# US 12,007,001 B2 · Cellulose-containing gear > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,007,001 B2 - Document ID: US12007001B2 - Status: Granted - Kind: B2 - Application number: 17/980,459 - Filed: 2022-11-03 - Published: 2023-05-25 - Granted: 2024-06-11 - Earliest claimed: 2018-04-23 - Assignees: Asahi Kasei Kabushiki Kaisha - Applicants: Asahi Kasei Kabushiki Kaisha - Inventors: Junichi Tsuzuki; Sara Kusumoto - Web page: https://patentgrep.com/patent/US12007001B2 ## CPC - F16H 1/16: comprising worm and worm-wheel - B62D 5/0409: {Electric motor acting on the steering column} - C08J 5/045: {with vegetable or animal fibrous material} - C08K 7/02: Fibres or whiskers - C08L 1/02: Cellulose; Modified cellulose - C08L 59/04: Copolyoxymethylenes - C08L 77/02: Polyamides derived from omega-amino carboxylic acids or from lactams thereof (C08L77/10 takes precedence) - C08L 77/06: Polyamides derived from polyamines and polycarboxylic acids (C08L77/10 takes precedence) - F16H 19/04: comprising a rack - F16H 55/06: Use of materials; Use of treatments of toothed members or worms to affect their intrinsic material properties - F16H 55/22: for transmissions with crossing shafts, especially worms, worm-gears - F16H 57/0464: {Grease lubrication} - F16H 57/0498: {Worm gearings} - B62D 5/0424: {the axes of motor and final driven element of steering gear, e.g. rack, being parallel} - C08J 2329/14: Homopolymers or copolymers of acetals or ketals obtained by polymerisation of unsaturated acetals or ketals or by after-treatment of polymers of unsaturated alcohols - C08J 2377/00: Characterised by the use of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Derivatives of such polymers - C08J 2401/02: Cellulose; Modified cellulose - C08K 2201/003: Additives being defined by their diameter - C08L 2205/16: Fibres; Fibrils - F16H 2055/065: {Moulded gears, e.g. inserts therefor} - F16H: GEARING - B62D: MOTOR VEHICLES; TRAILERS (steering, or guiding on a desired track, of agricultural machines or implements A01B69/00; wheels, castors, axles, increasing wheel adhesion B60B; vehicle tyres, tyre inflation or tyre changing B60C; connections between vehicles of a train or the like B60D; vehicles for use on rail and road, amphibious or convertible vehicles B60F; suspension arrangements B60G; heating, cooling, ventilating or other air treating devices B60H; windows, windscreens, non-fixed roofs, doors or similar devices, protective coverings for vehicles not in use B60J; propulsion plant arrangements, auxiliary drives, transmissions, controls, instrumentation or dashboards B60K; electric equipment or propulsion of electrically-propelled vehicles B60L; power supply for electrically-propelled vehicles B60M; passenger accommodation not otherwise provided for B60N; adaptations for load transportation or to carry special loads or objects B60P; arrangement of signalling or lighting devices, the mounting or supporting thereof or circuits therefor, for vehicles in general B60Q; vehicles, vehicle fittings or vehicle parts not otherwise provided for B60R; servicing, cleaning, repairing, supporting, lifting, or manoeuvring, not otherwise provided for, B60S; brake arrangements, brake control systems or parts thereof B60T; air-cushion vehicles B60V; motor-cycles, accessories therefor B62J, B62K; testing of vehicles G01M) - C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29) - C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09) - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) ## Abstract A gear is provided that has excellent continuous moldability for practical use, and both high slidability and high durability. The provided gear is a molded resin constructed of a resin composition comprising a thermoplastic resin (A) and cellulose nanofibers (B) with an average fiber diameter of 1000 nm or smaller, and having a number average molecular weight of the thermoplastic resin (A) in the range of 10,000 to 150,000, wherein a sliding surface of the gear with another gear teeth has an arithmetic mean surface roughness Sa of 3.0 μm or lower. ## Claims ### Claim 1 A gear which is a molded resin constructed of a resin composition comprising a thermoplastic resin (A) and cellulose nanofibers (B) with an average fiber diameter of 1000 nm or smaller, wherein: the thermoplastic resin (A) includes a polyamide resin or a polyacetal resin, the thermoplastic resin (A) has a number average molecular weight in the range of 10,000 to 150,000, and a sliding surface of the gear with another gear teeth has an arithmetic mean surface roughness Sa of 3.0 jam or lower. ### Claim 2 (depends on 1) The gear according to claim 1, wherein the resin composition includes the thermoplastic resin (A) at 45 to 95 mass % and the cellulose nanofibers (B) at 5 to 50 mass %. ### Claim 3 (depends on 1) The gear according to claim 1, wherein the resin composition further includes a surface treatment agent (C). ### Claim 4 (depends on 3) The gear according to claim 3, wherein the resin composition includes the surface treatment agent (C) at 1 to 50 parts by mass with respect to 100 parts by mass of the cellulose nanofibers (B). ### Claim 5 (depends on 1) The gear according to claim 1, wherein the resin composition