JP2764413B2 - Body structure of motorcycle - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vehicle body structure of a motorcycle.

(Related Art) Generally, in a motorcycle, a rear arm is pivotally supported on a body frame so as to be vertically swingable, and a rear wheel is supported on a swing end of the rear arm. Further, a shock absorber is provided for damping an impact transmitted from the running surface to the vehicle body frame via the rear wheels and the rear arm.

In addition to the above, there is the one configured as follows. That is, a cross member and a rear arm, which constitute a part of the body frame and extend in the vehicle width direction, are connected by a link mechanism, and the shock absorber is erected between the body frame and the link mechanism. The case is made of cast material, and a support piece is integrally provided on the crankcase, and a support piece is also provided on the cross member, and the two support pieces are fastened to each other to connect the crankcase portion to the cross member. Has been supported.

(Problems to be Solved by the Invention) In the case of the above-described conventional configuration, a part of the impact transmitted from the rear arm to the vehicle body frame side is transmitted to the cross member via the link mechanism, which is further transmitted via both support pieces. It will also be transmitted to the crankcase.

Therefore, in order to firmly support the engine with respect to the vehicle body frame, it is conceivable to increase the thickness of the support piece of the crankcase and the portion where the support piece protrudes to have the strength to withstand the impact. .

However, in this case, when casting the crankcase, the amount of molten metal in the combined portion of the support piece and the portion where the support piece is protruded is larger than that of the other portions, and the combined portion is accordingly increased. There is a possibility that a casting problem that a cast cavity or sink is easily generated may occur.

(Object of the Invention) The present invention has been made in view of the above-mentioned circumstances, and does not require a thicker part of a crankcase for connecting a link mechanism side, that is, a casting problem in a crankcase. An object of the present invention is to allow an engine to be firmly supported on a vehicle body frame without causing any problem.

(Structure of the Invention) A feature of the present invention for achieving the above object is that a pair of left and right rear arm brackets 6, 6 in which the body frame 2 extends in the vertical direction, and a pair of rear arm brackets 6, 6 which extend in the vehicle width direction. And a cross member 30 for connecting the lower ends of the rear arm bracket 6 to each other.
The rear arm 15 is pivotally supported on a swinging end of the rear arm 15 in the up and down direction in the middle of the rear wheel 16.
And a pair of left and right brackets 31, 31 project from the cross member 30 rearward and upward, with one end pivotally supported by the rear arm 15 and the other end positioned between the brackets 31, 31. A link mechanism 19 pivotally supported by a pivot shaft 32 is provided at the projecting end of both brackets 31, 31, and the upper end side of the rear arm brackets 6, 6 and the link mechanism 1 are provided.
In the motorcycle in which a shock absorber 18 is provided between the engine bracket 9 and the vehicle body frame 2, the engine 20 is supported on the vehicle body frame 2. (1) The side brackets 31, 31 and the A connecting member 47 made of sheet metal is provided in a space between the rear lower end portion of the crankcase 40, and the connecting member 47 is connected to a board 49 that is fastened to the crankcase 40 above the pivot shaft 32. A pair of left and right vertical plates 48, 48 integrally projecting forward and downward so as to enter the space between the cross member 30 and the rear lower end of the crankcase 40 from both ends of the board 49 in the vehicle width direction. And the above cross member 3
0, a pair of left and right support pieces 46, 46 are protrudingly provided.
Each of the vertical plates 48, 48 is fastened to the corresponding one of the brackets 6, 46 by a support bolt 51 parallel to the cross member 30. (2) As described above, the link mechanism pivotally supported by the protruding ends of the brackets 31, 31 This is the point that the other end of 19 and the connecting body 47 are located at substantially the same position in the vehicle width direction.

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

2 and 3, 1 is a motorcycle, 2 is a body frame thereof, and the body frame 2 has a semi-double cradle shape. That is, the vehicle body frame 2 has a head pipe 3 at a front portion thereof.
The main frame 4 extends rearward and downward from the upper part of the
A pair of left and right seat pillar tubes 5, 5 extend downward from the rear end of the main frame 4, and rear arm brackets 6 extending vertically are attached to the lower ends thereof.

