JPH0651477B2 - Motorcycle body frame - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a left-right two-divided body frame in a motorcycle.

(Prior Art) Conventionally, for example, Japanese Unexamined Patent Application Publication No. Sho 5-
There is one disclosed in Japanese Patent Publication No. 9-53285.

According to this, the steering shaft tube that supports the steering shaft provided on the front fork and the pair of left and right frame bodies that extend rearward and downward from the steering shaft tube and are located apart from each other are provided. Has been.

(Problems to be Solved by the Invention) By the way, in order to facilitate the molding of the vehicle body frame, the steering shaft tube is divided into left and right parts, and the body frame is divided into left and right parts. Cast individually,
It is conceivable to connect these together.

However, when the body frame is divided into two as described above, the strength of the connecting portion between the divided steering shaft tube and the frame body extending from the steering shaft tube becomes insufficient. , The connection strength of the divided ones is insufficient,
There is a risk that the body frame may not have sufficient strength.

Further, the divided steering shaft tube and the frame main body have different shapes from each other, and a constriction or a bend is likely to occur between them.

Therefore, during casting, when the molten metal flows from one of the two molds to the other, the smooth flow of the molten metal is obstructed between the two molds, and the desired cast product may not be obtained. .

(Object of the Invention) The present invention has been made by paying attention to the above circumstances, and ensures sufficient strength in the vehicle body frame, and at the time of casting the vehicle body frame, allows the molten metal to flow smoothly, The purpose is to enable the desired casting.

(Structure of the Invention) A vehicle body frame of a motorcycle according to the present invention for achieving the above object is provided with a pair of left and right support members so as to wrap a vertically oriented steering shaft provided on a front fork from the left and right. A frame main body is extended from each support member so as to be directed rearward and downward and apart from each other to the left and right, and each support member and a frame main body corresponding thereto are integrally formed by casting, and the support member The vertical dimension and the vertical dimension of the connecting portion of the frame main body with respect to each of these supporting members are substantially the same, and fasteners for directly fastening the left and right supporting members to each other are provided at front and rear positions of the steering shaft. In a vehicle body frame of a motorcycle in which at least a pair of upper and lower sides are provided, and the steering shafts are supported by the left and right supporting members fastened to each other, ribs are provided on upper and lower edges of the connecting portion. While integrally projecting, boss portions are integrally formed on the upper and lower outer surfaces of the same connecting portion, and these boss portions are used as fastening portions by the fasteners on the rear side of the steering shaft. The respective bosses are brought close to the respective ribs, and the outer ends of the bosses are located at substantially the same position in the left-right direction as the outer surface of the support member.

(Operation) The operation of the above configuration is as follows.

The terms in parentheses below correspond to the terms in the claims.

Left and right semi-cylindrical bodies (support members) for supporting the steering shaft 3a
The vertical dimensions of 17, 17 and the vertical dimensions of the connecting portion 16 of the frame body 10 with respect to the respective semi-cylindrical bodies (support members) 17 are made substantially the same, and the ribs 11a are provided on the upper and lower edges of the connecting portion 16. 12b are integrally formed to project, and bolts (fasteners) 1 are provided on the upper and lower outer surfaces of the connecting portion 16 of the same as above.
Bosses 16a and 16a for 8'and 18 'are integrally formed.

Therefore, when traveling on an uneven road surface or the like, a large stress tends to be generated in the upper and lower portions of the connecting portion 16 by the external force applied to the vehicle body frame 2. However, this stress causes the ribs 11a and 12b to be damaged. The boss portions 16a, 16a effectively oppose each other. Therefore, the strength of the connecting portion 16 against the external force is sufficiently improved.

Moreover, the ribs 11a, 12b and the boss portions 16a, 1
6a and each semi-cylindrical body (supporting member) 17 are reinforced, and as described above, the vertical dimension of the frame body 10 in the connecting portion 16 is increased according to the semi-cylindrical body (supporting member) 17, Since the boss portions 16a and 16a are formed on the upper and lower portions of the connecting portion 16, the vertical bolts (fasteners) 18 'and 18' on the rear side of the steering shaft 3a are largely separated vertically. Therefore, it becomes possible to firmly fasten the two semi-cylindrical bodies (supporting members) 17, 17 to each other by these bolts (fasteners) 18 ', 18'.

By the way, the semi-cylindrical body (support member) 17 and the frame body 10 have different shapes from each other, and a constriction or a bend is likely to occur between them.

Therefore, when the molten metal flows from one of the two molds to the other during casting, there is a risk that the smooth flow of the molten metal may be hindered between the two molds.

Therefore, first, the boss portions 16a, 16a are brought close to the ribs 11a, 12b.

Therefore, the runner between the two molds has the ribs 11a, 1
2b and the boss portions 16a, 16a enlarge the area, so that the flow of the molten metal becomes smoother.

