JPH0299480A - Car body frame for motor bicycle and tricycle - Google Patents

Abstract

PURPOSE:To provide a frame constituting body made of castings which is light and high in strength by a method wherein a submember formed integrally with a main member and suspending an engine is formed in a tubular manner by means of a branch core branched from a main core for forming the hollow part of the main member. CONSTITUTION:A car body frame has a pair of frame constituting bodies made of castings joined with each other, and is provided with at least a submember formed integrally with a tubular main member and for suspending an engine. In this case, in casting of the frame constituting body, a plurality of sand cores 251 and 252 each having a main core 23 for forming the hollow part of the main member and a branch core 24 branched from the main core 23 to form the hollow part of the submember are placed in a recessed part 27 of a matrix 26. This method forms a cavity C for forming the frame constituting body which is formed between the sand cores 251 and 252 and the recessed part 27, and hollow part forming regions Ca and Cb for the main member and the submember, respectively, are formed.

Description

[Detailed Description of the Invention] A1 Object of the Invention (1) Industrial Application Field The present invention relates to body frames for motorcycles and tricycles, and in particular, includes a pair of left and right cast frame frames that are joined to each other, and The vehicle body consists of a pipe-shaped main member having a head pipe component at the front end and a swing arm support at the rear end, and an engine suspension sub-member integrally provided with the main member. Concerning frame improvements.

(2) Prior Art Conventionally, as this type of vehicle body frame, one in which sub-members are formed into a solid single-shaped cross section is known.

(3) Problems to be Solved by the Invention However, since the sub-members are formed thick in order to ensure their strength, the weight increases and it is not possible to meet the demand for weight reduction of the vehicle body frame. There's a problem.

An object of the present invention is to provide the above-mentioned vehicle body frame which can solve the above-mentioned problems.

B7 Structure of the Invention (1) Means for Solving the Problems The present invention comprises a pair of left and right cast frame structures that are joined to each other, each frame structure having a hend pipe structure at its front end and a hend pipe structure at its rear end. In a vehicle body frame for a motorcycle or three-wheeled vehicle comprising a vib-like main member each having a swing arm support portion at an end, and an engine suspension sub-member integrally provided with the main member, the sub-member is formed into a vib-like shape. In order to form the sub-member, the hollow part is formed by a branch core branching from the hollow part-forming soil core of the main member.

(2) Function When the sub-member is formed in the shape of a vibrator as described above, the weight of the sub-member is reduced, thereby reducing the weight of the vehicle body frame.

Furthermore, if the hollow part of the sub member is formed by a branch core branching from the main core for forming the hollow part of the main member, the main member forming area and the sub member forming area in the cavity of the mold are configured in series during casting, As a result, the molten metal flows smoothly between the two regions, and casting defects such as incomplete shape due to poor molten metal flow and pinholes due to gas entrainment are avoided.

For example, if the frame structure is configured such that the ends of the vibrator-like sub-members are connected to the outer circumferential wall of the main member, the main member and the sub-members are connected to each other by a part of the outer circumferential wall of the main member. A partition wall is formed that blocks the rain hollow part of the member.

When such a frame structure is cast, a turbulent flow of the molten metal occurs in the partition forming area of the cavity, which tends to generate pinholes (also, due to an increase in the volume of the partition forming area, the surrounding surface of the molten metal solidifies). As a result, the continuous portion becomes discontinuous, and stress tends to concentrate in that portion.

In the present invention, the above-mentioned partition wall does not exist, so the above-mentioned problem does not occur.

(3) Embodiment FIG. 1 shows a motorcycle M, and its body frame F is shown in detail in FIGS. 2 to 7. Body frame I? A pair of left and right castings (in the illustrated example, aluminum alloy castings) are connected to each other, and each frame structure 13,1 has a head vibrator component 2 at its front end. It also consists of a vibrator-like main member 4 each having a swing arm support portion 3 at its rear end, and an engine suspension sub-member 5 integrally provided with the main member 4.

As clearly shown in FIGS. 2 to 4, each frame structure 14
, 1 □, the opposing joint surfaces 6 on the front end side are abutted and welded together with the fuel tank supporting protrusion p in between, and the gutter-shaped head vibe component 2 is Upper and lower collars 7, . 7. are welded in a state where they are sandwiched, thereby forming the head vibrator 8.

Both frame structures 14.12 as shown in FIG.
A lower cross member 9 is attached to the lower end of the swing arm support portion 3. The swing arm 10 is attached to the lower cross member 9□ (Fig. 1), and both ends of the upper cross member 91 are welded to the upper ends of the swing arm support portions 3 of both frame structures 13.1□. is welded, and a seat support stay ti is attached to the upper cross member 9 (FIG. 1).

