JPS61205582A - Method of forming rear fork for two-wheel barrow - 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 The present invention relates to a method for forming a rear fork for a two-wheeled vehicle, and more specifically, the present invention relates to a method for forming a rear fork for a two-wheeled vehicle, and more particularly, press working is performed on one end of a fork pipe constituting the rear fork to form the end into a predetermined shape. Furthermore, the present invention relates to a method for forming a rear fork for a two-wheeled vehicle, which allows the rear fork to be formed in an extremely short time and easily by fixing end pieces to the ends thereof.

Generally, an end piece for attaching a rear wheel shaft is fixed to a fork pipe that constitutes a rear fork for a two-wheeled vehicle. Therefore, the end portion of the fork pipe is subjected to a predetermined forming process corresponding to the shape of the end piece.

FIG. 1 shows an example of a general fork pipe and an end piece fixed to the fork pipe. That is, in the figure, reference numeral 2 indicates a fork pipe constituting the rear fork, and the fork pipe 2 has a rectangular tube shape, and therefore, the inside thereof is defined as an opening 4. A slope 6 of a predetermined length is formed at one end of the fork pipe 2 and slopes inward. Note that reference numeral 8 indicates the tip of the fork pipe including the slope 6. There, the end piece 14 is attached and fixed through the opening 10 defined in the tip 8. That is,
An attachment portion 15 formed at one end of the end piece 14 is fitted into an opening 10 in the tip portion 8 to secure the attachment portion 15 to the tip portion 8. In this case, an oval opening 17 is defined in advance in the plate 16 formed at the other end of the mounting portion 15, and the rotation shaft 20 of the rear wheel 18 is fitted into this opening 17. It is for.

Incidentally, conventionally, in order to form the fork pipe 2 into a predetermined shape and fix the end piece 14 to the fork pipe 2, a manufacturing process as shown in FIG. 2, for example, has been carried out.

First, one end of the rectangular cylindrical fork pipe 2a is cut to define an opening 22 having a triangular space. In this case, one end surface defining the opening 22 is parallel to the side surface of the fork pipe 2a. After the fork pipe 2a is thus cut, one end of the fork pipe 2a is bent to form a tip 8a having a slope 6a of a predetermined length. Therefore, the opening 22 changes its spatial shape from a triangle to a slit shape to become an opening 22a, and furthermore, the tip 8a
An opening 10a having a predetermined shape is defined inside by reducing the opening 4a. Next, the end piece 14 is inserted into the opening 10a of the tip 8a, and both end surfaces defining the slit-shaped opening 22a are welded and fixed. Thereafter, the welded part 23 of the fork pipe 2a is smoothed using a grinder or the like, and a brazing material is provided at the abutting part between the end piece 14 and the tip part 8a, and the end piece 14 is brazed.
is fixed to the fork pipe 2a.

As described above, the conventional technology includes a cutting process for defining an opening at one end of the fork pipe, a pressing process for forming a tip of a predetermined shape on the fork pipe, and a welding process for embedding and fixing the opening. The work of forming the fork pipe and fixing the end piece to the fork pipe is completed by performing the finishing process of the welding surface and the brazing process of fixing the end piece to the fork pipe.

Therefore, when manufacturing a rear fork, three different steps are required to form the fork pipe, including fixing the end piece, making the manufacturing process of the entire rear fork extremely complicated and the manufacturing process difficult. It is pointed out that this method is time-consuming and extremely inconvenient especially when producing rear forks in large quantities on a production line. Furthermore, since welding is performed on the outer surface of the fork pipe, the appearance may become unsightly and it may be difficult to use the product as a product, and the product yield has not improved much.

The present invention has been made to overcome the above-mentioned disadvantages, and includes a pressing step of inserting a core into one end of a fork pipe and directly pressing it to form a tip of a predetermined shape; An object of the present invention is to provide a method for forming a rear fork for a motorcycle, which can be manufactured extremely easily and in a short period of time, and which can produce a product with excellent appearance through a mounting process of inserting and fixing an end piece into the rear fork. shall be.

In order to achieve the above-mentioned object, the present invention includes a first step of inserting a core having an inclined surface into one end of a cylindrical pipe member, and a repressing process over a predetermined length of the pipe member. a second step of inclining one side; a third step of inserting a wheel axle mounting end piece into the opening defined in the end of the vibe member by the second step; and a third step of inserting the end piece into the pipe member. and a fourth step of welding.

Next, preferred embodiments of a method for forming a rear fork for a two-wheeled vehicle according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 3 shows a process diagram of a method for forming a rear fork for a two-wheeled vehicle according to the present invention.

