JP2008296832A - Vehicle body frame structure for motorcycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle body frame structure for a motorcycle capable of optimizing rigidity balance of a vehicle body frame, reducing manufacturing cost and enhancing flexibility in design. <P>SOLUTION: The vehicle body frame structure for the motorcycle is provided with a head pipe 13; a main frame of an approximately quadrangle cross section rearwardly downwardly extending from the head pipe 13; a pair of right and left pivot plates 15 joined to a side surface of a rear part of the main frame 14; a pair of right and left upper rear part frame 16 joined to a rear part of the main frame 14 and extending rearwardly and upwardly; and a pair of right and left lower rear part frame 17 arranged below the upper rear part frame 16 and extending rearwardly and upwardly. A release side of a plate member 61 having an approximately C shaped cross section is joined to both side surfaces of a rear end of the main frame 14 and both side surfaces at a closure side of the plate member 61 are joined to the lower rear part frame 17. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a body frame structure of a motorcycle, and more particularly to a body frame structure of a motorcycle including a main frame and a pair of left and right upper rear frames and a lower rear frame extending rearward and upward from the main frame.

  As a conventional motorcycle body frame structure, a main frame having a substantially square cross section extending rearward and downward from the head pipe and a rear fork that pivotally supports the rear wheel joined to the rear side surface of the main frame are swingably supported. A pair of left and right pivot plates, a pair of left and right upper rear frames joined to the rear part of the main frame and extending rearwardly, and arranged below the upper rear frame, on the rear end of the main frame and on the back plate of the pivot plate A pair of left and right lower rear frames that are joined and extend rearward has been proposed (see, for example, Patent Document 1).

Japanese Patent No. 3548173

  By the way, in the body frame structure of the motorcycle described in Patent Document 1, both the pair of left and right upper rear frames and lower rear frame are joined to the main frame having a substantially rectangular cross section having high rigidity. However, it is necessary to extend the main frame to the rear, the cost is slightly high, and there is room for improvement in the yield of the main frame. Further, when attaching the pillion step to the lower rear frame for cost reduction, it is necessary to increase the pipe diameter in order to increase the strength of the lower rear frame. Further, when the engine is made compact and the width of the engine is reduced, it is necessary to reduce the interval between the pivot plates accordingly. In any case, since the distance between the pair of left and right lower rear frames is narrowed, in order to join the lower rear frame to the main frame, the width of the rear end of the main frame to which the lower rear frame is joined is pressed. There is a possibility that the manufacturing cost increases because it is necessary to reduce the width by processing or the like.

  The present invention has been made to solve such problems, and its purpose is to optimize the rigidity balance of the body frame, to reduce the manufacturing cost, and to increase the degree of design freedom. It is an object of the present invention to provide a motorcycle body frame structure that can be improved.

  In order to achieve the above object, the invention according to claim 1 includes a head pipe that rotatably supports a front fork that pivotally supports a front wheel, a main frame having a substantially rectangular cross section extending rearwardly downward from the head pipe, A pair of left and right pivot plates joined to the rear side surface of the main frame and pivotably supporting a rear fork pivotally supporting the rear wheel; and a pair of left and right upper rear frames joined to the rear part of the main frame and extending rearwardly A pair of left and right lower rear frames arranged below the upper rear frame and extending rearwardly, and having a substantially U-shaped plate member in cross section. The open side is joined to both sides of the rear end portion of the main frame, and the both sides of the closed side of the plate member are joined to the lower rear frame.

  The invention according to claim 2 is characterized in that, in addition to the configuration of claim 1, the plate member has a narrower width in the vehicle width direction toward the closing side disposed behind the motorcycle.

  The invention according to claim 3 is characterized in that, in addition to the configuration of claim 2, the portion where the width of the plate member is narrowed is a curved surface.

  According to a fourth aspect of the present invention, in addition to the configuration of the second or third aspect, a back plate for connecting the pair of left and right pivot plates in the vehicle width direction is provided, and the front ends of the pair of left and right lower rear frames are joined to the back plate. In addition, the inner width of the pair of left and right lower rear frames at the joint portion is narrower than the width of the main frame.

