JP2795645B2 - Vehicle soundproofing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a soundproofing device applied to a motorcycle or the like having a fuel tank disposed so as to straddle a main tube extending obliquely downward and rearward from a steering shaft barrel. It is about.

BACKGROUND OF THE INVENTION In a vehicle such as a motorcycle, there is known a vehicle in which a fuel tank is mounted on a main tube extending obliquely downward and rearward from a steering axle, and an engine is mounted below the fuel tank. In this type of vehicle, the driver sits on the driving seat behind the fuel tank, so that the engine is located below between the driver's feet. For this reason, there is a problem that the noise of the engine becomes harsh to the driver and hinders comfortable driving.

In addition, the fuel tank is normally held at its front and rear portions by a vehicle body frame via rubber dampers to prevent the vibration of the vehicle body from being transmitted to the fuel tank. If the rubber damper is softened in order to prevent the transmission of the vibration, there arises a problem that the holding of the fuel tank becomes unstable.

Further, electrical components such as an ignition device need to be held on the vehicle body frame via an elastic material and protected from vibration.

(Object of the Invention) The present invention has been made in view of such circumstances,
The engine noise that is unpleasant to the driver can be reduced, driving can be made comfortable, the fuel tank can be stably held on the body frame while the vibration damping effect of the fuel tank is enhanced, and the protection of electrical components It is an object of the present invention to provide a soundproofing device for a vehicle that can also shake.

(Constitution of the Invention) According to the present invention, an object of the present invention is to provide a vehicle in which a fuel tank is disposed so as to straddle a main tube extending obliquely downward and rearward from a steering axle tube above an engine. And while holding the rear part to the vehicle body frame via a damper, an electric component is accommodated inside the inner bottom plate of the fuel tank, a sound absorbing material is attached to the lower surface of the inner bottom plate of the fuel tank, and the sound absorbing material is attached to the main tube. This is achieved by a soundproofing device for a vehicle, wherein an intermediate portion of the fuel tank is held by the main tube in close contact with an outer periphery, and the electrical component is supported in contact with the sound absorbing material.

(Embodiment) FIG. 1 is a side view of a motorcycle to which the present invention is applied, and FIG.
FIG. 3 is a plan view, FIG. 3 is a rear view, FIG.
5 is a side sectional view of the fuel tank, FIG. 6 is a sectional view taken along line VI-VI in FIG. 5, FIG. 7 is a front view showing a radiator arrangement, FIG. 8 is a side view of the fuel tank, FIG. Is a view on arrow IX.

These 10 are semi-double cradle type body frames, a steering shaft tube 12, a main tube 14 and a down tube 16 extending diagonally downward and rearward from the steering shaft tube 12,
A pair of left and right seat pillar tubes 18 (only one is shown) extending downward from the main tube 14 and a down tube 16
A pair of left and right bottom tubes 20 connecting the lower ends of the seat pillar tubes 18, a pair of left and right seat rails 22, a pair of left and right back tubes 24, and a tension pipe 26 connecting the down tube 16 and the main tube 14 (fourth to fourth). 7
Figure). A steering front wheel 29 is attached to a lower end of a front fork 28 rotatably held on the steering shaft barrel 12 left and right,
A steering handlebar 30 is attached to the upper end.
Reference numeral 32 denotes a driving rear wheel, which is attached to the frame 10 by a rear arm 34 so as to be vertically movable. As shown in FIG. 4, the rear arm 34 is provided with a downward return behavior by a cushion unit 40 via a lever 36 and a link 38.

Reference numeral 42 denotes a liquid-cooled two-stroke engine mounted on the bottom tube 20. As shown in FIG. 6, the engine 42 includes a substantially hollow exhaust control valve 44 for controlling the opening timing of the exhaust port based on the engine speed. Downstream of the carburetor 46 connected to the intake port side, a chamber 48 for absorbing intake pulsation and improving intake efficiency is connected. The output of the engine 42 is controlled by the chain 50
Conveyed to.

52 is a fuel tank. The fuel tank 52 is attached so as to straddle the main tube 14. That is, the fifth to ninth
As shown in the figure, the edges of an upwardly convex upper plate 54 and a similarly upwardly convex inner bottom plate 56 are welded to each other, and a fuel is accommodated in a space between the two plates 54 and 56, The main tube 14 passes back and forth on the lower surface, that is, inside, of the bottom plate 56. An annular rubber damper 60 is symmetrically attached to the main tube 14 via a bracket 58 shown in FIG.
U-shaped brackets 62, 62 that open forward
(See FIG. 9). This fuel tank 52
Engages the metal fittings 62, 62 with the damper 60 on the side of the main tube 14 from the rear and pushes forward, holding the tank 52 on the seat rail 22 via the tongue 64 at the rear end via a damper (not shown). By doing so, it is attached to frame 10.

In FIG. 1, reference numeral 66 denotes an operation seat, which is provided so as to extend on the seat rail 22 from the upper surface of the fuel tank 52.

