JP4628841B2 - Motorcycle body structure - Google Patents

Description

  The present invention relates to a vehicle body structure of a motorcycle using an engine as a part of a vehicle body frame.

2. Description of the Related Art As a body structure of a motorcycle, one using an engine for a part of a body frame is known (for example, see Patent Document 1).
In this vehicle body structure, a front frame that supports a front fork via a head pipe and a rear frame that supports a seat above a rear wheel are coupled to the front and rear of the engine. The engine is disposed at a substantially lower position in the center of the vehicle body, and forms a substantially V-shaped skeleton structure together with the front frame and the rear frame. A fuel tank and a seat on which a rider sits are arranged side by side at an upper position from the front frame to the rear frame.
JP 2004-256005 A

  However, in this conventional motorcycle body structure, the fuel tank having a substantially flat bottom surface is disposed at the same height as the head pipe and straddles the upper side of the front and rear frames. If it is going to secure large, the amount of bulging from the upper part to the rear part of the fuel tank will increase. When the fuel tank bulges from the upper side to the rear side, the distance between the center of gravity of the rider seated on the seat behind the fuel tank and the center of gravity of the vehicle body increases, and the height of the center of gravity of the vehicle body increases. For this reason, improvement of this point is desired for improving the running performance of the vehicle.

  Therefore, the present invention is intended to provide a vehicle body structure of a motorcycle that can suppress the amount of bulging from the upper side to the rear side of the fuel tank and can advantageously improve the running performance.

As means for solving the above problems, the invention according to claim 1 is directed to a front fork (for example, a front fork 2 in an embodiment described later) via a head pipe (for example, a head pipe 8 in an embodiment described later). ) And a front frame (for example, a front frame 3 in an embodiment described later) and a rear wheel (for example, a rear wheel 5 in an embodiment described later) above a seat (for example, a seat 24 in an embodiment described later). A supporting rear frame (for example, a rear frame 6 in an embodiment described later) is coupled to the front and rear of an engine (for example, an engine 7 in an embodiment described later) to form a substantially V-shaped skeleton structure. fuel tank (e.g., a fuel tank 23 in the embodiment) over the upper side of the rear frame and the frame is placed with the sheet itself The vehicle structure of the two-wheeled vehicle, as well as disposing the fuel tank in a substantially V-shaped space formed by the rear frame and the front frame in a side view, the fuel tank, the bottom surface (e.g., 23a in the embodiment described later ) Bulges downward in a convex shape along the top surface of the engine, which is the bottom of the substantially V-shaped space , and the upper part is raised in a mountain shape, and the rear frame is formed in a substantially L shape. A portion of the rear frame that forms one side of the L-shape is integrally coupled to a side surface of a transmission portion of the engine (for example, a transmission portion 14 in an embodiment described later), and a swing arm that supports the rear wheel ( For example, a pivot (for example, a pivot 21 in the later-described embodiment) that supports the swing arm 11) in a later-described embodiment so as to swing up and down is provided. A link mechanism (for example, a link mechanism 22 in an embodiment described later) is provided at a lower position of the bot, and the upper end side is the swing arm below the portion that forms the other side of the rear frame and extends upward and rearward. The lower end of a rear cushion (for example, a rear cushion 12 in an embodiment described later) pivotally connected to the lower end is supported via the link mechanism .
In the case of the present invention, the fuel tank bulges toward the bottom of the V shape formed by the vehicle body skeleton. For this reason, the volume of the fuel tank is expanded to the vehicle body lower side.

According to a second aspect of the present invention, in the first aspect of the invention, the front frame includes a pair of main frames that extend obliquely rearward and downward from the head pipe and sandwich the front portion of the engine from the left and right. Then, at least the front part of the fuel tank is formed so as to have substantially the same width as the vehicle width of the left and right main frames and along the inclination of the upper surface of the main frame.
In this case, the volume of the fuel tank is further expanded.

According to a third aspect of the present invention, in the first or second aspect of the present invention, a front portion of the fuel tank (for example, a front portion 23c in an embodiment described later) is formed in a substantially U shape that opens forward. The engine intake system components (for example, the throttle body 17 and the air cleaner 18 in the later-described embodiment) are disposed in the substantially U-shaped opening (for example, the opening 25 in the later-described embodiment) of the fuel tank.
In this case, the volume of the fuel tank can be efficiently expanded while avoiding interference with engine intake system components.

