JPS61291281A - Car body frame structure of motorcycle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a motorcycle body frame structure made of a light metal material such as an aluminum alloy.

(Prior art) A steering head made of a light metal such as aluminum, in which the body frame of a motorcycle is made of a rectangular extruded section made of aluminum material instead of the conventional steel tube, and the joint section is integrally cast with the head pipe in the shape of a hollow box. We have already proposed a configuration in which the connector is fitted into a fitting groove with a rectangular cross-section provided in the holder and then welded together.

(Special Patent Application No. 58-41737) According to this, weight reduction and high rigidity can be achieved by integrally forming the head pipe and the conventional gusset part, and the rectangular cross section of the vehicle body frame member can be fitted. By providing a fitting groove for attaching the steering head, it is possible to improve the bonding strength around the steering head.

(Problem to be solved by the invention) By the way, in the above conventional technology, the head pipe, gusset, and fitting groove were formed by integral casting and functioned as a part of the vehicle body frame as a steering head, so the main frame and down tube... It is necessary to join these parts together, and a special jig is required for welding these parts together.Furthermore, since welding to the surrounding area of the steering head causes thermal distortion, and since this is the part where the load is most concentrated, cracks may occur later... Problems such as ... are also likely to occur.

The technical problem of the present invention is to improve the strength and rigidity of the upper structure of the vehicle body frame, such as the steering head, main frame, down tube, etc., to simplify and reduce the weight, and to securely connect the frame members. The goal is to make it easier to improve productivity.

(Specific measures for solving the technical problems) The specific measures taken to solve the above technical problems are the superior integrally molded steering head detailed in the above-mentioned patent application No. 1983-41737. Further improving and developing the features, the head pipe, main frame, sub frame, and front frame under the head pipe are integrally formed by casting or forging of light metal such as aluminum alloy or magnesium alloy, and the lower part of the front frame and A joint part with a fitting groove for fitting with the body frame member is integrally provided and formed at the rear of the main frame, and the body frame member is fitted into this fitting groove and fixed by welding, screwing, etc. The gist is that.

(Embodiment) A preferred embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

Figures 1 to 3 show the main parts of a semi-double cradle type vehicle body frame F to which the present invention is applied. Down tubes, 4 and 5 are a pair of left and right center frames, 6 and 7 are a pair of left and right seat rails, 8 and 9 are a pair of left and right backstays, and 10 is a pivot bracket.

The above-mentioned vehicle body frame F is entirely made of light alloy, and in particular, aluminum alloy is used in the embodiment, except for the vehicle body frame structure 1, which will be described in detail later.
This is an extruded section with a rectangular closed cross section that is bent into the shape shown.

The vehicle body frame structure 1 has a head pipe portion 13 provided with bearing fitting portions 12 above and below at the upper front.
A main frame section 14 extends rearward and downward from the rear of the upper end of the head pipe section 13, and an upper support section for a shock absorber (not shown) protruding from the rear end of the main frame section 14. 15 and a joint part 18.19 which is slightly forward of the support part 15 and has a pair of rectangular fitting grooves 16.17 which protrude left and right in plan view of the main frame part 14 and extend downwardly. A joint part 22,23 having a rectangular fitting groove 20°21 extending substantially horizontally rearward from the rear side of parts 18 and 19, and a gusset part 2 that connects these parts, respectively.
4.25, and further has reinforcing ribs 26 suitably arranged inside from the rear of the head pipe part 13. The front frame part 27 extends downwardly from the head pipe part 13, and has a pair of left and right square fittings, respectively. The joint portion 30.31 provided with the matching groove 28.29 is curved and protrudes downward,
In addition, a sub-frame part 32 is connected between the rear of the front frame part 27 and the rear of the main frame part 14, forming a substantially triangular shape in side view with the end pipe part 13 as the apex, as shown in the figure. I will do it.

In addition, 33 in the figure indicates a part of the engine no. 34 and 35
Reinforcing ribs and gusset parts are shown, respectively.

The vehicle body frame structure 1 having the above configuration is all integrally molded by casting to form a so-called monocoque type, and especially if die casting is used, detailed ribs 26, 34.
35, joints 18, 19, 22, 23, 30, 31, rectangular fitting grooves 16, 17, 20, 21, 28, 29, etc. Furthermore, the wall thickness of each component can be formed thin and uniformly. It is advantageous in terms of quality.

