JPS6393437A - Manufacture of frame for bicycle - Google Patents

Abstract

PURPOSE:To manufacture the frame for bicycle having a fixed intensity with good efficiency by cutting the side wall between the rib members extending in the longitudinal direction inside an angular pipe in fixed length and pressing the rib member in the direction separating each other. CONSTITUTION:The angular pipe 10 having a pair of the rib members 20a, 20b extending in the longitudinal direction at the inner part is formed practically by extrusion forming. The side walls 14c, 18c between the rib members 20a, 20b are cut in the fixed length and the other side wall parts 14a, 14b, 18a, 18b are preferably bent to the inner part. a punch is then inserted from one end part of said rib members 20a, 20b therein, said respective rib member 20a, 20b is pressed in the direction separating each other and said angular pipe 10 is squeezed. Said angular pipe 10 is thereafter bent in the fixed shape by the punch for forming and frame forming. The frame for bicycle having the curved face excellent in the external appearance and having no fear of causing stress concentration, etc., and having the necessary intensity is thus formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a frame for a two-wheeled vehicle, and more particularly, when manufacturing a frame for a two-wheeled vehicle such as a motorcycle or a bicycle, the present invention relates to a method for manufacturing a frame for a two-wheeled vehicle such as a motorcycle or a bicycle. Using a square pipe with a pair of ribs,
The present invention relates to a method for manufacturing a frame for a two-wheeled vehicle, in which two legs are formed by forming a notch along the lip of the square pipe, and the legs are bent and spaced apart by a predetermined distance to form a frame.

Conventionally, when manufacturing frames for two-wheeled vehicles, a set of rear frame members, main frame members, etc. to form the frame are formed separately, and then the rear frame members, main frame members, etc. are joined by welding or the like. ing. In this way, each member is manufactured individually and joined together to obtain a frame, which makes the manufacturing process extremely complicated, requires welding, etc., and requires considerable skill. Moreover, it has been pointed out that when the individually formed frame members are joined together, the members are distorted due to the heat during welding, resulting in a reduction in the processing accuracy of the frame. Furthermore, a frame with such poor machining accuracy requires a subsequent correction process, making the manufacturing process itself increasingly complex.

Therefore, in recent years, frames made of light metal materials such as aluminum have come into use in order to reduce the weight of frames for two-wheeled vehicles and make them easier to process. That is, a method has been devised that utilizes the ease of processing of the light metal material to minimize the number of steps required to manufacture the frame. A good example of the above-mentioned method is the technical idea disclosed in Japanese Patent Application Laid-open No. 59-50938.

That is, in the method for manufacturing a frame for a motorcycle, a rib member extending in the axial direction is provided approximately in the center of a rectangular pipe made of aluminum, and the rib member is cut to a predetermined length along the axis. The branched portion thus formed is bent to form a part of the motorcycle frame.

However, with the above method, it is substantially difficult to cut the square pipe together with the rib member to a predetermined length. Moreover, if one dares to carry out the process, there is a problem in that a considerable amount of working time is required for the processing work.

Furthermore, when the branch parts formed by processing the square pipe are bent in directions that separate them from each other, unevenness occurs at the bent parts, resulting in a poor appearance.

For this reason, the product value is reduced, and depending on the bent state of the square pipe, stress is concentrated at the bent portion, resulting in the disadvantage that the frame itself becomes brittle.

The present invention has been made to overcome the above-mentioned disadvantages, and when manufacturing frames for two-wheeled vehicles such as motorcycles and bicycles, first, a pair of rib members extending in the longitudinal direction are separated by a predetermined distance. A square pipe formed by extrusion molding is performed, and the side wall disposed between the pair of rib members of the square pipe is cut to a predetermined length, and the pair of rib members and the square pipe are separated. The respective side wall portions disposed between the side wall portions to be formed are bent inwardly from each other,
Next, a punch is applied from the cut end of the square pipe, thereby pressing the pair of rib members in a direction away from each other to deform the square pipe, and then shaping the square pipe into a shape. The main frame and rear frame are integrally formed by curving them into a predetermined shape using a corresponding punch, and the bent portions of the frame are beautifully finished to prevent stress concentration, etc. An object of the present invention is to provide a method for manufacturing a frame for a two-wheeled vehicle, which makes it possible to form a frame for a two-wheeled vehicle having a predetermined strength and to improve the production efficiency of the two-wheeled vehicle frame at once.

