# US 10,864,946 B2 · Automotive panel structure > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,864,946 B2 - Document ID: US10864946B2 - Status: Granted - Kind: B2 - Application number: 16/170,837 - Filed: 2018-10-25 - Published: 2019-05-02 - Granted: 2020-12-15 - Earliest claimed: 2017-11-01 - Assignees: Mazda Motor Corporation - Applicants: Mazda Motor Corporation - Inventors: Tomoya Yoshida; Shuhei Narita; Keisuke Yamakawa; Takashi Sasaki; Ryuji Nonaka; Masanori Ishikawa; Katsumi Shiraishi; Seiji Nakano - Web page: https://patentgrep.com/patent/US10864946B2 ## CPC - B32B 3/266: {characterised by an apertured layer, the apertures going through the whole thickness of the layer, e.g. expanded metal, perforated layer, slit layer regular cells B32B3/12} - B62D 25/02: Side panels {(B62D33/046 takes precedence; sideboards for open load compartments B62D33/023)} - B32B 3/02: characterised by features of form at particular places, e.g. in edge regions {(non-uniform thickness B32B3/263)} - B32B 3/04: characterised by {at least one} layer folded at the edge, e.g. over another layer {; characterised by at least one layer enveloping or enclosing a material} - B32B 3/06: for securing layers together; for attaching the product to another member, e.g. to a support {, or to another product, e.g. groove/tongue, interlocking} - B32B 3/08: characterised by added members at particular parts {(layer formed of separate pieces of material which are juxtaposed side-by-side B32B3/14, B32B3/18)} - B32B 3/12: characterised by a layer of regularly- arranged cells, e.g. a honeycomb structure - B32B 3/30: characterised by a layer formed with recesses or projections, e.g. {hollows, grooves, protuberances, ribs (apertured layer B32B3/266; layer with cavities or internal voids B32B3/26)} - B32B 5/12: characterised by the relative arrangement of fibres or filaments of {different layers, e.g. the fibres or filaments being parallel or perpendicular to each other} - B32B 5/18: characterised by features of a layer {of} foamed material - B32B 5/245: {another layer next to it being a foam layer} - B32B 5/26: another layer {next to it} also being fibrous or filamentary {(relative arrangement of fibres or filaments of different layers B32B5/12)} - B32B 7/02: Physical, chemical or physicochemical properties - B32B 7/022: Mechanical properties - B32B 7/08: by mechanical means - B32B 7/12: using interposed adhesives or interposed materials with bonding properties - B32B 15/043: {of metal (B32B15/01 takes precedence)} - B32B 15/08: of synthetic resin - B32B 15/14: next to a fibrous or filamentary layer - B32B 15/18: comprising iron or steel {(B32B15/011, B32B15/012 and B32B15/013 take precedence)} - B32B 15/20: comprising aluminium or copper {(B32B15/016 and B32B15/017 take precedence)} - B32B 25/045: {of foam} - B32B 25/10: next to a fibrous or filamentary layer - B32B 27/065: {of foam} - B32B 27/08: of synthetic resin - B32B 27/12: next to a fibrous or filamentary layer - B32B 27/32: comprising polyolefins {(comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30)} - B32B 27/36: comprising polyesters - B62D 24/00: Connections between vehicle body and vehicle frame (B62D23/00, B62D33/077 take precedence) - B62D 25/20: Floors or bottom sub-units {(sub-frames for mounting engine or suspensions B62D21/11; drip trays F16N31/006)} - B62D 27/06: readily releasable - B62D 29/043: {Superstructures (B62D25/161 takes precedence)} - B62D 29/048: {Connections therefor, e.g. joints (B62D29/045 takes precedence)} - B32B 2250/40: Symmetrical or sandwich layers, e.g. ABA, ABCBA, ABCCBA - B32B 2260/021: Fibrous or filamentary layer - B32B 2260/046: Synthetic resin - B32B 2262/0246: Acrylic resin fibres - B32B 2262/0253: Polyolefin fibres - B32B 2262/0261: Polyamide fibres - B32B 2262/0276: Polyester fibres - B32B 2262/04: Cellulosic plastic fibres, e.g. rayon - B32B 2262/062: Cellulose fibres, e.g. cotton - B32B 2262/101: Glass fibres - B32B 2266/0207: Materials belonging to B32B25/00 - B32B 2266/0278: Polyurethane - B32B 2266/06: Open cell foam - B32B 2307/10: having particular acoustical properties - B32B 2307/102: Insulating - B32B 2307/304: Insulating - B32B 2307/306: Resistant to heat - B32B 2307/51: Elastic - B32B 2307/56: Damping, energy absorption - B32B 2307/72: Density - B32B 2307/724: Permeability to gases, adsorption - B32B 2307/732: Dimensional properties - B32B 2605/003: Interior finishings - B32B 2605/08: Cars - B60R 13/0815: {Acoustic or thermal insulation of passenger compartments (wall or roof liners integrating the insulating function B60R13/02; insulating floor mats or carpets B60N3/04)} - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM - 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) - B60R: VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR ## Abstract In order to increase road noise transmission loss, a double-wall panel includes a core material. The core material is enclosed between an outer wall and an inner wall facing each other, and has at least a predetermined thickness across the panel in all in-plane directions of the walls. The core material has a specific surface area of 20,000 (mm2/cm3) or more, where the specific surface area is defined as a surface area per unit volume. ## Claims ### Claim 1 An automotive panel structure wherein the panel structure includes a double-wall panel, the double-wall panel includes an inner wall, an outer wall facing the inner wall, and a core material enclosed between the inner wall and the outer wall, and having at least a predetermined thickness across the panel in all in-plane directions of the walls, the core material has a specific surface area of 20,000 mm2/cm3 or more, where the specific surface area is defined as a surface area per unit volume. ### Claim 2 (depends on 1) The automotive panel