt rearward and downward. And a middle member 50 hanging down to a middle portion of the main frame 30 so as to tilt slightly downward, and a rear member 70 arranged to connect a rear portion of the main frame 30 to a lower portion of the middle member 50.
Consists of Rear member 70 and front middle member 50
An air cleaner (not shown) is arranged in a substantially triangular space 23 formed by the main frame 30 and the upper frame. A head pipe 22 is provided at the front end of the main frame 30 so as to be slightly inclined forward and downward. The upper surface of the main frame 30 is formed so that the front part to the middle part is slightly curved downward, there is a difference in height between the middle part and the front and rear parts, and the rear part is one step higher, but the upper surface is substantially flat. Yes, it extends in the front-rear direction in a substantially horizontal state. At the rear of the mainframe 30,
A stay 81 for attaching and supporting the rear portion of the sheet 8 is provided so as to hang downward.

FIG. 4 is a plan view of FIG. As shown in the figure, the main frame 30 is formed such that the width W1 of the front portion 30a is narrow, the width W2 of the rear portion 30c is wide, and the middle portion 30 is formed.
The width of b increases rearward so as to integrally connect the spaces.

FIG. 5 is an exploded perspective view of the constituent members of the frame 21. The main frame 30 is composed of an upper member 31 having a downward concave cross section and a lower member 32 having a downward concave cross section, and has a vertically symmetric shape. Each front end is provided with an arc-shaped concave portion 31a (not shown in the lower member 32, but also provided with a concave portion) in which the upper rear half of the head pipe 22 fits. The upper member 31 and the lower member 32 are formed by, for example, pressing a steel plate material. Upper member 31, Lower member 32
Opposite ends of the left and right side walls 31b, 32b
Flange portions 31c, 32c bent outward and projected
Are provided integrally.

The upper surface 31d of the upper member 31 is substantially flat, and the mounting bosses 31e and 31f of the electrical component are integrally formed by pressing at the front middle part in the front-rear direction and the middle part in the width direction. Provided. Immediately after the rear mounting boss portion 31f of the upper surface 31d, an electric component mounting stay 33 having a concave cross section is welded, and the mounting stay 33 is erected and installed so as to cross the upper surface 31d as wide as possible.

The fuel tank 7 and the mounting stay 34 for the seat 8 are provided at the middle part in the width direction at the middle part in the front-rear direction of the upper surface 31d of the upper member 31. This mounting stay 34
Is formed by swelling the upper surface 31d upward and notching the rear portion, and screwing a mounting piece (not shown) provided on the rear lower surface of the fuel tank 7 through a mounting hole 34a. The tongue-shaped mounting piece (not shown) provided on the lower surface of the
b, and supports the front portion of the seat on the upper surface of the main frame 30. The mounting stay 34 is attached to the upper member 3
The upper member 31 is formed so as to swell from below by press working, so that a member separate from the constituent members of the main frame is not required, and the upper member 31 can be formed simultaneously in the step of forming the upper member 31. Therefore, the number of parts can be reduced, and there is no need to weld another part, so that it is easy to manufacture, and since there is no need to attach another part, the weight can be reduced. This is because the mounting boss portion 3
The same applies to 1e and 31f.

The side wall portions 31 of the upper and lower intermediate portions of the upper member 31 and the upper and lower symmetrical portions of the respective intermediate rear portions of the lower member 32 are formed.
b, 32b have flange portions 31c, 3 protruding on both sides.
2c, the upper member 31 side is downward and the lower member 32 side is upward symmetrically.
32g are provided integrally. When the upper member 31 and the lower member 32 are vertically overlapped and the flange portions 31c and 32c are abutted and overlapped and welded, the concave portions 31g and 32 are used.
g is a circle, between which the shaft-shaped cross member 3 for attaching and supporting the upper end of the cushion unit 6 at both ends is provided.
5 and welded together to integrate with the main frame 30.

At this time, the rear cowl mounting stay 36 having a concave shape as viewed from the front is disposed on the upper surface 31d, and the lower ends of the left and right side walls 36a of the mounting stay 36 are welded to the upper halves near both ends of the cross member 35. Are welded to this portion of the upper surface 31d of the upper member 31. still,
On the upper surface of this portion of the upper member 31, a mounting base that swells upward is formed integrally by press working, and front and rear protruding pieces 36b, 36b are welded to the upper surface of this portion.

