JPH0371317B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a scooter type motorcycle in which a unit swing type power unit is disposed below a seat.

[Conventional technology]

This type of scooter-type motorcycle has a frame that is bent significantly downward between the front fork and the seat, and a flat step is attached to the bent bottom. Disposed behind this step is an engine and a unit swing type power unit that extends rearward from one side of the engine's crankcase and has a rear wheel at its rear end. This power unit is located just below the seat, and the area around the engine of this power unit and below the seat is integrally covered with a cover.

By the way, conventionally, the engine of this power unit has a cylinder that is erected upward on the front upper surface of the crankcase, as seen in, for example, ``Patent Publication No. 123751/1983''. The carburetor was located at the rear of the cylinder.

[Problem to be solved by the invention]

However, according to this conventional configuration, since the cylinder stands up toward the space below the seat, the carburetor behind the cylinder also largely enters the space, and much of this air enters the cylinder and carburetor. As a result, it becomes exclusive. In particular, scooter-type motorcycles use a unit swing type power unit, so the engine cylinder, carburetor, and air cleaner also swing together with the rear wheel. It is necessary to secure enough space in advance so as not to impede the swinging.

In this type of motorcycle, the space between the seat and the engine is a space for installing the fuel tank and other electrical transmission parts, and is also a space for storing small items such as maps and rain gear. There may be restrictions on the placement of the fuel tank mentioned above,
There is a problem where there is not enough storage space.

Therefore, according to the present invention, the entire intake system including the engine cylinder, carburetor, and air cleaner can be made flat, and the vertical direction necessary to allow the intake system to swing can be made flat. The space between the engine and the seat can be kept small to ensure a large space for parts installation.In addition, the air cleaner can prevent dirt and other foreign objects that fly from the rear wheels toward the front carburetor while driving. To provide a scooter type two-wheeled motor vehicle which can be used to cover a large area between the engine and the seat without requiring a special mudguard.

[Means to solve the problem]

Therefore, in the present invention, a pair of left and right back stays are connected to the rear part of the down tube connected to the head pipe, the rear parts of these back stays are raised upward, and a seat is provided on the upper part of this rising part. The front end of the unit swing type power unit is made up of an engine and a transmission case that extends rearward from one side of the engine's crankcase in the left and right direction and has a rear wheel at its rear end. In a scooter-type motorcycle in which the area around the engine of the power unit and below the seat is covered with a cover, the cylinder of the engine is tilted approximately horizontally forward from the front end of the crankcase. The upper surface of the cylinder and the crankcase are formed to be substantially flush with each other, and a carburetor and an air cleaner connected to the carburetor are arranged in front and behind each other on the crankcase, and the air cleaner is arranged between the carburetor and the rear wheel. The air cleaner has a rear wall located immediately in front of the rear wheels, and a connection port connected to the carburetor and a duct for sucking outside air are installed on the front side of the air cleaner within the horizontal width of the air cleaner. The seat is arranged side by side on the left and right, and is characterized in that a housing space for accommodating the components is provided between the intake system components including the air cleaner and the carburetor and the seat.

[Effect]

According to this configuration, by tilting the cylinder substantially horizontally, the entire upper surface of the crankcase is widely opened upward, and the carburetor and the air cleaner can be arranged here, one behind the other. Therefore, in addition to eliminating the need for the cylinder to protrude significantly above the crankcase, the carburetor and air cleaner can be placed as close to the top of the crankcase as possible, allowing the cylinder, carburetor, and air cleaner to be placed at a lower position. I can do it. The duct that sucks outside air into the air cleaner and the connection port that connects the carburetor are lined up in the left and right direction of the air cleaner, so the height dimension of the air cleaner can be kept low, allowing the intake air from the carburetor to the air cleaner to be kept low. The entire system parts can be made flat.Therefore, even though these intake system parts swing up and down together with the power unit, the vertical adjustment is required to enable the swinging of these intake system parts. This means less space is required in both directions, allowing more space between the engine and the seat to place the fuel tank and other parts.

In addition, the rear wall of the air cleaner functions as a mudguard that covers the rear wheels from the front, so even if the rear wheels are close to the carburetor, ducts, etc., mud will scatter from the rear wheels toward the front and the carburetor side while driving. Foreign matter such as mud can be blocked by the air cleaner itself. For this reason, in the limited space around the engine,
There is no need to install a special mudguard, which of course reduces the number of parts, and the space between the engine and the seat can be used more widely as space for parts such as the fuel tank. .

〔Example〕

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

Reference numeral 1 in the figure is an underbone frame, and a front fork 3 is pivotally supported on a head pipe 2 at the front end of the frame. A downwardly extending down tube 4 is welded to the lower rear surface of the head pipe 2. The lower end of the down tube 4 extends horizontally toward the rear, and left and right backstays 5 extending rearward are welded to the rear end of this extended portion 4a. A flat footrest board 6 is placed on the upper surface of the extension 4a of the downtube 4 and the backstay 5, and this footrest board 6 is continuous with the leg shield 7 fixed to the headpipe 2 and the downtube 4. ing.