The cross-sectional shapes of the main frame section 14 and the sub-frame section 32 may be arbitrary, but if they are approximately U-shaped with their opposing inner sides open and their outer sides curved as shown in Figure 6, they will support the core in die-cat molding. It is advantageous for

FIG. 7 shows another embodiment of this, in which the above-mentioned member has a ribbed square shape with an open inner side, and FIG. 8 shows a main frame portion 14 having a U-shaped closed cross section and a subframe portion 32. It shows an open-angle cross-section with internal ribs on the top and bottom, and FIG. 9 shows a cross-section with an open-angle cross-section with increased wall thickness at the four corners to improve strength.

Therefore, the fitting groove 28.2 below the front frame part 27
9, fit the upper end of the square down tube 2.3,
They are fitted and integrally connected to the wall ends of the fitting grooves 28 and 29 by welding. FIG. 5 shows the above cross section.

Further, at the rear of the main frame part 14, there are fitting grooves 16°17.
the upper end of the center frame 4.5, and the fitting groove 20.
．． 21, the front ends of the seat rails 6.7 are integrally connected to each other by means similar to those described above.

In this way, the body frame structure 1 integrates the upper body frame around the head pipe, where stress is most likely to concentrate in the body frame F, the shock absorber support part, the main frame, and the sub frame together with reinforcing ribs and gaskets. Cast molding and a welded connection structure through a fitting groove greatly shorten and reduce the length of the weld bead, resulting in problems such as twisting, bending, warping, etc. due to thermal strain. can be prevented from occurring, and the external design can be improved.

Next, instead of the two-piece down tube 2.3 shown in FIG. 2, a single down tube 38 is used as shown by the chain line, and the front frame has a hollow rectangular cross-section as shown in FIG. Square fitting groove 39 at the front end of 27
After fitting it with this, it can be welded together.

(In this embodiment, the vehicle body frame members are fitted into the plurality of fitting grooves and fixed. However, instead of these fitting grooves, a protrusion, a so-called boss, is integrally provided on the body frame structure 1, and this is used as a guide. (The end of the frame member may be welded and fixed after insertion.) Figure 10 shows another embodiment of the present invention, in which a fitting groove is effectively used instead of welded and fixed in the above embodiment. The vehicle body frame members are screwed together with bolts, and the lower frame, such as the down tube, center frame, seat rail, backstay, etc., can be freely attached to and detached from the upper vehicle body frame structure.

That is, each joint portion 18° 19 of the vehicle body frame structure 1.
22.23.3 (The arrangement is the same as 131, but the parts corresponding to the above-mentioned fitting grooves 16, 17, 20, 21, 28, 29, 39 are the mating grooves forming the fitting grooves as shown in Fig. 11. A chip bar fitting groove 44 is formed in which both groove walls 41 and 42 are integrally formed in a so-called taper shape with an angle θ.The tip of the down tube 43 is integrally formed with a joint member 45 forming the same angle as a part of this taper. These can be connected more tightly and strongly by fitting the taper portions shown in the figure through the bolts 46 and 47 after fitting. It is also effective in preventing the .47 from loosening.

Figures 10 (a), (b), (c), and (d) show how to assemble the down tube 43, center frame 48, seat rail 49, etc. to the vehicle body frame structure 1 using the above coupling means/means. It shows.

Also, FIG. 12 is a side view of the main part of FIG. 10, which has the same shape as the taper fitting groove 44 described above, but in order to further improve the bonding strength, a tapered fitting is fitted to both groove walls of the tapered groove as shown in the figure. Triangular tooth shapes, so-called serrations 51, are carved in the groove direction of the groove 50, and serrations 53 are similarly provided on the joint member 52 that meshes with the serrations 51, so that these are fitted, engaged, and further screwed.

According to this, the load in the longitudinal direction and the load in the groove direction of the frame members, as well as vibrations peculiar to motorcycles, and stresses that act in a complex manner can be reliably and extremely strongly connected together, and the rigidity of the vehicle body frame can be increased. It has many advantages, such as being able to further improve the accuracy of the vehicle body frame and improving the precision of the vehicle body frame without any effects from thermal distortion during welding.

With the above configuration, it is possible to obtain a high-precision car body frame while greatly reducing and reducing the number of welding assembly jigs needed to connect each car body frame member to the upper car body frame structure 1, for example. Therefore, it requires less space, which is a major factor contributing to cost reduction.