On the other hand, there are provided a pair of left and right down tubes 7, 7 extending rearward and downward from the lower portion of the head pipe 3 and having their rear ends connected to corresponding lower ends of the rear arm brackets 6, 6, respectively. In this case, the rear end of each down tube 7 is screwed to the outer surface of the lower end of the rear arm bracket 6 with a bolt 8. A pair of left and right seat rails 9, 9 extend rearward and upward from the rear end of the main frame 4, and the rear end of each seat rail 9 is supported by the lower end of each rear arm bracket 6 by a back stay 10. .

A front fork 12 is supported on the head pipe 3 so as to be steerable. A lower end of the front fork 12 supports a front wheel, and a handle 13 is attached to an upper end of the front fork 12.

A rear arm 15 is pivotally supported by a pivot shaft 14 at a vertically intermediate portion of the rear arm brackets 6, 6 so as to be vertically swingable. A rear wheel 16 is supported on a swing end of the rear arm 15. Also, the upper ends of the seat pillar tubes 5, 5 on the upstream end side of the rear arm brackets 6, 6, and the rear arm 1
A shock absorber 18 and a link mechanism 19 are interposed between the shock absorber 5 and 5.

Reference numeral 20 denotes a four-cycle two-cylinder engine, which is located inside the body frame 2 and supported by the body frame 2. The engine 20 is provided with a drive chain 21, while the rear wheel 16 is provided with a driven chain 22,
A transmission chain 23 is wound around 1,22. Others
24 is a fuel tank and 25 is a seat.

If the rear wheel 16 is driven by the drive of the engine 20 via the transmission chain 23 and the like, the motorcycle 1 can run.

1 and 3, the shock absorber 18 and the link mechanism 19
Will be described in more detail.

The shock absorber 18 is a telescopic hydraulic cylinder damper 27.
And a spring 28 that urges the damper 27 in the extending direction. The upper end of the damper 27 is pivotally supported on the upper end of the seat pillar tube 5 by a pivot shaft 29.

On the other hand, the lower ends of the left and right rear arm brackets 6, 6 are
Cross members 30 extending in the vehicle width direction in the shape of a circular pipe are firmly connected to each other, thereby increasing the rigidity of the body frame 2. The cross member 30 is sufficiently reinforced by welding a patch 30a to the rear peripheral surface thereof,
The patch 30a includes a pair of left and right sheet metal brackets 3.
1,31 are welded. Each of the brackets 31 protrudes rearward and upward from the cross member 30.

One end of the link mechanism 19 has the rear arm 15
The other end is positioned between the brackets 31 and 31, and the projecting ends of the brackets 31 and 31 are pivotally supported by a pivot shaft 32.

Explaining the above configuration more specifically, the link mechanism 19 has a main link 33 pivotally supported by the left and right brackets 31 and 31 by a pivot shaft 32 so as to be vertically rotatable. The lower end of the damper 27 is pivotally supported by a pivot shaft 34 at the pivot end. Further, a pair of left and right connecting links 36, 36 is pivotally supported by a pivot shaft 37 in the front and rear halfway of the main link 33,
The pivotal ends of these connecting links 36, 36 are pivotally supported by pivot shafts 39 on brackets 38 projecting from the lower surfaces of the front and rear halfway portions of the rear arm 15.

The shock absorber 18 absorbs an impact transmitted from the running surface to the vehicle body frame 2 through the rear wheel 16 and the rear arm 15, and at this time, the link mechanism 19 operates as follows. In other words, when the rear wheel 16 receives an impact from the running surface and the rear arm 15 rotates upward while the motorcycle 1 is traveling, the link mechanism 19 causes the reduction amount of the damper 27 to be non-linear as the rear arm 15 rotates upward. This improves the ability of the rear wheel 16 to follow the running surface.

Next, the support structure of the engine 20 to the vehicle body frame 2 will be described in more detail.

In FIG. 2, the crankcase 40 of the engine 20 is shown.
Is formed by casting, and a lower front portion of the crankcase 40 is fastened to a middle portion in the front-rear direction of the down tube 7 by a fastener 41. The upper rear part of the crankcase 40 is a fastener
By 42, it is fastened to the middle part of the seat pillar tube 5 in the vertical direction.

1, 3 and 4, a vertically intermediate portion of a rear portion of the crankcase 40 is supported by the pivot shaft 14. That is, the pivot shaft 14 is mounted on left and right rear arm brackets 6, 6, and a front end of the rear arm 15 is a pair of left and right pivot pipes supported by the pivot shaft 14.
43,43. And the above crankcase 4
A projecting portion 44 integrally projecting from the rear portion of the shaft 0 is externally fitted to the pivot 14 between the left and right pivot pipes 43. That is, thereby, the rear part of the crankcase 40 is supported by the left and right rear arm brackets 6, 6 via the pivot shaft 14.

