JPS59143722A - Motorcycle - Google Patents

Abstract

PURPOSE:To accommodate an exhaust pipe compactly within a limited space by connecting, in front of a crank case, the exhaust pipe to an expansion chamber of a silencer in a detachable manner. CONSTITUTION:Since exhaust pipes 14 and 15 and a silencer 21 are connected together in front of a crank case 18, the space of this connection part can be opened widely both forward and sideward. As a result, the exhaust pipes 14 and 15 and the silencer 21 can be attached and detached easily, enhancing work efficiency. Looped parts 16 and 17 of the exhaust pipes 14 and 15 are located between both right and left down tubes 4 and 4, while they are bent within a plane nearly parallel to the front surface of an engine 13. With this contrivance, despite their elongated length, the exhaust pipes 14 and 15 can be accommodated compactly within a limited space without jutting out sideward from the frame of motorcyle.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a motorcycle in which an expansion chamber of a muffler is disposed below a crankcase.

For motorcycles, as shown in Japanese Utility Model Application Publication No. 52-86149 or Japanese Patent Application Publication No. 56-149273, the expansion chamber of the silencer connected to the exhaust pipe is placed below the crankcase, and the bank angle is There are known devices that allow a large amount of .

By the way, if the expansion chamber is disposed below the crankcase, the length of the exhaust pipe will be short, which may have a negative effect on the output characteristics, especially at low speeds. For this reason, in cases where the exhaust pipe and the muffler are constructed separately, as in the above-mentioned Japanese Utility Model Publication No. 52-86149, in order to secure as much pipe length as possible, the exhaust pipe is connected to the muffler below the crankcase. It was connected. However, with this structure, the connecting part between the exhaust pipe and the muffler is located at the bottom of the crankcase, which requires more time and effort to attach and detach the two parts, resulting in reduced functionality. There is.

The present invention was developed based on these circumstances.
The exhaust pipe and muffler can be easily attached and detached, and the length of the exhaust pipe can be kept to a certain length, and the exhaust pipe does not stick out to the side as a whole, so it can be compactly stored in a limited space. The aim is to provide motorcycles that can

That is, in order to achieve the above object, the present invention has an exhaust pipe formed in a loop shape between a pair of left and right downcheaves located in front of the engine, and in a plane substantially parallel to the front surface of the engine. The downstream end of the loop portion is routed downward and is removably connected to the expansion chamber of the muffler in front of the engine crankcase.

The present invention will be explained below based on an embodiment shown in the drawings.

1 in the figure is a frame as a vehicle body, and this frame 1
A pair of left and right tank rails 3.3 extending rearward and a pair of left and right down tubes 4.4 extending downward are connected to the steering head/main tube 2 at the front end. A front fork 7 is rotatably supported on the steering head knob 2, and the front fork 7 pivotally supports a front wheel 8 at its lower end.

The tank rails 3, 3 are bent 1m downward from the middle,
The rear arm 9 is attached to the bracket 5.5 provided at the lower end.
The end of the Ail is swingably supported. The rear arm 9 pivotally supports a rear wheel 10 at its rear end. In addition, the code|symbol 11 shows a fuel tank, and 12 shows a notebook.

On the other hand, in the part surrounded by the tank rails 3, 3 and down tube 4.4 of the upper Ne"y seam 1, a 4-stroke single-cylinder ennon 13 is mounted with a son, and each exhaust hole has an exhaust pipe. 14 and 15 are connected to each other.These exhaust pipes 14 and 15 are connected to the down tube 4 as shown in FIG.
The upper end of the down tube is within the width of the down tube 4.4 and is approximately parallel to the front of the Quen J713. It falls in a plane and is curved into a loop shape. And each exhaust pipe 14゜J soroof part ie, J7
The downstream ends of the down tubes 4.4 and 4 are led downward along the down tube 4.4 VC, and the lower end portions of the down tubes are brought together in front of the crankcase 18. A muffler 21 is removably connected to this collecting portion 19 via a cranometer fitting 20.

The muffler 21 has a substantially cylindrical shape and is disposed below the crankcase 18 along the longitudinal direction of the vehicle body, with its front end raised up along the front surface of the crankcase 18. Therefore, the exhaust pipe is 14°15
A connecting portion between the silencer 2 and the silencer 2 is located at the front of the crankcase 18.