  According to the first aspect of the present invention, the open side of the plate member having a substantially U-shaped cross section is joined to both side surfaces of the rear end portion of the main frame, and both the closed side surfaces of the plate member are joined to the lower rear frame. Therefore, only a portion requiring high rigidity can be used as a main frame having a substantially rectangular cross section, and a portion not requiring rigidity as much as the main frame can be used as a plate member having a substantially U-shaped cross section. As a result, the rigidity balance of the vehicle body frame can be optimized, and the length of the main frame can be shortened to improve the yield, so that the manufacturing cost can be reduced.

  According to the invention of claim 2, since the plate member has a narrower width in the vehicle width direction as it is closer to the rear side of the motorcycle, the plate member is optimal in accordance with the distance between the pair of left and right lower rear frames to be joined. It can be formed into any shape.

  According to the invention of claim 3, since the portion where the width of the plate member is narrowed is a curved surface, the plate member and the lower rear frame can be easily and reliably formed even if the lower rear frame is constituted by a round pipe. Can be joined by welding or the like. Further, since the plate member is formed from a plate material, it can be easily processed into a curved surface by pressing or the like.

  According to the fourth aspect of the present invention, the pair of left and right pivot plates are connected in the vehicle width direction by the back plate, and the front ends of the pair of left and right lower rear frames are joined to the back plate. Since the inner width of the rear frame is narrower than the width of the main frame, the pair of left and right lower rear frames that are narrower than the width of the main frame can be reliably joined to the main frame via the pivot plate and the back plate. . Thereby, the rigidity of the rear end portion of the main frame can be ensured and the rigidity in the vicinity of the pivot plate can be improved. In addition, since the pair of left and right lower rear frames can be freely arranged, the degree of freedom in design can be improved.

  Hereinafter, each embodiment of the body frame structure of a motorcycle according to the present invention will be described in detail with reference to the accompanying drawings.

(First embodiment)
First, a first embodiment of a body frame structure for a motorcycle according to the present invention will be described with reference to FIGS. The drawings are viewed in the direction of the reference numerals.
1 is a side view of a motorcycle adopting a body frame structure of a motorcycle according to the present invention, FIG. 2 is a side view of the body frame shown in FIG. 1, FIG. 3 is a plan view of the body frame shown in FIG. 2 is a rear view of the vehicle body frame shown in FIG. 2, FIG. 5 is an enlarged perspective view of the main part of the vehicle body frame, FIG. 6 is a view taken in the direction of arrow A in FIG. 7 is a side view of the storage box shown in FIG. 7, FIG. 9 is a plan view of the storage box shown in FIG. 7, and FIG. 10 is a rear view of the storage box shown in FIG. In the following description, front and rear, left and right, and top and bottom are indicated as Fr in the front, Rr in the rear, L in the left, R in the left, R in the right, U in the upper, and D in the lower according to the direction viewed from the driver.

  As shown in FIG. 1, the motorcycle 10 of the present embodiment includes a vehicle body frame 11, and the vehicle body frame 11 supports a front fork 12 in a rotatable manner as shown in FIGS. 2 to 4. The head pipe 13, the main frame 14 extending downward from the head pipe 13, a pair of left and right pivot plates 15 joined to the rear part of the main frame 14 and extending downward, and joined to the rear part of the main frame 14 to rise rearward. A pair of left and right upper rear frames 16 that extend and a pair of left and right lower rear frames 17 that are disposed below the upper rear frame 16 and extend rearwardly are provided. Each member of the body frame 11 is joined by welding or the like.

  A front wheel WF is pivotally supported at the lower end portion of the front fork 12, and a handle 18 is attached to the upper end portion of the front fork 12. A front fender 19 is attached to the front fork 12 so as to cover the front wheel WF.

  A rear fork 20 that pivotally supports the rear wheel WR is supported on the pivot plate 15 in a swingable manner. A rear shock 21 is interposed between the upper rear frame 16 of the vehicle body frame 11 and the rear end of the rear fork 20. Provided.