In order to achieve the above object, the present invention provides a manufacturing method for manufacturing a frame for a two-wheeled vehicle, which includes a first step of molding a square pipe having a pair of rib members extending in the longitudinal direction therein. a second step of cutting the side wall existing between the pair of lip members of the square pipe to a predetermined length; and inserting a punch between the pair of lip members from one end thereof to separate the respective rib members. It is characterized by comprising a third step of crushing the square pipes by pressing them in directions away from each other, and a fourth step of bending the square pipes into a predetermined shape by punching and punching.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a method for manufacturing a frame for a two-wheeled vehicle according to the present invention will be described in detail below with reference to the accompanying drawings, with reference to preferred embodiments in relation to an apparatus for carrying out the method.

In FIG. 1, reference numeral 10 indicates a square pipe that is used in the method of manufacturing a frame for a two-wheeled vehicle according to the present invention and substantially forms the frame of the two-wheeled vehicle, and the square pipe 10
is extruded from a light metal material such as aluminum. Said square pipe 10 has substantially four side walls 12.14.16.
．． 18, and rib members 20a and 20b, which are oriented in the axial direction of the square pipe 10 and extend substantially parallel to each other, are disposed in the hollow portion formed by the respective side walls 12 to 18. Therefore, the hollow portions of the square pipe 10 include hollow portions 22a and 22b defined between the respective rib members 2Qa and 20b and the side walls 12.16, and the rib members 2Qa.
, 20b, and a hollow portion 22C defined between them.

In this case, the side walls 14 and 18 are the side walls 14a114
Hollow portions 22a to 22c are defined as the side walls 18a, 14G and the side walls 18a, 18b, and 18c, respectively, and the hollow portions 22a and 22b are selected to have approximately the same size.

Next, the first mold device 30 for processing the square pipe 10 will be explained.

As shown in FIGS. 2 and 3, the first mold device 3
0 includes a lower mold 32, and a cam 34 is provided on the upper surface of the lower mold 32.
．． 36 are arranged at predetermined intervals.

One side of the cam 34 is inclined in a tapered shape to form a tapered surface portion 34a, and the other end of the cam 34 has a
In the figure, bending punches 38.40 are placed above and below.
A cutter 42 is attached, which is disposed between the bending punch 38, 40 and the bending punch 38,40. Similarly, a tapered surface portion 36a is formed on the cam 36, and a bending punch 38a is formed on the cam 36.
, 40a and a cutter 42a are attached. In this case, the tips of the bending punches 38, 40, 38a, 40a and the cutter 42, 42a are connected to the first mold device 3.
It can be easily understood from the figure that the direction is inward of 0.

A cam driver 44 attached to an upper mold (not shown) is disposed above the lower mold 32. A substantially trapezoidal recess 44a is defined at one end of the same-day pig cam driver 44.

That is, this recessed portion 44a is defined so as to be surrounded by tapered surface portions 45a and 45b forming the cam driver 44. Furthermore, holes 46a and 46b having a large diameter part and a small diameter part are arranged in parallel in the approximate center of the cam driver 44, and one end side of guide members 48a and 48b slides into the holes 46a and 46b, respectively. Fit freely. That is, the flange portions formed on one end side of the guide members 48a, 48b fit into the large diameter portions of the holes 46a, 46b, respectively, and the other end side of the guide members 48a, 48b is formed from the flange portion. It extends downward, passes through the small diameter portions of the holes 45a and 46b, and projects into the recess 44a. The other end sides of the guide members 48a, 48b engage with a pad member 50 within the recess 44a, and the band member 50 is suspended vertically downward by the coil springs 52a, 52b within the recess 44a. Located in

Next, a second mold device 60 for further processing the square pipe 10 processed by the first mold device 30 is shown in FIGS. 4 and 5.

