JPH064431B2 - Body frame for motorcycles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a casting frame obtained by aluminum die casting, to which a rear cushion unit is advantageously attached.

[Prior Art] A main frame portion that constitutes a vehicle body frame of a motorcycle is cast into two parts, left and right, using aluminum light alloy or the like, and a cross pipe is formed between recesses formed on the inner surface of the rear part of both the main frames. There is one in which the rear cushion unit upper end portion of the rear suspension is attached to a bracket provided in the middle part of the rear suspension unit. Also, in this example, a separate bracket that forms a rear swing arm support portion is joined to the rear portion of the main frame portion by post-processing (Japanese Patent Laid-Open No. 61-61160)
-215186 gazette).

[Problems of Prior Art] In the case of the above example, since the cross pipe which is separate from the divided main frame portion is used, the stress concentration on the holding portion becomes relatively large.

Further, as the cross pipe becomes longer, the load in the bending direction due to the upper end portion of the rear cushion unit is likely to be applied.

Furthermore, since the number of separate parts such as the bracket forming the rear swing arm support portion and the bracket provided on the cross pipe is relatively large, the number of man-hours on the assembly line is large.

In addition, it is desired that the mounting structure of the rear cushion unit be strong and simple, and further that a strong connecting portion for connecting the left and right divided frames be easily provided.

The present invention aims to solve these problems.

[Means for Solving Problems] A vehicle body frame for a motorcycle according to the present invention is composed of left and right divided frames obtained by casting, and a thick rear cushion unit mounting portion is provided on the left and right along the mating surfaces. Each of them is integrally provided, and a space into which the upper mounting end of the rear cushion unit can be inserted is formed on the mating surface of the rear cushion unit mounting portion, and the upper mounting end of the rear cushion unit is inserted in this space. The left and right rear cushion unit mounting portions are pivotally supported, and each of the left and right rear cushion unit mounting portions is provided with a shaft attachment portion for the upper end portion of the rear cushion unit and a coupling portion for the left and right split frames. To do.

[Operation of the Invention] The rear cushion mounting portion is formed integrally with the split frame and forms a thick rigid portion. Therefore, when the load applied to the upper portion of the rear cushion unit is transmitted to the rear cushion mounting portion, this load is widely distributed over the entire body frame, concentration of the load on the rear cushion mounting portion is avoided, and the rear cushion mounting portion is Since it is formed on the mating surface of the split frame, the support point spacing becomes narrower,
The load applied in the bending direction by the upper end of the rear cushion unit is reduced.

Further, since the rear swing arm support portion is integrated and the bracket provided on the cross pipe for attaching the upper end portion of the rear cushion unit is unnecessary, the number of parts is reduced.

Further, since the left and right rear cushion unit mounting portions are provided with the shaft mounting portions for the upper end portion of the rear cushion unit and the coupling portions of the left and right split frames, the rear cushion unit mounting structure is strong and simple. In addition, the rear cushion unit mounting portion can be used to form a strong joint between the left and right split frames.

[Embodiment] FIGS. 1 to 5 show an embodiment of the present invention. In the motorcycle shown in FIG. 1, reference numeral 1 is a handlebar, 2 is a front fork, and 3 is a front wheel. The front fork 2 is attached to the front end of the vehicle body frame 5 via a head pipe 4. P is a resin cover mounted above the vehicle body frame 5 and covering a fuel tank (not shown).

The body frame 5 is a diamond type frame,
The engine 6 is suspended and supported below it. A radiator 7 is attached to the front of the engine 6. A rear swing arm 8 is rotatably attached to a rear portion of the vehicle body frame 5, and a rear wheel 9 is supported at a rear end of the rear swing arm 8.

The vehicle body frame 5 is composed of left and right divided frames 10 and 11, and is formed by bolt connection so as to form a substantially U-shaped cross section that opens downward (see FIG. 4).

Each of the divided frames 10 and 11 is an integrally cast product by aluminum die casting, and has an average wall thickness of 2.5.
mm, which is the most advantageous in terms of correlation with moldability and strength.

The divided frames 10 and 11 are symmetrical,
Since the respective constituent parts are also formed symmetrically, the divided frame 10 (left side) will be described in principle in the following description. Therefore, in principle, the components of the right divided frame 11 are indicated by the same reference numerals as those of the left divided frame 10.

The split frame 10 extends below a front portion A, a main frame portion B that supports the engine 6 such as a fuel tank (not shown), a rear swing arm support portion C that is bent behind the main frame portion B, and a main frame portion B. And an extended portion D that The upper surface of the main frame portion B is folded back in the horizontal direction to form an upper wall surface E. Further, on the mating surface of the upper wall surface E, a mating portion F having a standing wall shape is formed in the front-rear direction.

The front portion A is provided with a head pipe mounting portion 12 that is curved and formed in a semi-cylindrical shape in order to hold the head pipe 4. A coupling portion 13 having a large number of bosses for bolting is formed at the tip portion thereof. Head pipe mounting part 1
A duct 14 is formed slightly behind 2 and a boss portion 15 for bolting is formed in the recess.
The duct 14 takes in outside air while traveling and also serves as a heat exhaust port of the radiator 7 when the vehicle is stopped.

The extension portion D is formed by a truss member 16 protruding downward from the main frame portion B in a triangular shape, and an opening 17 is formed inside thereof, and a bracket 16a provided on the front portion of the truss member 16 is formed. Attached to radiator 7
And also serves as a maintenance port for the cylinder head portion 6a of the engine. An engine hanger 18 is formed at the lower end.

A step portion is formed in the longitudinal direction on the side surface of the main frame portion B, and characters and the like are stamped on the step portion.

On the rear side of the main frame portion B, an opening portion 19 which is an adjustment opening in the upper part of the carburetor (not shown) is formed,
A mounting boss 20 and an engine hanger 21 are formed above and below it.

The rear swing arm support portion C is bent from the rear end portion of the main frame portion B and extends downward, and a pivot mounting portion 22 having a hole is formed in the center thereof, and an engine mounting hole is formed in the lower portion. 23, mounting holes 24a for step holders (not shown) and main stand mounting holes 25a, 25b
Are formed. A rear cushion unit mounting portion 26 is formed on the upper portion. The rear cushion unit mounting portion 26 forms a thick portion of the divided frames 10 and 11, and has a high rigidity structure.

A boss portion 24b to which the other side of the step holder is attached is formed below the rear cushion unit attachment portion 26.

The upper wall surface E has a boss 27 along the front-back direction of the mating portion F.
To 31 and bulges 32 to 34 for reinforcement are formed between adjacent bosses. Each boss 2
7 to 29 are reinforced by ribs 35 to 39.
Of these, the ribs 35 and 36 and the ribs 37 and 38 are formed so as to sandwich the bulging portions 32 and 33, respectively. Bulge 34
A rib 40 is formed at the center of the.

A substantially U-shaped notch 41 is formed between the bosses 29 and 30 of the upper wall surface E, and the left and right split frames 10 and 11 are formed.
When they are combined, the engine adjustment port is formed. Further, a cutout portion 42 for forming a cab adjusting opening is provided at a portion behind the cutout portion 41 and separating the mounting bosses 30 and 31. The rear cushion unit mounting portion 26 is thickly formed on the rear end edge portion of the notch portion 42 for reinforcement, and the shaft mounting portion 43 of the rear cushion unit and the left and right divided frames 10 and 11 are coupled thereto. The portion 44 is formed.

A large number of ribs are formed on the inner side surface of the divided frame 10. Of these, the front portion A and the main frame portion B are formed with ribs 45 intersecting with each other in a substantially rhombic shape, whereby the rib cross section is widened and a high strength structure similar to a honeycomb structure is obtained.

The rear swing arm support portion C is a pivot attachment portion 2
Mainly includes ribs 46 radially formed around the center 2 and ribs 47 that partially intersect the ribs 46 are provided. The ribs are densely arranged according to the required strength, and the pivot mounting portion 22 and the rear cushion unit mounting portion 2 are arranged.
The rear swing arm support portion C having 6 is the densest, and the main frame portion B is the roughest. Further, a rib 48 continuous in a triangular shape is also formed in the extended portion D portion.

Combining the divided frames 10 and 11, each boss portion 13 and 15
And 27-31 are bolted together. As a result, the strong body frame 5 is opened downward and has a substantially U-shaped cross section.
Is assembled.

Here, the mounting parts for the vehicle body frame 5 will be briefly described. First, the seat rail 50 is composed of a main pipe 51 and a reinforcing pipe 52, and mounting ends 53 and 54 are provided on each of them. The mounting ends 53 and 54 are mounted on the mounting boss 2.
0 and the connecting portion 44.

An upper mounting end 56 of a rear cushion unit 55 vertically installed in a space formed at the front end of the rear swing arm 8 is adapted to be supported by the rear cushion unit mounting part 26, and a lower mounting end thereof. The part 57 is connected to the bottom surface of the rear swing arm 8 by a bell crank 58, and one end of a link 59 connected to the bell crank 58 is fastened together with a main stand described later.

The main stand 60 has a pair of brackets 61 and 62, each of which has a main stand mounting hole 25a and 2
Mounting holes 63a and 63b facing 5b and a stand mounting hole 63c are formed. In addition, cross pipes 63d and 63e are horizontally provided between the brackets 61 and 62. One end of the link 59 is pivotally attached to the crossbar 63e. The stand leg 6 is provided in the stand mounting hole 63c.
The upper end of 4 is pivotally mounted.

