JPH0547431B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a motorcycle equipped with a parallel multi-cylinder engine.

[Prior Art] In a conventional motorcycle, a head pipe and a pivot portion of a rear arm are connected by a pair of left and right main frame members, and an engine is disposed below these main frame members. In order to avoid interference with the cylinders of the engine, this main frame member is composed of a so-called main pipe section that passes above the engine, and a backstay section that continues from the main pipe section and wraps around behind the engine. A fuel tank is installed on the main pipe section, and an air cleaner is arranged in a space below the seat sandwiched between the backstay sections.

[Problems to be Solved by the Invention] However, in the case of this conventional configuration, the main pipe portion that supports the fuel tank passes above the engine, so its position is inherently high. Therefore, if an attempt was made to increase the capacity of the fuel tank by enlarging its shape, there was a problem in that the fuel tank would protrude significantly upward.

Additionally, since the air cleaner is located below the seat, if the air cleaner is made larger, the seat will not only be higher, but the bottom of the seat will also protrude from side to side, significantly impairing the footing. I end up.

For this reason, when considering the ease of riding, it is difficult to ensure sufficient capacity for the fuel tank and air cleaner, and there remains room for improvement in this respect.

The present invention has been developed based on the above circumstances, and allows the space between the left and right main frame members to be used without waste as installation space for the fuel tank and air cleaner, and the capacity of these fuel tanks and air cleaners to be fully utilized. By placing the heavy and large fuel tank as close to the front as possible, heavy objects can be concentrated around the engine, and even if the remaining amount of fuel in the fuel tank fluctuates, the center of gravity of the vehicle will always be close to the engine. The purpose of the present invention is to provide a motorcycle that can be placed in a vehicle.

[Means for Solving the Problems] Therefore, in the present invention, a pair of left and right main frame members extending in a substantially straight line in a side view from a head pipe that pivotally supports a front fork toward a pivoting portion of a rear arm rearward and diagonally downward; a parallel multi-cylinder engine with a horizontal crankshaft disposed below the main frame member, the cylinders of the engine extending forward of the main frame member through the center in the height direction of the main frame member. When the frame centerline is drawn, the cylinder axis is tilted forward so as to intersect the frame centerline in front of the head pipe, and an intake passage extends upward in a substantially straight line in the cylinder head that is connected to the front end of the cylinder. In addition, between the left and right main frame members, there is an air cleaner and a fuel tank located between the head pipe at the front end and the seat behind the engine, and connected to the upper end of the intake passage. The air cleaner and the intake passage are arranged forward of the rear end of the cylinder which is tilted forward in side view, and the fuel tank is arranged so that the rear end of the cylinder is The fuel tank is disposed above the continuous crankcases, and the bottom of the front part of the fuel tank extends downward through the main frame members, and this extended part is surrounded by the upper surface of the crankcases, the cylinder, and the rear surface of the intake passage. It is characterized by being located in a space with a large area.

[Operation] According to this configuration, the air cleaner can be installed using a wide space open above the engine, and space constraints are relaxed compared to the conventional case where the air cleaner is provided under the seat.
Therefore, a sufficient capacity of the air cleaner can be secured, and engine output is improved. On top of that,
Since there is no air cleaner under the seat, the seat height can of course be lowered, and the lower part of the seat can be made narrower, providing better footing.

In addition, since the main frame member extends diagonally downward in a substantially straight line, if a fuel tank is installed behind the air cleaner, the main frame member will be much larger than the head pipe in the area where the fuel tank is installed. It goes down to a lower position, and
The fuel tank can be made to protrude significantly above the main frame member.

At the same time, the engine's intake system is placed below the fuel tank by tilting the cylinder significantly forward to follow the rear-sloping main frame member, and by directing the intake passage connected to the cylinder head upward in a straight line. Instead, just extend the bottom of the front part of this fuel tank downwards,
It can be placed close to the top surface of the crankcase. Therefore, the front part of the fuel tank can be made longer in the vertical direction, and a sufficient tank capacity can be ensured.

Since the intake passage and the air cleaner are concentrated in front of the cylinder, the front portion including the extended portion of the fuel tank can be positioned as far as possible toward the front end of the crankcase. For this reason, the center of gravity of the heavy and large fuel tank can be positioned far forward of the seat, and even if the amount of fuel remaining in the fuel tank fluctuates, the center of gravity of the vehicle will always remain close to the heavy engine. can be done.

[Example] An example of the present invention will be described below based on the drawings.

A frame of a motorcycle, indicated by reference numeral 1 in the figure, is provided with a head pipe 2 at its front end. A front fork 10 is pivotally supported on the head pipe 2. A front wheel 12 is supported at the lower end of the front fork 10.
0 is steered by a handle 11.

