JPH02256580A - Intake passage for engine of motorcycle - Google Patents

Abstract

PURPOSE:To reduce the intake resistance by securing the sufficient sectional surface of an intake passage by utilizing the inner space of the right and left main frames having a broad box-shaped section, at least as a part of an intake passage leading from an air cleaner to a fuel feeding device. CONSTITUTION:As for the car body frame 2 of a motorcycle 1, the right and left main frames 4 and 4 in pairs each of which has a wide box-shaped section and extends in nearly straight line form are extended rearward and downward from a head pipe 3, and a rear arm bracket 6 extending downward is installed at the rear edge. An engine 22 is installed under the main frame 4, and a carburetor 33 as a fuel feeding device for the engine 22 is arranged between the rear parts of the right and left main frames 4 and 4. In such a motorcycle, the inner space of the main frame 4 is utilized as at least a part of an intake passage 64 leading to the carburetor 33 from an air cleaner 35 arranged between the right and let main frames 4 and 4 in pairs on the upper side of the carburetor 33.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an intake passage for an engine of a motorcycle formed using a body frame.

(Prior art) A motorcycle has a pair of left and right main frames extending downward from the head vibrator, and a rear arm that supports the rear wheel is pivotally supported on the rear end side of the left and right main frames. It is more common than before to have the engine installed below the frame.

In order to support the load from the rear wheel side with sufficient strength, the main frame is formed into a wide box shape in cross section, and the section from the head vibe side to the rear arm pivot is almost straight. There is one formed in Also, in this case,
Utilizing the space between the rear parts of the left and right main frames, a fuel supply system for the engine is provided in this space, and an intake air cleaner for the engine is arranged between the left and right main frames above this fuel supply system. established and.

There is one in which an intake pipe is used to form an intake passage that guides the suction from the air cleaner to the fuel supply device.

(Problem to be Solved by the Invention) As described above, if each main frame is made into a box shape with a wide cross section, the space occupied by this main frame becomes large, and as a result, other components This results in a narrower installation space.

Moreover, in addition to this, the cross-sectional area of the intake passage must be increased to a certain extent in order to reduce intake resistance.
The intake pipe is required to be as straight as possible, and as a result, the volume of the intake pipe increases, further reducing the installation space for other components.

For this reason, in the case of the above-mentioned conventional configuration, there is a disadvantage that the degree of freedom in installing components such as the exhaust pipe is greatly restricted.

(Object of the Invention) This invention was made in view of the above-mentioned circumstances.The main frame has a wide box shape in cross section, and the intake resistance of the intake passage is suppressed to a low level. The purpose is to ensure sufficient flexibility when installing components such as exhaust pipes.

(Structure of the Invention) A feature of the present invention for achieving the above object is that the internal space of the main frame is at least part of the intake passage leading from the air cleaner to the fuel supply device.

(for production) The effects of the above configuration are as follows.

When the engine 22 operates, intake air passes through the intake passage 64 and reaches the carburetor (fuel supply device 33), where it is mixed with fuel and supplied to the engine 22.

In the above case, the intake passage 64 from the air cleaner 35 to the carburetor (fuel supply device) 33 is formed inside the main frame 4. Since the main frame 4 has a wide box-like cross section, the intake passage 64 has a sufficient cross-sectional area. Moreover, this main frame 4 connects the carburetor (fuel supply device) from the air cleaner 35 side.
It extends linearly toward the 33 side. Therefore, the intake resistance in the intake passage 64 can be kept small.

According to the above configuration, since the intake passage 64 is formed using the main frame 4, the space in the vehicle body is reduced compared to the conventional structure in which a separate intake pipe is provided for the intake passage 64. Narrowing is prevented.

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

In FIG. 2, 1 is a motorcycle and 2 is its body frame. This vehicle frame assembly has a head vibrator 3 at the front thereof, and a pair of left and right main frames 4.4 extend from the head vibrator 3 toward the rear and lower side. Each main frame 4 has a wide cross section, a rectangular box shape, and an elongated shape, and has a rear arm bracket 6 extending downward at its rear end. In addition, seat rails 7 are provided from the front and rear midpoints of each of the main frames 4 toward the rear and upper sides.
．． 7 protrudes, and each seat rail t is connected to the backstay 8.
reinforced by.

A front fork 9 is supported on the head vibe 3 so as to be steerable. A front wheel 10 is supported at the lower end of this front fork 9, and a handle 11 is attached to the upper end of the improved front fork 9. 12 is a front fender.

