# US 11,994,445 B2 · Condition monitoring for plain bearings by means of structure-borne noise > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,994,445 B2 - Document ID: US11994445B2 - Status: Granted - Kind: B2 - Application number: 17/045,768 - Filed: 2019-03-12 - Published: 2021-05-27 - Granted: 2024-05-28 - Earliest claimed: 2018-04-11 - Assignees: ZF Friedrichshafen AG - Applicants: ZF Friedrichshafen AG - Inventors: Andreas Vath; Sebastian Schmidt - Web page: https://patentgrep.com/patent/US11994445B2 ## CPC - G01M 13/045: Acoustic or vibration analysis - G01M 13/021: Gearings - G01M 13/028: Acoustic or vibration analysis - F16C 2233/00: Monitoring condition, e.g. temperature, load, vibration - F16C 2361/61: Toothed gear systems, e.g. support of pinion shafts - G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR - F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS ## Abstract A method for determining an operating condition of at least one plain bearing includes measuring, by a sensor, structure-borne noise arising from a toothed engagement of a first gear and a second gear, wherein the first gear is rotatably mounted via the plain bearing and meshes with the second gear. The method further includes assigning, to a signal of the sensor, a variable that correlates with the operating condition of the plain bearing. ## Claims ### Claim 1 A method for determining an operating condition of at least one plain bearing, the method comprising: measuring, by a sensor, structure-borne noise arising from a toothed engagement of a first gear and a second gear, wherein the first gear is rotatably mounted via the plain bearing and meshes with the second gear; assigning, to a signal of the sensor, a variable that correlates with an absolute or relative bearing play of the plain bearing; and filtering the signal, wherein the filtered signal corresponds to a signal of the structure-borne noise arising from the toothed engagement, wherein a simulated structure-borne noise from the toothed engagement of the first gear and the second gear, a simulated signal of the sensor, and a simulated filtered signal are determined by simulation using a model of the first gear, the second gear, and the plain bearing, and wherein the model images the operating condition of the plain bearing correlating with the absolute or relative bearing play. ### Claim 2 (depends on 1) The method according to claim 1, further comprising calculating a frequency spectrum and/or an order spectrum of the signal and/or of the filtered signal. ### Claim 3 (depends on 1) The method according to claim 1, further comprising detecting a rotational speed of the first gear and/or a temperature of the plain bearing and/or a torque applied to the first gear. ### Claim 4 (depends on 2) The method according to claim 2, wherein a simulated frequency spectrum and/or a simulated order spectrum of the signal or filtered signal is determined by simulation using the model of the first gear, the second gear, and the plain bearing. ### Claim 5 (depends on 1) The method according to claim 1, wherein the simulation is carried out iteratively over several operating conditions of the plain bearing. ### Claim 6 (depends on 1) The method to claim 1, wherein the variables determined by simulation are in each case compared with a corresponding variable ascertained by measurement. ### Claim 7 (depends on 1) The method to claim 1, comprising arranging the sensor on or in a component other than the plain bearing. ### Claim 8 (depends on 7) The method of claim 7, wherein the sensor is arranged on a surface of a transmission housing, the at least one plain bearing, the first gear, and the second gear being arranged within the transmission housing. ### Claim 9 (depends on 1) The method according to claim 1, wherein the model is an artificial neural network trained by machine learning. ### Claim 10 An arrangement, comprising: at least one plain bearing; a first gear mounted via the plain bearing; a second gear with which the first gear meshes; a sensor configured to measure structure-borne noise from a toothed engagement of the first gear and the second gear; and a controller configured to assign, to a signal of the sensor, a variable that correlates with an absolute or relative bearing play of the plain bearing, wherein the controller is further configured to filter the signal, wherein the filtered signal corresponds to a signal of the structure-borne noise arising from the toothed engagement, and wherein the controller is configured to simulate structure-borne noise from the toothed engagement of the first gear and the second gear, signals of the sensor, and filtered signals using a model of the first gear, the second gear, and the plain bearing, and wherein the model images the operating condition of the plain bearing correlating with the absolute or relative bearing play. ### Claim 11 (depends on 10) The arrangement of claim 10, wherein the sensor is arranged on or in a component other than the plain bearing. ### Claim 12 (depends on 11) The arrangement of claim 11, wherein the sensor is arranged on a surface of a transmission housing, the at least one plain bearing, the first gear, and the second gear being arranged within the transmission housing. ### Claim 13 A method for determining a bearing gap of at least one plain bearing, the method comprising: measuring, by a sensor, structure-borne noise arising from a toothed engagement of a first gear and a second gear, wherein the first gear is rotatably mounted via the plain bearing and meshes with the second gear; assigning, to a signal of the sensor, a variable that correlates with the bearing gap of the plain bearing; and filtering the signal, wherein the filtered signal corresponds to a signal of the structure-borne noise arising from the toothed engagement, wherein a simulated structure-borne noise from the toothed engagement of the first gear and the second gear, a simulated signal of the sensor, and a simulated filtered signal are determined by simulation using a model of the first gear, the second gear, and the plain bearing, and wherein the model images an operating condition of the plain bearing correlating with the bearing gap.