JPH0364352B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a frame for a motorcycle, and more particularly to a frame that includes a pair of left and right main frames extending rearward and downward from the head pipe side.

(Prior Art) In the case of the frame described above, a large compressive or tensile load is applied to the main frame from the front and rear directions while the motorcycle is running. Therefore, conventionally, it has been proposed to make the main frame almost linear in side view so that the load is generally supported as an axial force of each main frame, that is, to firmly support the load. ing.

(Problem to be Solved by the Invention) Incidentally, the engine for driving a motorcycle is normally installed in the space below the left and right main frames mentioned above. If the main frame is formed into a substantially straight line when viewed from the side, the space for installing the engine will be narrower, compared to, for example, a case where the main frame extends backward from the head pipe side and then is bent downward. In other words, the degree of freedom in its installation is greatly restricted.

(Purpose of the Invention) This invention was made in view of the above-mentioned circumstances, and even when the rear-sloping main frame is formed into a substantially straight line when viewed from the side, the degree of freedom in installing the engine is limited. The purpose of the present invention is to prevent this from occurring and to ensure sufficient rigidity of the frame in such a case.

(Structure of the Invention) A feature of this invention to achieve the above object is that the gap between the left and right main frames at the position corresponding to the engine is wide, and the wide part of the left and right frames is connected from the head pipe side. The width between the left and right main frames is temporarily increased between the two main frames, while the width between the left and right main frames is gradually decreased from the wide part of the above towards the lower rear, and the engine is supported by the wide parts of the left and right main frames. That's what I did.

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

When the main frames 11, 11 are extended rearward and downward from the head pipe 14 side in a substantially straight line in side view, the space below the main frames 11, 11 becomes narrower, and the degree of freedom in installing the engine 8 in this space is increased. This may cause the inconvenience that the area is narrowed.

Therefore, in this invention, the space between the left and right main frames 11, 11 at the position corresponding to the engine 8 is widened,
Therefore, when installing the engine 8, for example, if the upper part of the engine 8 is fitted between the left and right main frames 11, 11 of the wide part,
A sufficient degree of freedom in installing the engine 8 is ensured.

In addition, when widening the left and right main frames 11, 11 as described above, the width dimension between the left and right main frames 11, 11 is gradually increased from the head pipe 14 side to the wide part of the left and right main frames 11, 11. On the other hand, the width dimension between the left and right main frames 11, 11 is gradually decreased from the wide part as shown above towards the rear and lower side.

As a result, each main frame 11 has a curved shape protruding outward in plan view, which is caused by
Compared to the case where the main frame 11 extends linearly rearward in plan view, greater rigidity can be exhibited against loads from the lateral direction.

By the way, as mentioned above, each main frame 11 in plan view
If the main frame 11 is curved, a bending moment will be applied to each main frame 11 due to loads applied to each main frame 11 in the front and rear directions. Therefore, the shape of the main frame 11 is such that the main frame 11 can withstand the load described above.
This causes a decrease in the rigidity of 1.

Therefore, in the present invention, the engine 8 is supported by the wide portions of the left and right main frames 11, 11, and the left and right main frames 11, 11 are connected to each other by the engine 8. Therefore, the main frames 11, 11
Decrease in rigidity due to widening a part of the engine 8 is prevented by supporting the engine 8 in this part.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

1 to 3 show a first embodiment.

In the figure, a motorcycle 1 has a body frame 2
, a front fork 3 pivotally supported on the front end of this body frame 2, and a steering handle 4 attached to the upper and lower parts of this front fork 3, respectively.
and a front wheel 5, a rear wheel 7 mounted to the rear of the vehicle body frame 2 so as to be vertically swingable via a rear arm 6, an engine 8 that drives the rear wheel 7 supported inside the vehicle body frame 2, and a vehicle body. It is mainly composed of a fuel tank 9 and a seat 10 supported on a frame 2.

The vehicle body frame 2 has a pair of left and right main frames 11, 1.
1. Both main frames 11, 11 are formed by bending a single circular pipe into a substantially U-shape when viewed from above, and are substantially linear when viewed from the side. It extends backwards and downwards.

The bent portion 12, which is a connecting portion between the front ends of the two main frames 11, 11, detours around the front of the head pipe 14 so as to pass approximately on an arc centered on the axis of the head pipe 14. The upper and lower parts of the head pipe 14 and the front end of the bent portion 12 are connected by a pair of upper and lower first reinforcing members 15, 15,
Also, the upper part of the head pipe 14 and each main frame 1
Main frame middle part 13, 13 which is the front and back middle part of 1, 11
and are connected by a pair of left and right second reinforcing members 16, 16 that gradually slope backward as they move toward the outside of the vehicle body.