On the other hand, the rear arm bracket 6.6 has a pivot shaft 13.
The rear arm 14 is pivotally supported to be able to swing up and down, and a rear wheel 15 is supported at the swinging end of the rear arm 14.

In this case, each main frame 4 is formed in a substantially straight line from the head pipe 3 side to the pivot portion of the rear arm 14. In other words, each main frame 4 has a box-shaped cross section as described above. In conjunction with this, it is formed to maintain sufficient strength against the load from the rear wheel 15 side.

Further, a shock absorber 16 is installed between the rear part of the main frame 4 and the rear arm 14 via a link mechanism 17. The shock absorber 16 buffers the impact transmitted from the rear wheel 15 side to the vehicle body frame 2 side, and is located at the center in the vehicle width direction and is slightly inclined forward.

In the above case, the shock absorber 16 is located between the rear portions of the left and right main frames 4° 4, and the upper end, which is one end side, of the shock absorber 16 is a left and right bracket that projects upward from the upper rear surface of each main frame 4. 4a, 4a by a pivot shaft 18. Further, at this time, the upper part of the shock absorber 16 overlaps each of the brackets 4a in a side view.

19 is a seat, and this seat 19 is attached to the main frame 4.
4 and the seat rail 8.8, the seat 19 covers the space between the left and right main frames 4.4 and the space between the left and right backstays 8.8 from above. Further, a straddle fender 20 is provided behind the seat 19.

Reference numeral 22 denotes a cycle engine 2 for driving the rear wheels 15, and this engine 22 is firmly supported by the vehicle body frame 2. At the rear of this engine 22 is a power transmission device 2.
3 are connected in series, and the rear wheel 15 is operatively connected to this power transmission device 23 by a chain transmission means 24. This chain transmission means 24 includes a driving chain wheel 26, a driven chain wheel 27 attached to the rear wheel 15, and both chain wheels 2B, 27.
The transmission chain 28 is wound around the transmission chain 28. The power of the engine 24 is transmitted to the power transmission device 23.
The signal is transmitted to the rear wheels 15 via the transmission chain 28 and the like.

1 to 5, the engine 22 has a crankcase 30, and a cylinder 31 projects forward from the crankcase 30, and a spark plug 32 is attached to the projecting end. Further, a carburetor 33, which is a fuel supply device, is attached to an intake boat formed at the front of the earthen wall of the crankcase 30. This carburetor 33 is provided between the rear portions of the left and right main frames 4.4, and is connected to an air cleaner 35 through an intake pipe 34.

On the other hand, an exhaust pipe 36 extends rearward from an exhaust boat formed on the rear surface of the forward-inclined cylinder 31, and a muffler 36a is attached to the exhaust pipe 36. A silencer 37 is attached to the rear end. In addition, the above-mentioned exhaust, trachea 3
6 extends rearwardly above the carburetor 33 and passes between the left and right main frames 4.4. When the engine 22 is in operation, the running air A is passed through the inlet holes 38 and air cleaners provided through each main frame 4. 35 and intake pipe 34 , this is mixed with fuel in the carburetor 33 , and this air-fuel mixture passes through the crankcase 30 and is sucked into the cylinder 31 . Then, it is combusted here, and thereafter passes through the exhaust pipe 36, muffler 36a, and silencer 37 in order and is exhausted to the rear of the vehicle body.

A fuel tank 3 made of sheet metal that feeds fuel to the carburetor 33
9 is provided. The fuel tank 39 includes a tank body 40 located in front of the crankcase 30 and below the cylinder 31, a tank left side 41 extending rearward from the left side of the tank body 40, and a tank left side 41 extending rearward from the right side of the tank body 40. It consists of an extending tank right side 42, which are formed as a body.

The upper surface of the tank body 40 is lower than the upper surfaces of the tank left side 41 and the tank right side 42, that is, a recess 43 is formed on the upper side of the tank body 4o. The maintenance 1 of the spark plug 32 is then carried out through this recess 43.
Inspection and replacement work is now possible.

Further, the fuel tank 39 is supported by the vehicle body frame 2 in the following manner.