FIG. 5 shows the upper mounting end 5 of the rear cushion unit 55.
6 shows a mounting structure for No. 6. That is, the notch 26b is formed along the mating surfaces 26a of the left and right rear cushion unit mounting portions 26. The notch portion 26b is a space for accommodating the upper mounting end portion 56 of the rear cushion unit 55, and the upper mounting end portion 56 is accommodated therein, and the bolt 43a and the nut 43b which are passed through the shaft mounting portion 43 from the lateral direction. It is attached by the bolt and nut connection.

As described above, the left and right rear cushion unit mounting portions 26 are tightly coupled to the coupling portion 44 by the bolts 44a and the nuts 44b, and at the same time, the mounting portion 53 of the seat rail 50 is also tightened.

Next, the operation of the embodiment will be described. Rear swing arm 8
The load due to the vertical movement of the link 59, the bell crank 58
Is transmitted from the lower mounting end portion 57 to the upper mounting end portion 56 via the rear cushion unit 55 and further transmitted to the rear cushion unit mounting portion 26. Then, the rear cushion unit mounting portion 26 is integrated with the divided frames 10 and 11,
Moreover, since the structure is thick and has high rigidity, stress concentration on the rear cushion unit mounting portion 26 is small, and this load is well dispersed to the entire body frame 5.

Further, the rear cushion unit mounting portion 26 has a mating surface 26.
Since it is formed in a, the support point interval with respect to the upper mounting end portion 56 becomes shorter, and the bending load from the upper mounting end portion 56 side is less likely to be applied.

Moreover, since the thickness of the rear cushion unit mounting portion 26 on the side of the divided frames 10 and 11 can be freely controlled by the mold shape at the time of casting, sufficient strength for supporting the rear cushion unit mounting portion 26 is ensured. .

Further, since the upper mounting end portion 56 is mounted using the notch portion 26b formed in the mating surface 26a, the bolt 43
It is sufficient to use a and the nut 43b, and no special bracket or the like is required. Also, the rear swing arm support portion C
Is integrally formed with the main frame portion B, the number of parts can be reduced as compared with the conventional case.

Furthermore, on the left and right rear cushion unit mounting portions 26,
Since the shaft mounting portion 43 is provided for the upper mounting end portion 56 of the rear cushion unit 55, the rear cushion unit mounting structure is strong and simple.

Moreover, since the rear cushion unit mounting portion 26 is provided with the joint portion 44 of the left and right divided frames 10 and 11, the rear cushion unit mounting portion 26 is effectively used to form a strong joint portion between the left and right divided frames 10 and 11. It can be easily provided.

EFFECTS OF THE INVENTION According to the present invention, the rear cushion unit mounting portion is integrally formed by utilizing the mating surfaces of the left and right divided frames, and the upper mounting end portion of the rear cushion unit is directly mounted on the rear cushion unit mounting portion. It is possible to satisfactorily disperse and absorb the entire body frame without concentrating on the rear cushion unit mounting portion.

Moreover, since the support point interval with respect to the upper mounting end can be shortened, the bending load from the upper mounting end is less likely to be applied to the rear cushion unit mounting portion. Therefore, the body frame can be further reduced in weight.

Moreover, since separate parts such as a cross pipe provided with a bracket for supporting the rear cushion unit and a bracket for supporting the swing arm as in the conventional case are not required, the assembling work becomes easy.

In addition, since the left and right rear cushion unit mounting portions are provided with the shaft mounting portion for the upper end portion of the rear cushion unit and the coupling portions of the left and right split frames, the rear cushion unit mounting structure is strong and simple. Besides,
By using the rear cushion unit mounting portion, a strong joint portion between the left and right split frames can be easily provided.

[Brief description of drawings]

1 to 5 show an embodiment, FIG. 1 is a side view of a motorcycle, FIG. 2 is a developed perspective view of a body frame and its mounting parts, and FIG. 3 is a side view of a body frame portion. 4 is a sectional view taken along the line IV-IV in FIG. 3, and FIG. 5 is an exploded perspective view of a main part. (Explanation of symbols) 5 ... Body frame, 10 ... Divided frame, 11 ... Divided frame, 26 ... Rear cushion unit mounting portion, 2
6a ... Mating surface, 26b ... Notch, 55 ... Rear cushion unit, 56 ... Upper mounting end.

Claims (1)

[Claims] 1. A left and right divided frame obtained by casting, and thick left and right rear cushion unit mounting portions are integrally provided along the mating surfaces, and a rear cushion is provided on the mating surface of the rear cushion unit mounting portions. Form a space where you can put the upper mounting end of the unit,
The upper mounting end of the rear cushion unit is interposed in this space to support the left and right rear cushion unit mounting parts, and the left and right rear cushion unit mounting parts are respectively attached to the upper end part of the rear cushion unit. A vehicle body frame for a motorcycle, characterized in that it is provided with a portion and a connecting portion of left and right divided frames.