In FIGS. 1, 5 and 7, 68 and 70 are radiators. These radiators 68, 70 are vertically arranged on the left and right sides of the down tube 16, and the right radiator 68 is shorter than the left radiator 70 (FIG. 7). Below this radiator 68 on the right side, an exhaust pipe 72 of the engine 42 is led in a loop from the front of the engine 42, and this exhaust pipe 72 extends to the rear to form a muffler 74 (first
3). The coolant of the engine 42 is guided to the radiators 68 and 70 by a branch pipe 76 (FIG. 7). In FIG. 7, reference numeral 78 denotes a tube connecting the upper chambers of the radiators 68 and 70.

On the outside of these radiators 68, 70, wind guide plates 80,
82 (Figs. 1 and 2) is installed. That is, these air guide plates 80, 82 have their rear edges smoothly connected to the outer surface of the fuel tank 52, and project forward to cover the outer edges of the radiators 68, 70. As a result, a space substantially triangular in side view is formed above the engine 42 by the inner bottom plate 56 of the fuel tank 52, the radiators 68, 70, and the air guide plates 80, 82.

Various parts are accommodated in this substantially triangular space as shown in FIGS. 5 and 6, while the inner bottom plate 56 is provided with sound absorbing materials 84 and 86 such as sponge-like urethane foam and wool. . These sound absorbing members 84 and 86 are separately adhered to the left and right side walls of the inner bottom plate 56 to improve the assemblability. This sound absorbing material 8
4, 86 are pressed by the main tube 14 as shown in FIG. 6 with the fuel tank mounted, and have a function of stably holding the fuel tank 52 while preventing vibration. The components housed here are, for example, an ignition coil 88, a CDI unit 90, a servomotor 92, a wire cylinder 94, and the like. These are attached to the main tube 14, the tension tube 26, and the like by appropriate brackets. The servomotor 92 drives the exhaust control valve 44 (FIG. 6) of the engine 42 via a wire 96. For example, during low-speed operation, the opening timing of the exhaust port is delayed to prevent scavenging blow-through. During high-speed operation, the opening timing is advanced to increase the scavenging efficiency. The wire cylinder 94 has a function of dividing the operation of the throttle lever into two systems and separately operating the carburetor 46 and a metering pump (not shown) for controlling the amount of lubricating oil. Parts contained in this space are sound absorbing material
It is also possible to make it vibrate at the same time by contacting 84,86. Sound absorbing material 8 to stabilize and contact parts
Appropriate locations of 4, 86 may be thinned (see FIG. 9a, 86a) or portions may be cut out.

In this embodiment, a part that emits a part that emits a sound such as the servomotor 92 is stored inside the inner bottom plate 56 of the fuel tank 52,
The sound absorbing members 84 and 96 absorb this sound, so that the driver does not hear the sound. When components are stored inside the inner bottom plate 56, traveling wind may enter the inner bottom plate 56 and generate wind noise when passing between the components. However, since the sound absorbing members 84 and 86 attached to the inner bottom plate 56 absorb the wind noise, the driver does not feel harsh.

(Effect of the Invention) As described above, since the sound absorbing material is attached to the inner bottom plate of the fuel tank located above the engine as described above, the engine sound, particularly the engine sound that enters the inner bottom plate, can be absorbed.
The noise entering the driver's ear can be reduced. Therefore, comfortable driving becomes possible.

Also, while the fuel tank holds its front and rear parts to the body frame with rubber dampers, while holding the middle part of the inner bottom plate with the sound absorbing material in close contact with the outer periphery of the main tube,
It is possible to stably hold the fuel tank while preventing vibration of the fuel tank. Further, since the electric component is disposed inside the inner bottom plate in contact with the sound absorbing material, it is possible to simultaneously prevent vibration of the electric component.

[Brief description of the drawings]

1 is a side view of a motorcycle to which the present invention is applied, FIG. 2 is a plan view, FIG. 3 is a rear view, FIG. 4 is a side view of a main part, FIG. 5 is a side sectional view of a fuel tank, FIG. 6 is a view similar to FIG.
VI-VI sectional view, FIG. 7 is a front view showing the radiator arrangement,
FIG. 8 is a side view of the fuel tank, and FIG. 14 ... Main tube, 42 ... Engine, 52 ... Fuel tank, 56 ... Inner bottom plate, 60 ... Rubber damper, 84,86 ... Sound absorbing material, 90 ... CDI unit as electrical equipment.

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Claims (1)

(57) [Claims] 1. A vehicle having a fuel tank disposed so as to straddle a main tube extending obliquely downward and rearward from a steering axle tube above an engine, wherein a front portion and a rear portion of the fuel tank are connected to a body frame via a damper. On the other hand, the electrical equipment is accommodated inside the inner bottom plate of the fuel tank, a sound absorbing material is attached to the lower surface of the inner bottom plate of the fuel tank, and the sound absorbing material is brought into close contact with the outer periphery of the main tube so that the fuel tank is closed. A soundproofing device for a vehicle, wherein an intermediate portion is held by the main tube, and the electrical component is supported in contact with the sound absorbing material.