Gear

• US 8,096,205 B2
• Filed: 07/23/2008
• Issued: 01/17/2012
• Est. Priority Date: 07/31/2003
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Okamoto, Yusuke, Yasuda, Yoshiteru, Yamaguchi, Takuro, Kano, Makoto
• Primary Examiner(s): Ridley, Richard W
• Assistant Examiner(s): Boes, Terence
• Application Number:
  US12/177,943
• Publication Number:
  US 20080276755A1
• Time in Patent Office: 1,273 Days
• Field of Search: 744/67, 744/68, 744/60, 744/64, 184/6.12, 508/113, 475/344
• US Class Current: 74/468
• CPC Class Codes: C23C 14/0605 Carbon
• CPC Class Codes: F16H 57/041 Coatings or solid lubricants, e.g. antiseize layers or pastes
• CPC Class Codes: Y10T 428/30 Self-sustaining carbon mass or layer with impregnant or other layer
• CPC Class Codes: Y10T 74/19 Gearing
• CPC Class Codes: Y10T 74/19995 Teeth

Abstract

A gear comprised of a tooth surface and a hard carbon film formed on at least a part of the tooth surface. When the gear is used in lubricant including a specific component, a friction of a tooth surface of the gear is largely decreased, and therefore the gear performs an excellent power transmission efficiency. Further, when the gear is employed in a planetary gear mechanism or speed reducing mechanism which has a plurality of meshing portions of gears, the power transmission efficiency of the mechanism is also improved.

Claims

1. A gear comprising:

a tooth surface on the gear;

a hard carbon film formed on at least a part of the tooth surface; and

a lubricant in contact with the hard carbon film,

wherein a main component of the lubricant is a hydroxyl-compound, and an amount of the hydroxyl-compound in the lubricant is greater than or equal to 85 percent by volume,

wherein the hydroxyl-compound of the lubricant interacts synergistically with the hard carbon film of the tooth surface to improve a reduction of friction of the tooth surface, and

wherein an amount of hydrogen in the hard carbon film is less than or equal to 1 atomic percent wherein the hydroxyl compound comprises glycerin or ethylene glycol.

2. The gear as claimed in claim 1, wherein the gear is a planetary gear mechanism gear.

3. The gear as claimed in claim 1, wherein the gear is a speed reduction mechanism gear.

4. The gear as claimed in claim 1, wherein the amount of hydrogen in the hard carbon film is less than or equal to 0.3 atomic percent.