That is, the upper surfaces of the tank left side 41 and the tank right side 42 are screwed to the corresponding main frames 4.4 by bolts 48, respectively. Further, a pair of left and right support pieces 44, 44 are protruded from the lower surface of the tank body 40. On the other hand, a support frame 45 is provided to protrude downward from the front and rear midpoints of each main frame 4, and each support frame 45 is connected to the left and right side surfaces of the cylinder 31 and the tank left side 4.
145 and the tank right side 42 and extends downward. Then, the support piece 44 is screwed to the lower end of each support frame 45 with a bolt 47 via a rubber Alfllr body 46, whereby the fuel tank 39
is supported by the vehicle body frame 2.

A radiator 50 for cooling the cylinder 31 is provided. This radiator 50 is screwed and fixed to the main frame 4.4 and the support frame 45, and when viewed from the side, the radiator 50 is attached to the cylinder 31.
It is located on the -F side of the fuel tank 39 and between the front fender 12 and each main frame 4, and is also located approximately at the center between the left and right main frames 4.4 when viewed from the front.

Side cowls 51 are provided on each side of the radiator 50, and these left and right side cowls 51.51 are formed to gradually expand as they move forward. Further, the protruding end of the cylinder 31 and the front upper surface of the fuel tank 39 are located between the lower ends of the left and right side cowls 51, 51 on the front side of the radiator 50. Therefore, the running wind A is guided by the left and right side cowls 51, 51, the protruding end of the cylinder 31, and the front upper surface of the fuel tank 39, and is forcibly sent toward the radiator 50, and is thus Therefore, the cooling effect of the radiator 50 is enhanced.

A discharge hole 52 is formed in a portion of each side cowl 51 between the radiator 50 and the main frame 4. Further, a resin guide i61 facing the radiator 50 is provided behind the radiator 50, and this guide plate 61 is installed between the left and right main frames 4.4,
In addition, each side end of this guide plate 61 is attached to the lower surface of each main frame 4 by screwing or gluing. The high temperature air after passing through the radiator 50 is guided outward by the guide plate 61, and is discharged outward from the vehicle body through the discharge hole 52. Note that the guide plate 61 may be made of sheet metal and welded to each main frame 4.4.

In the case of the above configuration, a large volume space 4 is provided in a portion surrounded by the left and right main frames 4.4, the lower surface 19a of the seat 19, J5, and the rear side of the guide plate 61.
9 is formed, and furthermore, this space 49 is connected to the guide plate 6.
Due to the function 1, it is a part that is not affected by the above-mentioned high temperature air.

Therefore, the air cleaner 35 is disposed in this space 49, that is, the space 49 is effectively utilized, and
The air cleaner 35 is installed so as not to impair its function.

The side cowls 51 are screwed to the main frame 4.4 and the radiator 50 with bolts 54.

Further, the front portion of the side cowl 51 covers the introduction hole 38 from the outside. The front part of the side cowl 51 guides the running wind A to the introduction hole 38, while also preventing the introduction hole 38 from being easily visible and preventing foreign matter from jumping into the introduction hole 38. ing.

According to the above embodiment, the heavy fuel tank 39, which was conventionally provided on the main frame 4, is provided below the main frame 4 and near the engine 22, thereby lowering the center of gravity of the vehicle. centralization and mass concentration will be achieved. Furthermore, since a lightweight air cleaner 35 is provided in place of the conventional fuel tank 39, the lowering of the center of gravity is even more effective.

On the other hand, a rigid protection plate 55 is provided to cover and protect the lower surfaces of the crankcase 30 and fuel tank 39. This protective plate 55 is dish-shaped and downwardly downwards, and brackets 56 are attached to the lower ends of each of the support frames 45 and the lower ends of the rear arm brackets 6.
They are firmly screwed together with bolts 57 and 58, respectively. Further, a protrusion 60 is formed on the lower surface of the fuel tank 39, and this protrusion 6o is fitted into the front part of the protection plate 55.

The intake passage 64 of the engine 22 will be described in detail with reference to FIG. 1 and FIGS. 5 to 8.

Each main frame 4 in front of the air cleaner 35.
As described above, the introduction holes 38 that connect the outside of each main frame 4 to the space 49 are formed in the portion 4, and each introduction hole 38 constitutes the upstream side of the intake passage 64. . Further, each of these introduction holes 38 is inclined toward the rear as it goes inward in the vehicle width direction.

The running wind A is smoothly introduced into the introduction hole 38 and is led to the space 49.