  A power unit P configured by integrating the engine E and the transmission M is disposed below the main frame 14, and the power unit P includes a hanger plate 22 and a pivot plate 15 provided in an intermediate portion of the main frame 14. Supported by

  A throttle body 24 that adjusts the amount of air-fuel mixture supplied to the engine E is connected to the upper side wall of the cylinder head 23 of the engine E. An air cleaner 25 that cleans intake air is connected to the upstream end of the throttle body 24. Is connected. An exhaust pipe 26 is connected to the lower side wall of the cylinder head 23, and a muffler 27 for reducing exhaust noise is connected to the downstream end of the exhaust pipe 26.

  A fuel tank 28 is disposed above the rear wheel WR, and a storage box 30 for storing small items such as a helmet is disposed in front of the fuel tank 28. In addition, the upper part of the fuel tank 28 and the storage box 30 is covered with a tandem type riding seat 29 in the present embodiment, and the riding seat 29 is supplied with fuel to the fuel tank 28 and small items to the storage box 30. It is configured to be openable and closable so that it can be stored.

  In FIG. 1, reference numeral 41 is a side cover, reference numeral 42 is a leg shield, reference numeral 43 is a front cover, reference numeral 44 is an inner cover, reference numeral 45 is a rear side cover, reference numeral 46 is a rear fender inner, reference numeral 47 is a rear fender, reference numeral 48 is Grab rail, reference numeral 49 is a tail lamp, reference numeral 50 is a fuel pump cover, reference numeral 51 is a change pedal, reference numeral 52 is a main step, reference numeral 53 is a main stand, reference numeral 54 is a side stand, reference numeral 55 is a pillion step holder, reference numeral 56 is a pillion step Reference numeral 57 denotes a chain cover.

  In the vehicle body frame 11 of the present embodiment, as shown in FIGS. 2 to 6, the main frame 14 is composed of a pipe member having a substantially square cross section. The pivot plate 15 is joined in parallel so as to extend downward.

  In this embodiment, the open side of the plate member 61 having a substantially U-shaped cross section is joined to both side surfaces of the rear end portion of the main frame 14. A pair of lower rear frames 17 are joined. Further, the plate member 61 has a narrower width in the vehicle width direction toward the closed side disposed behind the motorcycle 10, and the corners on both sides of the closed side of the plate member 61 with the reduced width are arc-shaped. A curved surface portion 61a is formed. The radius of the curved surface portion 61a is set to be approximately the same as the radius of the outer peripheral surface of the lower rear frame 17 that is a round pipe. Thereby, the lower rear frame 17 and the curved surface portion 61a of the plate member 61 are reliably joined. Further, a top plate 62 is joined to the upper end surface of the substantially U-shaped plate member 61 so as to close the opening formed by the plate member 61 and the main frame 14. The rigidity of is strengthened.

  Further, in the present embodiment, a back plate 63 that connects the pair of left and right pivot plates 15 in the vehicle width direction is joined to the rear end surfaces of the pair of left and right pivot plates 15. It is formed in a U shape. Further, a pivot pipe 64 is fixed to the pair of left and right pivot plates 15 so as to penetrate the pair of left and right pivot plates 15 in the vehicle width direction, and the front end portion of the rear fork 20 is rocked to the pivot pipe 64. It is supported movably.

  In the present embodiment, the front end portions of the pair of left and right upper rear frames 16 are joined between the hanger plate 22 and the pivot plate 15 on both side surfaces of the rear portion of the main frame 14 so as to extend rearwardly. Further, the middle part and the rear end part of the pair of left and right upper rear frames 16 are connected by cross members 65 and 66 in the vehicle width direction.

  In the present embodiment, the pair of left and right lower rear frames 17 are disposed below the pair of left and right upper rear frames 16, and the front ends thereof are joined to the rear surface of the back plate 63 so as to extend rearwardly. In addition, the rear end portion is joined to the middle lower portion of the upper rear frame 16. Further, as shown in FIG. 6, the inner width W2 of the front end portion of the pair of left and right lower rear frames 17 joined to the back plate 63 is set to be narrower than the width W1 of the main frame 14. Further, the pair of left and right lower rear frames 17 are connected to the pair of left and right upper rear frames 16 by a reinforcing frame 67, thereby increasing the strength. Furthermore, a holder mounting member 68 for mounting the pillion step holder 55 is provided on the outer surface of the middle part of the pair of left and right lower rear frames 17.