structure of claim 1, wherein the core material has a packing density of 0.11 g/cm3 or less. ### Claim 3 (depends on 1) The automotive panel structure of claim 1, wherein the core material is a fibrous substance and has a fiber thickness of 0.1-3 denier. ### Claim 4 (depends on 3) The automotive panel structure of claim 3, wherein the fibrous substance contains at least one of polyester, acrylic resin, nylon, polypropylene, cotton, and rayon. ### Claim 5 (depends on 1) The automotive panel structure of claim 1, wherein the core material is a gas-permeable foam substance and has a framework thickness of 3-7 μm. ### Claim 6 (depends on 5) The automotive panel structure of claim 5, wherein the foam substance contains at least one of polyurethane and rubber. ### Claim 7 (depends on 1) The automotive panel structure of claim 1, wherein the predetermined thickness is in the range of 15-50 mm. ### Claim 8 (depends on 1) The automotive panel structure of claim 1, wherein the double-wall panel further includes a core layer including a gas and the core material, the core material is formed of a fibrous substance or a gas-permeable foam substance, and a stiffness of the outer wall is lower than a stiffness of the inner wall. ### Claim 9 (depends on 8) The automotive panel structure of claim 8, wherein the stiffness of the outer wall is lower than or equal to the stiffness of PP or PE, and the stiffness of the inner wall is higher than or equal to the stiffness of glass fiber-reinforced resin. ### Claim 10 (depends on 8) The automotive panel structure of claim 8, wherein the double-wall panel further includes a vertical wall configured to join the inner wall and the outer wall together, wherein the vertical wall is disposed at a peripheral portion of the inner and outer walls, and the vertical wall is mostly formed of the same material as that of the outer wall. ### Claim 11 (depends on 8) The automotive panel structure of claim 8, wherein the double-wall panel further includes a vertical wall configured to join the inner wall and the outer wall together, wherein the vertical wall is disposed at a peripheral portion of the inner and outer walls, and the vertical wall is mostly formed of the same material as that of the inner wall. ### Claim 12 (depends on 8) The automotive panel structure of claim 8, wherein the core layer is disposed closer to the outer wall between the inner wall and the outer wall, and the double-wall panel further includes a stiff material having a stiffness higher than or equal to that of the inner wall, and disposed closer to the inner wall between the inner wall and the outer wall. ### Claim 13 (depends on 8) The automotive panel structure of claim 8, wherein the core layer contains the core material formed of a fibrous substance, and the core material is disposed with a fiber direction thereof pointing along a wall surface of the outer wall. ### Claim 14 (depends on 8) The automotive panel structure of claim 8, wherein the inner wall and the outer wall have the same mass. ### Claim 15 (depends on 1) The automotive panel structure of claim 1, wherein the double-wall panel is a hollow double-wall panel, and an edge of the hollow double-wall panel is joined to a joint surface of a joint mating member, in the hollow double-wall panel, peripheral edges of the two walls are joined together, and a closed space between the two walls is filled with the core material to such an extent that an inside of the edge of the hollow double-wall panel is filled with the core material, and when the edge of the hollow double-wall panel is joined to the joint surface of the joint mating member, the core material contained in the edge of the hollow double-wall panel covers the joint surface of the joint mating member. ### Claim 16 (depends on 15) The automotive panel structure of claim 15, wherein the joint mating member is a framework member of a car body, or a panel having the same structure as that of the hollow double-wall panel, the edge of the hollow double-wall panel is joined to the joint surface of the joint mating member by a fastening part, a through-hole through which the fastening part is inserted is provided in the edge of the hollow double-wall panel, penetrating through the edge in a thickness direction of the edge, the hollow double-wall panel has an aperture ratio of less than 1%, where the aperture ratio is defined as the proportion of the opening area of one of openings of the through-hole to the area of one of main surfaces of the hollow double-wall panel, and a gap between the edge of the hollow double-wall panel and the fastening part is sealed by a sealing material. ### Claim 17 (depends on 15) The automotive panel structure of claim 15, wherein a core layer formed of the core material contained in the closed space of the hollow double-wall panel has a thickness in the range of 7-50 mm. ### Claim 18 (depends on 15) The automotive panel structure of claim 15, wherein the two walls are formed of materials have different masses, and has a mass difference percentage ΔM in the range of ±10%. ### Claim 19 (depends on 15) The automotive panel structure of claim 15, wherein the hollow double-wall panel has the edge, and a panel body excluding the edge, the edge has a vertical portion protruding perpendicularly to the panel body, and a surface in a thickness direction of the vertical portion is joined to the joint surface of the joint mating member. ### Claim 20 (depends on 15) The automotive panel structure of claim 15, wherein the hollow double-wall panel has the edge, and a panel body excluding the edge, the edge has a sloping portion sloping in one direction in a thickness direction of the panel body, and a surface facing in a thickness direction of the sloping portion is joined to the joint surface of the joint mating member.