The head pipe 2 includes a pair of left and right main frame members 3 that extend rearward and diagonally downward, and a pair of left and right down tubes 4 that extend downward (only one is shown).
are joined. The lower end of the down tube 4 is extended rearward, and the rear end is extended upward to form the left and right seat pillar tubes 5.
The rear end portion of the main frame member 3 is joined to the intermediate portion of the seat pillar tube 5.

A rear arm bracket 6 is joined to the joint between the main frame member 3 and the seat pillar tube 5. On the rear arm bracket 6,
The front end of the rear arm 7 is pivotally supported via a pivot shaft 8. A rear wheel 9 is supported at the rear end of the rear arm 7. Therefore, the main frame member 3 connects the head pipe 2 and the pivot portion of the rear arm 7 in a substantially straight line when viewed from the side, and the main frame member 3 has a main frame member 3 in the front part on the side of the head pipe 2. As shown in plan in FIG. 2, it has a bent portion 3a that swells outward.

A pair of left and right seat rails 13 are joined to the main frame member 3. The seat rail 13 is
It extends substantially horizontally toward the rear from the rear portion of the bent portion 3a. A midway portion of the seat rail 13 is supported by the upper end of the seat pillar tube 5, and a reinforcing tube 14 is installed between the seat pillar tube 5 and the rear end of the seat rail 13. A seat 15 is placed on the seat rail 13.

Incidentally, an engine 18 is mounted in a space surrounded by the main frame member 3 and the down tube 4. The engine 18 of this embodiment is a water-cooled parallel four-cylinder engine in which a crankshaft 19 is placed horizontally along the left-right direction of the frame 1, and four not-shown It is provided with a cylinder block 21 in which cylinders are arranged side by side in the left and right direction of the frame 1. This cylinder block 21 is located below the main frame member 3, as shown in FIG. As shown in Fig. 1, when a frame center line X extending forward of the main frame member 3 is drawn through the center of the main frame member 3 in the height direction, It is largely tilted forward so as to intersect the frame center line X.

Further, a cylinder head 22 connected to the front end of the cylinder head 21 is provided with four intake ports 23 that open upward. A vaporizer 24 is connected to each of these intake ports 23 . vaporizer 2
4 is a down draft type in which the flow direction of intake air is vertical along the vertical direction, and these carburetors 2
4 and the intake port 23 constitute an intake passage that extends in a straight line upwardly of the cylinder head 21. The carburetor 24 is juxtaposed in the left-right direction of the frame 1 between the bent portions 3a of the main frame member 3, and is located in parallel with the cylinder head 22.
is located directly above. The intake upstream end of each carburetor 24 is communicated with an air cleaner 25 . The air cleaner 25 is arranged between the front parts of the main frame member 3 immediately after the head pipe 2, and most of it protrudes above the main frame member 3 when the motorcycle is viewed from the side. .
Moreover, as mentioned above, by tilting the cylinder block 21 forward, the intake port 23 and the carburetor 24
is located forward of the rear end of the cylinder block 21, and the air cleaner 25 connected to the carburetor 24 also has its rear end located forward of the rear end of the cylinder block 21.
It is located forward of the rear end of 1.

A fuel tank 2 is located directly above the crankcase 20.
6 is placed. The fuel tank 26 is located between the air cleaner 25 and the seat 15. Therefore, between the left and right main frame members 3, an air cleaner 2 is installed from the front head pipe 2 side.
5 and a fuel tank 26 are arranged in this order, and the space between the head pipe 2 and the seat 15 is exclusively occupied by the air cleaner 25 and the fuel tank 26.

The upper part of the fuel tank 26 largely projects upward from between the main frame member 3 and the seat rail 13, and the front surface of this projecting portion 26a is close to the air cleaner 25. Further, the bottom of the front half of the fuel tank 26 extends downward through the space between the main frame members 3. The extended portion 26b of the fuel tank 26 is a space 3 surrounded by the upper surface of the crankcase 20, the rear surface of the cylinder block 21, and the rear surface of the intake port 23.
It stands out towards 1. For this reason, the extension part 2
The bottom surface of 6b is close to the top surface of crankcase 20, and the front surface of extension portion 26 is close to the rear surface of cylinder block 21 and intake port 23.

The range from the top surface to the circumferential surface of the air cleaner 25 and fuel tank 26 is covered by a cover 27 that forms a conventional fuel tank shape, that is, a cover 27 that is shaped so that the driver can squeeze it between his/her knees. This cover 27 is connected to the front end of the seat 15.

According to this configuration, the air cleaner 25 can be installed using the space open above the cylinder head 22 of the engine 18, and there are fewer space constraints than in the past where the air cleaner is installed under the seat. eased. Therefore, sufficient capacity of the air cleaner 25 can be secured,
The output of the engine 18 can be increased.

