JPH0547432B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to a saddle type vehicle such as a four-wheeled vehicle for traveling on rough terrain.

b. Conventional Example In this type of straddle-type vehicle, since the wheelbase is relatively short, there are many problems in processing the muffler that should be disposed at the rear end of the exhaust pipe.
In other words, if a long muffler is attached to the rear end of a predetermined length of exhaust pipe in order to obtain a sufficient noise reduction effect, the rear end will protrude rearward from the rear wheels due to the short wheelbase of the vehicle. This causes the inconvenience that the muffler cannot be completely housed inside the vehicle.

If the rear end of the muffler protrudes from the rear of the vehicle in this manner, it not only impairs the overall design of the vehicle, but also is unfavorable from the viewpoint of driving safety.

On the other hand, if the exhaust pipe is bent sharply and routed, it is possible to completely fit the exhaust pipe of sufficient length into the vehicle, but in this case, exhaust resistance (resistance to the flow of exhaust gas) becomes larger. In addition, the exhaust pulsation effect unique to 2-cycle engines (that is, the effect of using exhaust pulsation to return exhaust gas that is about to blow through the exhaust port into the cylinder before the exhaust stroke ends)
can't get enough of it.

c. Purpose of the Invention The present invention was invented in view of the above-mentioned circumstances, and its purpose is to reduce exhaust resistance and achieve sufficient exhaust pulsation by devising the routing shape of the exhaust pipe. Furthermore, by devising the location of the expansion chamber formed in the middle of the exhaust pipe, the length of the exhaust pipe can be freely adjusted and its routing can be freely performed. Therefore, it is an object of the present invention to provide a straddle-type vehicle in which even if a long muffler is used, the muffler can be completely housed inside the vehicle.

d Structure of the Invention The present invention is characterized by a steering head that has two front wheels and two rear wheels equipped with balloon tires on each of the front left and right sides and rear left and right sides of the frame, and that rotatably supports the steering shaft with respect to the frame. A seat is placed vertically in the approximate center of the frame from the rear of the frame toward the rear of the frame, and the front two wheels are connected via a bar handle provided at the upper end of the steering shaft and an arm on the front wheel side that is linked to the lower end of the steering shaft. In a straddle-type vehicle that is steered, bar steps are placed on the left and right sides of the frame below the seat between the front and rear wheels, and the engine mounted between the front and rear wheels drives the wheels and travels on rough terrain, the exhaust port of the engine is installed. The exhaust pipe connected to the exhaust pipe extends downward from the exhaust port toward the front, is bent gently upward from near the lower frame into an almost U-shape, and is folded back near the upper frame. Furthermore, the exhaust pipe has a shape that extends rearward along the upper frame, and a muffler is attached to the rear end of the exhaust pipe near the rear wheel, and a part of the expansion chamber formed in the middle part of the exhaust pipe is This is because the reinforcing frame section is disposed on the front side of the reinforcing frame section which is arranged in an inclined manner between the front frame section and the lower frame section of the frame.

e Embodiment FIG. 1 shows a straddle-type four-wheel vehicle 1 to which the present invention is applied. This straddle-type four-wheel vehicle 1 is equipped with balloon tires on the front left and right sides and the rear left and right sides of a body frame 2. Each has two front wheels 3 and two rear wheels 4 equipped with
Steering shaft 5 relative to body frame 2
A seat 8 is placed vertically in the approximate center of the vehicle body frame 2 from the rear of the steering head portion that rotatably supports the steering head toward the rear of the frame, and a bar handle 6 provided at the upper end of the steering shaft 5 is attached to the lower end of the steering shaft 5. The front two wheels are steered via an arm (not shown) on the front wheel 3 side that is linked to the front wheel 3, and bar steps (not shown) are arranged between the front and rear wheels 3 and 4 on the left and right sides of the frame below the seat 8. This is a type of vehicle that drives the wheels with a two-stroke engine 16 mounted between the front and rear wheels and travels on rough terrain. In addition, in FIG. 1, 7 is a fuel tank.

The vehicle body frame 2 described above is composed of an upper frame section 10, a front frame section 11, a lower frame section 12, a rear frame section 13, and a plurality of reinforcing frame sections 14a, 14b, 14c, 14d. And Atsupah Frame 1
0, an engine 16 is mounted in an area surrounded by the lower frame part 12 and a pair of reinforcing frame parts 14a and 14b, and the intake port 16a of this engine 16 is located at the rear, and the exhaust port 16b
is placed in front. Further, a carburetor 17 is connected to the intake port 16a of the engine 16,
This carburetor 17 has an air cleaner 18
is installed.