In the lower area of the main frame 11, a pair of left and right lower frames 17, 17 protrudes from the lower part of the head pipe 14 toward the rear and lower side, and the rear ends of the lower frames 17, 17 and the middle part of the main frame 13, 13 are connected by connecting members 18, 18 which are upwardly shaped at the rear.

A midway portion of a rear upwardly shaped rear stay 19 is connected to the rear end of each main frame 11, and the rear end of this rear stay 19 and the rear part of the main frame 11 are connected by a rear connecting member 20.
This rear connecting member 20 extends rearward and has a free end. In the above case, both the connecting members 18 and 20 are disposed approximately on the same axis.

The front fork 3 is pivotally supported on the head pipe 14, and the rear arm 6 is rotated via a pivot shaft to a connecting plate 21 installed between the rear end of the main frame 11 and the rear stay 19. It is pivoted for free movement. In addition, first, second, and third fixing plates are attached to the connecting plate 22 installed between the rear part of each main frame 11 and the rear connecting member 20, the rear end of the lower frame 17, and the front end of the rear stay 19, respectively. The engine 8 is removably fixed via tools 23, 24, and 25.
Moreover, on the outer surface of the pair of left and right connecting members 18, 18,
A cowling 26 that covers the lower front surface and both sides of the engine 8 is detachably attached via a fourth fixing member 27.

The support frame 28 that supports the fuel tank 9 and the seat 10, or only the seat 10, includes a pair of left and right support frames 29, 29 in the front and rear longitudinal directions, and these support members 2.
The front end of each support member 29 is formed with a horizontal member 30 that connects the middle part of each main frame 11 with a horizontal member 30 that connects the middle part of each main frame 11 with a bolt or nut. The rear end of each support member 29 is removably fixed to the rear end extension portion of the rear connecting member 20 via a second fastener 33. . That is, the support frame 28 is the main frame 1
It is said to be removable compared to the 1st class.

In the above configuration, each main frame intermediate portion 13 corresponds to the engine 8 in plan view, and these left and right main frame intermediate portions 1
The area between 3 and 13 is formed to be wide.
A head cover 34, which is removably fixed to the cylinder head in the upper part of the engine 8 to cover the camshaft and the like, is fitted between the wide middle parts 13 of the left and right main frames.

In addition, as mentioned above, the left and right main frame middle parts 13, 13
When widening the main frame 11, 1 between the head pipe 14 side and the main frame middle part 13, 13,
1 such that the width dimension of each main frame 11 gradually increases.
is formed, and furthermore, the main frame middle part 13,
From 13 toward the rear and lower side, the left and right main frames 11, 11
Each of these main frames 11 is arranged so that the width dimension between them gradually decreases.
is formed.

Further, the first fasteners 32 fasten and secure the left and right sides of the head cover 34 to the corresponding main frame intermediate parts 13, 13, respectively, so that the engine 8 is supported by the main frames 11, 11. .

Although each of the above-mentioned frame members is illustrated as a circular tube, it may also be a rectangular cylinder or the like.

According to the configuration of the above embodiment, since the support frame 28 is removable together with the seat 10 from the main frame 11 etc., the cylinder head and the carburetor attached thereto,
This is advantageous because maintenance and inspection of each device located between the left and right main frames 11, 11, such as an air cleaner, becomes easy. Further, since the cowling 26 is not directly attached to the engine 8 but is fixed to the connecting member 18, the vibrations of the engine 8 are not directly transmitted to the cowling 26, which is advantageous because the cowling 26 is stably maintained.

Further, the width between the main frames 11, 11 gradually decreases toward the rear thereof, and the width at the rear of both is narrow. Therefore, when the rider straddles the vehicle body, the main frames 11, 11 are prevented from coming into contact with the rider's legs, and a predetermined knee grip can be obtained. Further, the wind from traveling is prevented from directly hitting the legs of the occupant.

4 to 7 show a second embodiment.

Hereinafter, to explain the configuration different from the above embodiment, each main frame 11 is formed of a square pipe with a rectangular cross section, and a front member 12 is provided between the front ends of the left and right main frames 11, 11.
A is being constructed. In this case, this front member 12
Both ends of a pass through the front end of the main frame 11 and are welded. Bent part 12 formed by all the above members 12a
The front member 12a is configured to bypass the front of the head pipe 14, and the upper and lower parts of the head pipe 14 and the front member 12a
The axial center portion of the upper and lower first reinforcing members 15,1
They are connected by 5.

