JPS5933050B2 - motorcycle frame - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a frame for a two-wheeled vehicle such as a bicycle or an autobicycle.

The head pipe and main pipe of a conventional two-wheeled vehicle frame are usually formed as separate members, and are integrally formed by welding the two members via a rack or the like or by a joining method such as casting.

Fig. T shows an example in which a head pipe a and a main pipe b are joined by welding c, and Fig. 8 shows an example in which a plate material d having a shape as shown in a is press-worked to form the arrows e and f. This figure shows an example in which the abutted portions are joined by welding g after being bent as shown in FIG. However, all of the above-mentioned conventional methods have disadvantages in that the structural members are heated, resulting in a decrease in strength due to thermal changes in the material, and production efficiency is poor because the joining members or joining operations are complicated.

The present invention has been made to eliminate the above-mentioned drawbacks, and by integrally constructing the main frame and head portion of a motorcycle frame with a single pipe material, it improves the strength of the frame itself and improves production efficiency. The purpose is to improve.

Embodiments of the present invention will be described below with reference to FIGS. 1 to 6.

Figure 1 shows a material tube A for a motorcycle frame formed by a single pipe using the method of molding a frame tube for a motorcycle developed by the present applicant (Japanese Patent Application Laid-Open No. 136245/1983). The substantially linear straight portions include an upward bulging portion 2, a downward bulging portion 3, and a pressing end portion 4 of the material tube on the side of the upper and lower bulging portions. In the present invention, as shown in FIG. 1, a material tube A is used, in which upper and lower bulges 2 and 3 are provided at one end of the tube, and the top plate portion 2a of the upper bulge 2 is shown in FIG. As shown in FIG. 3, a hole is drilled with a drill 5, and an upper ring T is press-fitted into this hole 6 as shown in FIG. The same hole is drilled, and the lower ring 9 is press-fitted into this hole 8 to form the lower bearing holding part of the head part, and the pressing end 4 of the material tube A on the upper and lower bulges 2 and 3 side is pressed into the hole 8 as shown in FIG. A head portion 10 is formed by cutting along the X-X line, and a two-wheeled vehicle frame is integrally formed using the straight portion 1 of the material tube A on the opposite side connected to the head portion 10 as a main frame. Fig. 4 shows an embodiment in which a decorative plate or name plate 12 is glued to cover the cut opening 11 where the pressing end 4 is cut, and Fig. 5 shows a wire for a brake brake or a wire for a derailleur of a two-wheeled vehicle, etc. A wire 13 is inserted through the cutting opening 11 into the main frame 1.

Moreover, FIG. 6 is an overall view of a bicycle using the frame for a two-wheeled vehicle of the present invention. In the motorcycle frame of the present invention constructed as described above, the head portion 10 and the main frame 1 are made into an integral structure by cold working from a single material tube A, so they cannot be heat welded like conventional frames. There is no decrease in rigidity due to thermal changes, that is, there is no decrease in strength per unit of constituent material, and there is no need to perform a complicated welding process. Further, there is no fear of accidents due to parts coming apart, and since there is no need for a rack or the like interposed at the joint, it is possible to significantly reduce the weight of the vehicle. Further, the front-opening cut surface can be shielded with a nameplate 12 or the like, and the nameplate 12 can also be attached to a flat surface rather than to a curved surface as in the past, making the work easier.

Furthermore, this opening 11 can be used as a hole for inserting the wire 13, etc. into the frame, and in this way, the wire 13 can be prevented from being bent strongly from the handle part as shown in FIG. Can be inserted. Therefore, there is no need to drill a wire insertion hole in the side of the main frame as in the conventional case, and the strength of the frame does not deteriorate.
2) The opening 11 of the frame of the present invention can also be used for fixing a cargo basket fixing device, a cowling for an infant vehicle, etc. to the vehicle body. As described above, the present invention is effective in increasing the strength of a motorcycle frame and improving production efficiency, and also has the effect of being able to provide a motorcycle frame that is unique in shape.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a material tube used in the present invention;
Fig. 2 is a cross-sectional view showing the drilling process of the material pipe, Fig. 3 is a cross-sectional view showing the head portion of the frame of the present invention, Fig. 4 is a cross-sectional view of an embodiment in which the cutting opening is shielded with a name plate, Figure 5 is a cross-sectional view of an embodiment in which a wire is inserted into the cutting opening, Figure 6 is a side view showing the entire bicycle using the frame of the present invention, and Figure 7 is an example of a conventional connection between a head pipe and a main pipe. FIG. 8A is a developed view of a plate showing another conventional method, and FIG. 8B is a side view of the plate material bent and welded at the joints. A...Material pipe, 1...Straight part (main frame),
2... Upper bulge, 3... Lower bulge, 4... Pressing end, 5... Drill, 6... Drill, 7... Upper one, 8... Hole. 9... Lower one, 10... Head portion, 11... Cutting opening, 12... Polarized plate, 13... Wire.

Claims (1)

[Claims] 1. An upper bearing holding portion of a head portion formed by press-fitting an upper one into a hole in a top plate portion of an upper bulge portion of a material tube having a bulge portion above and below at one end of the tube, and the lower bulge portion. The lower bearing holding part of the head part is formed by press-fitting the lower one into the hole in the bottom plate part of the head part, and the head part is formed by cutting the pressing end of the material tube on the side of the upper and lower bulge parts. A frame for a two-wheeled vehicle that is integrally equipped with a main frame formed by connecting material pipes on the opposite side.