This muffler 21 is formed to have a larger diameter as it goes rearward, and the inside of this large diameter portion 22 forms an expansion chamber 22a of a predetermined capacity, and a plurality of partition walls VC are provided on the downstream side of this expansion chamber 22a. A series of partitioned silencing rooms are formed. And this silencer 21 is exactly the front wheel 8 and rear wheel 10.
Down tube 4.4r, which is inserted into the lower side of the crankcase 18 between! The large diameter portion 22 is supported by the down cheek 4.4 via the bracket 24.24f. Further, the rear end portion of the muffler 21 is located immediately in front of the rear wheel 10, and an exhaust outlet 25 that opens toward the side of the vehicle body is formed at this rear end portion. Therefore, the entire silencer 2 and the exhaust outlet 25 are housed inside the vehicle body width.

According to such a configuration, the exhaust pipe 14.15 and the silencer 2
1 is connected to the front of the crankcase 18, this connection part is widely opened to the front and sides of the engine 13, so that the exhaust pipe 14, 15 and the muffler 21 can be easily separated from each other. Improves work efficiency. Furthermore, if the exhaust pipe 14.15 and the muffler 21 are connected in front of the crankcase 18 in this way, the length of the exhaust pipe 14.15 is conversely reduced. After being led out from the engine 13, it is bent into a loop in front of the engine 13, and the downstream ends of these loop portions 16 and 17 are guided downward, so that the length of the exhaust pipe 14 and 15 is the same as that of the silencer 2.
It can be secured sufficiently until it is connected with 1. Therefore, exhaust pulsation can be used effectively and engine characteristics are not adversely affected. Moreover, in this case, exhaust pipe 1
Since the loop portions 16 and 17 of 4.15 are bent between the left and right down tubes 4.4 and in a plane approximately parallel to the front surface of the engine 13, the lengths of the exhaust pipes 14 and 15 have increased. Nevertheless, these exhaust pipes 14, 15 do not protrude to the sides of the vehicle body, and can be compactly accommodated within a limited space.

In this embodiment, the entire silencer 2 is installed in the crankcase 1.
8, between the front wheel 8 and the rear wheel 10, the silencer 2 fits inside the width of the vehicle body, and does not protrude to the side of the vehicle body or rear wheel 10 as in the conventional case. It's over. therefore,
Even if the motorcycle falls over, it is less likely to cause damage, and since the muffler 21 does not extend, the width of the motorcycle is narrow, which contributes to reducing wind resistance while driving.

Note that the present invention is not limited to the above embodiments.

For example, the engine is not limited to a single cylinder engine, but may be a multi-cylinder engine, or may be a two-stroke engine.

Also, the silencer does not have to be located entirely below the crankcase; it is sufficient that the expansion chamber is located below the crankcase, and the silencer chamber connected downstream of this expansion chamber is led out to the side of the rear wheel. You may let them.

According to the present invention described in detail above, the exhaust pipe is bent into a loop shape between a pair of left and right down tubes and in a plane substantially parallel to the front surface of the ennon, and the downstream end of this loop portion is bent downward. In addition, since it is removably connected to the expansion chamber of the silencer at the front of the crankcase, it is easy to attach and detach the silencer from the exhaust pipe and trachea, which improves workability and reduces the length of the exhaust pipe. It can be secured sufficiently at the front of the engine, and there is no negative effect on the engine characteristics.Also, even though the overall length of the exhaust pipe has been increased, the exhaust pipe does not bulge out to the side of the vehicle body, so it is limited. The advantage is that it can be accommodated in a compact space.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, the first being a side view and the second being a side view.
The figure is a perspective view, and FIG. 3 is a bottom view. 1-...Vehicle body (frame), 2...Steering head pipe, 4...Down tube, 8...Front wheel, 1
0... Rear wheel, 13... Engine, 14.15... Exhaust pipe, 16.17... Loop part, 18... Crank case, 21... Silencer, 22a... Expansion chamber.

Claims (1)

[Claims] Place the exhaust pipe led forward from the engine between a pair of left and right down tubes extending downward from the steering head pipe, and connect this exhaust pipe between the down tubes and approximately parallel to the front of the engine. is curved into a loop shape in a plane, and the downstream end of this loop portion is routed downward, and the expansion chamber of the muffler connected to the exhaust pipe is arranged below the crankcase of the engine,
What about these exhaust pipes and silencer expansion chambers? A motorcycle characterized by a detachable connection at the front of the crankcase.