As clearly shown in FIG. 2, the sub member 5 has a substantially ■ shape,
Both ends thereof are connected to the lower surface of the main member 4. A support bracket 12 is protruded from the bottom outer surface of each sub-member 4, and includes a pair of support holes 13 and 14 of each support bracket 12, a support hole 15 at the lower end of each swing arm support part 3, and a support hole 15 at the lower end of each swing arm support part 3.
Two support holes 16 are used to suspend the engine E (FIG. 1).

The sub member 5 is formed in the shape of a vibrator, and both ends of its hollow part 17 are open to the hollow part 18 of the main member 4, and the rain hollow part 1
No partition wall exists on the boundary of 7.18.

By forming the sub-member 5 into a vibrator shape in this way, the weight of the sub-member 5 can be reduced and the weight of the vehicle body frame F can be reduced.

In the main member 4, thin partition walls 19 and 20 are provided in the intermediate portion between both the connecting parts of the sub member 5 and in the vicinity of the rear connecting part in the sub member 5, respectively. 20 is due to the fact that the rain hollow parts 18 and 17 of the main member 4 and the sub-member 5 are formed using a split sand core. Further, a plurality of sand removal holes 21 and 22 are formed in the main member 4 and the sub member 5, respectively. , 22 are closed with rubber lids or the like.

FIG. 8 schematically shows the casting work of the left side flange 1 and the structural body 11, and shows the soil core 23 forming the hollow part 18 of the main member 4.
and the hollow part 1 of the sub-member 5 branching from the main core 23.
7 and a branch core 24 forming a first. Second sand core 2
5. ．． 25□ is the amphibious core 23 in the recess 27 of the mold 26.
The end faces of the branch cores 24 and the end faces of both branch cores 24 are placed opposite to each other. In this case, the distance between both opposing end faces d,,d! is set narrowly.

This leads to the first. Second sand core 25. ．． 25□ and recess 27
A frame structure forming cavity C is defined in between, and the cavity C includes a hollow part forming area Ca of the main member 4 formed by the double core 23 and a sub member 5 formed by the double branch cores 24.
The hollow part forming region Cb is provided.

During casting, molten aluminum alloy is injected into the cavity C through a sprue (not shown). In this case, 1.
Second sand core 25. ．． Due to the integration of the soil core 23 and the branch core 24 in 25□, the main member forming area Ca and the sub member forming area cb are configured in series, so that a double-headed area Ca is formed.

The molten metal flows smoothly between the cbs, thereby avoiding casting defects such as incomplete shapes due to poor molten metal flow and pinholes caused by gas entrainment, resulting in high-quality and high-strength frames. Component 11 is cast.

As a result of this casting, partition walls 1920 are formed between the end faces of both live cores 23 and between the end faces of both branch cores 24, but the distance dl between the end faces facing each other.

Because d2 is narrow, the amount of molten metal existing between them is small, and therefore the shrinkage caused by solidification of the molten metal does not affect the surroundings of both partition walls 19 and 20. Rather, these partition walls 19, 20 provide a noise-muffling effect of blocking engine noise propagating within the vibrator frame structure 1.21□.

Note that the present invention is also applied to a body frame for a tricycle.

C0 Effects of the Invention According to the present invention, it is possible to provide a body frame for motorcycles and tricycles that is lightweight, has a high-quality and high-strength casting frame structure, and is capable of meeting demands for weight reduction. Can be done.

BRIEF DESCRIPTION OF THE DRAWINGS The drawings show an embodiment of the present invention; FIG. 1 is a side view of a motor vehicle, FIG. 2 is a side view of a vehicle body frame, and FIG. 3 is a side view of a vehicle body frame. Fourth
．． Figure 5 is a view from the arrows III, IV, and V in Figure 2, and Figure 6.
Figure 7 is a cross-sectional view of Figure 2 along lines v+-vi and VU-■, and Figure 8.
The figure is a sectional view showing an outline of the casting operation, and corresponds to FIG. 2. E...Engine, F...Vehicle frame, 1. ,．． 1
□...Frame J/structure, 2...Head vibe component, 3...Swing arm support part, 4...Main member, 5...(J part, 17.18... Hollow part, 2
3... Main core, 24... Branch core Patent applicant Honda Motor Co., Ltd. Agent Kendo Ochiai 1) Takahide Naka

Claims (1)

[Claims] A pair of left and right casting frame structures are joined to each other, and each frame structure includes a pipe-shaped main member having a head pipe structure at the front end and a swing arm support at the rear end, and In a vehicle body frame for a motorcycle or tricycle that includes an engine suspension sub-member integrally provided with a main member, in order to form the sub-member into a pipe shape, the hollow portion of the sub-member is connected to the hollow portion of the main member. A body frame for motorcycles and tricycles, characterized in that it is formed by branch cores branching from a main core for forming parts.