CB125T hand tube bender bending mold design

    Chongqing University Chen Xia Wen Tong

 

    [Abstract] introduced CB125T motorcycle handlebar tube bender bending process and die, and in that piece as an example of CNC bending machine bending mold design geometry calculations.

 

    Keywords: pipe bender bending mold design

 

    1 Introduction

 

    Figure 1 CB125T motorcycle handlebar tube, the material is 20 steel - is a typical thin-walled steel pipe bending parts. The basic process sequence of: tube cutting, straightening, bending, knurling, drilling, testing. Bending is one of the very important aspects of machining, bending their quality, the subsequent processing steps and the overall level of quality control of parts a great impact.

 

To ensure the productivity and machining quality, CB125T motorcycle handlebar pipe bending using a suitable large-volume, high-precision CNC machining required tube (CNC) bending machine, model OPTON Japan's MS-50R type. This type of bending machine can bend a maximum pipe diameter is 50mm, the maximum tube wall 2. 3mm, the maximum bending radius of 150mm, the bending angle o. ~ 1950.

 

2 CB125T hand tube bender bending process and die

 

    Bender bending method is "wound" bend, the way each tube sequentially bent elbow, the final completion of the entire pipe bends. For structural reasons, the different types of pipe bender on the geometry and size of the pieces has certain requirements. Bender device model apart from the determined parameters such as the maximum diameter pipe D, the maximum tube length L, the maximum bending angle, the minimum and maximum bending radius r and R endures, but also requires each of the two pipe bends ends of the tube between the head and the head of a sufficiently long straight line Z. In order to bend the pipe clamping and bending, the general value of L is greater than (1.5 ~ 3) D.

 

    According to Figure 1 shows. CB125T handlebar tube diameter D. Tube length L, the relative thickness t / D, the maximum bending angle P, bending radius R and r, etc. to meet the requirements of MS-50R bender. However, knowledge of the member is calculated after the two ends of the line segment length between the elbow, is 5. 52mm (calculation method see below), MS-50R is less than the minimum allowable bending machine line segment length. To be able to be produced on existing equipment must be used with the traditional standard Bender Bending molds of different structural forms. Thus, we use OPTON MS-50R-type CNC bending machine can be installed to process the same two sets of pipe bending mode this function, designed two sets of curved mold to bend the handlebar tube. The first set of common standards for the bending mold and the bending mold as bending machine, known as the standard type, the second non-standard, known as shaped - structure shown in Figure 2. Shaped bend bending mode and standard mode main difference is that the clamping die mating parts. According CB125T

 

Tubular handlebar tube characteristics, shaped bending mold clamping mold made of symmetrical mating portion of the arc-shaped groove in both directions, so we ensure that there is sufficient bending clamping length, and not leave pipe fittings and flexural modulus interference occurs, enabling the winding pipe bending machine, whether from the left or right end of handlebar bend, the first bend are used in a standard type, a second elbow-shaped, and the third an elbow with the standard type, and finally shaped.

 

3 shaped curved mold design and geometric calculation

 

    CB125T shaped handlebar bend die design of the main contents of the arcuate groove in the right foot design, the relationships are determined some space geometry shaped bending mold shown in Figure 2 the length of the line segment Z (two arcs between true length of the line EF), angle a and p are the size.

 

    More than one segment are not coplanar Tube Bending (curved space) parts of the shape, no matter how complicated geometry calculations can always used the tube center axis of the pipe section to indicate that the simplified Brilliant multistage continuous lines and curves after calculation section, and finally considering pipe diameter size. Space elbow piece geometry calculation methods commonly used three-dimensional geometric calculations and vector calculations.

 

    Calculated using the three-dimensional geometric space bend geometry, first under the tubular parts diagram to find out the relationship between the various axes. Since the parts in the figure, the different views are the generally tubular space perpendicular to the plane formed by the projection, which determine the tube axis of the space between each of the mapped geometry axes reflect a perspective view, are shown in Figure 3 shows the calculation of L as CB12sT handlebar diagram symmetry, only half drawn). First, to establish the vector calculation coordinate system, shown in Figure 3, according to the geometry of the parts diagram obtained coordinates of the point is calculated. In practice often with both calculations. Below CB125T handlebar example.

 

4 Conclusion

 

    By actual test bender bending process and the bending mold is fully capable of bending a qualified CB125T handlebar tube bending parts, resulting in between a C, NC bender bending out CB125T motorcycle handlebar tubes, prove that the bending process and die design is successful. Currently, the tool has been used in mass production, and made great economic benefits. The pipe bending and bending mold structure, the CNC bender for bending tube short line segments have a higher reference value.