JPH0245286A - Frame of motorcycle - Google Patents

Abstract

PURPOSE:To enable a driver to put his foot down onto the ground in a parallel multi-cylinder engine type motorcycle by setting the distance rearer than a main pipe seat rail provided on the way slantly downward in the rear direction to be in a range from the width of the seat rail to the width of a crank case. CONSTITUTION:A pair of right and left main pipes 6 connecting a head pipe 2 to a rear arm 9 are formed linearly slantly downward in the rear direction, and on its way, a seat rail 15 is formed. An engine 20 is mounted on a space surrounding the main pipes 6, down tube 7 and rear arm bracket 8, with its cylinder being inclined forward. The distance of the pipes 6 rearer than the rail 15 is set in a range from the right - left width of the rail 15 to that of a crank case 21. It is thus possible to improve foot resting performance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a motorcycle equipped with a parallel multi-cylinder engine, and particularly to the structure of its frame.

[Prior Art] A large force is applied to the frame of a motorcycle while it is running through the front fork and rear arm. Great rigidity is required for the front fork and rear arm pivots.

Therefore, in the past, for example, "Unexamined Japanese Patent Publication No. 58-1498
As seen in "Publication No. 74," the main pipe is formed in a substantially straight line extending rearward and downward when viewed from the side, and the bracket that pivotally supports the rear arm is made larger around the rear arm's pivot point. At the same time, the rigidity is increased by providing ribs, etc.

[Problem to be solved by the invention] However, according to this configuration, since the main pipe is tilted backward, the rear part of the main pipe passes directly above the engine crankcase, and is connected to the rear end of the main pipe. A large bracket will be positioned to recess the rear end of the crankcase.

In this case, the area around the rear of the crankcase is also the place where you can just put out your feet that have been removed from the footrest when you stop at a traffic light, for example, so these feet tend to interfere with the bracket. Then, since this bracket is provided with reinforcing ribs and a pivot shaft of the rear arm, there is a possibility that boots or pants may get caught on the shaft ends of these ribs or pivot shafts, impairing the ability of the rider to secure his/her feet.

The present invention was made based on these circumstances, and
To provide a frame for a motorcycle that can prevent the foot from interfering with a pivot part of a rear arm when the foot is put out at a stop, and improves the foot landing property.

[Means for Solving the Problems] Therefore, in the present invention, the pair of left and right main pipes connecting the head vibe that pivots the front fork and the pivot part of the rear arm are arranged so that the left and right main pipes are oriented diagonally downward at the rear when viewed from the side. A parallel multi-cylinder engine with a horizontal crankshaft is arranged below these main pipes, and a pair of left and right seat rails that support the seat and extend rearward are connected in the middle of the main pipes. However, the left-right distance at the rear of the main pipe located below the seat rail is wider than the left-right distance of the seat rail, and narrower than the left-right width of the crankcase of the engine.

[Function] According to this configuration, below the seat, the engine crankcase protrudes laterally than the pivot part of the rear arm that connects to the rear end of the main pipe.
For example, when you put your foot out when the car is stopped, the position of your foot is automatically determined by the crankcase, and your foot will never go inside the crankcase.

Therefore, the feet do not come into contact with the pivot portion of the rear arm, which has a complicated structure, thereby preventing damage to the boots and pants, and making it easier to put the feet on.

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

The frame indicated by reference numeral l in the figure is equipped with a head vibrator 2 at its front end. A front fork 3 is pivotally supported on the head vibe 2, and the front fork 3 is operated by a handle 4 and supports a front wheel 5 at its lower end.

A pair of left and right main vibrators extending diagonally downward toward the rear and a pair of left and right down tubes 7 extending downward are joined to the head vibrator 2. down tube 7
The lower end portion extends rearward below the main vibro, and a rear arm bracket 8 is joined between the rear end portions of these down tubes 7 and the rear end portions of the main vibro. A front end of a rear arm 9 is inserted between the rear arm brackets 8 and is pivotally supported via a pivot shaft 10, and a rear wheel 11 is supported at the rear end of the rear arm 9. There is.

Therefore, the main vibro connects the head vibrator 2 and the rear arm bracket 8, which is a pivot point of the rear arm 9, in a substantially straight line when viewed from the side.However, when viewed from above, as shown in FIG. As it moves toward the rear of the head vibrator 2, it protrudes to both the left and right sides, and is bent inward again at a position shifted rearward from the protruding end. From this, the main vibro has a curved portion 6a that bulges out laterally in the front half on the head vibrator 2 side, and the rear half 6b of the main vibro that is connected to the rear end of this curved portion 6a is connected to the rear arm bracket 8. The rear arm bracket 8 is connected to the rear arm bracket 8 with an interval equal to the left and right intervals.

Note that there is a cross member 1 between the front ends of the down tube 7.
2 is installed, and a tension pipe 1 is installed between the head vibrator 2 and the curved part 6a of the main vibrator.
3 has been constructed.

