JP2646356B2 - Motorcycle frame structure - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a frame structure of a vehicle body applied to a motorcycle.

(Background of the Invention) In a motorcycle, increasing the rigidity of a body frame is required to improve running performance. In order to obtain higher rigidity than before, a pair of left and right side members extending obliquely downward and rearward from the steering shaft barrel are formed of members having a channel-shaped cross section and having a wide width in the vertical direction. However, in this case, the wide side member covers the side of the engine and the lower part of the operation seat, so that the weight is easily increased. There is a problem that tools are difficult to enter and workability is very poor. Since the upper side of such a wide side member is usually covered with a fuel tank or an operation seat, there is a problem that heat of the engine is easily trapped between these two side frames.

(Object of the Invention) The present invention has been made in view of such circumstances,
It is an object of the present invention to provide a motorcycle frame structure that can reduce the weight of a vehicle body frame while increasing the rigidity thereof, and also can improve the maintainability around the engine and the cooling performance.

(Constitution of the Invention) According to the present invention, it is an object of the present invention to provide a motorcycle in which a fuel tank is disposed above a pair of left and right pipe side members extending obliquely downward and rearward from a steering axle supporting a front steering wheel. In the frame structure used for the above, the left and right side members have a structure in which an upper member, a lower member, and a plurality of connecting members connecting these members form a plurality of triangles in side view, while two upper and lower plates are overlapped. A member having a hollow plate shape and a flat shape, on which the electrical components can be attached, is rigidly attached to the left and right upper members while forming a gap between the left and right upper members immediately after the steering barrel. This is achieved by a motorcycle frame structure characterized by being connected.

(Embodiment) FIG. 1 is a side view showing the vicinity of a frame according to an embodiment of the present invention.
2 is a plan view, FIGS. 3, 4, and 5 are side views, a plan view, and a bottom view of side members of the frame. FIG. 6 is a plan view of a planar member connecting the side members. FIG. 8 is a side view and a sectional view taken along line VIII-VIII of FIG.
FIG. 10 is a side view of a motorcycle to which the embodiment is applied.

In FIG. 10, reference numeral 10 denotes a vehicle body frame according to the present invention, which will be described later. Reference numeral 12 denotes a water-cooled two-cycle single-cylinder engine mounted near the center of the vehicle body. The engine 12 includes a cover-type exhaust valve 14 rotatably provided at an exhaust port as shown in FIG. The exhaust gas is guided backward through the expansion pipe 16.

Reference numeral 18 denotes a front fork, which is rotatably held by the steering shaft barrel 100 of the frame 10. A steering front wheel 20 is attached to the lower end of the front fork 18, and a steering handlebar 22 is attached to the upper end.

Reference numeral 24 denotes a driving rear wheel, and a front end of the rear wheel 24 is a pivot shaft.
It is attached to the rear end of a rear arm 28 connected to 26. The rear arm 28 is supported by a cushion unit (not shown) disposed substantially vertically behind the pivot shaft 26 via links 30 and 32. 34 is a radiator for cooling the engine 12, 36 is a carburetor, 38 is a fuel tank, and 40 is an operation seat.

Next, the frame 10 will be described. The frame 10 includes a steering barrel 100, a pair of left and right side members 102, 102 extending diagonally downward and rearward from the steering barrel 100, and a planar member 104 rigidly connecting the two side members 102, 102 to each other. And a functioning cast air cleaner box 106.

The side member 102 is an upper member 1 made of a pipe having a round cross section.
08, a lower member 110, a connecting member 112 (112a, 112b, 112c) for connecting the upper and lower members 108, 110, and an end member 11 fixed to the rear ends of the upper and lower members 108, 110 and extending downward.
And 4. The connecting member 112 is welded so as to partition the upper and lower members 108 and 110 into a triangle when viewed from the side.
8, 110 and 112 have a substantially truss structure in which no force in the bending direction acts. The connecting members 112b and 11
2c is bent while pressing and deforming the middle of one pipe as shown in FIG. 11A, and this deformed bent portion is
(See FIGS. 1 and 3). This connection is 11B
As shown in FIG. 11 and FIG. 11C, both connecting members 112b, 112
c may be welded to each other and then to the lower member 110. The end member 114 is formed by superimposing a pair of sheet metal members in the middle, projecting a part of the member in a pipe shape, and press-welding the upper and lower members 108 and 110 from the rear ends. The left and right end members 114, 114 are suitable cross members 116, 118, 120
Are joined by 3 and 4, reference numeral 121a denotes a bracket for supporting the upper end of the cushion unit, and reference numeral 121b denotes a bracket for supporting the rear upper portion of the engine 12.