Further, secondly, the outer ends of the bosses 16a are located at substantially the same position in the left-right direction as the outer surface of the semi-cylindrical body (support member) 17.

For this reason, the inner surface of the runner between the semi-cylindrical body (support member) 17 and each mold of the frame body 10 has small irregularities, and thus the semi-cylindrical body (support member) 17 and the frame body 10 are formed.
The flow of the molten metal from one of the molds to the other mold becomes smoother.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

1 to 4, reference numeral 1 denotes a motorcycle, a front wheel 4 is supported on a front portion of a vehicle body frame 2 via a front fork 3, and a handle (not shown) is supported on an upper portion of the front fork 3. It On the other hand, a rear arm 6 is supported on the rear portion of the vehicle body frame 2, and a rear wheel 7 is supported on the rear end of the rear arm 6.

To explain the body frame 2 in more detail,
This body frame 2 has a double cradle type.

That is, a steering shaft tube 9 is provided in the front portion of the vehicle body frame 2, and the steering shaft tube 9 is provided on the front fork 3 via bearings 8 and 8 and extends vertically. Is supported. A pair of left and right frame bodies 10, 10 are provided so as to extend rearward and downward from both left and right sides of the steering shaft tube 9 and to be separated from each other.

The frame main bodies 10 are respectively extended from the respective side portions of the upper portion of the steering shaft tube 9 to the rear and lower sides, respectively, of the main frame 1.
1 and a sub-frame 12 extending below each of the main frames 11 from the respective side portions of the lower portion of the steering shaft tube 9 toward the rear lower side, and the main frame 11 and the sub-frame 12 are provided. The rear ends of the are connected to each other by a rear arm bracket 15.

An engine (not shown) is supported in the frame formed by the left and right main frames 11 and the sub-frame 12.

A rear frame 13 is screwed by a bolt 14 so as to project rearward from the rear portion of the main frame 11, and a seat (not shown) is supported on the rear frame 13.

The vehicle body frame 2 is formed by casting a light alloy aluminum (including aluminum alloy). In this case, the vehicle body frame 2 is a left and right half-divided type, and specifically has the following configuration. There is.

The steering shaft tube 9 is divided into left and right parts. That is, the steering shaft tube 9 is composed of a pair of left and right semi-cylindrical bodies 17, 17 that support the steering shaft 3a so as to sandwich the steering shaft 3a from the left and right.
The frame main body 10 extends from the upper part of each of the semi-cylindrical bodies 17 toward the rear lower side.
The vertical dimensions of each of the above semi-cylindrical bodies 17 and each of these semi-cylindrical bodies 1
The vertical dimension of the connecting portion 16 of the frame body 10 with respect to 7 is substantially the same.

The left and right assemblies of the semi-cylindrical body 17, the frame body 10 and the rear arm bracket 15 are each in a flat shape, and these are integrally formed by casting.

The body frame 2 is formed by joining the left and right assemblies to each other as follows.

That is, the left and right wall thickness dimensions of the left and right semi-cylindrical bodies 17, 17 are
In particular, as shown in FIG. 3, the rear side of the steering shaft 3a is larger than the front side thereof.

The two semi-cylindrical bodies 17, 17 are screwed in front of the steering shaft 3a by a pair of upper and lower front bolts 18, 18 which are fasteners. The steering shaft 3a is screwed to the rear side by a pair of upper and lower rear bolts 18 'and 18' which are fasteners. And, by this, the left and right semi-cylindrical bodies 17, 17
Are connected to each other, in this case the left and right semi-cylindrical bodies 17, 17
The mating surfaces of are directly joined.

In order to firmly connect the upper and lower ends of the both semi-cylindrical bodies 17 and 17, the connecting rings 19 and 19 are press-fitted onto the outer peripheral surfaces of the upper and lower ends of the semi-cylindrical bodies 17 and 17, respectively.

Same as above, a pair of upper and lower ribs 11a, 11b are integrally formed on the outer side surface of each main frame 11 so as to integrally project outward from the upper and lower edges of the side surface. The upper rib 11a of the two ribs 11a and 11b is extended to the upper edge of the frame body 10 in the connecting portion 16.

A pair of upper and lower ribs 12a and 12b are integrally formed on the outer side surface of each sub-frame 12 so as to integrally project outward from the upper and lower edges of the side surface. The lower rib 12b of the ribs 12a and 12b is extended to the lower edge of the frame body 10 in the connecting portion 16.

A pair of upper and lower boss portions 16a, 16a are integrally formed on the outer surfaces of the upper and lower portions of the connecting portion 16.
6a is a fastening portion for the bolts 18 ', 18'. Further, the boss portions 16a are placed close to the ribs 11a and 12b corresponding to the boss portions 16a.

Further, as shown in FIG. 3 in particular, the outer ends of the boss portions 16a are substantially at the same position as the outer surface of the semi-cylindrical body 17 in the left-right direction.

