JPH11152074A - Motorcycle mounted with unit-swing type engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motorcycle mounted with a unit-swing type engine, which uses its dead space efficiently and facilitates the layout of the engine intake/exhaust systems. SOLUTION: A unit-swing type engine 15 integrally includes an engine body 17, a transmission case 18 extending backward from one side of the engine body 17, and a magnet case 39 formed on the other side of the engine body 17. To this engine body 17 are connected an engine intake system 42, an exhaust pipe 48 and a muffler 49. The engine intake system 42 is arranged in the space defined by the lower portion of a fuel tank 5 and the front portion of the unit- swing type engine 15. The exhaust pipe 48 is extended from the lower portion of the engine body 17 back to the magnets case 39 along the underside of the engine body 17, where it is directed around the rear external wall of the magnet case 39 to above the engine body 17 and then connected to the muffler 49.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a motorcycle equipped with a unit swing type engine.

[0002]

2. Description of the Related Art A fuel tank is disposed between a handlebar and a driver's seat, and an engine is disposed below the fuel tank.
There is also a sports-type motorcycle equipped with an engine intake system such as an air cleaner and a carburetor in a space below and in front of a driving seat.

On the other hand, a unit swing type engine having a step floor between a handlebar and an operation seat, and integrally including an engine body below the operation seat and a conduction case extending rearward from one side of the engine body. There is also a scooter-type motorcycle equipped with.

Recently, motorcycles have been developed in which a fuel tank is disposed between a handlebar and an operation seat, and a unit swing type engine is mounted below the operation seat.

[0005] In a four-cycle engine, a small amount of gas with pressure generated in the combustion chamber, ie, blow-by gas, leaks into the engine case through the gap between the piston and the cylinder. Therefore, the engine is provided with a breather device which is a mechanism for returning the blow-by gas to the intake system, sending the blow-by gas again to the combustion chamber, and recombusting the blow-by gas.

[0006] In many 4-cycle engines, a breather chamber is provided in a cylinder head of the engine, and a breather hose connected to an air cleaner is connected to the breather chamber to constitute a breather device.

[0007]

However, in the case of a motorcycle equipped with a unit swing type engine, the height of the driver's seat is reduced in order to improve the rider's feet, but the minimum ground clearance of the engine is reduced. If it is attempted to secure a sufficient space, the space between the driving seat and the engine becomes very narrow, and it becomes difficult to arrange engine intake system equipment and exhaust system equipment. In particular, since the engine intake / exhaust system swings with the engine, the layout conditions of each device are severe.

[0008] Further, if an engine intake system device is arranged between the driving seat and the engine, the stroke amount of the rear shock absorber cannot be sufficiently secured, and the riding comfort deteriorates.

Further, since the distance between the intake system equipment and the cylinder head of the engine is large, the breather hose becomes long, and its fixing to the piping and the vehicle body becomes complicated.

On the other hand, when the unit swing type engine is arranged below the operation seat while the fuel tank is arranged between the handlebar and the operation seat, a large dead space occurs below the fuel tank.

The present invention has been made in view of the above circumstances, and has as its object to provide a motorcycle equipped with a unit swing type engine that makes effective use of dead space and facilitates layout of an engine intake / exhaust system. And

[0012]

According to a first aspect of the present invention, there is provided a motorcycle equipped with a unit swing type engine, which is provided between a handlebar and a driving seat. While placing the fuel tank,
In a motorcycle having a unit swing type engine swingably mounted below the driving seat, the unit swing type engine includes an engine body, a conductive case extending rearward from one side of the engine body, and another side of the engine body. An engine intake system, an exhaust pipe and a muffler are connected to the engine body while being surrounded by a lower part of the fuel tank and a front part of the unit swing type engine. While disposing the engine intake system in the space formed, extending the exhaust pipe from the lower part of the engine body to the rear of the magneto case side from the lower part of the engine body, and further extending the exhaust pipe to the rear part of the outer wall of the magneto case. It turns around and extends toward the top of the engine body and is connected to the muffler

In order to solve the above-mentioned problem, a breather chamber is provided in the engine body at the forefront of the unit swing type engine, and the breather chamber and the engine intake system are provided. And a breather hose.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a left side view showing an example of a first embodiment of a motorcycle to which the present invention is applied.

As shown in FIG. 1, the motorcycle 1 has a body frame 2. The body frame 2 is composed of a tank rail 3 and a seat rail 4. The tank rail 3 extends from the front of the vehicle body to the rear obliquely downward, and from the rear end the seat rail 4 extends obliquely upward toward the rear part of the vehicle body. The vehicle body frame 2 extends to form a substantially V-shaped side surface.

A fuel tank 5 is provided above the tank rail 3, and an operation seat 6 is provided behind the fuel tank 5 and above the seat rail 4. Further, a pair of left and right center frames 7 extend downward from the lower rear end of the tank rail 3, and a footrest 8 is provided at a lower end of the center frame 7.

On the other hand, a head pipe 9 is provided at the front end of the tank rail 3, and a steering mechanism 10 is provided on the head pipe 9. The steering mechanism 10 includes a front fork 12 that rotatably and elastically supports the front wheel 11, a handlebar 13, and the like. The handlebar 13 steers the front wheel 11 to be able to rotate left and right.

A pivot shaft 14 is installed between the left and right center frames 7 in the vehicle width direction, and the front upper portion of the unit swing type engine 15 is suspended on the pivot shaft 14 by a suspension stay 1.
6 is pivotally connected via a swing.

The unit swing type engine 15 has four
An engine body 17 of a cycle air-cooled single cylinder and a conduction case 18 extending rearward from one side of the engine body 17 are integrally provided. The transmission case 18 also serves as a swing arm, and is elastically supported by the body frame 2 by a rear shock absorber 19. And the conduction case 18
A rear wheel 20, which is a driving wheel, is held at the rear end of the vehicle. The lower front part of the unit swing type engine 15 is covered and protected by the underguard 21.

FIG. 2 is an enlarged left side view of the unit swing type engine 15, and FIG. 3 is a sectional view taken along line III-III of FIG. 2, that is, a plan sectional view of the unit swing type engine 15.

As shown in FIGS. 2 and 3, the engine body 17 is mainly composed of an engine case 22, a cylinder block 2 and the like.
3 and a cylinder head 24. The reciprocating motion of a piston 25 in the cylinder block 23 is
6, the crankshaft 27 extending in the vehicle width direction in the engine case 22 is rotated.

A transmission case 18 extending rearward from one side of the engine body 17, in this embodiment, from the left side, forms a belt chamber 28 therein, and a V-belt type automatic transmission 29 is disposed in the belt chamber 28. .

The transmission case 18 of the crankshaft 27
The drive pulley 30 of the V-belt type automatic transmission 29 is attached to the side, the left side in this embodiment, and the end. A driven shaft 31 provided at the rear of the unit swing type engine 15 has a driven pulley 3.
2 is rotatably supported, and the driven pulley 3
2, the driving force of the engine body 17 is transmitted from the drive pulley 30 via the V-belt 33.

The rotational driving force of the engine body 17 transmitted to the driven pulley 32 is transmitted to the driven shaft 31 via the centrifugal clutch mechanism 34. The driven shaft 31 is connected to a rear axle 36 via a transmission mechanism 35 which is a reduction gear mechanism and a power transmission device, and the driving force of the engine body 17 is transmitted to the rear wheels 20 via the transmission mechanism 35. ing.

On the other hand, a magneto device 37 is provided at the right end of the crankshaft 27 in the present embodiment.
The magneto device 37 includes a fan 3 for cooling the engine.
8 is provided integrally with the rotation.

A magnet case 39 is integrally formed on the magnet side of the engine case 22, and a magnet device 37 is housed in the magnet case 39. The magneto case 39, the cylinder block 23, and the cylinder head 24 are covered with a shroud 40, and a cooling air intake 41 is opened in the shroud 40 outside the cooling fan 38.

As shown in FIG. 1, an engine intake system 42 is disposed in a space surrounded by the rear part of the front wheels 11, the lower part of the fuel tank 5, and the front part of the unit swing type engine 15. The engine intake system 42 mainly includes an air cleaner 43.
And a carburetor 44 provided so as to be surrounded by the air cleaner 43.
From there, the intake pipe 45 extends toward the upper part of the engine body 17. Reference numeral 46 denotes an air intake of the air cleaner 43.

On the other hand, as shown in FIGS. 1 to 3, an engine exhaust system 47 is provided on the right side of the unit swing type engine 15.
Is provided. The engine exhaust system 47 mainly includes an exhaust pipe 48 and a muffler 49. The muffler 49 is disposed on the upper right of the unit swing type engine 15, and the
For example, it is fixed to the engine case 22 through the “0”.

The exhaust pipe 48 extends from the lower part of the cylinder head 24 toward the rear of the magnet case 39 toward the rear of the magnet case 39, that is, toward the right rear.
9, which extends around the rear part of the outer wall and extends upwardly of the engine case 22 and is connected to the muffler 49.

In the four-cycle engine, a small amount of gas with pressure generated in the combustion chamber 51, that is, blow-by gas leaks into the engine case 22 through the gap between the piston 25 and the cylinder block 23.
The unit swing type engine 15 shown in the present embodiment is provided with a breather device 52 which is a mechanism for returning the blow-by gas to the air cleaner 43, sending the blow-by gas to the combustion chamber 51 once more, and reburning the blow-by gas.

The breather device 52 includes a breather chamber 53 provided in the cylinder head 24 of the engine body 17 which is the foremost part of the unit swing type engine 15, an air cleaner 43 disposed immediately before the breather chamber 53, and a breather chamber 53. And a breather hose 54 which communicates the above.

Next, the operation of the present embodiment will be described.

The engine intake system 42 is formed not by the narrow space between the driving seat 6 and the engine as in the conventional case but by the rear part of the front wheels 11, the lower part of the fuel tank 5, and the front part of the unit swing type engine 15. The exhaust pipe 48 is not limited to a narrow space between the operation seat 6 and the engine as in the conventional case, but extends from the lower part of the cylinder head 24 toward the rear of the magnet case 39 toward the rear of the magnet case 39. By extending around the rear part of the outer wall of the case 39 and extending upwardly of the engine case 22 and connecting it to the muffler 49, the height of the driving seat 6 is reduced to improve the rider's feet, while the minimum height of the engine is reduced. A sufficient ground clearance can be secured.

Further, since the stroke of the rear shock absorber 19 can be sufficiently ensured, the riding comfort is improved. Furthermore, the length of the exhaust pipe 48 can be sufficiently secured.

Since the distance between the air cleaner 43 and the cylinder head 24 of the engine is short, the breather hose 54 is shortened, so that its piping is easy and its fixing to the vehicle body is unnecessary.

FIG. 4 is a left side view showing an example of the second embodiment of the motorcycle to which the present invention is applied. The difference between the motorcycle 61 shown in the second embodiment and the motorcycle 1 shown in the first embodiment is the shape and arrangement position of the air cleaner, and an engine intake system 62 of the motorcycle 61.
Is integrally formed below the fuel tank 5 and connected to the carburetor 44 via a bellows-like connecting pipe 64.

The motorcycle 61 shown in the second embodiment
Since the other configuration requirements are the same as those of the motorcycle 1 shown in the first embodiment, the same reference numerals are used and the description is omitted.

[0039]

As described above, according to the motorcycle equipped with a unit swing type engine according to the present invention, the fuel tank is disposed between the handlebar and the driving seat, while the unit is disposed below the driving seat. In a motorcycle on which a swing type engine is swingably mounted, the unit swing type engine includes an engine body, a conduction case extending rearward from one side of the engine body, and a magneto case formed on the other side of the engine body. An engine intake system, an exhaust pipe, and a muffler are connected to the engine body, and the engine is disposed in a space surrounded by a lower part of the fuel tank and a front part of the unit swing type engine. An intake system is arranged, and the exhaust pipe is connected from the lower part of the engine To the rear of the magnet case, and further extending the exhaust pipe around the rear part of the outer wall of the magnet case and extending toward the upper part of the engine body and connected to the muffler, so that the dead space under the fuel tank can be effectively used, and The layout of the engine intake and exhaust system also becomes easy.

In addition, a breather chamber is provided in the engine body at the forefront of the unit swing type engine, and the breather chamber is communicated with the engine intake system by a breather hose, so that breather hose piping is facilitated.

[Brief description of the drawings]

FIG. 1 is a left side view showing a first embodiment of a motorcycle equipped with a unit swing type engine according to the present invention.

FIG. 2 is an enlarged left side view of the unit swing type engine.

FIG. 3 is a sectional view taken along the line III-III in FIG. 2;

FIG. 4 is a left side view showing a second embodiment of the motorcycle equipped with a unit swing type engine according to the present invention.

[Explanation of symbols]

 Reference Signs List 1,61 Motorcycle 2 Body frame 5 Fuel tank 6 Operation seat 13 Handlebar 15 Unit swing type engine 17 Engine body 18 Conductive case 37 Magneto device 39 Magneto case 42,62 Engine intake system 43,63 Air cleaner (Engine intake system) 44 Carburetor (engine intake system) 47 Engine exhaust system 48 Exhaust pipe (engine exhaust system) 49 Muffler (engine exhaust system) 52 Breather device 53 Breather chamber 54 Breather hose

Claims (2)

[Claims] 1. A motorcycle in which a fuel tank is disposed between a handlebar and a driving seat, and a unit swing type engine is swingably mounted below the driving seat. A transmission case extending rearward from one side of the engine body 17;
The engine body 17 is connected to an engine intake system 42, an exhaust pipe 48, and a muffler 49, while a lower part of the fuel tank 5 and the unit swing are connected to the engine body 17. The engine intake system 42 is provided in a space surrounded by the front portion of the
And the exhaust pipe 48 extends from the lower portion of the engine body 17 to the lower surface of the engine body 17 toward the rear of the magneto case 39 side.
8 extends around the rear portion of the outer wall of the magneto case 39 toward the upper side of the engine main body 17 to extend the muffler 49.
A motorcycle equipped with a unit swing type engine, which is connected to a motorcycle. 2. A breather chamber 53 is provided in the engine body 17 at the forefront of the unit swing type engine 15, and the breather chamber 53 and the engine intake system 4 are provided.
2. The motorcycle equipped with a unit swing type engine according to claim 1, wherein the motorcycle is connected with a breather hose 54.