# US 10,767,688 B2 · Bearing system for an articulating motor device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,767,688 B2 - Document ID: US10767688B2 - Status: Granted - Kind: B2 - Application number: 16/366,565 - Filed: 2019-03-27 - Published: 2019-10-03 - Granted: 2020-09-08 - Earliest claimed: 2018-03-27 - Assignees: Roller Bearing Company of America, Inc. - Applicants: Roller Bearing Company of America, Inc. - Inventors: Robert Pallini; Michael Coppola - Web page: https://patentgrep.com/patent/US10767688B2 ## CPC - F16C 19/18: with two or more rows of balls - F16C 19/546: {Systems with spaced apart rolling bearings including at least one angular contact bearing} - F16C 13/006: {Guiding rollers, wheels or the like, formed by or on the outer element of a single bearing or bearing unit, e.g. two adjacent bearings, whose ratio of length to diameter is generally less than one} - F16C 19/163: {with angular contact} - F16C 19/547: {with two angular contact rolling bearings} - F16C 33/6607: {Retaining the grease in or near the bearing} - F16C 33/7826: {of the opposing surface cooperating with the seal, e.g. a shoulder surface of a bearing ring} - F16C 33/784: {mounted to a groove in the inner surface of the outer race and extending toward the inner race} - F16C 33/7859: {with a further sealing element} - F16C 33/7886: {mounted outside the gap between the inner and outer races, e.g. sealing rings mounted to an end face or outer surface of a race} - H02K 5/1732: {radially supporting the rotary shaft at both ends of the rotor (H02K5/1737 takes precedence)} - F16C 19/06: with a single row or balls - F16C 2204/66: High carbon steel, i.e. carbon content above 0.8 wt%, e.g. through-hardenable steel - F16C 2208/10: Elastomers; Rubbers - F16C 2208/20: Thermoplastic resins - F16C 2226/10: Force connections, e.g. clamping - F16C 2240/14: Preload - F16C 2240/80: Pitch circle diameters [PCD] - F16C 2240/82: Degree of filling, i.e. sum of diameters of rolling elements in relation to PCD - F16C 2300/34: Vertical, e.g. bearings for supporting a vertical shaft - F16C 2300/52: low temperature, e.g. cryogenic temperature - F16C 2380/26: Dynamo-electric machines or combinations therewith, e.g. electro-motors and generators - 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 A bearing system for a rotating vertical shaft includes a first ball bearing, having a first pitch diameter and a first axial stiffness and a second ball bearing having a second pitch diameter and a second axial stiffness. The first ball bearing is a deep groove Conrad bearing. The second ball bearing is an angular contact bearing. The first and second ball bearings are coaxial, secured to one another and rotatable together. The first pitch diameter is at least 1.5 times greater than the second pitch diameter. The bearing system has an axial stiffness ratio defined by the first axial stiffness divided by the second axial stiffness. The axial stiffness ratio is based on an axial preload force applied to the second outer ring such that an operating torque of the bearing system is within a predetermined range at temperatures from minus 40 to positive 85 degrees Celsius. ## Claims ### Claim 1 A bearing system for a rotating vertical shaft, the bearing system comprising: a first ball bearing, having a first pitch diameter and a first axial stiffness, the first ball bearing having a first inner ring disposed in a first outer ring and a first plurality of balls rollingly positioned between the first inner ring and the first outer ring so that the first plurality of balls rollingly engage a first exterior raceway of the first inner ring and a first interior raceway of the first outer ring at respective first axial centerlines of the first exterior raceway and the first interior raceway; a second ball bearing having a second pitch diameter and a second axial stiffness, the second ball bearing having a second inner ring disposed in a second outer ring, and a counterbore formed in one of the second inner ring and the second outer ring; and a second plurality of balls rollingly positioned between the second inner ring and the second outer ring so that the second plurality of balls rollingly engage a second exterior raceway of the second inner ring and a second interior raceway of the second outer ring at an angle offset from second axial centerlines of the second exterior raceway and the second interior raceway; the first inner ring and the second inner ring being coaxial, secured to one another and rotatable together; the first pitch diameter being at least 1.5 times greater than the second pitch diameter; and the bearing system having an axial stiffness ratio defined by the first axial stiffness divided by the second axial stiffness, wherein the magnitude of the axial stiffness ratio is based on an axial preload force applied to the second outer ring such that an operating torque of the bearing system is within a predetermined range at temperatures from minus 40 degrees Celsius to positive 85 degrees Celsius. ### Claim 2 (depends on 1) The bearing system of claim 1, wherein the preload force is from 15 to 35 pounds. ### Claim 3 (depends on 1) The bearing system of claim 1, wherein the operating torque is between zero and 50 foot-pounds. ### Claim 4 (depends on 1) The bearing system of claim 1, wherein the first pitch diameter is at least 2.0 times greater than the second pitch diameter. ### Claim 5 (depends on 1) The bearing system of claim 1, wherein the axial stiffness ratio is from 1.1 to 1.7. ### Claim 6 (depends on 1) The bearing system of claim 1, wherein the first inner ring and the second inner ring are secured to one another by a shaft. ### Claim 7 (depends on 6) The bearing system of claim 6, wherein the first inner ring and the second inner ring are manufactured from an iron based alloy and the shaft is manufactured from a material other than an iron based alloy. ### Claim 8 (depends on 7) The bearing system of claim 7, wherein the shaft is manufactured from an aluminum alloy. ### Claim 9 (depends on 6) The bearing system of claim 6, further comprising a load distribution member adjustably secured to the shaft via at least one fastener and the load distribution member engaging one of the second inner ring and second outer ring to apply the axial preload force thereto. ### Claim 10 (depends on 9) The bearing system of claim 9, further comprising an axial gap between the load distribution member and an adjacent axial end of the shaft. ### Claim 11 (depends on 6) The bearing system of claim 6, wherein at least one of the first inner ring and the second inner ring are secured to the shaft by slip fit. ### Claim 12 (depends on 1) The bearing system of claim 1, wherein the first outer ring and the second outer ring are connected to one another by a frame. ### Claim 13 (depends on 12) The bearing system of claim 12, wherein the frame is manufactured from a material other than an iron based alloy. ### Claim 14 (depends on 12) The bearing system of claim 12, wherein the frame is manufactured from an aluminum based alloy. ### Claim 15 (depends on 12) The bearing system of claim 12, wherein at least one of the first outer ring and the second outer ring is secured to the frame by an interference fit. ### Claim 16 (depends on 1) The bearing system of claim 1, wherein at least one of the first inner ring, the first outer ring, the first plurality of balls, the second inner ring, the second outer ring and the second plurality of balls is manufactured from an iron based alloy. ### Claim 17 (depends on 1) A motor device comprising the bearing system according to claim 1, further comprising a stator in fixed relation to the frame, the first outer ring and the second outer ring and a rotor in fixed relation to the shaft, the first inner ring and the second inner ring, the rotor being positioned in the stator and rotatable therein upon introduction of an electric current to the rotor. ### Claim 18 (depends on 1) The bearing system of claim 1, wherein the second outer ring includes a circumferentially extending seal groove, and further comprising: a first seal having a sealing portion, a retaining shield, and a base portion, the base portion disposed in the seal groove such that the base portion frictionally engages the seal groove, wherein the sealing portion includes a neck portion extending from the base portion terminating at a tip portion, the tip portion slidingly engaging the second ball bearing. ### Claim 19 (depends on 18) The bearing system of claim 18, further comprising: a second counterbore axially opposing the first counterbore; and a second seal axially opposing the first seal. ### Claim 20 (depends on 18) The bearing system of claim 18, wherein the second ball bearing further comprises a circumferentially extending groove and a snap wire is disposed in the groove, in slidable contact with the first seal. ### Claim 21 A bearing system for a rotating vertical shaft, the bearing system comprising: a first ball bearing, having a first pitch diameter and a first axial stiffness, the first ball bearing having a first inner ring disposed in a first outer ring and a first plurality of balls rollingly positioned between the first inner ring and the first outer ring so that the first plurality of balls rollingly engage a first exterior raceway of the first inner ring and a first interior raceway of the first outer ring at respective first axial centerlines of the first exterior raceway and the first interior raceway; a second ball bearing having a second pitch diameter and a second axial stiffness, the second ball bearing having a second inner ring disposed in a second outer ring, and a counterbore bore positioned in one of the second inner ring and the second outer ring; a second plurality of balls rollingly positioned between the second inner ring and the second outer ring so that the second plurality of balls rollingly engage a second exterior raceway of the second inner ring and a second interior raceway of the second outer ring at an angle offset from second axial centerlines of the second exterior raceway and the second interior raceway; the first inner ring and the second inner ring being coaxial, secured to one another and rotatable together; the first pitch diameter being at least 1.5 times greater than the second pitch diameter; and the bearing system having an axial stiffness ratio defined by the first axial stiffness divided by the second axial stiffness, wherein the magnitude of the axial stiffness ratio is based on an axial preload force applied to the second outer ring such that an operating torque of the bearing system is within a predetermined range at temperatures from minus 40 degrees Celsius to positive 85 degrees Celsius; wherein the second outer ring includes a circumferentially extending seal groove, and further comprising: a first seal having a sealing portion, a retaining shield, and a base portion, the base portion disposed in the seal groove such that the base portion frictionally engages the seal groove; wherein the sealing portion includes a neck portion extending from the base portion terminating at a tip portion, the tip portion slidingly engaging the second ball bearing, and wherein the second ball bearing further comprises a circumferentially extending groove and a snap wire is disposed in the groove, in slidable contact with the first seal.