That is, the second mold device 60 includes rectangular receiving molds 64a disposed substantially parallel to each other with a predetermined spacing on the base 62;
64b. Further, the second mold device 60 includes a punch 66, and the bonder 66 is configured to be movable in the direction of arrow A and the direction of arrow B by a drive source (not shown).

In this case, the punch 66 is moved in the direction of arrow A to enter between the receiving molds 54a and 64b.

Near the tip of the punch 66, the width is tapered toward the end to form a protrusion 66a.

A plurality of free rollers 68a to 68d, preferably made of steel, are rotatably attached to the tapered portion of the punch 66 via roller receiving plates 70a and 70b (see FIG. 5). .

Square pipe 1 processed by the second mold device 60
A bending device 71 for finishing 0 into a predetermined shape is shown in FIG. The bending device 71 basically comprises Satoshi dies 72a, 72b and a frame forming punch 74. In this case, the frame forming punch 74 is configured to be able to move forward and backward relative to the Satoshi molds 72a and 72b under the driving action of a drive source (not shown), that is, a linear actuator.

The apparatus for carrying out the method for manufacturing a frame for a two-wheeled vehicle according to the present invention is basically constructed as described above, and its operation and effects will be explained next.

First, as shown in FIG. 2, the square pipe 10 is placed between the cams 34 and 36 that constitute the first mold device 30. Next, the upper mold (not shown) of the first mold device 30 is moved downward. Accompanying this, the cam driver 44 is displaced downward. Under the displacement action of the cam driver 44, the pad member 50 comes into pressure contact with the square pipe 10 to prevent displacement of the square pipe 10, and the tapered surface portion 45a145b of the cam driver 44 contacts the tapered surface portion 34a of the cam 34.36.
, 36a. Furthermore, when the cam driver 44 is displaced downward, one of the Taper surface portions 45a of the cam driver 44 causes the Taper surface portion 34 of the cam 34 to
a undergoes sliding displacement. That is, a predetermined displacement operation of the cam driver 44 causes the cams 34 and 36 to move toward each other. As a result, the bending punch 38.38a attached to the cam 34.36 comes into contact with one end side of the square pipe 10, and eventually bends the side walls 14a, 18a of the square pipe IO toward the hollow part 22a. It leads to bending towards the direction. Similarly, the side wall 14b118b is bent toward the hollow portion 22b using the bending punch 40.40a. At the same time, the cutter 42.42a attached to the cam 34.36 cuts the side walls 14e, 18c near one end of the square pipe 10 by a predetermined amount (see FIG. 7).

In this case, as can be easily understood from Figure 3, the first
Under the driving action of the mold device 30, the square pipe 1 is cut by cutters 42, 42a constituting the first mold device 30.
One end side of 0 can be divided relatively easily. Therefore, it is possible to perform the work efficiently.

As described above, the rectangular pipe 10 that has been processed in a predetermined manner through the first mold device 30 is placed in the second mold device 60 to perform the next stage of processing.

That is, the receiving mold 64a constituting the second mold device 60
, 64b, the square pipe 10 is disposed between them.

Next, as shown in FIG. 4, a punch 66 is inserted from one end of the square pipe 10 between the rib members 20a and 20b of the square pipe 10. At this time,
The free rollers 68a and 68b are the rib members 20a.
, 20b, no unnecessary sliding friction or the like is caused between the punch 66 and the rib members 20a, 20b. As a result, the rib members 20a, 2
0b are pressed in the direction of the side walls 12 and 16, respectively, and the space between the rib members 20a and 20b is expanded, and one end of the square pipe 10 is crushed by a predetermined length (see FIG. 8).

At that time, the square pipe 1 is
The side walls 14a, 14b, 18a, and 18b of the punch 66 are bent in advance, and free rollers 68a to 68d are provided near the tip of the punch 66. Therefore, the punch 66 can easily enter from one end of the square pipe 10, and damage to the square pipe 10 can be prevented as much as possible.

Next, the square pipe 10 is fitted between the molds 72a and 72b, and the frame forming punch 74 is inserted between the rib members 20a and 20a under the driving action of a drive source (not shown) in the same way as in the previous step.
Enters between 0b. That is, the square pipe 10 is bent at a predetermined portion by the punch 74, and as shown in FIG.
a and 82b are integrally molded.

In this case, the square pipe 10 is easily curved into a desired shape by the pushers 72a, 72b and the frame forming punch 74, so the curved surface has an excellent appearance, and therefore,
A frame for a two-wheeled vehicle having desired strength can be formed without the risk of stress concentration or the like.

As described above, according to the present invention, when manufacturing a frame for a two-wheeled vehicle such as a motorcycle or a bicycle, a square pipe having a pair of rib members in the hollow portion is first extruded from a light metal material such as aluminum. Next, the side wall existing between the pair of rib members of the square pipe is cut to a predetermined length, and the side walls located on both sides of the cut side wall and substantially forming the rear frame portion are cut inside. bend towards the direction. Next, a punch is inserted between one end of the square pipe and between the pair of rib members, and the respective rib members are pressed in a direction away from each other, thereby crushing one end of the square pipe. Furthermore, the square pipe is arranged in a Satoshi mold, and one end side of the square pipe is bent into a predetermined shape using the Satoshi mold and a frame forming punch, thereby forming the main frame portion and the rear frame portion. It is integrally formed. Therefore, it is possible to easily and effectively manufacture the frame for a two-wheeled vehicle. Further, since the work of bending the square pipe is carried out using a mold and a forming punch, the square pipe can be formed into a desired shape easily and beautifully. Therefore, it is possible to prevent the occurrence of stress concentration, etc., and it is possible to manufacture a frame for a two-wheeled vehicle with excellent strength.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments, and various improvements and changes in design can be made without departing from the gist of the present invention. Of course.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a square pipe used in the method for manufacturing a frame for a two-wheeled vehicle according to the present invention, and FIGS. 2 and 3 are a first mold used in the method for manufacturing a frame for a two-wheeled vehicle according to the present invention. 4 is a partially omitted sectional view of the device; FIG. 4 is a partially omitted explanatory diagram of the second mold device used in the method for manufacturing a motorcycle frame according to the present invention; FIG. 5 is the second mold shown in FIG. 4. FIG. 6 is a partially omitted explanatory view showing the final step of the method for manufacturing a motorcycle frame according to the present invention, and FIG. 7 is a partially omitted longitudinal sectional view of the apparatus, and FIG. A partially omitted perspective view showing the square pipe processed by the molding device, FIG. 8 is a partially omitted perspective view showing the square pipe shown in FIG. 7 further processed by the second molding device shown in FIGS. 4 and 5. It is a partially omitted perspective view showing the state. 10... Square pipe 20a, 20b... Lip member 30... Mold device 38.40...
Bending punch 42.42a...Cutter 60...
- Mold devices 54a, 64b - Molds 68a to 68d...Free rollers 72a, 72b - Satoshi molds

Claims (4)

[Claims] (1) A manufacturing method for manufacturing a frame for a two-wheeled vehicle, which includes a first step of forming a square pipe having a pair of rib members extending in the longitudinal direction therein; a second step of cutting the side wall existing between the rib members to a predetermined length; and inserting a punch between the pair of rib members from one end thereof to press the respective rib members in a direction to separate them from each other, thereby cutting the respective corners. A method for manufacturing a frame for a two-wheeled vehicle, comprising: a third step of crushing the square pipe; and a fourth step of bending the square pipe into a predetermined shape using a die and a punch. (2) In the method according to claim 1, the second
A method for manufacturing a frame for a two-wheeled vehicle, comprising the step of bending inward a side wall portion of the rib member formed in the second step between the step and the third step. (3) A method for manufacturing a frame for a two-wheeled vehicle according to claim 1 or 2, wherein the square pipe is substantially formed by extrusion molding. (4) In the method according to any one of claims 1 to 3, when the punch enters from one end between the pair of rib members, the free roller provided near the tip of the punch A method for manufacturing a frame for a two-wheeled vehicle, which comprises rolling on the inner wall surface of the rib member.