  According to the present invention, the volume of the fuel tank can be expanded downward on the vehicle body by causing the bottom surface of the fuel tank to bulge downward along the shape of the upper surface of the engine. The amount of bulging from the rear to the rear can be suppressed, and the running performance can be further improved.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the directions such as front, rear, left and right in the following description are the same as those in the vehicle unless otherwise specified. In the figure, the arrow FR indicates the front side of the vehicle, and the arrow UP indicates the upper side of the vehicle.

  In the motorcycle 1 of this embodiment, the main part of the vehicle body frame has a front frame 3 that supports the front fork 2, a rear frame 6 that supports the seat 24 above the rear wheel 5, and a substantially center in the vehicle longitudinal direction. The engine block 7 includes a front frame 3 and a rear frame 6 that are coupled to the front and rear, respectively.

  A head pipe 8 is integrally coupled to the front end portion of the front frame 3, and the front fork 2 is supported on the head pipe 8 via a steering stay 20 so as to be steerable. A handle 9 is provided on the upper end side of the front fork 2, and a front wheel 10 is supported on the lower end side. The suspension 4 that supports the rear wheel 5 includes a swing arm 11 that pivotally supports the rear wheel 5 on the rear frame 6, and a rear cushion 12 that is interposed between the rear frame 6 and the swing arm 11. It is mainly composed.

  In the engine 7 of this embodiment, a lower half of an engine main body 13 that houses a cylinder, a piston, a crankshaft, etc. (not shown) and a transmission section 14 that also contains a clutch and a transmission (not shown) are housed in an integral casing. Thus, the engine main body 13 is inclined forward so that the upper end side of the cylinder faces toward the head pipe 8. The front frame 3 is constituted by a pair of main frames that are similarly provided on the left and right sides of the vehicle body so as to branch from the head pipe 8. The pair of main frames constituting the front frame 3 extend obliquely downward and rearward from the head pipe 8, and the rear ends of the main frames are the left and right side surfaces of the engine main body 13 (the front side surface of the case integral with the transmission unit 14). Are integrally coupled so as to sandwich the engine body 13 therebetween. A radiator 28 is disposed on the front lower side of the front frame 3.

  A throttle body 17 having an injector 16 protrudes vertically upward from the cylinder head 15 of the engine body 13, and an air cleaner 18 disposed on the rear side of the head pipe 8 is connected to the throttle body 17. Further, an exhaust pipe 19 extending to the rear side of the vehicle body is connected to the lower surface side of the front portion of the cylinder head 15.

  The entire rear frame 6 is substantially L-shaped, and the same shape is similarly provided on the left and right sides of the vehicle body. A portion forming one side of the L shape of the rear frame 6 is integrally coupled to the left and right side surfaces (the rear side surface of the casing integral with the engine main body portion 13) of the transmission unit 14 at two locations, upper and lower. A pivot 21 is provided at a substantially middle position of the transmission coupling portion of the rear frame 6, and the swing arm 11 is supported by the pivot 21 so as to be swingable in the vertical direction. Further, a link mechanism 22 is provided at a position below the pivot 21 and the transmission coupling portion of the rear frame 6, and the lower end of the rear cushion 12 whose upper end side is pivotally connected to the swing arm 11 is supported via the link mechanism 22. Has been. The portion of the rear frame 6 that forms the other side of the L-shape extends obliquely upward at the rear of the vehicle body and supports the seat 24 and the like.

On the upper side from the front frame 3 to the rear frame 6, a fuel tank 23 and a seat 24 on which a rider is seated are arranged side by side. The fuel tank 23 protrudes upward in a mountain shape on the front side of the seat 24, and the bottom surface 23a bulges downward to a position directly above the mission unit 14 so as to follow the upper surface shape of the engine 7, and the rear end The part 23 b goes around the lower side of the sheet 24. The front portion 23c side of the fuel tank 23 is formed to have substantially the same width as the vehicle width of the front frame 3 (the width of the left and right main frames extending in the vehicle width direction), and the lower edge thereof is inclined to the upper surface of the front frame 3 (left and right). The main frame is inclined so as to follow the inclination of the upper surface of the main frame.
Further, the front portion 23c of the fuel tank 23 is formed in a substantially U shape so that the center of the front surface is recessed, and a throttle body 17 and a part of the air cleaner 18 which are engine intake system components are disposed in the U-shaped opening 25. Has been.

In FIG. 1, 29 is a fuel tank cover that covers the periphery of the fuel tank 23 and the air cleaner 18 , and 129 is a fuel tank cover of a conventional vehicle shown for comparison with the fuel tank cover 29 in height. .

