Steer-By-Wire Steering Shaft Friction Control With Preloaded Bearings
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Solution Overview
Problem
Conventional steer-by-wire steering devices lack the ability to provide a better steering feeling to the driver due to limited friction adjustment range and stiffness, leading to component complexity, increased costs, and potential deformation of the steering shaft.
Innovation Solution
A steer-by-wire steering device design featuring a housing with stepped surfaces and angular ball bearings, where pre-load is applied through coupling members to increase frictional force and maintain it constant, reducing component count and preventing deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional spring-based friction mechanism is used, then the steering shaft is supported, but the friction adjustment range is limited and the maximum friction is low
Solution Approach 1:
The patent changes the fundamental mechanism from spring-based elastic force to direct mechanical pressing force. The pressing member applies axial force to press the bearing against the steering shaft, enabling continuous adjustment of frictional force over a wide range, from light to heavy friction, overcoming the limited adjustment range of conventional spring mechanisms.
Solution Approach 2:
The patent introduces a dynamic friction adjustment mechanism where the pressing member can be positioned at different locations along the steering shaft. By changing the position of the pressing member, the frictional force can be dynamically adjusted to match different driving conditions and driver preferences, enhancing adaptability.
2Ease of operation
If multiple components are used to create friction, then the steering feeling can be enhanced, but the device complexity increases and assembly becomes difficult
Solution Approach 1:
The patent merges multiple functions into a single integrated structure. The pressing member serves multiple purposes: it applies frictional force, supports the bearing, and its position can be adjusted to control friction. This consolidation reduces the number of separate components and simplifies the overall device structure while maintaining enhanced steering feeling.
Solution Approach 2:
The pressing member is designed as a multi-functional component that can perform different functions depending on its position and configuration. It can adjust friction levels, support the bearing, and adapt to various steering conditions, making the device simpler while achieving complex operational requirements.
3Device complexity
If yoke is supported on one side of the steering shaft, then the structure is simple, but the steering shaft may be deformed over time due to spring elastic force
Solution Approach 1:
The patent uses asymmetric positioning of the pressing member and bearing support to distribute forces more evenly. By strategically positioning these components, the design compensates for the one-sided support configuration and prevents uneven stress concentration that would lead to steering shaft deformation over time.
Solution Approach 2:
The pressing member is designed to apply pre-load force to the bearing, creating a preliminary counteracting force that prevents the steering shaft from deforming under operational loads. This pre-application of force in the opposite direction of potential deformation prevents the harmful effect before it occurs.
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
Enhances driver steering feedback by increasing the range of friction adjustment on the steering shaft while reducing component complexity and costs, and preventing shaft deformation.
Implementation Method 1
conventional steer-by-wire steering devices create friction by radially pressurizing the steering shaft with yokes and springs
Implementation Method 2
the presence of many components results in a hardship in assembly and disadvantages in view of costs. Moreover, as the yoke is supported only on one side of the steering shaft, the steering shaft may be deformed over time due to the elastic force of the spring
Data Source
AI summary
According to the embodiments of the present invention, the range of control for the frictional force on a steering shaft is increased, the frictional force can be sustained at a set level to enhance the steering feel, the number of parts is reduced to improve ease of assembly and reduce cost of production, and deformation of the steering shaft can be minimized.