A pair of left and right seat rails 15 extending substantially horizontally toward the rear are joined in the middle of the main vibro. When viewed in plan, the front half 15a of the seat rail I5 is located above the rear half 8b of the main vibro and the rear arm bracket 8, as shown in FIG. They are inclined toward each other as they move toward the rear. Therefore, the left-right distance L2 of the front half 15a of the seat rail 15 is narrower than the left-right distance L1 of the rear arm bracket 8.

A midway portion of the seat rail 15 is supported by a backstay 16 extending upward from the rear arm bracket 8, and a seat 17 on which the driver A is seated is installed on the seat rail 15.

In addition, the engine 20 is located in the space surrounded by the main vibro, down tube 7 and rear arm bracket 8.
is installed. This engine 20 is a water-cooled parallel four-cylinder engine in which a crankshaft (not shown) is placed horizontally along the left-right direction of the frame 1, and the front end of the crankcase 21, which also serves as a transmission case, is attached to a bracket 2.
It is supported by a down tube 7 via a tube 9, and is also supported by a rear arm bracket 8 at three locations on the top and bottom of the rear end. Therefore, the rear end of the crankcase 21 is surrounded by the rear arm bracket 8 just below the seat I7, and the left-right width L3 of the rear part of the crankcase 21 is the width of the rear arm bracket 8 as shown in FIG. It is formed wider than the left-right distance L1.

Therefore, the crankcase 21 of the engine 20 protrudes on both left and right sides of the frame 1 immediately before the rear arm bracket 8, and as shown in FIG.
When cut vertically near the front end of the seat I7, a line X connecting this seat 17 and both left and right sides of the crankcase 21
1 is inclined so as to widen as it goes downward.

A cylinder 22 is provided on the upper surface of the front end of the crankcase 21 and is formed by four cylinders (not shown) arranged side by side in the left-right direction. As shown in FIG. 1, the cylinder 22 is located below the main vibro, and is tilted forward so that its cylinder axis is approximately parallel to the main vibro. A cylinder head 23 that covers this cylinder 22 is provided with four intake ports 24 that open upward. A vaporizer 25 is connected to each intake port 24, and these vaporizers 25 are located between the curved portions 6a of the main vibe 6. The carburetor 25 is connected to an air cleaner 26 placed directly above it, and this air cleaner 2B
is located immediately after head vibe 2.

A fuel tank 27 is located directly above the rear of the crankcase 21.
is located. The fuel tank 27 projects upward from between the main pipe B and the seat rail 15, and is located between the air cleaner 2B and the seat 17. Then, the air cleaner 26 and fuel tank 2
The periphery from the top surface to the side surface of 7 is covered by a cover 28 forming a conventional fuel tank shape, and this cover 28 is continuous with the front end of the seat 17. In this configuration, while driving the motorcycle For example, when the driver A stops at a traffic light, etc., the driver A lowers the foot B from the footrest (not shown) and places it on the ground, as shown by the imaginary line in FIG.
7, that is, near the pivot portion of the rear arm 9, and extends downward.

In this case, in the above configuration, both the left and right side surfaces of the crankcase 21 protrude laterally than the rear arm bracket 8, so when the foot B is put out when stopped, the position of the foot B is automatically adjusted due to the presence of the crankcase 21. Therefore, the foot B will not go inside the crankcase 21.

Therefore, the rear arm bracket 8 has a complicated structure.
This has the advantage that it prevents damage to boots and pants, and also makes it easier to put foot B on the ground.

[Effects of the Invention] According to the present invention described in detail above, when the driver puts his feet on the ground when stopping, the feet do not come into contact with the structurally complex pivot portion of the rear arm, thereby preventing damage to boots and pants. , which has the advantage of improving foot contact.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a partially sectional side view of a motorcycle, Fig. 2 is a plan view of the frame, and Fig. 3 is a partially sectional side view of a motorcycle.
The figure is a sectional view taken along an imaginary line in FIG. 1, and FIG. 4 is a front view of the frame. 2...Head vibe, 3...Front fork, 6
...Main vibe, 8...Rear arm bracket/nod, 9...Rear arm, 15...Seat rail, 17
... Seat, 20... Parallel multi-cylinder engine, 21.
··Crankcase.

Claims (1)

[Claims] A pair of left and right main pipes connecting the head pipe that pivots the front fork and the pivot part of the rear arm are formed in a substantially straight line diagonally downward to the rear when viewed from the side. In addition to arranging a stand-alone parallel multi-cylinder engine, a pair of left and right seat rails that support the seat and extend rearward are connected in the middle of the main pipe, and the rear part of the main pipe located below the seat rails is connected to the main pipe. A frame for a motorcycle, characterized in that a left-right distance is wider than a left-right distance between seat rails and narrower than a left-right width of a crankcase of the engine.