On the other hand, connection holes 20 and 20 are formed at the rear ends of the main frames 11 and the sub-frames 12, respectively, and both ends of the connection pipes 21 and 21 are fitted in and welded to the left and right connection holes 20 and 20, respectively. ing.

Then, as described above, the left and right main and sub frames 11,
The vehicle body frame 2 is formed by connecting 12 to each other.

Next, referring to FIG. 5, showing the state of the above assembly during casting, 22 is a mold, and this mold 22 is a lower mold 23 and an upper mold 2.
4, and the assembly is cast between the lower mold 23 and the upper mold 24. More specifically, the semi-cylindrical body 17
Of the main frame 11 and the sub-frame 12 in the vehicle width direction are formed on the upper surface of the lower mold 23, and the outer peripheral surface of the semi-cylindrical body 17 and the main ribs 11a and 11b are included. The outer surfaces of the frame 11 and the sub-frame 12 in the vehicle width direction are formed by the lower surface of the upper mold 24. 25 is a runway.

Although the above is based on the illustrated example, the rear frame 13 may be integrally cast with the main frame 11 and the sub frame 12.

(Effect of the Invention) According to the present invention, the vertical dimensions of the left and right support members for supporting the steering shaft and the vertical dimensions of the connecting portion of the frame main body with respect to these support members are made substantially the same. Ribs are integrally projected on the upper and lower edges of the connecting portion, and boss portions for fasteners are integrally formed on the upper and lower outer surfaces of the connecting portion.

Therefore, when traveling on an uneven road surface or the like, a large stress tends to be generated in the upper and lower portions of the connecting portion due to an external force with respect to the vehicle body frame, and the ribs and the boss portion have an effect on this stress. Against each other. Therefore, the strength of the connecting portion against the external force is sufficiently improved.

Moreover, the ribs and the boss portion reinforce each support member, and as described above, the vertical dimension of the frame main body at the connecting portion is increased in accordance with the supporting member, and the upper and lower portions of the connecting portion are the same. Since the boss was molded into
In particular, the vertical fasteners on the rear side of the steering shaft are largely separated vertically. Therefore, with these fasteners, the support members can be firmly fastened to each other, and the connection strength between the support members and the frame bodies can be improved.

Since the strength of each part is improved in this way, it is particularly useful for a vehicle body frame in which the left and right frame bodies are separated from each other and it is difficult to secure the strength.

By the way, the support member and the frame body have different shapes from each other, and a constriction or a bend is likely to occur between them.

Therefore, when the molten metal flows from one of the two molds to the other during casting, there is a risk that the smooth flow of the molten metal may be hindered between the two molds.

Therefore, first, the bosses are arranged close to the ribs.

Therefore, the runner between the two molds is enlarged by the ribs and the boss portion, so that the flow of the molten metal is smoothed by that amount and a desired cast product is obtained.

Further, secondly, the outer ends of the bosses are located at substantially the same position in the left-right direction as the outer surface of the support member.

For this reason, the inner surface of the runner between the supporting member and each mold of the frame main body has small irregularities, so that the flow of the molten metal from one of the supporting member and the frame main body to the other mold becomes smoother. The desired cast product is obtained.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, FIG. 1 is a simplified side view of a motorcycle, FIG. 2 is an exploded perspective view of a vehicle body frame, and FIG. 3 is a sectional view taken along the line III-III in FIG. FIG. 4 is a sectional view taken along the line IV-IV in FIG. 1 of the same as above, and FIG. 5 is a side sectional view when casting the left part of the divided body frame. 1 ... Motorcycle, 2 ... Body frame, 3 ... Front fork, 3a ... Steering shaft, 6 ... Rear arm, 10
...... Frame body, 11a ... rib, 12b ... rib,
16 ... Connection part, 16a ... Boss part, 17 ... Semi-cylindrical body (support member), 18, 18 '... Bolt (fastener).

Claims (1)

[Claims] 1. A pair of left and right support members are arranged so as to enclose a vertically oriented steering shaft provided on a front fork from the left and right, and the support members are respectively directed rearward and downward and separated from each other left and right. The frame main body is extended, and each of the support members and the corresponding frame main body are integrally molded by casting, and the vertical dimension of each of the support members and the vertical direction of the connecting portion of the frame main body with respect to each of the support members. At least one pair of fasteners having substantially the same dimensions and for directly fastening the left and right support members to each other are provided at the front and rear positions of the steering shaft, respectively. In a motorcycle body frame with a shaft supported, ribs are integrally formed on the upper and lower edges of the connecting portion, and boss portions are formed on the upper and lower outer surfaces of the connecting portion. The bosses are formed as a body and are used as fastening portions by the fasteners on the rear side of the steering shaft, the bosses are brought close to the ribs, and the outer ends of the bosses are supported by the supporter. The body frame of the motorcycle, which is located at approximately the same position in the left-right direction as the outer surface of the member.