  The motorcycle 1 of this embodiment is coupled to the engine 7 so that the front frame 3 and the rear frame 6 form a substantially V shape in a side view as described above, and the bottom surface 23a of the fuel tank 23 is the bottom of the V shape. Since the upper surface of the engine 7 bulges downward in a convex shape, the volume of the fuel tank 23 is greatly expanded to the lower side of the vehicle body, and the amount of bulge from the upper side of the fuel tank 23 to the rear of the vehicle body is increased. This can be greatly reduced (see fuel tank covers 29 and 129 in FIG. 1).

Therefore, in this motorcycle 1, the position of the vehicle center of gravity G when the fuel is filled can be kept sufficiently low, and the seat 24 on which the rider is seated is placed low and forward so that the vehicle center of gravity G The rider's center of gravity Gm can be brought closer. In FIG. 1, Gm ′ is the rider's center of gravity in the case of a conventional vehicle.
Therefore, the motorcycle 1 that employs the vehicle body structure according to the present invention can further improve the running performance.

  In the motorcycle 1 of this embodiment, the front portion of the fuel tank 23 is substantially the same width as the vehicle width of the front frame 3 (a pair of main frames), and the upper surface of the front frame 3 (main frame) is inclined. Therefore, this is also advantageous in increasing the volume of the fuel tank 23 to the lower side of the vehicle body.

  Further, in this embodiment, the front portion of the fuel tank 23 is formed in a substantially U shape, and the throttle body 17 and the air cleaner 18 are disposed in the opening 25. Therefore, interference with the throttle body 17 and the air cleaner 18 occurs. Therefore, the fuel tank 23 can be sufficiently close to the upper surface of the front frame 3 to further expand the volume of the fuel tank 23.

  In addition, this invention is not limited to said embodiment, A various design change is possible in the range which does not deviate from the summary.

1 is a partially cutaway side view of a motorcycle showing an embodiment of the present invention. The expanded sectional view of the principal part of the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Motorcycle 2 ... Front fork 3 ... Front frame 5 ... Rear wheel 4 ... Suspension 6 ... Rear frame 7 ... Engine 8 ... Head pipe 17 ... Throttle body (engine intake system parts)
18 ... Air cleaner (engine intake system parts)
23 ... Fuel tank 23a ... Bottom 23c ... Front part 24 ... Seat 25 ... Opening

Claims (3)

A front frame (3 ) that supports the front fork (2) via the head pipe (8) and a rear frame (6) that supports the seat (24) above the rear wheel (5) are located in front of the engine (7) . and coupled to the rear a substantially V-shaped framework structure, the upper side and the fuel tank (23) across the seat of the previous frame (3) and the rear frame (6) (24) is arranged In the body structure of the motorcycle (1) ,
The fuel tank (23) is disposed in a substantially V-shaped space formed by the front frame (3) and the rear frame (6) in a side view, and the fuel tank (23) has a bottom surface (23a). Along the upper surface of the engine (7) which is the bottom of the substantially V-shaped space, and bulges downward in a convex shape, with the upper part raised in a mountain shape,
The rear frame (6) is generally formed in an L shape, and a portion of the rear frame (6) forming one side of the rear frame (6) is integrally coupled to a side surface of the transmission section (14) of the engine (7). And a pivot (21) for swinging up and down the swing arm (11) that supports the rear wheel (5).
A link mechanism (22) is provided at a lower position of the pivot (21), and the upper end is below the swing arm (11) below the portion of the rear frame (6) that forms the other side of the L-shape and extends upward and rearward. The vehicle body structure of the motorcycle (1) , wherein the lower end of the rear cushion (12) pivotally connected to the vehicle is supported via the link mechanism (22) . The front frame (3), constituted by a pair of main frames for clamping the front portion of the from the head pipe (8) extending downwardly obliquely rearward engine (7) from the left and right,
Automatic according to claim 1, wherein said the at least a front portion of the fuel tank (23) in the vehicle width substantially equal the width of the left and right main frames, and is formed along the inclination of the upper surface of the main frame Body structure of the motorcycle (1) . A front portion (23c) of the fuel tank (23) is formed in a substantially U shape that opens forward, and an engine intake system component (17, 18 ) is formed in a substantially U-shaped opening (25) of the fuel tank (23). body structure of a motorcycle (1) according to claim 1 or 2), characterized in that a.

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