  Further, mounting brackets 69 and 70 for fixing the storage box 30 are provided on the rear upper surface of the main frame 14 and the intermediate upper surface of the pair of left and right upper rear frames 16.

  The storage box 30 is a bottomed box-shaped member made of synthetic resin and opened upward. As shown in FIGS. 7 to 10, a bottom plate 31, a peripheral wall 32 extending upward from the outer peripheral edge of the bottom plate 31, and Is provided. Further, a bolt insertion hole 31 a for inserting a bolt for fastening the bottom plate 31 to the mounting bracket 69 of the main frame 14 is formed in the front portion of the bottom plate 31. A pair of left and right mounting stays 33 for mounting the storage box 30 to the mounting brackets 70 of the pair of left and right upper rear frames 16 are formed above the rear part of the peripheral wall 32. A bolt insertion hole 33a for inserting a bolt for fastening the mounting stay 33 into the mounting bracket 70 of the upper rear frame 16 is formed. A hinge portion 34 is formed above the front portion of the peripheral wall 32 so as to support the front end portion of the riding seat 29 so as to be opened and closed.

  The storage box 30 houses an electronic control unit 80, a battery 81, and electrical components 82 such as a fuse and a relay at the bottom thereof, and the upper part thereof is closed by the inner lid 35. Thereby, small items such as a helmet can be stored in the upper space of the inner lid 35.

  As described above, according to the body frame structure of the motorcycle of the present embodiment, the open side of the plate member 61 having a substantially U-shaped cross section is joined to both side surfaces of the rear end portion of the main frame 14, and the plate member In order to join both sides of the closed side 61 to the lower rear frame 17, only a portion requiring high rigidity is a main frame 14 having a substantially rectangular cross section, and a portion not requiring rigidity as the main frame 14 is substantially U-shaped in cross section. The plate member 61 can be formed. Thereby, the rigidity balance of the vehicle body frame 11 can be optimized, and the length of the main frame 14 can be shortened to improve the yield, so that the manufacturing cost can be reduced.

  Further, according to the vehicle body frame structure of the motorcycle of the present embodiment, the plate member 61 has a narrower width in the vehicle width direction toward the closed side disposed behind the motorcycle 10, and therefore the pair of lower left and right sides to be joined together. It can be formed into an optimum shape in accordance with the interval between the side rear frames 17.

  Further, according to the vehicle body frame structure of the motorcycle of the present embodiment, since the curved surface portion 61a is formed in the portion where the width of the plate member 61 is narrowed, even if the lower rear frame 17 is configured by a round pipe, The plate member 61 and the lower rear frame 17 can be easily and reliably joined by welding or the like. Further, since the plate member 61 is formed from a plate material, it can be easily processed into a curved surface by pressing or the like.

  Furthermore, according to the vehicle body frame structure of the motorcycle of this embodiment, the pair of left and right pivot plates 15 are connected in the vehicle width direction by the back plate 63, and the front ends of the pair of left and right lower rear frames 17 are joined to the back plate 63. Since the inner width W2 of the pair of left and right lower rear frames 17 at the joint portion is narrower than the width W1 of the main frame 14, the pair of left and right lower rear frames 17 having a distance W2 narrower than the width W1 of the main frame 14 is The main plate 14 can be reliably joined to the main plate 14 via the pivot plate 15 and the back plate 63. Thereby, the rigidity of the rear end portion of the main frame 14 can be ensured and the rigidity in the vicinity of the pivot plate 15 can be improved. In addition, since the pair of left and right lower rear frames 17 can be freely arranged, the degree of freedom in design can be improved.

(Second Embodiment)
Next, a second embodiment of the vehicle body frame structure for a motorcycle according to the present invention will be described with reference to FIG. Note that portions that are the same as or equivalent to those of the first embodiment are denoted by the same reference numerals in the drawings, and description thereof is omitted or simplified.
FIG. 11 is an enlarged perspective view of an essential part for explaining a second embodiment of the body frame structure of the motorcycle according to the present invention.