The planar member 104 has a hollow plate shape and a planar shape formed by superimposing two upper and lower plates in the middle, and an intake sub-chamber 122 is formed in the latter half thereof. The flat member 104 is fixed by screws to a bracket appropriately fixed to the upper member 108 of the side member 102. Here the planar member 104
Is rigidly coupled to the left and right upper members 108, 108 while forming a gap between the left and right upper members 108, 108 behind the steering barrel 100. The sub-intake chamber 122 is connected to the vaporizer 36 by a tube 124.
And has a function of suppressing the pressure fluctuation in the intake passage, smoothing the flow of the intake air, and improving the intake efficiency. Various members are attached to the planar member 104. That is, a servo motor 126 for controlling the rotation of the exhaust valve 14 by a wire is provided on the lower surface thereof, and a control unit 128 for controlling the servo motor 126, a rectifier / voltage regulator 130, and an ignition circuit unit are provided on the upper surface thereof. Electrical components such as 132 and a flasher relay unit 134 are attached (see FIGS. 1 and 2). These members 126 to 134 are assembled in advance to the planar member 104, and the planar member 104 is rigidly fixed to the side member 102 in this state. 6 to 8, reference numeral 136 denotes a mounting plate fixed to the upper surface of the planar member, and the control unit 128 and the rectifier / voltage regulator 130 are fixed to the planar member via the mounting plate 136.

As shown in FIGS. 1 and 2, the air cleaner box 106 has a substantially inverted trapezoidal box shape when viewed from the side.
The bracket 1 is fixed to brackets 132, 132 fixed to the bracket 102, and the rear lower corner portion is a bracket 1 protruding from the cross member 116.
Fixed to 34. The front portion of the air cleaner box 106 protrudes from between the left and right side members 102 toward the carburetor 36 and is connected to the carburetor 36 by a duct. As shown in FIG. 2, a window 136 is opened on the upper surface of the air cleaner box 106, and an element holder 138 is mounted through the window 136. A pedestal 140 is provided behind the window 136 in the air cleaner box 106.
A tongue-like member 142 for locking the bottom plate 40a of the seat 40 is riveted to the pedestal 140, and the rear end of the fuel tank 38 is attached to the upper surface of the pedestal 140 via a cushion rubber 144. I have. A rear frame 146 extending rearward is fixed to a rear portion of the air cleaner box 106, and the seat 40 and the tail cover 148 are attached to the rear frame 146. The tail cover 148 contains a lubricating oil tank and a battery.

In this embodiment, not only the various members 126 to 134 are held by using the planar member 104 connecting the left and right members 102, 102, but also the intake sub-chamber 122 is integrally formed. Lean arrangement is possible. In this embodiment, the air cleaner box 106 is made of cast aluminum or the like, and is used as a planar member for connecting the left and right side members 102, 102 by utilizing its high rigidity.

The side member 102 and the connecting member 112 are not limited to pipes having a round cross section, but preferably have a closed cross section.

(Effect of the Invention) As described above, since the frame has the side member divided into triangles by the connecting member, the side member has a structure close to a so-called truss structure, and is extremely resistant to a vertical load. Structure. In addition, since the front part of each side member is rigidly connected by a hollow plate-like planar member, the frame has a very strong torsional rigidity. As a result, the weight can be reduced without reducing the rigidity of the frame. On the other hand, the members on the one side are largely open to the sides between the members constituting the members, so that tools and hands are easy to enter, and maintainability around the engine is improved. Further, the traveling wind freely passes between the members, and a gap is formed between the peripheral edge of the planar member and the upper member, so that the traveling wind not only satisfactorily hits the lower surface of the planar member but also the peripheral edge thereof. Satisfactorily flows between the gap and the lower surface of the fuel tank. Therefore, the hot air of the engine is less likely to be trapped between the frames, and the cooling performance is improved.

[Brief description of the drawings]

1 is a side view of the vicinity of a frame according to an embodiment of the present invention, FIG. 2 is a plan view of the same, FIGS. 3, 4, and 5 are side views of a side member of the frame, a plan view and a bottom view, and FIG. The figure is a plan view of a planar member connecting the respective side members, FIGS. 7 and 8 are side views and a sectional view taken along the line VIII-VIII, and FIG.
FIG. 10 is a side view of a motorcycle to which this embodiment is applied, and FIGS. 11A to 11C are views showing an example of a fixing structure of a connecting member of a side member. 10 ... frame, 100 ... steering shaft cylinder, 102 ... side frame, 104 ... planar member 106 ... air cleaner box 108 ... upper member, 110 ... lower member, 112 ... connecting member, 128 ... Control unit, 130 ... Rectifier / voltage regulator, 132 ... Ignition circuit unit, 134 ... Flasher relay unit.

Claims (1)

(57) [Claims] 1. A frame structure used for a motorcycle having a fuel tank disposed above a pair of left and right side members made of pipes extending obliquely downward and rearward from a steering axle supporting a front steering wheel. The upper member, the lower member, and the plurality of connecting members connecting the members form a structure in which a plurality of triangles are formed in a side view. A motorcycle, wherein a member enabling electrical components to be attached thereto is rigidly connected to the left and right upper members while forming a gap between the left and right upper members immediately after the steering shaft barrel. Frame structure.