At the rear of the upper surface 31d of the upper member 31, a plurality of concave ribs 37 having a length in the front-rear direction are formed by press working to increase rigidity. Also upper surface 31d
The rear part is provided with two rear grip mounting holes 39 at the front and one rear grip mounting hole 39 at the rear. On the other hand, on the side of the middle part of the lower member 32, there are provided mounting pieces 38 provided with mounting stays 38 for engine accessories in the front and rear.
a, welding at 38a.

As shown in FIG. 3, the front member 40 connects the rear half of the head tube 22, the front end of the front half of the main frame 30, and the upper edge. The front member 40 has a structure corresponding to the upper half of a so-called down tube, and includes left and right members 41, 41 each of which is formed by pressing a steel plate material and has a substantially "L" shape in a side view. The upper and lower portions of each of the left and right plate portions 41a are bent inward, and the entire cross section of each plate portion is concave. Each lower wall piece 41b of each plate-shaped portion 41a
Each has an inwardly projecting piece 41c, and each plate-like portion 41a
The upper edge portion is provided with an upper wall piece 41f which is bent inward from the surface and bent in a Z-shape. Each of the plate portions 41a has a symmetrically outwardly protruding circular portion 42 at the front end thereof, and each of the protruding circular portions 42 has a pipe-like mounting stay 43 for mounting the front portion of the fuel tank 7. Mounting hole 43 penetrating through
a.

A substantially triangular lightening window 44 is provided in the middle of each plate-like portion 41a, and an inwardly bent edge 44a is provided at the periphery of the window 44 to increase rigidity. Enhanced. Each plate-shaped portion 41a is provided with a lower extending portion 41d inclined backward and downward, and the cross-sectional shape of this portion is also a left-right symmetric concave shape,
The above-mentioned lower wall piece 41b extends to below this portion as it is. The rear edge 41e of the Z-shaped rear wall bent inwardly and rearwardly is provided at the rear edge of the plate-shaped portion 41a.
Are provided. At the lower portion of each lower extension portion 41d, mounting holes 45, 45 are provided, which are vertically separated from each other.
Cross members 46, 46 made of a pipe material are passed between d.

As shown in FIG. 3, the middle member 50 is provided so as to hang downward from an intermediate portion of the main frame 30. In the embodiment, it is described as a middle member from the relationship with other frame members.
The sub-frame member according to claim 1. A description will be given below as a middle member. Middle member 50
Consists of a main member 51 and a sub member 61,
These are obtained by pressing a steel plate material.

The main member 51 is concave (U-shaped) in plan view (cross-sectional view), has a large depth in the rear, is long vertically, and has left and right side walls 51b, 51b and a rear wall 51a. The upper portion of the rear wall portion 51a is cut out to form a forked portion 51c, 5.
1c. The forked portions 51c, 51c are formed slightly longer in the front-rear direction so as to increase the welding area.
Lower portions 51d, 51d of 1b, 51b swell forward in a substantially inverted L-shape so as to have a certain height vertically.
The main member 51 of the middle member 50 applies bifurcated portions 51c, 51c long from front to back from outside the side wall portions 32b on both sides of the lower member 32 of the main frame 30. Spot welding is performed on the side wall 32b. Thereby, as shown in FIG.
The main member 51 of the middle member 50 which is a sub-frame member is joined and integrated so as to be suspended from the lower member 32 of the main frame 30.

A reinforcing gusset 52 whose cross section is concave (U-shaped) is welded to the upper part of each lower part 51d of each side wall part 51b of the main member 51 so as to line the concave cross section. I do. At both sides of this portion, mounting holes 53 are formed through which a support tube 54 for rotatably supporting the pivot at the front end of the swing arm 4 is inserted. At the lower part 51d of each side wall part 51b of the main member 51, a mounting hole 55 for mounting the engine 9 is provided symmetrically at the upper part of the front part, and at the rear part of each lower part 51d,
Mounting holes 56 for mounting stand mounting cross members 57 are provided. The upper portions of the mounting holes 53 of the side wall portions 51b are respectively protruded forward, and mounting holes 58 for mounting the engine 9 are provided symmetrically on the left and right sides of the respective protruding portions 51e.

Further, at the front of the lower portion 51d of each side wall portion 51b, a forwardly projecting portion 51f is provided so as to integrally project forward, and a mounting hole 5 for engine mounting and support is provided in this portion.
5 are provided respectively. As a result, engine mounting holes 58 and 55 are formed above and below the lower half of each side wall 51b.