In this case, since the air cleaner 25 is not present below the seat 15, the height of the seat 15 can be lowered and the width around the driver's legs can be made narrower, resulting in better foot contact. In addition, even if the driver holds the left and right sides of the cover 27 with both knees (knee grip) while driving, the driver's legs will not be spread wide, improving the ease of riding and the feeling of riding.

Furthermore, since the main frame member 3 extends in a straight line from the head pipe 2 toward the pivot point of the rear arm 7 rearward and diagonally downward, the fuel tank 26 can be installed continuously behind the air cleaner 25. , in the installation part of this fuel tank 26,
The main frame member 3 is lowered to a considerably lower position than the head pipe 2, allowing the fuel tank 26 to protrude significantly above the main frame member 3.

At the same time, the cylinder block 21 is largely tilted forward so as to follow the main frame member 3 that extends backward, and the intake passage composed of the intake port 23 and the carburetor 24 is aligned in a straight line above the cylinder head 22. As a result, the intake system of the engine 18 including the air cleaner 25 is concentrated directly above the cylinder head 22 without entering below the fuel tank 26, and the air intake system of the engine 18, including the air cleaner 25, is concentrated directly above the cylinder head 22. The bottom of the front half can be extended downward as it is.

From this, the extension portion 26 of the fuel tank 26
b is placed close to the upper surface of the crankcase 20, the front part of the fuel tank 26 can be formed to be long in the vertical direction, and the space created between the main frame member 3 and above the crankcase 20 can be effectively utilized. Therefore, sufficient tank capacity can be secured.

The extension portion 26b of the fuel tank 26 is
Upper surface of crankcase 20, cylinder block 2
1 and the rear surface of the intake port 23, the extended portion 26b for increasing the amount of fuel should be placed as close to the crankcase 20 as possible.
The center of gravity of the heavy and large fuel tank 26 can be positioned considerably forward of the seat 15. Therefore, even if the remaining amount of fuel in the fuel tank 26 fluctuates, the center of gravity of the vehicle can always be located near the heavy engine 18.

Therefore, it is possible to achieve both mass concentration and lower center of gravity, making it easier to ride.

[Effects of the Invention] According to the present invention detailed above, since the air cleaner can be installed using the space open above the engine, a sufficient capacity of the air cleaner can be secured, and the engine output can be increased. I can do it. In this case, since there is no air cleaner below the seat, the seat height can be lowered and the area around the driver's legs can be made narrower, resulting in better foot contact.

Further, since the engine intake system is integrated directly above the cylinder head without penetrating below the fuel tank, the fuel tank can be formed to be long in the vertical direction between the main frame members.
Therefore, the space created between the main frame members and above the crankcase can be effectively utilized as the installation space for the fuel tank, and the capacity of the fuel tank can also be sufficiently secured.

At the same time, the extension part of this fuel tank,
By shifting the crankcase toward the front end as much as possible, the center of gravity of the heavy and large fuel tank can be positioned far in front of the seat.Even if the amount of fuel remaining in the fuel tank fluctuates, the center of gravity of the vehicle remains constant. It can be located near a heavy engine. Therefore, it is possible to achieve both mass concentration and lower center of gravity, which has the advantage of providing a motorcycle that is easy to ride.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a side view of a motorcycle, and FIG. 2 is a plan view of the vehicle body. 2...Head pipe, 3...Main frame member,
7...Rear arm, 10...Front fork,
15... Seat, 18... Parallel multi-cylinder engine,
20... Crank case, 21... Cylinder block, 22... Cylinder head, 23, 24...
Intake passage (intake port, carburetor), 25...air cleaner, 26...fuel tank, 26b...extension portion, 31...space portion. .

Claims (1)

[Scope of Claims] 1. A pair of left and right main frame members extending obliquely rearward and downward in a substantially straight line when viewed from the side from a head pipe that pivotally supports the front fork toward the pivot portion of the rear arm; and a horizontally mounted parallel multi-cylinder engine with a horizontal crankshaft, and the cylinders of the engine are defined by a frame center line extending forward of the main frame member through the center in the height direction of the main frame member. The cylinder axis is tilted forward so as to intersect the frame center line in front of the head pipe, and an intake passage extending upward in a substantially straight line is connected to the cylinder head connected to the front end of the cylinder. An air cleaner and a fuel tank are located between the head pipe at the front end of the frame members and the seat behind the engine, and the upper end of the intake passage is connected to the fuel tank. are arranged side by side, the air cleaner and the intake passage are arranged forward of the rear end of the forward-inclined cylinder in side view, and the fuel tank is arranged above the crankcase where the rear end of the cylinder is connected, The bottom of the front part of the fuel tank is extended downward through the space between the main frame members, and this extended part is located in a space surrounded by the upper surface of the crankcase, the cylinder, and the rear surface of the intake passage. A motorcycle characterized by: