Steering Nut Pulley Alignment Using Spring Washer Preload
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Solution Overview
Problem
The existing steering devices with ball-screw mechanisms face challenges in aligning the nut and nut-side pulley due to excessive movement when the fastening force of the fastening bolts is too weak, leading to prolonged alignment time, and difficulty in alignment when the force is too strong, resulting in suboptimal coaxiality and increased noise and vibration.
Innovation Solution
A method involving the use of spring washers between the fastening bolts and the nut-side pulley to apply a controlled frictional force, allowing for temporary tightening, axis deviation adjustment, and final tightening to achieve improved coaxiality between the nut and nut-side pulley, thereby reducing alignment time and improving steering performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the fastening force of the fastening bolts is increased to prevent excessive movement of the nut-side pulley, then the alignment precision is improved, but the alignment time increases and the difficulty of alignment increases
Solution Approach 1:
The patent applies preliminary action by performing temporary fastening with controlled force before final alignment. The fastening bolts are initially tightened to a predetermined torque value that is sufficient to prevent excessive movement but not so strong as to hinder adjustment. This preliminary fastening state allows the alignment probe to effectively adjust the nut-side pulley position, after which the bolts are fully tightened to maintain the achieved alignment.
2Ease of operation
If the fastening force of the fastening bolts is decreased to allow easy movement of the nut-side pulley, then the ease of operation is improved, but the alignment precision deteriorates
Solution Approach 1:
The patent applies preliminary action by performing temporary fastening with controlled force before final alignment. The fastening bolts are initially tightened to a predetermined torque value that is sufficient to prevent excessive movement but not so strong as to hinder adjustment. This preliminary fastening state allows the alignment probe to effectively adjust the nut-side pulley position, after which the bolts are fully tightened to maintain the achieved alignment.
3Reliability
If the fastening force of the fastening bolts is increased to maintain relative position, then the reliability is improved, but the ease of operation deteriorates
Solution Approach 1:
The patent applies preliminary action by performing temporary fastening with controlled force before final alignment. The fastening bolts are initially tightened to a predetermined torque value that is sufficient to prevent excessive movement but not so strong as to hinder adjustment. This preliminary fastening state allows the alignment probe to effectively adjust the nut-side pulley position, after which the bolts are fully tightened to maintain the achieved alignment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method enables efficient alignment of the nut and nut-side pulley, reducing alignment time and enhancing coaxiality, which minimizes belt tension fluctuations, improves steering feel, and reduces noise and vibration.
Implementation Method 1
A method involving the use of spring washers between the fastening bolts and the nut-side pulley to apply a controlled frictional force
Data Source
AI summary
The alignment of a nut and a nut-side pulley is performed by: a nut insertion step of inserting the nut into the nut-side pulley; a temporary tightening step of, after the nut insertion step, inserting a shaft portion of a fastening bolt in a fastening bolt insertion hole of the nut-side pulley, with the shaft portion being inserted through a spring washer, and then, tightening the shaft portion into an internal thread of the nut until a dimension of the spring washer becomes shorter than a free length and longer than a fully compressed length; an axis deviation adjusting step of adjusting a position of the nut-side pulley relative to the nut to decrease a deviation of the nut-side pulley relative to a rotation axis of the nut after the temporary tightening step; and a final tightening step of further tightening the fastening bolt after the axis deviation adjusting step.