The sub-member 61 is concave (U-shaped) in cross section and has a length in the height direction between the forked portion 51c from above the mounting hole 53 of the main member 51 described above. The depth of the U-shaped cross section of the sub member 61 is smaller than the depth of the main member 51. The side wall portions 61b, 61b bent forward from both sides of the rear wall portion 61a have a small amount of protrusion from the rear wall portion 61a, and the upper portion 61c bends forward and bends to form a ceiling portion. 32
To the lower surface of the bottom surface 32d. In addition, an indentation 61d having an inverted concave shape is provided at the center in the width direction at the lower end of the rear wall 61a. The upper portion 61c is joined to the lower surface 32d of the lower member 32 by spot welding or the like. The above sub-member 61 is fitted and welded from the front of the main member 51.

A rear member 70 connects the rear part of the main frame 30 and the lower part of the middle member 50 as shown in FIG. The rear member 70 includes the main member 7
1 and a sub-member 74, which are obtained by pressing a steel plate material. The main member 71 has a “bow” shape in a side view, and the cross-sectional shape is a concave shape having a large depth, and a rear wall portion 71a,
At the middle of each side wall 71b, a mounting boss 72 of the left and right side cowl 15 is provided integrally, and a mounting hole 72a is provided in this portion. A mounting hole 72b is provided.

The lower part 71c of each side wall part 71b protruding forward of the main member 71 is provided with a bifurcated part 73 which is symmetrical in the left and right and opens forward. This forked part 73 is
The main member 51 of the middle member 50 is sandwiched between the projections on both sides of the support tube 54 of the middle member 50.
Is welded to the side wall 51b of this portion. Sub-member 74
Has a rear wall portion 74a and left and right side wall portions 74b bent forward from both side portions thereof, and has a concave cross-sectional shape.
The concave depth is smaller than that of the main member 71 and, as shown in FIG.
5 between the mounting bosses 72. Sub-member 7
4 is fitted between the side wall portions 71b between the mounting boss portions 72 of the side cowl 15 from above the forked portion 73 of the main member 71, and the side wall portions 71b and 74b are welded to integrate them. As a result, this portion of the rear member 70 has a closed cross-sectional structure, and has increased rigidity and strength.

Next, the joining structure of the main frame 30, the front member 40, the middle member 50, and the rear member 70 will be described with reference to FIGS. FIG. 6 is an enlarged sectional view taken along line 6-6 of FIG. The upper member 31 and the lower member 32 overlap the opposing flange portions 31c, 32c vertically, and are welded to a predetermined portion by, for example, spot welding or the like, and are integrally joined to form a hollow main frame 30 having a closed cross-sectional structure.
To form The weld is indicated by a. The left and right front members 40 are the plate-like portions 4 of the left and right members 41, 41.
The upper wall pieces 41f, 41f of the upper edge portions 1a, 41a are applied to the left and right side walls 32b, 32b of the lower member 32 of the main frame 30 from outside, and are joined by spot welding or the like.

A pipe-shaped mounting stay 43 penetrates between the mounting holes 42a provided in the bulging circular portions 42, 42, and the stay 43 and peripheral portions of the mounting holes 42a, 42a are formed by MIG welding or the like. It is joined and the mounting stay 43 is integrally installed. The weld location is indicated by b. Plate portions 41a, 41a
Is joined to the outer peripheral portion of the head pipe 22 by MIG welding or the like. Also, the lower wall portions 41b, 4 of the plate portions 41a, 41a
The ends of 1b were butted against each other, and a gusset 47 was applied to the lower surface thereof. The gusset 47 and the outer ends of the lower walls 41b, 41b were joined by MIG welding or the like, and the welded portion was indicated by c.
The front end of the gusset 47 is joined to the periphery of the lower rear half of the head pipe 22 by MIG welding or the like.

The flanges 31c, 31c protruding from both sides of the upper member 31,
The protrusions of the second flange portions 32c, 32c are made larger outward than the second flange portions 32c, and the respective tips are bent downward, so that the cross section of this portion is formed into a substantially inverted L-shaped bent portion 31h. This allows
The outer ends of the flange portions 32c, 32c of the lower member 32 at the lower portion are hidden, and the rigidity is increased by the bent portion 31h, and the entire main frame 30 including the upper member 31 and, therefore, the lower member 32 integrally joined therewith. rigidity,
Strength can be increased.