1, 3 and 4, a pair of left and right sheet metal supporting pieces 46, 46 are projected from the middle of the cross member 30 in the vehicle width direction by welding. The piece 46 protrudes forward from the cross member 30.

In a side view, a connector 47 is disposed in a space between the brackets 31, 31 and the rear lower end of the crankcase 40 of the engine 20. The connecting body 47 is formed by bending a single plate material, and includes vertical boards 48, 48 facing each other in the vehicle width direction, and a board connecting the upper ends of the vertical boards 48, 48.
49 and an inverted U shape when viewed from the front. The board 49 is located above the pivot shaft 32 and the crankcase 40
To the vertical plates 48, 48
Are the cross members 30 from both ends of the board 49 in the vehicle width direction.
And is integrally protruded forward and downward so as to enter a space between the crankcase 40 and the rear lower end.

Then, the vertical plates 48, 48 and the collar 50 sandwiched therebetween are fitted between the support pieces 46, 46, and the support bolts 51 parallel to the cross member 30 are used for the support pieces 51. 46,46, the engine 20
Are supported by the cross member 30.

Further, as described above, the other end of the link mechanism 19 pivotally supported by the protruding ends of the brackets 31, 31 and the connecting body 47 are located at substantially the same position in the vehicle width direction.

In the above configuration, if the rear wheel 16 receives an impact from the running surface while the motorcycle 1 is running, the rear arm 15 rotates upward as shown by the arrow A in FIG. Then, as shown by arrows B and C in the drawing, a part of the impact received by the rear arm 15
The information is transmitted to the cross member 30 via 36 and the front part of the main link 33. Further, the impact tends to be transmitted to the engine 20 via the support piece 46 and the connecting body 47. However, in this case, since the vertical plates 48, 48 of the connecting body 47 are made of sheet metal and can be slightly elastically deformed, the above-mentioned impact is applied to each of the vertical plates 48, 48.
Is absorbed by the above elastic deformation, and
The transmission of this impact to the engine 20 is suppressed.

In addition, in the above case, each vertical plate 48 of the connecting body 47 extends in a direction substantially orthogonal to the longitudinal direction of the front part of the main link 33 in a side view, that is, the front part of the main link 33 is crossed. Direction of impact load applied to member 30 (illustrated by arrow C in FIG. 1)
, Each vertical plate 48 has a shape that is easily bent by receiving a large bending moment due to the load. For this reason, the impact transmitted to the engine 20 side via the link mechanism 19 is more effectively reduced by the connecting body 47.

Although the above is based on the illustrated example, the connecting body 47 may be forged or cast as long as it is slightly elastically deformed, and its material may be any of iron, aluminum, and the like. .

According to the present invention, the vehicle body frame includes a pair of left and right rear arm brackets extending vertically and a cross member extending in the vehicle width direction and connecting the lower ends of the rear arm brackets to each other. The rear arm is pivotally supported up and down in the vertical direction of the rear arm bracket, and the rear wheel is supported at the swinging end of the rear arm. A pair of left and right brackets project upward and rearward from the cross member. A link mechanism that is pivotally supported at one end by the rear arm and positioned at the other end between the two brackets and at the protruding ends of the two brackets by a pivot shaft; and an upper end of the rear arm bracket. A motorcycle in which a shock absorber is installed between the side and the link mechanism, while an engine is supported on the body frame, 1) In a side view, a connecting member made of sheet metal is disposed in a space between the brackets and the rear lower end of the crankcase made of the engine, and the connecting member is placed above the pivot shaft. And a pair of left and right parts integrally projecting forward and downward from both ends of the board in the vehicle width direction into the space between the cross member and the rear lower end of the crankcase. And a pair of left and right support pieces projecting from the cross member, and the respective vertical pieces are fastened to these support pieces by support bolts parallel to the cross member.

For this reason, the crankcase of the engine is more firmly supported by the cross member of the body frame via the connecting body and the two support pieces.

By the way, when the motorcycle travels, a part of the impact from the rear wheel side is buffered by the shock absorber via the link mechanism. It is transmitted to the crankcase via the member, the two support pieces, and the connecting body.