Of course, the present invention is applicable not only to the motorcycle of the embodiment but also to other vehicles such as tricycles, tricycles, saddle-mounted four-wheel vehicles, ride-on type four-wheel buggies, etc. The gain is obvious.

(Special Effects of the Invention) As is clear from the above description, according to the present invention, the head pipe, which is the upper body frame, the main frame, the cassette,
Subframe, engine hanger, shock absorber support...
...etc. is hollow or partially hollow box-shaped, approximately triangular in side view, and has ribs on the inside to form a monocoque shape, and is connected to the vehicle body frame member through a fitting groove. The body frame structure, which is welded or bolted together, is formed by integral casting or forging, which greatly reduces the length of the welding beat when manufacturing the body frame, and reduces thermal distortion and material damage. It is possible to prevent deterioration and brittleness, it is possible to reduce the weight of the car body frame, it is possible to shorten the manufacturing process of the car body frame and requires less space, and it is also effective for productivity and mass production. For this reason, it exhibits various advantages such as automatic assembly and automatic welding, and the ability to easily maintain stable quality.

In particular, according to the present invention, for example, the body frame structure is integrally cast or forged with magnesium alloy, and the body frame member is made of a square extruded aluminum alloy and is connected with bolts of titanium alloy, thereby making it extremely lightweight. , a highly rigid light metal vehicle body frame can be obtained.

Although one embodiment of the vehicle body frame structure of the present invention has been described in detail as a semi-double cradle type structure, various structural modifications can be made within the scope of the claims without departing from the spirit of the present invention. It has many advantages and features, such as being able to be easily retrofitted with other vehicle body frames, making it ideal for light alloy vehicle body frames.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a side view of a light alloy vehicle body frame equipped with a vehicle body frame structure according to the present invention, FIG. 2 is a front view, and FIG. A plan view of the rear main part of the vehicle body frame structure at arrow 2 in the figure, FIG. 4 is a sectional view taken along lines C5 to C5 in FIG.
6 is a sectional view taken along line C1-C2 of FIG. 1, FIGS. and (a), (0), (c), and (d) are a side view showing another method of assembling and joining the vehicle body frame assembly and the vehicle body frame member, and a sectional view taken along line 07 to C8 in FIG.
FIG. 12 is an enlarged side view of the rear main part of FIG. 10. In the drawing, 1 is the body frame structure, 2 and 3 are down tubes, 4 and 5 are center frames, 6 and 7 are seat rails, 13 is a head pipe section, 14 is a main frame section,
15 is a support part of the shock absorber, 16.17. ．． 20.21.2
8.29 is a square fitting groove, 18°19.22.23.30
．． 31 is a joint part, 32 is a subframe part, 26.34.
35 is a reinforcing rib, 50 is a taber fitting m, and 51 is a haseration.

Claims (1)

[Scope of Claims] 1) A head pipe is arranged at the front end, and a sub-frame is connected to the rear part of the main frame connected to the rear of the head pipe and extends substantially horizontally forward, and a sub-frame extends downwardly from the head pipe. In a body frame structure of a motorcycle, which is formed by connecting a lower rear part of a front frame, the body frame structure is approximately triangular in side view, and has the head pipe as its apex, and is composed of the head pipe, main frame, sub frame, and front frame. An automobile characterized in that it is integrally formed into a hollow or hollow box shape by casting or forging, and a joint portion with a fitting groove for fitting with another body frame is provided protruding around the lower part of the front frame and around the rear part of the main frame. Two-wheeled vehicle body frame structure. 2) A body frame structure for a motorcycle according to claim 1, wherein the body frame structure is made of aluminum alloy, magnesium alloy, or other light alloy material. 3) Claim 1) comprising a center frame, a seat rail, and a shock absorber support part arranged protrudingly concentrated around the rear part of a main frame forming a vehicle body frame structure.
The body frame structure of the motorcycle described in 2. 4) Claim 1) in which the fitting groove has a rectangular cross-sectional shape
The body frame structure of the motorcycle described in 2. 5) A body frame structure for a motorcycle according to claim 1, wherein the groove wall of the fitting groove is tapered and a screw hole is provided at the bottom. 6) A vehicle body frame structure for a motorcycle according to claim 1, wherein the fitting groove and the joint portion on the vehicle body frame member side are fitted into a tapered groove and are engaged with serrations and screwed together. 7) A body frame structure for a motorcycle according to claim 1, wherein the body frame member is disposed in the lower part, and the upper part has a monocoque structure made of the body frame structure.