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Steering Gear Internal Rack Seal to Reduce Nibble and Judder Disclosure Number: IPCOM000031425D
Publication Date: 2004-Sep-24

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The Prior Art Database


Modern day rack & pinion steering systems typically seek to refine the driving experience by improving the linearity of steering vehicle response to driver steering maneuvers. In doing so, steering systems with rack & pinion design have reduced internal steering gear friction to enhance the performance. Conversely, less friction in the steering system has resulted in increased error states such as steering wheel rotation vibration due to tire/wheel imbalance excitation (nibble) and/or brake rotor wear induced excitation (judder). This innovative internal steering gear rack seal is capable of providing increased static friction to reduce low rack displacement motion for improvement in nibble & judder. The nibble seal provides increased friction only for low steering angles (less than 2 degrees) to address nibble and judder, with little or no increase in friction at larger steering angles corresponding to driver steering maneuvers. The nibble seal orifice tuning to reduce additional seal lip friction at high steering loads thereby significantly reduces the negative impacts on steering feel and returnability per Figure 1. The nibble seal functions as a second internal steering gear housing seal which is located inboard of the outer rack seal as seen in Figure 2. The nibble seal is integrated into the outer rack seal to improve function and reduce vendor component installation complexity, mis-seated components within housing, and/or potential seal lip damage during installation.