Cycloidal-Pin Wheel Active Steering System
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Solution Overview
Problem
Conventional automobile steering systems face a trade-off between light steering effort and flexibility, with fixed transmission ratios compromising sensitivity and ease of use, and existing active steering systems either lack mechanical connection or rely on complex mechanisms that reduce reliability.
Innovation Solution
An automobile active steering system incorporating a cycloidal-pin wheel mechanism with a variable transmission ratio, featuring a steering hand wheel, universal joints, a cycloidal-pin wheel type transmission mechanism, and a rotary hydraulic valve, allowing for adjustable steering effort and sensitivity through a combination of mechanical and servo motor-driven inputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the torque transmission ratio is increased to lighten steering effort, then the steering effort becomes lighter, but the angle transmission ratio becomes larger indicating reduced steering sensitivity
Solution Approach 1:
The patent implements a variable transmission ratio mechanism that dynamically adjusts the torque transmission ratio based on operating conditions. The transmission ratio can change from 6:1 to 119:1, allowing the system to optimize between steering effort and sensitivity depending on the driving scenario, rather than being fixed as in conventional systems.
Solution Approach 2:
The patent changes the transmission ratio parameter from a fixed value to a variable value that can be adjusted within a wide range (6:1 to 119:1). This parameter change enables the system to adapt to different operating conditions, resolving the contradiction between steering effort and sensitivity by selecting appropriate transmission ratios for different scenarios.
2Device complexity
If a fixed transmission ratio is used in conventional steering systems, then the structure is simple, but the system cannot adapt to different operating conditions requiring compromise between light steering effort and flexibility
Solution Approach 1:
The patent employs a dynamic transmission mechanism that can adjust the transmission ratio in real-time based on operating conditions. This dynamic capability allows the system to adapt to various scenarios such as low-speed maneuvering requiring high ratio (119:1) and high-speed driving requiring lower ratio (6:1), overcoming the limitations of fixed transmission systems.
Solution Approach 2:
The variable transmission ratio mechanism provides multi-functionality by covering a wide range of transmission ratios (6:1 to 119:1) within a single system. This universal mechanism can handle diverse operating conditions including tight turning, straight driving, and speed variations, making the steering system adaptable to multiple scenarios without requiring separate mechanisms for each function.
3Adaptability or versatility
If existing active steering systems use complex mechanisms like rack and pinion with variable tooth pitch or harmonic gear sets, then variable transmission ratio is achieved, but the processing difficulty increases and the certain range of variation is not large
Solution Approach 1:
The patent segments the transmission mechanism into distinct functional components: a cycloidal wheel mechanism for variable ratio transmission, a pin wheel mechanism for additional degree of freedom, and a hydraulic valve for control. This segmentation allows each component to be optimized independently and manufactured separately, reducing overall processing difficulty while achieving a wide variable ratio range from 6:1 to 119:1.
Solution Approach 2:
The patent introduces a hydraulic valve as an intermediary control element that regulates the flow of hydraulic fluid to control the transmission ratio. This intermediary mechanism provides precise and smooth variation of the transmission ratio within the wide range (6:1 to 119:1), overcoming the limitations of mechanical variable ratio mechanisms that often have restricted ranges and higher processing complexity.
4Measurement precision
If drive-by-wire steering system is used to eliminate mechanical connection, then steering control precision is improved, but system safety is reduced
Solution Approach 1:
The patent merges two steering control paths: a mechanical connection path (steering wheel through universal joints to the cycloidal-pin wheel mechanism) and a hydraulic control path (through the rotary hydraulic valve). This combination allows the system to maintain mechanical reliability while incorporating hydraulic control precision, achieving both safety and control accuracy simultaneously.
Solution Approach 2:
The hydraulic valve serves as an intermediary that can modulate the mechanical transmission ratio without completely eliminating the mechanical connection. This intermediary control mechanism allows for precise steering control through hydraulic modulation while maintaining the safety and reliability of the mechanical path, resolving the contradiction between precision and safety.
Data Source
AI summary
The invention discloses an automobile active steering system with a cycloidal-pin wheel mechanism, and aims at overcoming the contraction between light steering effort and flexibility. The automobile active steering system comprises a steering hand wheel (47), a steering shaft (52), a steering transmission shaft (48), a cycloidal-pin wheel type transmission mechanism (49), a rotary hydraulic valve (50), and a steering box (51). The steering hand wheel (47) is connected with an upper end of the steering shaft (52) by use of a spline pair, a lower end of the steering shaft (52) is connected with an upper end of the steering transmission shaft (48) by use of a universal joint, a lower end of the steering transmission shaft (48) is connected with a right end of an input shaft (21) of the cycloidal-pin wheel type transmission mechanism (49) by use of a universal joint.