# US 2018/0320772 A1 · Lightweight torque transmission gear > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0320772 A1 - Document ID: US20180320772A1 - Status: Published application - Kind: A1 - Application number: 15/771,601 - Filed: 2016-11-07 - Published: 2018-11-08 - Earliest claimed: 2015-11-07 - Assignees: Eaton Intelligent Power Limited - Applicants: Eaton Intelligent Power Limited - Inventors: Anuj Anand; Hari Prasad Konka; Peter James Fritz - Web page: https://patentgrep.com/patent/US20180320772A1 ## CPC - F16H 55/06: Use of materials; Use of treatments of toothed members or worms to affect their intrinsic material properties - F16H 55/02: Toothed members; Worms - F16H 55/17: Toothed wheels (worm wheels F16H55/22; chain wheels F16H55/30) - F16H 2055/065: {Moulded gears, e.g. inserts therefor} - F16H 2055/176: {Ring gears with inner teeth} - F16H: GEARING ## Abstract A torque transmitting gear includes a steel toothed annular flange having gear teeth defined on a periphery of the steel toothed annular flange. A steel hub is coaxially aligned with the steel toothed annular flange. A web is formed from a web material having a density less than or equal to 3.0 grams per cubic centimeter. The web is fixedly attached to the toothed annular flange and to the hub for rotation together with the toothed annular flange and the hub. The gear is to operatively transmit a torque of at least 500 Newton Meters for at least 6 million revolutions of the gear. An overall mass of the gear is less than two-thirds of an overall mass of a same-sized all steel gear having a solid steel web with a solid steel web thickness at least one-third of a face width of the toothed annular flange. ## Claims ### Claim 1 A gear for transmitting torque, comprising: a steel toothed annular flange having gear teeth defined on a periphery thereof; a steel hub coaxially aligned with the steel toothed annular flange; and a web formed from a web material having a density less than or equal to 3.0 grams per cubic centimeter (g/cm3), the web fixedly attached to the steel toothed annular flange and to the steel hub for rotation therewith, wherein the gear is to operatively transmit a torque of at least 500 Newton Meters (N·m) for at least 6 million revolutions of the gear; wherein an overall mass of the gear is less than two-thirds of an overall mass of a same-sized all steel gear having a solid steel web with a solid steel web thickness at least one-third of a face width of the steel toothed annular flange. ### Claim 2 (depends on 1) The gear as defined in claim 1 wherein: the web material is a fiber reinforced polymer composite; and the web material is reinforced with glass fiber, carbon fiber, or combinations thereof. ### Claim 3 (depends on 2) The gear as defined in claim 2 wherein: the web material includes a plurality of layers of fiberglass reinforcement; each layer includes fibers aligned parallel to a layer fiber alignment axis of each layer; and the layer fiber alignment axis of each layer is skewed with an adjacent layer fiber alignment axis of an adjacent layer. ### Claim 4 (depends on 2) The gear as defined in claim 2 wherein: the web is bonded to the steel toothed annular flange with a first layer of an adhesive; and the web is bonded to the steel hub with a second layer of the adhesive. ### Claim 5 (depends on 2) The gear as defined in claim 2 wherein: the web is retained in the steel toothed annular flange by a first mechanical interference joint between the steel toothed annular flange and the web; and the steel hub is retained in the web by a second mechanical interference joint between the web and the steel hub. ### Claim 6 (depends on 1) The gear as defined in claim 1 wherein the web material is aluminum or an aluminum alloy. ### Claim 7 (depends on 1) The gear as defined in claim 1, further comprising: a plurality of first lugs defined at spaced intervals on an interior surface of the steel toothed annular flange; a plurality of first grooves defined in an outer web circumferential surface wherein the plurality of the first grooves is complementary to the plurality of the first lugs, and wherein a total quantity of the first grooves is at least equal to a total quantity of the first lugs; a plurality of second lugs defined at spaced intervals on an exterior surface of the steel hub; and a plurality of second grooves defined in an inner web circumferential surface wherein the plurality of second grooves is complementary to the plurality of the second lugs, and wherein a total quantity of second grooves is at least equal to a total quantity of the second lugs. ### Claim 8 (depends on 7) The gear as defined in claim 7 wherein: a first ratio of a first lug arc length to a first inter-lug space arc length is equal to a first strength ratio of a shear strength of the web material to a shear strength of the steel in the steel toothed annular flange; a second ratio of a second lug arc length to a second inter-lug space arc length is equal to a second strength ratio of the shear strength of the web material to a shear strength of the steel in the steel hub; the first lug arc length and the first inter-lug space arc length are determined at a first root circle of the plurality of the first lugs; and the second lug arc length and the second inter-lug space arc length are determined at a second root circle of the plurality of the second lugs. ### Claim 9 (depends on 1) The gear as defined in claim 1 wherein the web has a uniform web thickness except in locations on the web where lightening apertures are defined in the web. ### Claim 10 (depends on 9) The gear as defined in claim 9 wherein: a total quantity of the lightening apertures is seven when the web material is aluminum or an aluminum alloy; and the total quantity of the lightening apertures is thirteen when the web material is a fiber reinforced polymer composite. ### Claim 11 A computer implemented method for designing a torque transmitting structure, comprising: inputting a finite element model of an initial structural design via a user interface; defining design and non-design space on the initial structural design; setting up topology optimization parameters; iteratively optimizing topology variations from the initial structural design by varying the topology optimization parameters in a computer simulator running a computer simulation until topology optimization criteria are satisfied to generate a topology optimized design; storing the topology optimized design in a first three dimensional modeling format; iteratively optimizing geometry variations from the topology optimized design by varying geometric optimization parameters of each geometry design iteration in the computer simulator running the computer simulation and evaluating geometry optimization criteria until geometry optimization targets are satisfied to