IP Library › Granted Patent US 12,305,251
Granted Patent B2
US 12,305,251 · App. 17/797,453 · Granted May 20, 2025

Heat treatment method for tubular shaft for drive shaft having ball spline structure and tubular shaft manufactured thereby

Inventors: Se Jung Park (Daegu, KR); Dal Soo Jang (Daegu, KR)
Assignee: ERAE AMS CO., LTD.
C21D9/28C21D1/06C21D1/18C21D8/105C23C8/22C23C8/80C21D2211/002C21D2211/008
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Quick Facts
Patent No.
US 12,305,251
App. No.
17/797,453
Granted
May 20, 2025
Kind
B2
Abstract

in a heat treatment method for a tubular shaft for a drive shaft having a ball spline structure for a plunging and an undercut region with a reduced diameter, a carburizing-austempering is performed such that a deep portion hardness of the undercut region is a value between HRC 35 to HRC 50.

Claims (10)

1. A heat treatment method for a tubular shaft for a drive shaft having a ball spline structure for a plunging and an undercut region with a reduced diameter, wherein a carburizing-austempering is performed such that a deep portion hardness of the undercut region is a value between HRC 35 to HRC 50.

2. The heat treatment method of claim 1 , wherein the deep portion hardness is a value between HRC 38 to HRC 48.

3. The heat treatment method of claim 1 , wherein the carburizing-austempering is formed such that the undercut region comprises both bainite structure and martensite structure.

4. The heat treatment method of claim 1 , wherein an effective hardening depth for the undercut region is a value between 0.6 mm to 2.0 mm from a surface.

5. The heat treatment method of claim 1 , wherein a surface hardness of the undercut region is a value between HRC 58 to HRC 62.

6. A tubular shaft for a drive shaft formed by a heat treatment method of claim 1 .

7. A tubular shaft for a drive shaft formed by a heat treatment method of claim 2 .

8. A tubular shaft for a drive shaft formed by a heat treatment method of claim 3 .

9. A tubular shaft for a drive shaft formed by a heat treatment method of claim 4 .

10. A tubular shaft for a drive shaft formed by a heat treatment method of claim 5 .

Assignments (2)
CHANGE OF NAME Recorded Sep 25, 2025
From: ERAE AMS CO., LTD.
To: HANSAE MOBILITY CO., LTD.
Reel/Frame 072935/0512 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Aug 4, 2022
From: PARK, SE JUNG; JANG, DAL SOO
To: ERAE AMS CO., LTD.
Reel/Frame 060717/0096 →
Priority Claims (1)
KR 10-2020-0015023 · Feb 7, 2020 · national
Continuity (1)
Related Publication 20230093813A1 · Mar 30, 2023
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