That is, the method of the present invention preferably consists of two steps, a pressing step and a welding step, and first, one end of the rectangular cylindrical fork pipe 2b is directly formed into a predetermined shape using a molding device which will be described later. Therefore, the cutting process, welding process, and finishing process that were conventionally performed can be eliminated, and the tip portion 8b with excellent appearance can be obtained. Next, the end piece 14 is inserted into the opening 10b in the tip 8b, and the end piece 14 is fixed to the fork pipe 2b, for example, by brazing.

FIG. 4 shows an example of a molding device for forming the tip end 8b on the fork pipe 2b. In this case, the mold device 24 includes a lower mold 26 on which the fork pipe 2b is placed, an upper mold 28 that moves up and down under the driving action of a press machine (not shown), and a core inserted into the opening 4b of the fork pipe 2b. 30
The upper mold 28 has a U-shape, and an opening 36 is defined inside thereof by both side surfaces 32a, 32a and an upper end surface 34. The upper end surface 34 has a slope 38 of a predetermined length that slopes downward from one end thereof, and side surfaces 32a,
The interval between the fork pipes 32a is set to be approximately the same length as the longitudinal width of the fork pipe 2b. Further, the core 30 has a prismatic shape,
A slope 40 that slopes corresponding to the slope 38 is formed on the upper end surface.

Therefore, the fork pipe 2b is placed on the lower die 26, and the core 30 is inserted into the opening 4b in the fork pipe 2b. After the fork pipe 2b is placed in a predetermined position in this manner, the upper mold 2 is placed under the driving action of a press machine (not shown).
8 is displaced in the direction of the arrow, the slope 38 comes into contact with the upper end surface of the fork pipe 2b and presses it in the direction of the arrow. If the upper mold 28 is further displaced in the direction of arrow A, the slope 38 presses and deforms one end of the fork pipe 2b,
As a result, the slope 3 of the upper mold 28 and the slope 4 of the core 30 are
0 to form a tip 8b of a predetermined shape (see FIG. 5). In this case, the tip 8b shrinks as shown by the arrow in FIG. 5, but both sides of the tip 8b are Since it is brought into contact with the stomach inner surfaces 32a, 32a of the upper mold 28, the shrinkage of the tip 8b shown by the arrow is due to the inner surfaces 42a, 42.
This appears as an increase in the thickness of the tip 8b, and the outer appearance of the tip 8b is extremely smooth. At this time, when forming the tip 8b, the thickness and dimensions of the fork pipe 2b are selected in advance so that the attachment part 15 of the end piece 14 can be inserted into the opening 10b in the tip 8b. put.

Therefore, the tip portion 8 formed in this way and having a slightly increased wall thickness is used.
After inserting the mounting portion 15 of the end piece 14 into the opening 10b of the end piece 10b, if these are welded, for example, brazed, the two will be firmly engaged and integrated.

According to the present invention, after the cylindrical fork pipe constituting the rear fork is formed by a direct molding device without cutting, the end piece is inserted into the end of the fork pipe and brazed. Then, form the fork pipe and fix the end piece. Therefore, the fork pipe and the end piece can be integrated very easily and in a short time, and a rear fork for a two-wheeled vehicle with excellent appearance can be obtained, which is extremely effective especially when forming the rear fork for a two-wheeled vehicle through mass production. You get the advantage of being

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments; for example, other welding methods may be used instead of brazing. Of course, various improvements and changes in design are possible without departing from the gist of the present invention.

[Brief explanation of the drawing]

Fig. 1 is a partial cross-sectional perspective view of a general rear fork for a two-wheeled vehicle, Fig. 2 is a process diagram showing a conventional method for forming a rear fork for a two-wheeled vehicle, and Fig. 3 is a formation of a rear fork for a two-wheeled vehicle according to the present invention. FIG. 4 is a partially omitted sectional view of a molding device for carrying out the method of forming a rear fork for a motorcycle according to the present invention, and FIG. 5 is a fork pipe and end formed by the method of the present invention. It is a partially omitted perspective view of a piece.

Claims (2)

[Claims] (1) A first step of inserting a core having an inclined surface into one end of a cylindrical pipe member, and a second step of inclining at least one side of the pipe member by press working over a predetermined length. and a third step of inserting a wheel axle mounting end piece into the opening defined at the end of the pipe member by the second step, and a fourth step of welding the end piece to the pipe member. A method for forming a rear fork for a two-wheeled vehicle, characterized in that: (2) In the method according to claim 1, the fourth
The process is to form a rear fork for a two-wheeled vehicle by brazing an end piece to a pipe member.