# US 10,479,401 B2 · Apparatus for detecting friction in a power steering system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,479,401 B2 - Document ID: US10479401B2 - Status: Granted - Kind: B2 - Application number: 14/065,839 - Filed: 2013-10-29 - Published: 2014-05-01 - Granted: 2019-11-19 - Earliest claimed: 2012-10-29 - Assignees: Ford Global Technologies, LLC - Applicants: Ford Global Technologies, LLC - Inventors: Frank Peter Engels - Web page: https://patentgrep.com/patent/US10479401B2 ## CPC - B62D 5/0481: {monitoring the steering system, e.g. failures} - B62D 5/0496: {by using a temperature sensor} - 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) ## Abstract A power steering system including a sensor arranged or located in the steering system. The sensor detects an acoustic vibration or an acceleration signal in the steering system during a change in the steering angle and generates a sensor signal representing the vibration or the acceleration signal. A control unit receives the sensor signal and compares the sensor signal with a threshold value to detect a fault state; for example when the sensor signal is larger than the threshold value. ## Claims ### Claim 1 A steering system comprising: a steering gear; a sensor operative to measure acceleration of the steering gear during a change in the steering angle and to generate a sensor signal representing structure-borne noise associated with said steering gear; and a control unit operative to compare the sensor signal with a threshold value and to detect a fault state if the sensor signal is larger than the threshold value. ### Claim 2 (depends on 1) A steering system as set forth in claim 1 wherein said sensor is selected from a group consisting of an acceleration sensor, a torque sensor, a position sensor and a power consumption sensor. ### Claim 3 (depends on 1) A steering system as set forth in claim 1 wherein said sensor an acceleration sensor. ### Claim 4 (depends on 3) A steering system as set forth in claim 3 wherein said acceleration sensor is an acceleration sensor of an airbag triggering system. ### Claim 5 (depends on 1) A steering system as set forth in claim 1 wherein said sensor is integrated into said control unit. ### Claim 6 (depends on 1) A steering system as set forth in claim 1 wherein the threshold value is an amplitude value; and said control unit operative to compare a maximum modulation of a sensor signal with said amplitude value. ### Claim 7 (depends on 1) A steering system as set forth in claim 1 wherein said control unit transmits a fault state to a human/machine interface. ### Claim 8 (depends on 1) A steering system as set forth in claim 1 including an electric auxiliary motor; and said control unit operative to deactivate said electric auxiliary motor upon detection of a fault state. ### Claim 9 (depends on 1) A steering system as set forth in claim 1 including a filter unit, said filter unit connected between said sensor and said control unit wherein said filter unit filters a sensor signal. ### Claim 10 (depends on 9) A steering system as set forth in claim 9 wherein said filter unit is suppresses frequency components of said sensor signal above an upper cutoff frequency. ### Claim 11 A steering system comprising: a steering gear; a sensor operative to measure acoustics of the steering gear during a change in the steering angle and to generate a sensor signal representing airborne noise associated with said steering gear; a control unit operative to compare the sensor signal with a threshold value and to detect a fault state if the sensor signal is larger than the threshold value; an electric auxiliary motor connected to steering gear; and said control unit operative to deactivate said electric auxiliary motor upon detection of a fault state. ### Claim 12 (depends on 11) A steering system as set forth in claim 11 including a filter unit, said filter unit connected between said sensor and said control unit wherein said filter unit filters the sensor signal. ### Claim 13 (depends on 12) A steering system as set forth in claim 12 wherein said filter unit is suppresses frequency components of said sensor signal above an upper cutoff frequency. ### Claim 14 (depends on 11) A steering system as set forth in claim 11 wherein the threshold value is an amplitude value; and said control unit operative to compare a maximum modulation of a sensor signal with said amplitude value. ### Claim 15 A steering system comprising: a steering gear; a sensor operative to detect vibration in the steering gear generated by friction during a change in the steering angle and to generate a signal representing the vibration; and a control unit operative to compare the sensor signal with a threshold value and to detect a fault state if the sensor signal is larger than the threshold value. ### Claim 16 (depends on 15) A steering system as set forth in claim 15 wherein said sensor is an acceleration sensor. ### Claim 17 (depends on 15) A steering system as set forth in claim 15 wherein said sensor is an acoustics sensor. ### Claim 18 A method for detecting friction in a steering system comprising the steps of: providing a steering gear; detecting vibration in the steering gear generated by friction during a change in the steering angle and generating a signal representing the vibration; comparing the signal with a threshold value and generating a fault state if the signal is greater than the threshold value. ### Claim 19 (depends on 18) The method of claim 18 including the step of using an acceleration sensor to measure acceleration in the steering gear wherein the acceleration represents vibration, structure-born noise. ### Claim 20 (depends on 18) The method of claim 18 including the step of using an acoustics sensor to measure acoustics generated by the steering gear wherein the acoustics represents vibration, air-born noise.