Bicycle seat pipe and pipe wall-molding device thereof

Abstract

The invention relates to a bicycle seat pipe and a pipe wall-molding device thereof. In the state of pushing a core bar of a first die into a seat pipe, material of the seat pipe beyond a molding hole is pushed towards a molding concave part of the core bar in the way of moving along the seat pipe through another second die, so that a thick pipe wall can be molded in the section of the seat pipe corresponding to the molding concave part. In addition, after the core bar of the first die is drawn out from the seat pipe, the second die moves along the seat pipe again to level the outer wall of the seat pipe, so that the bicycle seat pipe can have a pipe-wall thickened section in a position which is clamped by a bicycle frame and can correspondingly slide. Compared with the prior art, the invention has the advantages of improving the structural strength of joint parts of the seat pipe and the frame, promoting the lifespan and safety of bicycles, effectively controlling the use of materials and reducing the weight of bicycle bodies and production cost.

Description

technical field [0001] The invention relates to a bicycle seat tube and a tube wall forming device thereof. Background technique [0002] Such as figure 1 As shown, the general bicycle seat tube 10 is mainly used to form the connection between the seat cushion 20 and the vehicle frame 30, so that the purpose of adjusting the height of the seat cushion 20 can be achieved by changing the relative extension of the seat tube 10 into the vehicle frame 30; When riding a bicycle, under the action of the weight of the rider, the junction of the seat tube 10 and the vehicle frame 30 will produce a shear force. The jointed position of the frame 30 breaks, thereby affecting the use safety of the bicycle. [0003] Therefore, the general improvement methods are as follows figure 2 and image 3 As shown, the structural strength of the seat tube is improved by thickening the tube wall of the entire seat tube 10, but in terms of actual use, the seat tube 10 is mostly only connected to ...

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Problems solved by technology

[0004] Furthermore, if Figure 4 and Figure 5 As shown, another bicycle seat tube structure, this seat tube 10 mainly uses the method of changing the cross-sectional shape of the seat tube 10 to make the tube wall at the same position have different thickness differences, and then utilizes two corresponding tubes with thicker thickness. The side is used as the part to receive the strength test, in order to pass the shear test of the seat tube; this structural design cannot meet the actual use requirements, especially when the steering of the seat tube is offset, it may make the two thinner phases The corresponding side becomes the part clamped with the frame, and cannot exert the structural strength that the seat tube should have

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