JPH0331078A - Body frame of motorcycle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a body frame for a motorcycle that provides a comfortable riding feeling and has a simple structure that ensures rigidity.

[Prior Art] The body frame of a motorcycle includes a pair of left and right main frames made of extruded material extending rearward from a five-piece pipe and formed into a box-shaped cross section, and a pair of left and right rear arms provided with a pivot shaft that pivotally supports a rear arm. Some have brackets. An internal combustion engine is mounted on this body frame,
Since the rear arm is supported via the pivot shaft, it is formed to ensure a predetermined rigidity.

[Problems to be Solved by the Invention] A rider rides a motorcycle with his or her feet on a footrest provided near the bottom of a rear arm bracket, with the straddle lid closed. However, if the rider's legs are too tight against the main frame or rear arm bracket, there are problems such as it becomes unnatural to rest the feet on the footrest and increases rider fatigue.

In particular, in trial vehicles, riders ride with their legs sandwiching the vehicle body frame, so a solution to this problem is desired, but in this case consideration must be given to ensure that the rigidity of the vehicle body does not decrease.

This invention was made against this background,
To provide a motorcycle body frame that can easily ensure the rigidity of the body frame, provide good contact with the rider's legs, and provide a comfortable riding feeling.

[Means for Solving Eight Problems] In order to solve the above-mentioned problems, the present invention includes a pair of left and right main frames formed from extruded material extending rearward from a head pipe and having a box-shaped cross section, and a pivot that pivotally supports a rear arm. In a body frame of a motorcycle which has a pair of left and right rear arm brackets provided with a shaft and is connected to the main frame and the rear arm bracket, the pair of left and right main frames are formed by twisting the rear arm bracket side so that the upper side faces inward. The pair of left and right rear arm brackets is characterized in that the main frame sides thereof are inclined inwardly to connect the main frame and the rear arm bracket flush with each other.

[Operation] In this invention, a pair of left and right main frames are formed so as to be twisted inward on the rear arm bracket side, and the rear arm brackets are formed so that the main frames sides are inclined inwardly to each other, so that the main frame and the rear arm bracket are flush with each other. is connected to. For this reason, the connecting part between the main frame and the rear arm bracket has a smooth slope that follows the rider's legs, reducing the amount of contact with the rider's legs, resulting in a good riding position and a better foot rest. became natural,
Fatigue is reduced.

[Example] Hereinafter, an example of the present invention will be described in detail based on the accompanying drawings.

1 to 5 show an embodiment of the present invention applied to a trial vehicle, in which FIG. 1 is a side view of the motorcycle, FIG. 2 is a plan view of the body frame, and FIG. -I
II sectional view, Figure 4 is the rV-rV sectional view of Figure 2, and Figure 5 is the rV-rV sectional view of Figure 2.
The figure is a rear view of the motorcycle with some parts omitted.

In the figure, reference numeral 1 denotes a vehicle body frame, on which an internal combustion engine 2 is mounted, and on a head pipe 3 constituting the vehicle body frame 1, a front fork 5 on which a front wheel 4 is suspended is rotatably supported. It is steered by a bar handle 6.

The head pipe 3 has a pair of main frame side front parts 7a.
is welded and extends from the head pipe 3 to the rear of the vehicle body. The main frame 7 is made of extruded material and has a box-shaped cross section, and is formed substantially linearly when viewed from the side, and is twisted inward from a midway portion 7b to a rear portion 7c on the side of the rear arm bracket 8, as shown in FIGS. 2 and 4. As shown in FIG. 5, it is formed in a V-shape when viewed from the rear. For this reason, the pair of left and right main frames 7 have a shape in which the front parts 7a have parallel cross sections, are twisted at the center, and the upper cross sections face inward and approach each other at the rear part 7c, while the lower parts are separated from each other. It is formed into a twisting shape to provide rigidity,
It is designed to handle loads in the vertical and horizontal directions.

The lower part of the main frame 7 is reinforced by welding a reinforcement 9 whose front part is wide, and a cross member 10 is further welded to this welded portion. As shown in Figure 1, from the reinforcement 9, the stay 1 is inserted downward.
1 is welded, and the engine bracket 1 is attached to this stay 11.
3 are fixed, and the front side of the internal combustion engine 2 is supported by these,
The rear side is supported by a rear arm bracket 8. The lower part of the internal combustion engine 2 is covered with a protector 14 provided on an engine bracket 13 and a rear arm bracket 8.