FIG. 7 is an enlarged sectional view taken along line 7-7 of FIG.
As described above, the upper member 31 and the lower member 32 are welded by the flange portions 31c, 32c, and the mounting stay 38 of the above-described engine accessory is joined to one of the side wall portions 32b of the lower member 32 by spot welding or the like. . The weld location is indicated by d. The mounting stays 38 are front and rear mounting pieces 38.
a, the upper mounting piece 38a is welded to one of the side wall portions 32b of the lower member 32, and a main body portion 38b hanging down below the lower member 32 is used for attaching auxiliary equipment. Is provided.

FIG. 8 is an enlarged sectional view taken along line 8-8 in FIG.
This portion is a mounting portion of a shaft-shaped cross member 35 which is a support member of the rear cushion unit. The width of this portion of the main frame 30 is wider than the front portion as described above, and this portion of the flange portion of the upper member 31 and the lower member 32 is symmetrically formed into arc-shaped concave portions 31g, 32g, and the concave portions 31g, 32g. Both ends of the cross member 35 are sandwiched between them, and MIG welding or the like is performed between the peripheral edge of the cross member 35 and the cross member 35, and a welded portion is indicated by e. As a result, the cross member 35 is erected so as to extend laterally between the upper member 31 and the lower member 32, and integrally interposed therebetween, so that the rigidity and strength of the main frame 30 can be increased. Both ends 35a, 35a of the cross member 35 have a small diameter, and the left and right rear cushion units 6, 6
The mounting boss 6a at the upper end of each is mounted and supported.

The lower part of the lower member 31 is joined to the rear part of the main member 71 of the rear member 70 from this part to the rear. Specifically, the rear wall 71 a of the rear part of the main member 71 is attached to the lower surface 31 of the lower member 31.
d with a slight gap below the main member 71.
Left and right side walls 71b, 71b overlap from the outside of the side walls 32b, 32b of the lower member 32, and the side walls 71b, 3b
2b are joined by spot welding or the like, and the rear part of the main member 71 of the rear member 70 is joined to the main frame 30,
Integrated. The welding location is indicated by f.

FIG. 9 is an enlarged sectional view taken along line 9-9 of FIG.
On the upper surface 31d of this portion of the upper member 31 of the main frame 30, the two left and right concave ribs 3 are provided as described above.
7, 37 are formed in the front-back direction. Lower member 3
2 on the left and right side walls 32b, 32b,
The above-mentioned sheet mounting stays 81, 81 are welded, and the mounting stays 81, 81 have a left-right divided structure and are obtained by pressing a steel plate material. The stays 81, 81 have a cross-sectional shape substantially similar to a Z-shape, and include left and right single bodies 81A, 81B.
The vertical length is different. The stays 81, 81
The upper portions 81a, 81a are connected to the left and right side wall portions 3 of the lower member 32.
2b and 32b were arranged on the rear outer side and joined by spot welding or the like, and the welding location was indicated by g.

FIG. 10 is an enlarged view as viewed from the direction of arrow 10 in FIG. The shape of the gusset 47 in a front view is as shown in FIG.
Mounting holes 42a, 4 of the bulging circular portions 42, 42
2a, the mounting stay 43 at the front of the fuel tank is penetrated to the left and right, and the joint is joined by MIG welding or the like, and the joint is indicated by b. Protrude. Also, the welding location at the rear end of the gusset 47 is c as described above.

Each lower wall piece 41 of the left and right members 41, 41
b, 41b, butts the opposing ends of the lower half thereof, and joins the butted portions by MIG welding or the like. H
Indicated by In this part, the front wheel 2 is located in front,
In the case of vertical movement caused by the cushioning movement, it was configured so as not to generate an overhang due to welding forward, and to secure a cushion stroke of the front wheels. Also, convex pieces 41c, 41c provided on the upper portions of the lower wall pieces 41b, 41b.
Is overlapped before and after, joined by spot welding or the like, and the welding location is indicated by i. Also in this method, the welded portion does not protrude forward, and the cushion stroke of the front wheel is secured in the same manner as described above.

FIG. 11 is an enlarged sectional view taken along line 11-11 of FIG. This portion shows the lower part of the front member 40, and the left and right members 4 which are the front side of the front member 40 are shown.
Actually, the lower wall pieces 41b, 41b of the first and the first 41 are overlapped with each other back and forth as shown in the drawing, and the overlapped outer edges are welded. Since the rear wall pieces 41e, 41e, which are rear portions, are flange-shaped, they are superimposed on the left and right and joined by spot welding or the like, and the joint is indicated by k. Also in this part,
The upper and lower two pipe-shaped cross members 46 penetrated to the left and right through the mounting holes, and the outer peripheral portion of the mounting holes and the cross member 46 were joined by MIG welding or the like, and the joints were indicated by j.

