JPH01212683A - Frame for motorcycle - Google Patents

Abstract

PURPOSE:To reduce the number of parts and to facilitate manufacture of a title frame, by a method wherein each of lower metals approximately in a Y-shape on both sides mounted to the lower rear part of a frame is molded by casting in a manner to be divided into front and the rear parts, the division parts are welded together, and a plurality of mounting bosses are molded integrally with the lower metal. CONSTITUTION:Lower metals 1 on both sides are casted in a manner to be divided into front and rear parts based on a support hole 2 serving as a split face, and the division parts are matched and welded to each other to form an approximate Y-shape. An engine coupling boss 3, a step mounting boss 4, and a boss 5 for mounting a battery holder are molded integrally with the lower metal 1, and a screw hole is bored therein. A side stand bracket 6 is welded to the lower part of the lower metal 1. The lower end of a front pipe 8 welded to a main pipe 7 is inserted in and welded to the upper front end of the lower metal 1, and the front end of a rear pipe 9 is inserted in and welded to the upper rear end thereof. The lower end of a down pipe 10 is inserted in and welded to the lower end of the rear pipe, and the front ends of the main pipe 7 and the down pipe 10 are coupled to a head pipe 11 to form a frame.

Description

[Detailed description of the invention] [Industrial application field] This invention relates to motorcycle frames.

(Prior Art and its Problems) A motorcycle frame is made by selecting a pipe material with a rigidity suitable for the place where it will be used, cutting it to a desired length, bending it, etc., and welding it. And, as shown in the fourth factor,
The rear lower part of the frame A, where the rear fork support shaft is attached, is equipped with a metal fitting B made of press-molded plate material. However, the vicinity of bracket B requires a boss C to attach the engine, a boss E to attach the side stand bracket D1 to the main stand, etc. Are these attached to frame A or bracket B respectively? It is set up as SFI. For example, see Japanese Utility Model Application Publication No. 59-72191. For this reason, the number of parts is large and the number of welding points is large, making manufacturing time-consuming and high manufacturing costs.

[Purpose of the invention]

This invention reduces the number of parts by forging and welding the lower part of the lower part of the rear part of the frame into the front and back parts, and by welding and welding each part to the lower part of the frame. It is an object of the present invention to provide a motorcycle frame which can reduce manufacturing costs by reducing the number of welded parts and has good running performance.

[Structure of the invention]

The present invention will be explained below with reference to embodiments shown in FIGS. 1 to 3.

The left and right lower fittings 1 are formed by forging into front and rear parts with the support shaft hole 2 as a split surface, and are then welded together to form a substantially Y-shape. The lower metal fitting 1 has an engine connection boss 3, a step installation boss 4, and a battery holder installation boss 5.
are integrally formed and processed into screw holes. Also, the side stand bracket 6 is welded. The lower end of the front pipe 8 welded to the main pipe 7 is inserted and welded to the front upper end of the left and right lower metal fittings 1, and the front end of the rear pipe 9 is inserted and welded to the rear upper end. Further, the rear end of the down pipe 10 is inserted and welded to the lower end. The front ends of the main pipe 7 and the down pipe 10 are connected to a head pipe 11. A front fork 12 is attached to the head pipe 11. An engine case 13 is fastened to the boss 3. Step 14 is fastened to boss 4. A battery holder 16 with a main stand 15 attached is attached to the boss 5, and the battery holder 16
The battery 17 is placed on the holder. Bracket 6 has
The side stand 18 is pivoted. A rear fork 19 is pivotally attached to the spindle hole 2 by a spindle.

(Operation of the invention) The left and right lower metal fittings 1 are divided into front legs, forged, and joined by wjw, so they can be made into small parts and a31! I
Accuracy can be increased, and bosses 3, 4, 5, etc. can be integrally molded. This reduces the number of welded parts, reduces the number of welded parts, and reduces manufacturing costs. Then, the ends of the front pipe 8, rear pipe 9, and down pipe 10 can be inserted and welded into the left and right lower fittings 1, and compared to simply welding, the protrusions on the ends of the lower fittings 1 are inserted and fitted. Because of this, it can be made highly rigid. Further, since the lower metal fitting 1 is forged, there is a degree of freedom in its shape, and it can be set in a shape that does not interfere with other parts. The parts are assembled on the lower metal fitting 1, and the center of gravity is located at the bottom of the vehicle body, improving steering stability and running performance.

〔Effect of the invention〕

As explained above, in this invention, the left and right approximately Y-shaped lower metal fittings provided at the rear lower part of the frame are divided into front and rear parts, formed by forging and welded, and the engine is mounted on the lower metal fittings by attaching a boss such as a boss. The lower end of the front pipe is welded to the upper end of the front side of the lower metal fitting, the front end of the rear pipe is welded to the upper end of the rear side, and the rear end of the down pipe is welded to the lower end, so the small lower metal fitting and the boss can be integrated with high precision. It can be forged, reduces the number of welded parts with WI11 parts, reduces manufacturing costs, has high rigidity, and is lightweight. Additionally, parts can be gathered together by attaching them to the lower metal fittings, lowering the center of gravity and improving driving performance.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention, in which FIG. 1 is a side view of essential parts, FIG. 2 is an overall side view, and FIG. 3 is a perspective view.
FIG. 4 is a perspective view showing a conventional example. 1... Lower metal fitting, 3, 4.5-... Boss, 8... Front pipe, 9... Rear pipe, 10... Down pipe.

Claims (1)

[Claims] The left and right approximately Y-shaped lower metal fittings provided at the rear lower part of the frame are divided into front and rear parts, formed by forging and welded, and bosses such as engine mounting bosses are integrally formed on these lower metal fittings. A motorcycle frame characterized in that the lower end of the pipe is welded, the front end of the rear pipe is welded to the upper end of the rear side, and the rear end of the down pipe is welded to the lower end.