The rear arm bracket 8 is formed by press molding, casting, forging, or the like.

The left and right pair of rear arm brackets 8 are connected at their lower and upper portions by cross members 15 and 16, and this rear arm bracket 8 is provided with a pivot shaft 17, on which the front portions 18a of the left and right rear arms 18 are pivotally supported. has been done. A rear wheel 19 is attached to the rear part 18b of the rear arm 18.
A rear sprocket 20 for transmitting power to the internal combustion engine 2 is provided, and a chain 22 is passed between the rear sprocket 20 and a drive sprocket 21 of the internal combustion engine 2.

A link mechanism (not shown) is provided between the rear arm 18 and the rear arm bracket 8, and a lower end portion of the reaction 23 is provided in this link mechanism.
3 is attached to a support shaft 24 provided at the seat rail attachment portion 8a of the rear arm bracket 8.

As shown in FIGS. 2 and 5, the rear bracket 8 is parallel to the pivot shaft 17 downwardly, and a footrest 25 is provided at the lower part of the rear bracket 8. A main frame connecting portion 8b is formed, and the rear portion 7C of the main frame 7 and the main frame connecting portion 8b of the rear arm bracket 8 are connected flush with each other by welding. Therefore, this connection part is on the inside in the width direction of the vehicle, and the connection part to the rider's legs forms a smooth slope that follows the rider's legs, so the rider's legs are less likely to hit, resulting in a good riding position. Moreover, stepping onto the footrest 25 becomes natural and fatigue is reduced.

Seat rail installation of rear arm bracket 8 ilN+8
As shown in FIGS. 2 and 5, the main frame connecting portion 8 extends upwardly and inwardly from the main frame connecting portion 8b. A reaction 23 is attached to the support shaft 24 on this seat rail mounting portion 8a.
The tip of the seat rail 26 is tightened and fixed together with the upper part 23a of the seat rail 26, and the seat rail 26 extends to a position above the rear wheel 19, and is further supported by the rear arm bracket 8 via a stay 27. Seat 2 is placed on the seat rail 26.
8 is placed on the seat rail 26, and a lever fender 29 is attached to the seat rail 26.

The seat 28 covers the rear part of the fuel tank 30 mounted on the pair of main frames 7, and covers the rear part of the fuel tank 30.
It gives a sense of unity with.

As shown in FIGS. 3 and 4, the fuel tank 30 has a bottom 30a located on the main frame 7 at the rear of the main frame 7, and a bottom 30a of the fuel tank 30 located at the front of the main frame 7.
The bottom portion 30a of the main frame 7 is located between the main frames 7.

An exhaust pipe 31 connected to the front side of the cylinder of the internal combustion engine 2 passes from above the internal combustion engine 2 through a recess 30b formed in the bottom 30a of the fuel tank 30, and is silenced via the first silencer 32 and the second silencer 33. , this first silencer 3
2 is provided near the rear of the rear arm bracket 8,
The second silencer 33 is provided above the rear wheel 19.

An intake pipe 34 of the internal combustion engine 2 is connected to the rear side of the cylinder, a carburetor 35 is connected to this intake pipe 34, and a carburetor 35 is connected to the intake pipe 34.
An air cleaner 36 is connected to the air cleaner 3.
6 has a size that is positioned in the space formed by the seat rail 26 and the stay 27 when viewed from the side.

Figures 6 to ￥S8 show other embodiments in which the present invention is applied to sports cars, and Figure 6 is a side view of a motorcycle, N7
The figure is an enlarged side view of the main part, and Figure 348 is a cross-sectional view taken along the line -■ in Figure 7.

In the figure, reference numeral 40 denotes a vehicle body frame, and an internal combustion engine 41 is mounted on this vehicle body frame 40.
A front fork 43 is attached to the head pipe 42 that constitutes the
is rotatably supported.

Front parts 44a of a pair of main frames 44 are welded to the head pipe 42, and the main frames 44 are made of extruded material and have a box-shaped cross section.

The main frame 44 extends rearward from the helmet vibrator 42, is formed substantially linearly when viewed from the side as shown in FIG. It is shaped like a twist. This rear arm bracket 45 is also press-molded, cast, or
Alternatively, it is formed by forging or the like.

A reinforcement 46 is installed at the bottom of the main frame 44.
The internal combustion engine 41 is supported by a support vibe 47 welded to the reinforcement 46 and a rear arm bracket 45 connected to the main frame 44 .