The cross members 46, 46 are connected with bolts 83 at the front of an engine front hanger 82 shown by chain lines in FIG.
To the front part of the crankcase, and attaches and supports the engine 9 to the front member 40. At this time, the front member 40 is a welded / joined structure having a concave cross-sectional shape of the left and right pressed plate materials, and has a closed cross-sectional structure as a whole. Can be done. The left and right members 41, 4
1 is butt-welded and welded through the cross members 46, 46, so the structure is simple and easy to manufacture.

FIG. 12 is an enlarged sectional view taken along line 12-12 of FIG. The main member 51 of the middle member 50 has a rear wall portion 51a, left and right side wall portions 51b, 51b, and is formed by pressing a steel plate material as described above, and has a deep depth as shown in the figure. A sub-member 61 is arranged inside the sub-member 61, and the sub-member 61 is similarly provided with a rear wall portion 61a, left and right side wall portions 61b,
61b and similarly formed by pressing steel plate material,
The depth is shallow. Sub-member 61 inside main member 51
And a space is provided in the front-rear direction between the rear wall portion 61a of the sub-member 61 and the main member 51a, and the side wall portions 61b, 51b overlapping left and right (inside and outside) are joined to each other by spot welding or the like. Indicated by m.

The middle member 50 has a closed sectional structure as described above. In addition, since the left and right portions are welded by fitting the concave (U-shaped) structure, high rigidity is obtained, and sufficient rigidity and strength are required as the rear hanger of the engine 9 and the support structure of the swing arm 4. Can be secured. The transmission case 10 at the rear of the engine 9 is located between the protrusions 51e formed on the side walls 51b of the main member 51 of the middle member 50 formed above.
The upper part 10b of the bolt, and insert the bolt 8 into the mounting holes 58, 58.
4, and attaches and supports this portion 10b of the transmission case 10. Although not shown in the drawing, the lower portion of the transmission case 10 is similarly sandwiched between the protruding portions 51f,
Similarly, it is attached and supported between the lower portions 51d of the side wall portions 51d, 51b by bolts.

FIG. 13 is an enlarged view as seen from the direction of arrow 13 in FIG. The right and left forked portions 73 of the main member 71 of the rear member 70 are inserted from the rear surface of the attachment portion of the support member 54 of the main member 51 of the middle member 50 so as to sandwich the support tube 54 between the forked portions. Upper and lower parts 73 of left and right forked parts 73
a, 73a are superimposed on the side wall portions 51b, 51b of this portion of the main member 51, and are welded by spot welding or the like, and the welding locations are indicated by n in FIG. Both ends 54a, 54a of the support tube 54 are forked portions 7 of the side walls 51d, 51d.
3 and 73, projecting outward from the swing arm 4
Is rotatably supported. Therefore, the support pipe 5 is provided around the middle member 50 for mounting the engine and the support portion.
The rigidity and strength of this part are also increased by the fact that 4 is suspended.

Further, a reinforcing gusset 52 having a concave cross section is applied to the rear wall portion 51a and the left and right side wall portions 51b and 51b of the main member 51 where the support tube 54 is installed, and welded by overlapping. The arm support was reinforced. Rear wall 71a of main member 71 of rear member 70
An extension piece 71d is provided at the lower end, and this is joined to the lower portion of the rear wall 51a of the main member 51 by spot welding or the like, and the welded portion is indicated by p. The lower member 51d of the main member 51 is provided with the cross member 57 for mounting the stand so as to penetrate left and right through the mounting hole 56. The lower member 51d and the cross member 57 are joined by MIG welding or the like. , The welding location is indicated by q. These support tube 54 and stand mounting cross member 57 are both laterally suspended between the lower part and the lower part of the main member, and the sub member 61 is not disposed in this part. Also functions as a reinforcing beam, increasing the rigidity and strength of the engine mounting and the periphery of the support.

FIG. 14 is an enlarged view as seen from the direction of arrow 14 in FIG. The left and right lower ends of the inverted concave notch 61d of the sub-member 61 of the middle member 50 abut against the upper surface of the support pipe 54 and are joined by MIG welding or the like, and the welded portion is indicated by r.

