# US 2013/0154419 A1 · Sliding member and fluid dynamic pressure bearing apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0154419 A1 - Document ID: US20130154419A1 - Status: Published application - Kind: A1 - Application number: 13/712,503 - Filed: 2012-12-12 - Published: 2013-06-20 - Earliest claimed: 2011-12-19 - Assignees: Minebea Co., Ltd. - Inventors: Shinichi NIWA; Eiji FUJIMOTO; Toshiaki ASAKAWA - Web page: https://patentgrep.com/patent/US20130154419A1 ## CPC - F16C 32/0662: {Details of hydrostatic bearings independent of fluid supply or direction of load} - F16C 17/107: {with at least one surface for radial load and at least one surface for axial load} - F16C 32/0629: {supported by a liquid cushion, e.g. oil cushion} - F16C 33/043: {Sliding surface consisting mainly of ceramics, cermets or hard carbon, e.g. diamond like carbon [DLC]} - H02K 7/08: Structural association with bearings - F16C 2206/04: Diamond like carbon [DLC] - F16C 2223/60: by vapour deposition, e.g. PVD, CVD - F16C 2240/64: in the nanometer range - F16C 2370/12: Hard disk drives or the like - F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) ## Abstract There is provided a sliding member including: a substrate; and a protective film provided on the substrate, wherein the protective film is composed only of a metal base layer provided on the substrate, a low-hardness diamond-like carbon layer provided as a single layer on the metal base layer, and a high-hardness diamond-like carbon layer provided as a single layer directly on the low-hardness diamond-like carbon layer. The sliding member has the protective film which has excellent frictional wear resistance property and satisfactory adhesion property to the substrate, regardless of having a simple structure. ## Claims ### Claim 1 A sliding member comprising: a substrate; and a protective film provided on the substrate, the protective film consisting of a metal base layer provided on the substrate, one low-hardness diamond-like carbon layer provided on the metal base layer and one high-hardness diamond-like carbon layer provided directly on the low-hardness diamond-like carbon layer. ### Claim 2 (depends on 1) The sliding member according to claim 1, wherein the high-hardness diamond-like carbon layer has a homogenous structure within the high-hardness diamond-like carbon layer; and the low-hardness diamond-like carbon layer has a columnar structure extending in a thickness direction of the low-hardness diamond-like carbon layer. ### Claim 3 (depends on 1) The sliding member according to claim 1, wherein a ratio of a thickness of the high-hardness diamond-like carbon layer with respect to a total of the thickness of the high-hardness diamond-like carbon layer and a thickness of the low-hardness diamond-like carbon layer is 75% to 95%. ### Claim 4 (depends on 1) The sliding member according to claim 1, wherein a hardness of the high-hardness diamond-like carbon layer is not less than 28 GPa. ### Claim 5 (depends on 1) The sliding member according to claim 1, wherein a hardness of the low-hardness diamond-like carbon layer is not more than 17 GPa. ### Claim 6 (depends on 1) The sliding member according to claim 1, wherein both of the high-hardness and low-hardness diamond-like carbon layers do not contain hydrogen. ### Claim 7 (depends on 1) The sliding member according to claim 1, which is usable for a fluid dynamic pressure bearing apparatus. ### Claim 8 (depends on 7) The sliding member according to claim 7, which is usable for a fluid dynamic pressure bearing apparatus for a spindle motor of a hard disk drive. ### Claim 9 (depends on 7) The sliding member according to claim 7, wherein a groove, along which a fluid used in the fluid dynamic pressure bearing apparatus flows, is formed on a surface of the substrate; and the protective film is formed in the groove. ### Claim 10 (depends on 1) A fluid dynamic pressure bearing apparatus comprising the sliding member as defined in claim 1. ### Claim 11 (depends on 10) The fluid dynamic pressure bearing apparatus according to claim 10, which is usable for a spindle motor of a hard disk drive. ### Claim 12 A sliding member, comprising: a substrate; and a protective film provided on the substrate, the protective film consisting of a metal base layer, a first diamond-like carbon layer which has a columnar structure extending in a thickness direction of the first diamond-like carbon layer and which is formed on the metal base layer, and a second diamond-like carbon layer which has a homogeneous structure and which is formed on the first diamond-like carbon layer. ### Claim 13 (depends on 12) The sliding member according to claim 12, wherein a ratio of a thickness of the second diamond-like carbon layer with respect to total of the thickness of the second diamond-like carbon layer and a thickness of the first diamond-like carbon layer is 75% to 95%. ### Claim 14 (depends on 12) The sliding member according to claim 12, wherein both of the first and second diamond-like carbon layers do not contain hydrogen. ### Claim 15 (depends on 12) The sliding member according to claim 12, which is usable for a fluid dynamic pressure bearing apparatus. ### Claim 16 (depends on 15) The sliding member according to claim 15, which is usable for a fluid dynamic pressure bearing apparatus for a spindle motor of a hard disk drive. ### Claim 17 (depends on 15) A fluid dynamic pressure bearing apparatus comprising the sliding member as defined in claim 15. ### Claim 18 (depends on 17) The fluid dynamic pressure bearing apparatus according to claim 17, which is usable for a spindle motor of a hard disk drive. ### Claim 19 (depends on 11) A spindle motor apparatus of a hard disk drive comprising the fluid dynamic pressure bearing according to claim 11. ### Claim 20 (depends on 18) A spindle motor apparatus of a hard disk drive comprising the fluid dynamic pressure bearing according to claim 18.