A pair of left and right rear arm brackets 45 are connected at their upper and lower portions by cross members 48 and 49, and furthermore, a pivot shaft 50 is provided on the rear arm bracket 45, and the front portion of a rear arm 51 is pivotally supported on this pivot shaft 50. A rear sprocket 53 that transmits power to the rear wheel 52 is provided at the rear of the rear arm 51.
A chain 55 is provided between the engine 3 and the drive sprocket 54 of the internal combustion engine 41. The rear arm 51 is supported by the cross member 48 via a link mechanism 56, and a link 57 of the link mechanism 56 has a rear suspension 59 with a pin 58.
The lower end portion 59a of the rear arm bracket 45 is connected to the lower end portion 59a, and the upper end portion 59b is supported by the cross member 49 of the rear arm bracket 45 via a support shaft 60.

A footrest 61 is located below the rear arm bracket 45.
are provided, the upper parts from the pivot shaft 50 are inclined inwardly to each other, a main frame connection part 45a is formed, and the main frame connection part 45a is connected flush with the rear part 44C of the main frame 44 by welding,
As shown in FIG. 8, the vehicle width of this connecting portion is shortened and forms a smooth slope that follows the rider's legs.

Further, the upper part of the rear arm bracket 45 is inclined inward to face each other to form a seat rail attachment part 45b, and the tip of the seat rail 62 is tightened and fixed to the upper part with a bolt 63. It is supported via a stay 65 which is tightened and fixed to the lower part of the rail attachment part 45b with a bolt 64.

A seat 66 is placed on the seat rail 62.
The front side of the fuel tank 6 rests on a fuel tank 67 placed on a pair of main frames 44, giving a sense of unity. A carburetor 6 connected from this fuel tank 67 to a cylinder of the internal combustion engine 41
8, and an air cleaner 69 is connected to the carburetor 68. An exhaust pipe 70 is connected to the front side of the cylinder of the internal combustion engine 41, and the exhaust pipe 7o extends from below the internal combustion engine 41 to the rear.

[Effects of the Invention] As described above, in this invention, the main frame is made of extruded material and has a box-shaped cross section, and is formed in a shape that twists inward on the rear arm bracket side, and the rear arm brackets have the main frame sides inclined inwardly, Since the main frame and rear arm bracket are connected flush, this connection part forms a smooth slope that follows the rider's legs. Therefore, the contact between the main frame and the rear arm bracket with the rider's legs is reduced, resulting in a better riding position, allowing the rider's feet to rest naturally on the footrest, and reducing fatigue.

In addition, since the main frame is made of extruded material and is formed to be twisted, the main frame is made rigid through processing, and even though it is only made of extruded material, its rigidity can be increased.

[Brief explanation of drawings]

Figure 1~! Figure i45 shows an embodiment of this invention that was used as a trial vehicle, Figure 1 is a side view of the motorcycle, Figure 2 is a side view of the motorcycle, and Figure 2 is a side view of the motorcycle.
The figure is a plan view of the vehicle body frame, and Figure 3 is Figure 2 (7) I
II-II! Cross-sectional view, Fig. 4 is Fig. 2 No. rV-IV
A sectional view, FIG. 5 is a partially omitted rear view of the motorcycle,
6 to 8 show other embodiments in which the present invention is applied to a sports car, FIG. 6 is a side view of the motorcycle, FIG. 7 is an enlarged side view of the main parts, and FIG. It is a sectional view taken along ■-■ in the figure. In the drawings, reference numeral 1.40 is a vehicle body frame, 2.41 is an internal combustion engine, 7.44 is a main frame, 8.45 is a rear arm bracket, 17.50 is a pivot shaft, and 25.61 is a footrest. Figure 2 Figure 18 Figure 2

Claims (1)

[Claims] It has a pair of left and right main frames made of extruded material extending rearward from the head pipe and formed into a box-shaped cross section, and a pair of left and right rear arm brackets that are provided with pivot shafts that pivotally support the rear arms, and these main frames and rear arm brackets are connected. In the body frame of the motorcycle, the pair of left and right main frames are formed by twisting the rear arm bracket side so that the upper side faces inward, and the pair of left and right rear arm brackets have their main frame sides inclined inwardly, and A motorcycle body frame characterized in that a rear arm bracket and a rear arm bracket are connected flush with each other.