Tailor-layered tube with thickness deviations and method of manufacturing the same

Patent metadata

Field	Value
Publication number	US-10801647-B2
Application number	US-201916243324-A
Country	US
Kind code	B2
Filing date	Jan 9, 2019
Priority date	Dec 20, 2018
Publication date	Oct 13, 2020
Grant date	Oct 13, 2020

Abstract

A tailor-layered tube, includes an inner tube, an outer tube having a greater diameter than the inner tube and disposed outside the inner tube, and at least one intermediate tube disposed between the inner tube and the outer tube and having a length different from the inner tube and the outer tube to be locally disposed between the inner tube and the outer tube. The inner tube, the intermediate tube, and the outer tube are hydroformed in a state of being laminated so that the inner tube, the intermediate tube, and the outer tube are sequentially brought into close contact with each other in a region where the intermediate tube is disposed and the inner tube is brought into direct contact with the outer tube in a region where the intermediate tube does not exist, and accordingly regions having locally different thicknesses are successively arranged.

First claim

What is claimed is:

1. A method of manufacturing a tailor-layered tube, the method comprising:
inserting an inner tube into an outer tube and inserting an intermediate tube between the outer tube and the inner tube to align at a predetermined position, the intermediate tube having a length different from a length of the inner tube and a length of the outer tube;
placing a laminate of the outer tube, the inner tube and the intermediate tube in a cavity of a mold; and
supplying a fluid to an inside of the inner tube through one side portion of the cavity of the mold at a constant process pressure so that a pressure is applied to an inner peripheral surface of the inner tube, and simultaneously applying axial direction loads for axial feeding to both end portions of the laminate to perform a hydroforming operation, wherein, during the hydroforming operation, the inner tube, the intermediate tube, and the outer tube are hydroformed in a state of being laminated so that the inner tube, the intermediate tube, and the outer tube are sequentially brought into close contact with each other in a region where the intermediate tube is disposed and the inner tube is brought into direct contact with the outer tube in a region where the intermediate tube does not exist.

2. The method of claim 1 , wherein the constant process pressure of the fluid supplied in the supplying the fluid is obtained by sequentially performing operations of calculating yield starting pressures at which the inner tube, the intermediate tube, and the outer tube respectively start plastic deformation, determining a first forming pressure calculation formula of a two-layered tube laminate and a second forming pressure calculation formula of a three-layered tube laminate from the yield starting pressures, determining an average pressure having a stress ratio α of 0.5 to 1.0 as a forming pressure from the first forming pressure calculation formula and the second forming pressure calculation formula, and determining an average value of the forming pressure calculated in the first forming pressure calculation formula and the forming pressure calculated in the second forming pressure calculation formula as the process pressure of the fluid.

3. The method of claim 2 , wherein the axial direction load applied in the supplying the fluid is obtained by sequentially performing operations of calculating S 1 and S 2 which are distances at which both end portions of the two-layered tube laminate and the three-layered tube laminate are contracted as only an internal pressure of the fluid is applied to an interior of the tube in a state in which no axial direction load for axial feeding is applied to end portions of the tube, calculating Path-2L and Path-3L, which are load paths of the two-layered tube laminate and the three-layered tube laminate, using the calculated distances S 1 and S 2 and the process pressures, and determining a path having an average value of the load paths Path-2L and Path-3L as an optimal load path.

Assignees

• Pusan National Univ Industry—Univ Cooperation Foundation
• Nat Univ Pusan Ind Univ Coop Found

Inventors

• Moon Younghoon
• Han Sangwook
• Hwang Taewoo
• Woo Youngyun
• Oh Ilyeong

Classifications

• B32B15/011

  all layers being formed of iron alloys or steels · CPC title

• F16L9/02 Primary

  of metal (F16L9/16 - F16L9/22 take precedence) · CPC title

• F16L9/006 Primary

  specially profiled (F16L9/003 takes precedence) · CPC title

• B21D26/041

  Means for controlling fluid parameters, e.g. pressure or temperature · CPC title

• B21D39/04

  of tubes with tubes; of tubes with rods {(crimped pipe joints as such F16L13/14)} · CPC title