generate a geometry optimized design; storing the geometry optimized design in a second three dimensional modeling format; and generating a hardware prototype according to the geometry optimized design. ### Claim 12 (depends on 11) The method as defined in claim 11 wherein: the initial structural design includes a first material and a second material; the first material and the second material are dissimilar; and the first material is joined to the second material thereby forming a joint. ### Claim 13 (depends on 12) The method as defined in claim 12 wherein: the joint is a mechanical interference-based joint; and the computer simulation includes: an Augmented Lagrangian contact algorithm to define a frictional contact between the first material and the second material at the interference-based joint; and a finite element method algorithm to calculate stresses and strains under internal and external loads. ### Claim 14 (depends on 12) The method as defined in claim 12 wherein: the first material is bonded to the second material by an adhesive disposed between the first material and the second material, thereby forming the joint; and the joint is an adhesively bonded joint. ### Claim 15 (depends on 14) The method as defined in claim 14 wherein: a cohesive zone method is applied to model cohesive zone elements of the adhesively bonded joint; and a finite element method algorithm including a cohesive zone module calculates stresses and strains under internal and external loads. ### Claim 16 (depends on 15) The method as defined in claim 15 wherein the cohesive zone method includes: determining traction-separation laws for a mode I crack separation and a mode II crack separation of the first material and the second material bonded by the adhesive; defining the cohesive zone elements in a finite element model, wherein defining the cohesive zone elements includes generating a mesh for the cohesive zone elements and applying the traction-separation laws as elemental properties of the cohesive zone elements; and executing the finite element method algorithm including the cohesive zone module. ### Claim 17 (depends on 16) The method as defined in claim 16 wherein the determining traction-separation laws includes empirically determining the traction-separation laws from a double cantilever beam test to determine the traction-separation law for the mode I crack separation and a lap shear test to determine the traction-separation law for the mode II crack separation. ### Claim 18 (depends on 12) The method as defined in claim 12 wherein varying the topology optimization parameters includes: determining an elemental density for each element of the finite element model; determining a minimum density threshold based on a weight savings percentage target and a mapping of the elemental density on the finite element model; setting the elemental density to zero for each of the elements of the finite element model having an elemental density less than the minimum density threshold; and assigning the elemental density to 1 for each of the elements of the finite element model having an elemental density greater than or equal to the minimum density threshold; and varying the topology optimization parameters in the elements of the finite element model having the elemental density assigned to 1. ### Claim 19 (depends on 12) The method as defined in claim 12 wherein: the evaluating geometry optimization criteria includes: defining relationships between an overall cost and the geometric optimization parameters; and calculating the overall cost for each geometry design iteration; the overall cost includes a material cost and a manufacturing cost; the geometric optimization parameters include: a quantity of a variable design feature; a size of the variable design feature; or a shape of the variable design feature; and the variable design feature includes a hole, a fillet, or a chamfer. ### Claim 20 A gear for transmitting torque, comprising: a steel toothed annular flange having gear teeth defined on a periphery thereof; a steel hub coaxially aligned with the steel toothed annular flange; a web formed from a web material having a density less than or equal to 3.0 grams per cubic centimeter (g/cm3), the web fixedly attached to the steel toothed annular flange and to the steel hub for rotation therewith; a plurality of first lugs defined at spaced intervals on an interior surface of the steel toothed annular flange; a plurality of first grooves defined in an outer web circumferential surface wherein the plurality of the first grooves is complementary to the plurality of the first lugs, and wherein a total quantity of the first grooves is at least equal to a total quantity of the first lugs; a plurality of second lugs defined at spaced intervals on an exterior surface of the steel hub; and a plurality of second grooves defined in an inner web circumferential surface wherein the plurality of second grooves is complementary to the plurality of the second lugs, and wherein a total quantity of the second grooves is at least equal to a total quantity of the second lugs; wherein: the gear is to operatively transmit a torque of at least 500 Newton Meters (N·m) for at least 6 million revolutions of the gear; an overall mass of the gear is less than two-thirds of an overall mass of a same-sized all steel gear having a solid steel web with a solid steel web thickness at least one-third of a face width of the steel toothed annular flange; the web material is a glass fiber reinforced polymer composite; the web material includes a plurality of layers of fiberglass reinforcement; each layer includes fibers aligned parallel to a layer fiber alignment axis of each layer; the layer fiber alignment axis of each layer is skewed with an adjacent layer fiber alignment axis of an adjacent layer; the web is bonded to the steel toothed annular flange with a first layer of an adhesive; and the web is bonded to the steel hub with a second layer of the adhesive; a first ratio of a first lug arc length to a first inter-lug space arc length is equal to a first strength ratio of a shear strength of the web material to a shear strength of the steel in the steel toothed annular flange; a second ratio of a second lug arc length to a second inter-lug space arc length is equal to a second strength ratio of the shear strength of the web material to a shear strength of the steel in the steel hub; the first lug arc length and the first inter-lug space arc length are determined at a first root circle of the plurality of the first lugs; the second lug arc length and the second inter-lug space arc length are determined at a second root circle of the plurality of the second lugs; the web has a uniform web thickness except where lightening apertures are defined in the web; and a total quantity of the lightening apertures is thirteen.