further includes a metal ion component (D). ### Claim 6 (depends on 1) The gear according to claim 1, which further includes a sliding agent component (E). ### Claim 7 (depends on 1) The gear according to claim 1, wherein the resin composition has a flexural modulus of 3000 MPa or higher when measured according to 150179. ### Claim 8 (depends on 1) The gear according to claim 1 wherein, for a frictional coefficient measured at a linear speed of 50 mm/sec, a reciprocal distance of 50 mm, a temperature of 23° C., a humidity of 50% and a load of 19.8 N using a multipurpose test piece fabricated according to ISO 294-3, a reciprocating dynamic friction wear tester, and a SUS304 test sphere with a diameter of 5 mm as a partner material, a frictional coefficient ratio (II/1) is 0.8 or lower, as a ratio of a value (II) for the resin composition with respect to a value (I) of a composition with the same composition as the resin composition except for containing no cellulose nanofibers (B). ### Claim 9 (depends on 1) The gear according to claim 1, wherein a dimensional change with water absorption is no greater than 3% after exposure for 24 hours in hot water at 80° C. followed by holding for 120 hours under conditions of 80° C., 57% relative humidity. ### Claim 10 (depends on 1) The gear according to claim 1, which is an injection molded article. ### Claim 11 (depends on 1) The gear according to claim 1, which is a machined article. ### Claim 12 (depends on 1) The gear according to claim 1, which is an article cut from a molded round bar. ### Claim 13 (depends on 1) A gear system comprising: a gear mechanism constructed of a driven gear and a driving gear that engages with the driven gear, and a driving source that drives the driving gear, wherein the driven gear and/or the driving gear are gears according to claim 1. ### Claim 14 A gear which is a molded resin constructed of a resin composition comprising a thermoplastic resin (A) and cellulose nanofibers (B) with an average fiber diameter of 1000 nm or smaller, wherein: the gear has a roundness of 400 jam or smaller, the thermoplastic resin (A) includes a polyacetal resin, and the resin composition has a thixotropic index of 2 to 10 at a temperature of 25° C. higher than the melting point of the thermoplastic resin (A). ### Claim 15 (depends on 14) The gear according to claim 14 wherein, for a frictional coefficient measured at a linear speed of 50 mm/sec, a reciprocal distance of 50 mm, a temperature of 23° C., a humidity of 50% and a load of 19.8 N using a multipurpose test piece fabricated according to ISO 294-3, a reciprocating dynamic friction wear tester, and a SUS304 test sphere with a diameter of 5 mm as a partner material, a frictional coefficient ratio (II/1) is 0.8 or lower, as a ratio of a value (II) for the resin composition with respect to a value (I) of a composition with the same composition as the resin composition except for containing no cellulose nanofibers (B). ### Claim 16 (depends on 14) A gear system comprising: a gear mechanism constructed of a driven gear and a driving gear that engages with the driven gear, and a driving source that drives the driving gear, wherein the driven gear and/or the driving gear are gears according to claim 14. ### Claim 17 (depends on 14) A gear system comprising: a gear mechanism constructed of a driven gear and a driving gear that engages with the driven gear, and a driving source that drives the driving gear, wherein: the gear mechanism is a worm gear mechanism constructed of a worm and worm wheel, and the worm wheel is the gear according to claim 14 which is an injection molded compact of the resin composition. ### Claim 18 A gear system comprising: a gear mechanism constructed of a driven gear and a driving gear that engages with the driven gear, wherein the driven gear and/or the driving gear comprises a resin composition comprising a thermoplastic resin (A) and cellulose nanofibers (B) with an average fiber diameter of 1000 nm or smaller, wherein: the thermoplastic resin (A) includes a polyamide resin or a polyacetal resin, a number average molecular weight of the thermoplastic resin (A) is in the range of 10,000 to 150,000, and in the driven gear and/or the driving gear, a sliding surface of the gear with another gear teeth has an arithmetic mean surface roughness Sa of 3.0 jam or lower. ### Claim 19 (depends on 18) The gear system according to claim 18, wherein the driven gear and the driving gear are constructed of the same material. ### Claim 20 A gear system comprising: a gear mechanism constructed of a driven gear and a driving gear that engages with the driven gear, wherein the driven gear and/or the driving gear comprises a resin composition comprising a thermoplastic resin (A) and cellulose nanofibers (B) with an average fiber diameter of 1000 nm or smaller, wherein: the thermoplastic resin (A) includes a polyamide resin or a polyacetal resin, and the resin composition has a thixotropic index of 2 to 10 at a temperature of 25° C. higher than the melting point of the thermoplastic resin (A). ### Claim 21 (depends on 20) The gear system according to claim 20, wherein the driven gear and the driving gear are constructed of the same material.