However, in the above case, each of the vertical plates of the connecting body is made of sheet metal and has some elasticity, and furthermore, each of these vertical plates is formed of a substrate fastened to the crankcase above the pivot shaft. , Projecting until it enters the space between the cross member and the crankcase, that is, it is made to protrude more by utilizing this space, so that the impact from the link mechanism side is applied to each vertical plate of the connecting body. When transmitted to the protruding end portion, the vertical plates are greatly elastically deformed by the impact due to the large projection as described above, and the impact transmitted to the crankcase is reliably reduced. It will be.

Therefore, since the impact toward the portion of the crankcase where the substrate of the connecting body is screwed is reduced, the portion of the crankcase does not have to be too thick, and therefore, the crankcase is cast. If the crankcase is partly thickened in the case of molding, there is a possibility that cast cavities and the like may easily occur in the part, but this is avoided. In other words, the casting of the crankcase can be performed without any problem, and the impact is buffered as described above.
The engine will be more firmly supported.

In addition, in the above case, both brackets protrude rearward and upward from the cross member, while, in contrast to this direction, the vertical plates extend forward and downward from the board side fastened to the crankcase. It is protruding.

For this reason, in a side view, the two brackets and the two vertical plates are substantially parallel to each other, and an unnecessary large space is prevented from being generated between the two brackets and the two vertical plates. Will be made compact.

Therefore, as described above, although the engine is firmly supported, the effect of suppressing the generation of unnecessary surplus space in the vehicle body and making the vehicle body compact can be obtained.

(2) Further, as described above, the other end of the link mechanism pivotally supported by the protruding ends of the two brackets and the connecting body are located at substantially the same position in the vehicle width direction.

For this reason, when an impact is transmitted from the link mechanism side to the connecting body, the buffer is transmitted to the left and right vertical plates of the connecting body almost equally to each other, and the shock is caused by the elastic deformation of each vertical plate. Alleviated evenly.

Therefore, the impact transmitted to the crankcase is more effectively mitigated, and the effect that the engine is firmly supported on the body frame is further promoted.

[Brief description of the drawings]

1 shows an embodiment of the present invention. FIG. 1 is a partially enlarged view of FIG. 2, FIG. 2 is an overall side view of a motorcycle, and FIG.
FIG. 4 is a cross-sectional view taken along line III-III of FIG.
FIG. 4 is a partial cross-sectional view taken along line IV. 1 ... motorcycle, 2 ... body frame, 6 ... rear arm bracket, 15 ... rear arm, 16 ... rear wheel, 18 ...
… Buffer, 19 …… link mechanism, 20 …… engine, 30 ……
Cross member, 31… Bracket, 32… Pivot shaft, 40…
... Crankcase, 46 ... Support piece, 47 ... Connected body, 48 ...
… Vertical plate, 49 …… board, 51 …… fastener, 52 …… fastener.

Claims (1)

(57) [Claims] A vehicle body frame includes a pair of left and right rear arm brackets extending in a vertical direction, and a cross member extending in a vehicle width direction and connecting respective lower ends of the rear arm brackets to each other. A rear arm is pivotally supported in the middle part so as to be able to swing up and down, and a rear wheel is supported on the swinging end of the rear arm, and a pair of left and right brackets are projected from the cross member upward and rearward. A link mechanism pivotally supported by the rear arm and the other end is located between the brackets, and a link mechanism pivotally supported by a pivot shaft is provided at a protruding end of both brackets, and an upper end side of the rear arm bracket and the link mechanism are provided. A motorcycle in which an engine is supported by the vehicle body frame is provided between: (1) a side view; A connecting member made of sheet metal is provided in a space between the racket and the rear lower end portion of the crankcase made of the engine, and the connecting member is fastened to the crankcase above the pivot shaft. It comprises a board and a pair of left and right vertical plates integrally projecting forward and downward from both ends of the board in the vehicle width direction into the space between the cross member and the rear lower end of the crankcase. On the other hand, a pair of left and right support pieces protrude from the cross member, and the vertical plates are fastened to these support pieces by support bolts parallel to the cross member. (2) The protrusion of both brackets as described above A vehicle body structure for a motorcycle in which the other end of a link mechanism pivotally supported at an end and the connecting body are located at substantially the same position in the vehicle width direction.