On the other hand, the inside of the intake pipe 34 constitutes the downstream side of the intake passage 64, and this intake pipe 34 is connected to the amphibious frame 4.
．． 4, the left main frame 4, a sheet metal material 66 attached to the inner surface of this left main frame 4, and a communication hole 68 provided through the rear of this sheet metal material 66 are guided to the inlet of the carburetor 33. It is composed of a communicating vibro 9 made of rubber. Further, in this case, a circular air intake lower 1 and a circular air ratio lower 2 are formed spaced apart from each other in the front and rear on the inner side plate of the left main frame 4 constituting the intake pipe 34. In addition, the above-mentioned communication vibro 9 is J! ! The shock absorber 16 is bent into an arc shape to avoid interference with the W1316, thereby bringing the shock absorber 16 sufficiently close to the engine 22 and concentrating its mass.

The air filtered by the traveling wind A passing through the air cleaner 35 is guided to the carburetor 33 through the intake pipe 34 . In this case, part of the air 7
3 once flows into the left main frame 4 through the air intake lower j, then is discharged from the main frame 4 through the air ratio lower 2, and then passes through the communicating vibro 9 to the carburetor 33. It is designed to be inhaled from the side. That is, the internal space of the left main frame 4 is filled with air cleaner 35.
It constitutes a part of the intake passage 64 that extends from the carburetor 33 to the carburetor 33.

In addition, 74 is a partition plate, and this partition plate 74 partitions the inside of the left main frame 4 into front and back.

Note that when the main frame 4 is formed by joining left and right halves in the middle, the partition plate 74 can be easily provided. However, if the main frame 4 is an extrusion molded product, it is not easy to provide the partition plate 74. Therefore, in this case, the partition plate 74 may not be provided.

By the way, as described above, the main frame 4 has a wide cross section and a vertically long box shape. As described above, since a part of the intake passage 64 is formed by the main frame 4, a sufficient cross-sectional area of the intake passage 64 is ensured. Furthermore, the main frame 4 extends linearly from the air cleaner 35 side toward the carburetor 33 side. Therefore, the intake resistance in this intake passage 64 is kept small.

Further, in the above configuration, the bracket 4a protruding from the left main frame 4 is hollow, and the space 7 inside thereof is hollow.
6 communicates with the inside of the intake pipe 34, that is, the space 76 constitutes a part of the intake passage 64. Further, in this case, the space 76 has a sufficient volume and serves as an air chamber.

(Effects of the Invention) According to the present invention, the internal space of the main frame, which has a wide box-shaped cross section, is made into at least a part of the intake passage leading from the air cleaner to the fuel supply device, so that the internal space of the main frame is utilized. Therefore, a sufficient cross-sectional area of the intake passage can be ensured.

Moreover, this main frame extends linearly from the air cleaner side toward the fuel/rice supply device side. Therefore, the intake resistance in the intake passage can be kept small, which is beneficial in terms of engine performance.

According to the above configuration, since the intake passage is formed using the main frame, the space in the vehicle body is narrower than in the conventional case where a separate intake pipe was provided for this intake passage. is prevented.

In other words, even if the main frame is shaped like a box with a wide cross section and the intake resistance of the intake passage is kept low, the space in the vehicle body is prevented from being narrowed, and the exhaust pipes and other components are The degree of freedom in installing the system will be sufficiently secured.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is a partially enlarged view of Fig. 2, Fig. 2 is an overall side view of the motorcycle, Fig. 3 is a partial plan view, Fig. 4 is a partial front view, and Fig. 4 is a partial front view. Figure 5 shows V-V in Figure 1.
! 6 is a sectional view taken along the line Vl--Vl in FIG. 1, FIG. 7 is a sectional view taken along the line ■--■ in FIG. It is a sectional view taken along the line ■-■. l...Motorcycle, 2...Heavy frame, 3...Head pipe, 4...Main frame, 14.Rear arm, 15.
- Rear wheel, 22... Engine, 33... Carburetor (fuel supply device), 35... Air cleaner, 64... Intake passage. Figure 8

Claims (1)

[Claims] 1. A pair of left and right main frames are extended rearward and downward from the head pipe, and a rear arm that supports the rear wheel is pivoted to the rear end of these left and right main frames, and the main frame is shaped like a box with a wide cross section. It is formed in a substantially straight line from the head pipe side to the pivot part of the rear arm, and an engine is provided below the main frame, and a fuel supply device for this engine is provided between the rear parts of the left and right main frames. In addition, in a motorcycle in which an intake air cleaner for the same engine is provided between the left and right main frames above the fuel supply device, the motorcycle has an internal space of the main frame as at least a part of the intake passage leading from the air cleaner to the fuel supply device. Intake passage for motorcycle engines.