Metal pipe and structural member using metal pipe

Patent metadata

Field	Value
Publication number	US-10442468-B2
Application number	US-201716088479-A
Country	US
Kind code	B2
Filing date	Mar 28, 2017
Priority date	Apr 1, 2016
Publication date	Oct 15, 2019
Grant date	Oct 15, 2019

Abstract

A metal pipe has a circular cross section with an outer diameter D and a length not less than 6D. The metal pipe includes a high-strength portion (1A) and low-strength portions (1B). The high-strength portion (1A) is disposed along the entire circumference of the metal pipe to extend a dimension, as measured in the longitudinal direction of the metal pipe, that is not less than (⅔)D and not more than 3D of the metal pipe. The high-strength portion (1A) has a yield strength not less than 500 MPa (or a tensile strength not less than 980 MPa). The low-strength portions (1B) are disposed along the entire circumference of the metal pipe to be arranged in the longitudinal direction of the metal pipe to sandwich the high-strength portion (1A). The low-strength portions (1B) have a yield strength of 60 to 85% of that of the high-strength portion (1A).

First claim

The invention claimed is:

1. A metal pipe comprising:
a circular cross section with an outer diameter D and a length not less than 6D,
the metal pipe further comprising:
a high-strength portion disposed along an entire circumference of the metal pipe to extend a dimension, as measured in a longitudinal direction of the metal pipe, that is not less than ⅔D and not more than 4/3D, the high-strength portion having a yield strength not less than 500 MPa; and
low-strength portions disposed along the entire circumference of the metal pipe to be arranged in the longitudinal direction of the metal pipe to sandwich the high-strength portion, the low-strength portions having a yield strength of 60 to 85% of that of the high-strength portion.

2. The metal pipe according to claim 1 , wherein a dimension of the low-strength portions as measured in the longitudinal direction of the metal pipe is not less than ⅗D.

3. The metal pipe according to claim 1 , wherein the high-strength portion is located in a middle of the metal pipe as determined along the longitudinal direction.

4. The metal pipe according to claim 1 , wherein the metal pipe is curved.

5. A vehicle body, bumper or vehicle door comprising:
a metal pipe having a circular cross section with an outer diameter D, the metal pipe further comprising:
connections configured to be connected to another member, the connections being portions of the metal pipe located at two positions separated from each other by 6D or more in a longitudinal direction of the metal pipe;
a high-strength portion disposed between the connections along an entire circumference of the metal pipe to extend a dimension, as measured in the longitudinal direction, that is not less than ⅔D and not more than 4/3D, the high-strength portion having a yield strength not less than 500 MPa; and
low-strength portions disposed along the entire circumference of the metal pipe to be arranged in the longitudinal direction of the metal pipe to sandwich the high-strength portion, the low-strength portions having a yield strength of 60 to 85% of that of the high-strength portion.

6. The vehicle body, bumper or vehicle door according to claim 5 , wherein a dimension of the low-strength portions of the metal pipe as measured in the longitudinal direction of the metal pipe is not less than ⅗D.

7. The vehicle body, bumper or vehicle door according to claim 5 , wherein the high-strength portion of the metal pipe is located midway between the two connections.

8. The vehicle body, bumper or vehicle door according to claim 5 , wherein the metal pipe is curved to be convex toward an outside of a vehicle.

9. The vehicle body according to claim 5 , wherein the vehicle body has a space-frame structure.

Assignees

• Nippon Steel & Sumitomo Metal Corp
• Nippon Steel Corp

Inventors

• Hirose Satoshi

Classifications

• B62D21/08 Primary

  built up with interlaced cross members · CPC title

• B60R19/02

  Bumpers, i.e. impact receiving or absorbing members for protecting vehicles or fending off blows from other vehicles or objects ({B60R19/56 takes precedence; initiating brake action by contact of bumper with an external object B60T7/22; for rail vehicles B61F19/04; safety equipment for cycles B62J27/00;} integral with waterborne vessels or specially adapted therefor B63B59/02) · CPC title

• B60J5/00

  Doors (B60J10/00 takes precedence; window aspects B60J1/00 {; side board or tailgate structures for open load compartments B62D33/023}) · CPC title

• F16F7/128

  characterised by the members, e.g. a flat strap, yielding through stretching, pulling apart · CPC title

• F16F7/123

  Deformation involving a bending action, e.g. strap moving through multiple rollers, folding of members (F16F7/125, F16F7/128 take precedence) · CPC title