Although the embodiment has been described in detail, the welding technique is not limited to the spot welding and the MIG welding described above.
The frame can be joined using any welding technique such as seam welding or laser welding as the resistance welding, and is not limited to the welding technique of the embodiment. Although the frame component is described as pressing a steel plate material, the component member may be formed by pressing an aluminum plate material, and the material of the component member is weldable and rigid. As a condition, a pressed metal plate material that can be used can be used.

[0046]

According to the present invention, the following effects are exhibited by the above configuration. According to a first aspect of the present invention, a sub-frame member formed by pressing a metal plate having a U-shaped cross section is joined downward from the main frame extending rearward from the head pipe toward the lower side of the main frame, and the sub-frame member is hung down. Since the component mounting portion is integrally provided by press working, the component mounting portion is integrally provided on the sub-frame member, so that the component mounting portion can be manufactured as a separate member, or can be welded or screwed. There is no need for a separate member joining step. Therefore,
The number of components of the frame, especially the sub-frame members, can be reduced, and the man-hours for assembling and welding parts can be reduced.
Further, since no separate parts are required, the weight and cost of the frame can be reduced.

Since the sub-frame member has a U-shape in cross section, it can be welded to the lower half side of the main frame when welding or the like to the main frame. Also, the joint to the main frame can be arbitrarily set, and the joint area such as the welding area can be easily obtained. Therefore, the joining of the sub-frame member to the main frame having high rigidity and strength can be easily performed with a simple structure with good workability.

According to a second aspect of the present invention, the component mounting portion is an engine hanger portion in the first aspect. Therefore, in addition to the effect of the first aspect, a separate sub-frame member provided on the main frame as in the related art is provided. There is no need to weld upper and lower engine hangers or brackets as members. Therefore, simplification of the structure of the sub-frame, and hence the frame of the motorcycle, simplification of manufacture, cost reduction, and weight reduction can be achieved.

According to a third aspect, in the first aspect, a reinforcing member having a U-shaped cross section is disposed inside the sub-frame member, and the sub-frame member and the reinforcing member are joined and integrated. In addition to the effects of the first aspect, the joint between the sub-frame member and the reinforcing member has a closed-section structure, so that high rigidity and strength can be obtained in a component mounting portion such as an engine mounting and a support portion. Also, since the U-shaped reinforcing member can be fitted into the U-shaped sub-frame member and joined by welding or the like, the reinforcing member can be fitted into the sub-frame member, and the two can be joined by welding the overlapped portion. It is possible to obtain a sub-frame member having high rigidity and strength easily and inexpensively, which is easy to manufacture, requires a minimum number of frame components.

[Brief description of the drawings]

FIG. 1 is an external side view showing an example of a motorcycle employing a frame structure according to the present invention.

FIG. 2 is a plan view of FIG. 1;

FIG. 3 is an external side view of a frame according to the present invention.

FIG. 4 is a plan view of FIG. 3;

FIG. 5 is an exploded perspective view of a frame constituent member.

FIG. 6 is an enlarged sectional view taken along line 6-6 in FIG. 3;

FIG. 7 is an enlarged sectional view taken along line 7-7 of FIG. 3;

FIG. 8 is an enlarged sectional view taken along line 8-8 in FIG. 3;

FIG. 9 is an enlarged sectional view taken along line 9-9 of FIG. 3;

FIG. 10 is an enlarged view as viewed from a direction indicated by arrows 10 in FIG. 3;

FIG. 11 is an enlarged sectional view taken along line 11-11 of FIG. 3;

FIG. 12 is an enlarged sectional view taken along line 12-12 of FIG. 3;

FIG. 13 is a view as viewed from the direction of arrow 13 in FIG. 3;

14 is a view as seen from the direction of arrow 14 in FIG. 3;

[Explanation of symbols]

1 ... motorcycle, 9 ... engine, 22 ... head pipe, 30 ... main frame, 50 ... sub frame,
51e, 51f: a component mounting portion which is an engine hanger portion, 61: a reinforcing member.

Claims (3)

[Claims] 1. A sub-frame member formed by pressing a metal plate having a U-shape in cross section from a main frame extending rearward from a head pipe toward a lower portion of the main frame, and hanging down. The frame structure of a motorcycle, wherein a part mounting portion is integrally provided by press working. 2. The motorcycle frame structure according to claim 1, wherein said component mounting portion is an engine hanger portion. 3. The sub-frame member according to claim 1, wherein a reinforcing member having a U-shaped cross section is disposed inside the sub-frame member, and the sub-frame member and the reinforcing member are joined and integrated. Motorcycle frame structure.