On the other hand, one end 19a of an exhaust pipe 19 is connected to the exhaust port 16b of the engine 16. As shown in FIG. 1, an expansion chamber 20 is formed in the middle of the exhaust pipe 19, and one end 19a of the exhaust pipe 19 and a part of the expansion chamber 20 are connected to the engine 16.
It is arranged in front of the camera and has a shape that is bent at the front side and folded back to the rear side.

That is, one end 1 of the exhaust pipe 19
9a extends toward the front side of the engine 16, and the front part 20a of the expansion chamber 20 connected thereto is bent into a substantially U-shape, and the other part 2 of the expansion chamber 20
0b and the other end 19b of the exhaust pipe 19 connected thereto extend above the engine 16 from the front side to the rear side. A muffler 21 is provided at the other end 19b of the exhaust pipe 19.

In this embodiment, the front frame portion 11 and rear frame portion 13 of the vehicle body frame 2 are
A front portion 20a of the expansion chamber 20 is disposed in a space (dead space) A surrounded by a reinforcing frame portion 14a arranged in an inclined manner between the two. Note that more than 30% of the total length of the exhaust pipe 19 is arranged within the space A.

According to the straddle-type four-wheel vehicle 1 configured in this way,
Since the exhaust pipe 19 is bent largely and gently in front of the engine 16, there is little exhaust resistance and a sufficient exhaust pulsation effect can be obtained. Furthermore, since a part (front part 20a) of the expansion chamber 20 formed in the exhaust pipe 19 is arranged in the space A where no member is arranged as a so-called dead space in the past, the space inside the vehicle body frame 2 is saved. Not only can it be used effectively, but even when a relatively long exhaust pipe 19 is used, it can be routed freely and the entire exhaust pipe can be housed inside the vehicle. As a result, even when using a long muffler 21, the muffler can be prevented from protruding to the rear of the rear wheel 4 by making use of the space A and devising the routing of the pipe 19, which improves driving safety and design. advantageous in terms of sex.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment, and various modifications and changes can be made based on the technical idea of the present invention.

f. Effects of the Invention As described above, the present invention bends the exhaust pipe largely and gently so that a part of the expansion chamber of the exhaust pipe is arranged in an inclined manner between the front frame part and the lower frame part of the frame. Since the reinforcing frame is placed forward of the reinforcing frame, the exhaust resistance is low and a sufficient exhaust pulsation effect can be obtained, and the dead space in front of the reinforcing frame can be effectively used. It becomes possible to freely route the pipe and adjust its length. Therefore, even a relatively long exhaust pipe can be completely housed in the vehicle, and even if a relatively long muffler is used, problems such as the muffler protruding behind the rear wheels can be avoided.

[Brief explanation of the drawing]

FIG. 1 is a side view showing the configuration of a straddle-type four-wheel vehicle to which the present invention is applied. 1...Saddle type vehicle, 2...Vehicle body frame, 10
...Upper frame part, 11...Front frame part, 12...Lower frame part, 13...Rear frame part, 14a-14d...Reinforcement frame part, 16...Engine, 16a...Intake port, 1
6b...exhaust port, 19...exhaust pipe,
19a...one end, 19b...other end, 20...
Expansion chamber (chamber), 20a...front part, 20b
...Rear section, 21...Muffler.

Claims (1)

[Claims] 1 The front left and right sides of the frame and the rear left and right sides each have two front wheels and two rear wheels equipped with balloon tires.
A seat is placed vertically in the approximate center of the frame from the rear of the steering head, which rotatably supports the steering shaft to the frame, toward the rear of the frame. The front two wheels are steered via an arm on the front wheel side that is linked to the front wheel, and bar steps are placed between the front and rear wheels on the left and right sides of the frame below the seat, and an engine mounted between the front and rear wheels drives the wheels. In a straddle-type vehicle that travels on level ground, an exhaust pipe connected to the exhaust port of the engine extends downward from the exhaust port toward the front, and extends upward from near the lower frame into a substantially U-shape. The exhaust pipe is bent gently and turned back near the upper frame, and is further extended rearward along the upper frame, and a muffler is attached to the rear end of the exhaust pipe near the rear wheel. A part of the expansion chamber formed in the middle part of the exhaust pipe is placed forward of the reinforcing frame part which is arranged in an inclined manner between the front frame part and the lower frame part of the frame. A straddle-type vehicle with special features.