The head pipe 14 and the main frames 11, 11 are connected by second reinforcing members 16 in two stages, upper and lower. The upper second reinforcing members are comprised of a pair of left and right upper reinforcing members 16a, 16a that directly connect the upper part of the head pipe 14 and the main midway portions 13 of the main frames 11,11.

In addition, the second reinforcing material at the lower stage is the head pipe 14.
The first horizontal member 16b is constructed between the main frame intermediate parts 13, 13 near the rear of the main frame, and a pair of left and right lower reinforcing members 16c are constructed between the lower part of the head pipe 14 and the first horizontal member 16b. Both of the upper and lower reinforcing members 16a and 16c are shaped to gradually tilt backward as they proceed from the head pipe 14 to the outside of the vehicle body.

The lower frame 17 includes a lower frame main member 17a that protrudes backward and downward from the main frame midway portion 13, and a lower frame supplementary member 17 that is constructed between the front end of the main frame 11 and the lower frame main member 17a.
It consists of b.

The connecting member 18 and the rear stay 19 have the same structure as in the previous embodiment, but the front ends of the left and right rear stays 19, 19 are connected to each other by a second horizontal member 19a. The rear connecting member 20 is installed between an auxiliary member 20a installed between the main frame 11 and the rear stay 19 and the rear end of the rear stay 19, and the rear connecting members 20 are connected to the third and fourth horizontal members 20b. , 20c.

The other configurations are the same as those of the previous embodiment, and the drawings show
Explanatory numerals used in the above embodiments are used to omit the explanation.

In the above-mentioned embodiment, since the main frame 11 is made of a square pipe, it is easy to process the butt portions with other members, which is advantageous.

(Effect of the invention) According to this invention, there are the following effects.

In other words, if the main frame is extended rearward and downward from the head pipe side in a substantially straight line when viewed from the side, the space below the main frame will become narrow, and the degree of freedom in installing the engine in this space will be reduced. There is a risk that this may occur.

Therefore, in this invention, the space between the left and right main frames at the position corresponding to the engine is widened, so when installing the engine, for example, the upper part of the engine must be fitted between the left and right main frames at the wide part. By doing so, a sufficient degree of freedom in installing the engine can be ensured.

In addition, when making the left and right main frames wider as described above, the width between the left and right main frames is gradually increased from the head pipe side to the wide part of the left and right main frames, and the width between the left and right main frames is gradually increased from the wide part to the rear. The width dimension between the left and right main frames is gradually reduced toward the bottom.

As a result, each main frame has a curved shape that protrudes outward when viewed from above, compared to a case where the main frames extend linearly rearward when viewed from above.
This means that greater rigidity can be exhibited against loads from the lateral direction. Therefore, this is beneficial as it improves the strength of the vehicle body frame.

By the way, when each main frame has a curved shape in plan view as described above, when a load is applied to the main frame from the front and rear directions, the rigidity against this load decreases, but this decrease in rigidity is due to the main frame's This is prevented by supporting the engine with a wide part, that is, by connecting the left and right main frames to each other by the engine, and thus ensuring sufficient rigidity in these main frames.

[Brief explanation of drawings]

The figures show embodiments of the invention, with figures 1 to 3 showing embodiments of the invention.
The figure shows the first embodiment. Figure 1 is an overall side view, Figure 2 is a plan view of the same, Figure 3 is a view taken along the - line in Figure 1, and Figures 4 to 7 are the second embodiment. For example, Fig. 4 is a side view of the main part, Fig. 5 is a view taken along the - line of Fig. 4, Fig. 6 is a view taken along the - line of Fig. 4, and Fig. 7 is a side view of the main part.
The figure is a view taken along the - line in FIG. 4. 1...Motorcycle, 2...Vehicle frame, 5...
...Front wheel, 6...Rear arm, 7...Rear wheel, 8...
Engine, 11... Main frame, 13... Main frame middle part (wide part), 14... Head pipe.

Claims (1)

[Claims] 1. A pair of left and right main frames are extended rearward and downward from the head pipe side in a substantially straight line when viewed from the side, and a rear arm for supporting a rear wheel is pivotally supported on the rear end side of the main frames.
In a motorcycle frame in which the engine is installed on the lower side of the main frame, the space between the left and right main frames at the position corresponding to the engine is formed wide, and the wide part of the left and right main frames is connected from the head pipe side to the frame. While gradually increasing the width between the left and right main frames, the width between the left and right main frames was gradually decreased from the wide part of the above towards the bottom rear, so that the engine was supported by the wide parts of the left and right main frames. Frame for motorcycles.