JPS6332071Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to body frames for motorcycles, tricycles, etc.

The body frames of current motorcycles and tricycles are made of metal, but due to the small size of the vehicles,
In order to meet the demand for weight reduction, fiber-reinforced resins have been attracting attention as a material. When the body frame is molded from fiber-reinforced resin, there is a main part that connects the front wheel suspension installed at the tip of the car body and a rear wheel suspension installed at the rear end of the car body, and a part that hangs down from the main part. It is preferable that the power unit is bonded to the down tube that supports the fixed power unit by adhesive.

The present invention was developed in view of the above points.The main body is made of fiber-reinforced resin, and the down tube is made of fiber-reinforced resin. A pair of down tubes is constructed of a square member with a square cross section molded from reinforced resin, and one side of the upper part of a pair of down tubes is fixed to the inner side of the wall surface of the down tube attachment portion of the main body, respectively, and the down tubes are expanded downward. The feature is that the down tubes are opened and arranged in a V-shape, and a reinforcing member is installed between the pair of down tubes in an X shape. The purpose is to increase the strength and support rigidity and strength of the down tube.

An embodiment shown in the drawings will be described below.

The vehicle body frame 1 is made of fiber-reinforced resin, and includes a main section (so-called top tube) 2 that connects a front wheel suspension system installed at the tip of the vehicle body and a rear wheel suspension system installed at the rear end of the vehicle body. A down tube 4 hangs down from the front part of the main part 2 and supports a power unit 3 such as an engine, and a down tube 4 hangs down diagonally rearward from the approximate middle part of the main part 2 to support the power unit 3 and pivotally support the rear wheel support link. Seat tube 5
, a seat stay 6 that hangs diagonally forward from the rear of the main body 2 and is integrally molded with its lower end connected to the seat tube 5, and a tail part 7 that extends rearward from the rear of the main body 2. . The trunk portion 2, the down tube 4, the seat tube 5, the seat stay 6, and the tail portion 7 are formed of fiber-reinforced resin shaped members having a predetermined structural cross section.

The fiber-reinforced resin used in the present invention includes a matrix such as epoxy resin, polyester resin, phenolic resin, etc., and a filament such as carbon fiber, aromatic polyamide fiber, glass fiber, silicon carbide fiber, poron fiber, alumina fiber, etc. It is a reinforced material.

As shown in FIG. 5, the structural cross section of the main body 2 in the vicinity of the connecting portion of the down tube 4 has a substantially U-shaped cross section with the lower part of the vehicle body open. That is, both left and right walls 2
a, 2b and an upper wall 2c are connected by inclined walls 2d, 2e, and the down tube 4 is formed in a pair of right and left slightly diagonally rearward from the front side walls 2a, 2b of the main body 2, and has a second As shown in the figure, a pair of down tubes 4, 4 are integrally joined and fixed to the inclined walls 2d, 2e of the main body 2 by fixing one side of the upper part to the inclined walls 2d, 2e so as to be arranged in a substantially "V" shape. .

As shown in FIG. 3, the cross-sectional structure of the down tube 4 has a hollow square cross-section. Further, the down tubes 4 are connected by an X-shaped reinforcing member 8 as shown in FIG. This reinforcing member 8 has rods 8a and 8b arranged diagonally from one down tube 4 to the other down tube 4 so as to intersect at the center, and the cross sections of the rods 8a and 8b are hollow corners as shown in FIG. A joint 8c having a U-shaped cross section is formed on one rod 8a at the intersection, and the other rod 8b is connected to the joint 8c.
c to form an X-shape, and the rods 8a,
The connecting portions 8d at both ends of the connecting portions 8b are also formed in a U-shape so that the down tube 4 can be fitted and connected.

Although this reinforcing member 8 is also molded from fiber reinforced resin, it may also be made from metal. .

A power unit mounting bracket 9 is inserted from the lower end of the down tube 4 and fixed with adhesive.
Furthermore, it is fixed with reinforcing bolts 10, and the power unit 3 is supported with bolts 11.

Since the down tube 4 needs to support the power unit 3, it is required to have a fairly thick wall, but by using the reinforcing member 8, support rigidity and strength can be obtained even if the down tube 4 is made thin. It will be done. That is, the reinforcing member 8 only needs to be applied to the portions of the down tube 4 that require supporting rigidity and strength, and even if the reinforcing member 8 is provided, the weight of the down tube 4 can be reduced compared to increasing the thickness of the down tube 4.

As described above, the present invention is made of fiber-reinforced resin, with the down tube having a rectangular section made of fiber-reinforced resin. Since the shape is made of a body and one side of the upper part of the pair of down tubes is fixed to the inner side of the wall surface of the down tube attachment part of the main body, it is lightweight and compared to a round piece whose diameter is the same as the length of one side of the square piece. Square timber has a longer circumference, which increases the joining area and increases the joining strength, so it is suitable for integrally joining the down tube to the main body using adhesives or screws, compared to butt joining. Increases bonding strength. In addition, a reinforcing member was installed in an X-shape between the pair of down tubes arranged in a V-shape.
Even if the wall thickness of the down tube is made thinner, supporting rigidity and strength can be obtained.In particular, the V-shaped down tube generates inward force against the support of the power unit, but the X-shaped reinforcing member reduces the inward force. The rigidity can be improved against the force of. Moreover, since the reinforcing member only needs to act on the parts of the downtube that require support rigidity and strength, even if the reinforcing member is provided, the weight of the downtube can be made lighter than when the downtube is made thicker.

[Brief explanation of drawings]

The figures show one embodiment of the present invention, in which Fig. 1 is a front view of the vehicle body frame, Fig. 2 is a side view of the down tube, Fig. 3 is a sectional view taken along the line A-A in Fig. 2, and Fig. 4 is a sectional view of the down tube. FIG. 2 is a sectional view taken along line BB, and FIG. 5 is a sectional view taken along line CC in FIG. 1 is a vehicle body frame, 2 is a main body, 3 is a power unit, 4 is a down tube, and 8 is a reinforcing member.

Claims (1)

[Scope of utility model registration request] A main part that connects a front wheel suspension system installed at the tip of the vehicle body and a rear wheel suspension system installed at the rear end of the vehicle body, and a pair of left and right down tubes that support a power unit that is fixedly fixed to the main part. In the vehicle body frame, the main body is made of fiber-reinforced resin, and the down tube is made of fiber-reinforced resin, and the down tube is made of fiber-reinforced resin. The shape member is made of a square cross-sectional body formed by molding, and one side of the upper part of a pair of down tubes is fixed to the inner side of the wall surface of the down tube attachment portion of the main body, respectively, and the down tubes are expanded downward. A vehicle body frame characterized in that the frame is arranged in a V-shape, and a reinforcing member is installed in an X-shape between the pair of down tubes.