  As shown in FIG. 11, the vehicle body frame 90 of the present embodiment does not include the top plate 62 and the back plate 63 of the first embodiment, and the front end portions of the left and right lower rear frames 17 are connected to the pivot pipe 64. Directly joined. Also, above the pivot pipe 64, the lower surface of the main frame 14, the inner surfaces of the pair of left and right pivot plates 15, the upper outer peripheral surface of the pivot pipe 64, and the upper outer peripheral surface of the left and right pair of lower rear frames 17 are joined. An upper reinforcing plate 91 is provided. Further, below the pivot pipe 64, a lower reinforcing plate 92 joined to the lower outer peripheral surface of the pivot pipe 64 and the inner surfaces of the pair of left and right pivot plates 15 is disposed. The main frame 14, the pivot plate 15, the lower rear frame 17, and the pivot pipe 64 are connected to each other by the upper reinforcing plate 91 and the lower reinforcing plate 92, thereby increasing the strength. Rigidity is ensured.

As described above, according to the vehicle body frame structure of the motorcycle of this embodiment, the top plate 62 and the back plate 63 of the first embodiment are omitted, and the pair of left and right lower rear frames 17 are directly connected to the pivot pipe 64. Since the rigidity of the vehicle body frame 90 is ensured by the upper reinforcing plate 91 and the lower reinforcing plate 92, the number of parts can be reduced, and the manufacturing cost can be further reduced.
About another structure and an effect, it is the same as that of the said 1st Embodiment.

1 is a side view of a motorcycle adopting a body frame structure of a motorcycle according to the present invention. It is a side view of the vehicle body frame shown in FIG. FIG. 3 is a plan view of the vehicle body frame shown in FIG. 2. FIG. 3 is a rear view of the vehicle body frame shown in FIG. 2. It is a principal part expansion perspective view of a vehicle body frame. FIG. 3 is a view taken in the direction of arrow A in FIG. 2. It is a front view of the storage box shown in FIG. It is a side view of the storage box shown in FIG. It is a top view of the storage box shown in FIG. It is a rear view of the storage box shown in FIG. FIG. 6 is an enlarged perspective view of a main part for explaining a second embodiment of the body frame structure of the motorcycle according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Motorcycle 11 Body frame 12 Front fork 13 Head pipe 14 Main frame 15 Pivot plate 16 Upper rear frame 17 Lower rear frame 20 Rear fork 28 Fuel tank 29 Riding seat 30 Storage box 61 Plate member 61a Curved portion 62 Top plate
63 Back Plate 64 Pivot Pipe 65 Cross Member 66 Cross Member 67 Reinforcement Frame 90 Body Frame 91 Upper Reinforcement Plate 92 Lower Reinforcement Plate WF Front Wheel WR Rear Wheel W1 Main Frame Width W2 Interval (a pair of left and right lower rear frames at the junction) Inner width)

Claims (4)

A head pipe that pivotally supports a front fork that pivotally supports a front wheel, a main frame having a substantially quadrangular cross section extending rearward and downward from the head pipe, and a rear wheel that is joined to the rear side surface of the main frame. A pair of left and right pivot plates that swingably support the rear fork, a pair of left and right upper rear frames that are joined to the rear portion of the main frame and extend rearwardly upward, and are rearwardly disposed below the upper rear frame. A pair of left and right lower rear frames extending to the motorcycle body frame structure,
A plate member having a substantially U-shaped cross section, the open side of the plate member being joined to both side surfaces of the rear end portion of the main frame, and the both side surfaces of the closing side of the plate member being joined to the lower rear frame. The body frame structure of a motorcycle characterized by   2. The vehicle body frame structure for a motorcycle according to claim 1, wherein the plate member has a narrower width in a vehicle width direction toward the closing side disposed behind the motorcycle.   The body frame structure of a motorcycle according to claim 2, wherein the portion where the width of the plate member is narrowed is a curved surface.   A back plate for connecting the pair of left and right pivot plates in the vehicle width direction, front ends of the pair of left and right lower rear frames are joined to the back plate, and an inner portion of the pair of left and right lower rear frames at the joint portion; The body frame structure of a motorcycle according to claim 2 or 3, wherein a width is narrower than a width of the main frame.

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