The left and right back stays 5 are footrest boards 6
The upper end portions of these rising portions 8 extend rearward substantially horizontally to form left and right seat rails 9. A U-shaped cross tube 10 extending obliquely upward and forward is welded to the upper end of the rising portion 8, and a seat 12 is supported at the extending end of the cross tube 10 via a seat bracket 11. has been done. The seat 12 is located approximately above the front half of the seat rail 9,
A fuel tank 13 and an oil tank 14 are installed directly below this seat 12. fuel tank 13
is inserted between the seat rails 9, and the oil tank 14 is arranged inside the cross tube 10, and both the tanks 13 and 14
The outer periphery of is covered by a substantially cylindrical upper cover 15 with open upper and lower surfaces.

On the other hand, engine brackets 16 are welded to intermediate portions of the rising portions 8, respectively. A swing link 17 is pivotally supported on the engine bracket 16, and a pivot shaft 18 is connected between these swing links 17.
unit swing type power unit 19 via
The front end of is pivotally connected. This power unit 1
9 is a two-stroke engine 20 and this engine 2.
It is comprised of a transmission case 22 that integrally extends rearward from the left side of a crankcase 21 of No. 0, and is located below the seat 12. Transmission case 22
The rear end of the transmission case 22 is suspended from the left seat rail 9 via a hydraulic shock absorber 23, and a rear wheel 24 is cantilevered at the rear end of the transmission case 22. This rear wheel 24 is rotationally driven by a belt type transmission (not shown) housed within the transmission case 22.

Further, as shown in FIG. 1, the cylinder 25 of the engine 20 is attached to the front surface of the crankcase 21, and is tilted forward approximately horizontally with respect to the crankcase 21. Therefore, the upper surfaces of the cylinder 25 and the crankcase 21 are substantially flush with each other, and the cylinder head 2 that covers the cylinder 25
6 is directed forward and inserted between the lower ends of the rising portions 8 of the backstay 5.

The cylinder 25 and cylinder head 26 are surrounded by an air shroud 27 having a substantially box shape. Cooling air is forcibly blown into the air shroud 27 via a fan 28 that rotates together with the crankshaft, and this cooling air flows through the cylinder 25 and cylinder head 26.
After cooling, the air is discharged to the outside through the outlet 29 on the left side of the air shroud 27.

By the way, as described above, as the cylinder 25 is tilted forward approximately horizontally, this crankcase 21
A storage space 30 is provided between the upper surface of the seat 12 and the seat 12.
is formed, and the fuel tank 13 and oil tank 14 are arranged above the housing space 30. Further, an intake pipe 31 is connected to the front portion of the upper surface of the crankcase 21, which is the bottom of the housing space 30. As shown in FIGS. 1 and 2, the intake pipe 31 has an elbow shape, and its intake end extends forward. A carburetor 32 is connected to the intake end of this intake pipe 31. The carburetor 32 is provided close to the upper surface of the front end of the crankcase 21 and straddled between the crankcase 21 and the cylinder 25, and in the case of this embodiment, serves as the swing fulcrum of the power unit 19. It is located near the swing link 17. Further, the suction end of this carburetor 32 faces forward, and an air cleaner 34 is connected to this suction end via a joint 33 bent toward the rear.

For this reason, the carburetor 32 and the air cleaner 34 are
The carburetor 32 and the air cleaner 34 are arranged in front and back in close proximity to the upper surface of the crankcase 21, and the carburetor 32 and the air cleaner 34 are located at the lower part of the housing space 30, and are integrally swung up and down with the power unit 19. It is becoming more and more popular.

Further, the air cleaner 34 includes a box-shaped case 34a. This case 34a is located just in front of the rear wheel 24, and a rear wall 34b adjacent to the rear wheel 24 is curved in an arc shape and also serves as a mudguard that covers the rear wheel 24 from the front. On the front surface of the case 34a, as shown in FIG. 2, there is a connection port 34 to which the joint 33 of the carburetor 32 is connected.
b, and air ducts 35 protruding forward are arranged side by side on the left and right. These connection ports 34b
The air duct 35 is located within the width of the case 34a of the air cleaner 34 in the left-right direction, and an air intake port 36 is formed at the protruding end of the air duct 35 to open downward and draw in outside air.

Further, the periphery of the accommodation space 30 is covered by a side cover 37 that can be divided in the left-right direction. The side cover 37 covers the engine 2 of the power unit 19.
Fuel tank 13 and oil tank 1 from 0 rotation
4 is continuously covered by the upper cover 15, and the rear part of the side cover 37 extends rearward from the seat 12, extending from the rear fender 38 that covers the rear wheel 24 to the upper part of the rear half of the seat rail 9. It covers the whole part. moreover,
The rising portion 8 of the backstay 5 is covered from the front by a front cover 39. This front cover 39 is continuous with the upper cover 15 and the left and right side covers 37, and covers the accommodation space 30 and the cylinder head 26 of the engine 20 from the front.

The front end of the rear fender 38 is connected to the case 34a of the air cleaner 34.

According to such a configuration, the cylinder 25 of the engine 20 is inclined approximately horizontally from the front end of the crankcase 21, and the upper surfaces of the cylinder 25 and the crankcase 21 are approximately flush with each other, so that the entire upper surface of the crankcase 21 is covered. It is wide open upwards, and the carburetor 32 and air cleaner 34 can be arranged here, one behind the other. For this reason, the vaporizer 32
The cylinder 25, air cleaner 34 can be placed as close as possible to the crankcase 21, and the cylinder 25,
The installation positions of the vaporizer 32 and the air cleaner 34 can be lowered.

Since the air duct 35 for sucking outside air into the air cleaner 34 and the connection port 34c connected to the carburetor 32 are arranged in the left-right direction of the case 34a, the height dimension of the case 34a can be kept low. Therefore, the entire intake system components from the carburetor 32 to the air cleaner 34 can be made flat.

From this, the carburetor 32 and air cleaner 34
Despite the fact that the carburetor 32 and air cleaner 34 swing up and down together with the power unit 19,
The space required in the vertical direction to allow the engine to swing is small, and the accommodation space 30 between the engine 20 and the seat 12 does not become narrow.
Therefore, this housing space 30 can be widely opened as a housing space for the fuel tank 13, oil tank 14, or small items.

Moreover, according to the above configuration, the air cleaner 34
In addition to the rear wall 34b of the case 34a functioning as a mudguard that covers the rear wheel 24 from the front,
Since the connection port 34c and the air duct 35 on the front side of the case 34a are located within the width of the case 34a in the left and right direction, mud, etc., which is scattered from the rear wheel 24 toward the carburetor 32 side in front while driving, is removed. Foreign matter can be blocked using the case 34a.

Therefore, there is no need to install a special mudguard in the limited space between the engine 20 and the rear wheel 24, and the number of parts can be kept to a minimum, and the storage space 30 can be used for fuel storage. It can be widely and effectively used as an installation space for parts such as the tank 13.

At the same time, in the case of this embodiment, the vaporizer 32
is located near the pivot point of the power unit 19, so even when the power unit 19 swings during driving, changes in the attitude of the carburetor 32 can be suppressed to a minimum, and large fluctuations in the oil level of the carburetor 32 can be suppressed. There are also benefits to prevention.

〔Effect of the invention〕

According to the present invention described in detail above, the entire upper surface of the crankcase is wide open upward, so that
The carburetor and air cleaner can be placed as close as possible to the crankcase, allowing the carburetor and air cleaner to be installed lower than in the past. The duct that sucks outside air into the air cleaner and the connection port between the carburetor are also lined up in the left and right direction of the air cleaner, so the height dimension of this air cleaner can be kept low, and the intake system from the carburetor to the air cleaner The whole part can be made flat.

From this, even if the carburetor and air cleaner swing up and down together with the power unit, the vertical space required to allow these swings is small, and the connection between the engine and the seat is reduced. You can easily secure a large space between them.

Moreover, the rear wall of the air cleaner functions as a mudguard that covers the rear wheels from the front, so the air cleaner can be used to block foreign objects such as mud that fly from the rear wheels toward the carburetor side in front while driving. .
Therefore, there is no need to install special mudguards in the limited space between the engine and the rear wheels, and the number of parts can be kept to a minimum. can be widely and effectively used as installation space for parts such as fuel tanks.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a side view of the surroundings of a power unit, FIG. 2 is a plan view of the power unit, and FIG. 3 is a side view of a scooter type motorcycle. 2... Head pipe, 4... Down tube,
5...Backstay, 8...Rising part, 12...
... Seat, 15 ... Upper cover, 19 ... Power unit, 20 ... Engine, 21 ... Crank case, 22 ... Transmission case, 24 ... Rear wheel, 25
... cylinder, 30 ... storage space, 32 ... carburetor, 34 ... air cleaner, 34b ... rear wall,
34c... Connection port, 35... Duct (air duct), 37... Side cover, 39... Front cover.

Claims (1)

[Claims] 1. A pair of left and right back stays are connected to the rear part of a down tube connected to the head pipe, and the rear parts of these back stays are raised upward,
A seat is provided at the top of this rising section, and the rising section is composed of an engine and a transmission case that extends rearward from one side in the left-right direction of the engine's crankcase and has a rear wheel at its rear end. In a scooter-type motorcycle, the front end of a swing-type power unit is pivotably mounted, and a cover covers the area from around the engine of the power unit to below the seat. By tilting the case substantially horizontally forward from the front end, the upper surface of this cylinder and crankcase are formed substantially flush, and on this crankcase, a carburetor and an air cleaner connected to this carburetor are arranged one behind the other. The air cleaner is disposed between the carburetor and the rear wheel, and has a rear wall located just in front of the rear wheel, and has a connection port connected to the carburetor on the front side of the air cleaner, and a connection port connecting the carburetor to the outside air. Ducts for sucking the air are arranged side by side within the width of the air cleaner in the left and right direction, and a storage space is provided between the intake system parts including the air cleaner and the carburetor and the seat to accommodate the parts. A scooter-type motorcycle characterized by: