Power Steering Control Assembly Actuator
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Solution Overview
Problem
Conventional power steering systems require human input to overcome initial rotational resistance, which can vary with vehicle speed and load, and are not suitable for autonomous applications where human effort is unnecessary.
Innovation Solution
A control assembly with a valve assembly and actuator system that includes a first hydraulic circuit for assisted steering and a second hydraulic circuit to overcome rotational resistance, allowing the system to switch from an unassisted to an assisted condition without human input, using a shaft that rotates within a valve sleeve to apply hydraulic force and modulate or eliminate the need for human effort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a torsion bar is used to provide rotational resistance on the shaft, then the system provides correlated force measurement and traditional power steering assistance, but human input is required to overcome the initial rotational resistance to activate the supplementary steering force
Solution Approach 1:
The hydraulic system is segmented into two separate circuits: a first hydraulic circuit for traditional power steering assistance that activates after overcoming torsion bar resistance, and a second hydraulic circuit that provides preliminary assistance before the shaft rotates. This segmentation allows each circuit to serve its specific function independently, resolving the contradiction by enabling easy steering initiation through the second circuit while maintaining the traditional first circuit for correlated force measurement.
Solution Approach 2:
The second hydraulic circuit performs preliminary action by applying hydraulic force to the shaft before the shaft rotates and before the first hydraulic circuit activates. This preliminary hydraulic assistance overcomes the initial rotational resistance of the torsion bar, allowing the shaft to rotate and activate the main power steering system without requiring significant human input, thus resolving the contradiction between ease of operation and device complexity.
2Reliability
If the shaft must be rotated to activate supplementary steering force, then the system provides control through human effort, but the required human input varies drastically with vehicle speed and load, creating inconsistency
Solution Approach 1:
The system incorporates feedback mechanisms where sensors detect vehicle speed and load conditions, and this information is used by the control assembly to modulate the hydraulic force provided by the second hydraulic circuit. The feedback loop ensures that the preliminary hydraulic assistance is adjusted according to operating conditions, providing consistent steering initiation assistance regardless of vehicle speed or load variations, thus resolving the contradiction between reliability and ease of operation.
Solution Approach 2:
The hydraulic system is designed to be dynamic, with the second hydraulic circuit's force output varying based on real-time operating conditions. The system transitions from a static torsion bar resistance model to a dynamic hydraulic assistance model that adapts to changing vehicle speed and load, ensuring consistent steering initiation assistance across all operating conditions and resolving the contradiction between reliability and ease of operation.
3Extent of automation
If traditional hydraulic power steering is used, then supplementary steering force is provided, but the system is not suitable for autonomous applications where human effort is unnecessary
Solution Approach 1:
The second hydraulic circuit is designed to activate automatically without human input, sensing the need for steering assistance and providing preliminary hydraulic force to overcome torsion bar resistance. This self-service capability allows the system to initiate power steering assistance autonomously, making it suitable for autonomous vehicle applications where no human effort is required, thus resolving the contradiction between extent of automation and ease of operation.
Solution Approach 2:
The system replaces the purely mechanical torsion bar resistance mechanism with a hybrid system incorporating a second hydraulic circuit that can be controlled electronically. This substitution allows the system to transition from requiring mechanical human input to providing automated hydraulic assistance, enabling autonomous steering applications while maintaining ease of operation through electronic control rather than mechanical effort.
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 system reduces or eliminates the need for human input to initiate supplementary steering force, providing consistent assistance across varying conditions and enabling autonomous steering applications.
Implementation Method 1
an actuator having a second hydraulic circuit that is interchangeable from an unengaged condition to an engaged condition to apply a circumferential hydraulic force on the shaft that overcomes the rotational resistance of the torsion bar
Implementation Method 2
the first hydraulic circuit hydraulically actuates steering of the automobile via a hydraulic pressure cylinder
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A control assembly (20) for overcoming a rotational resistance required to activate supplementary steering force associated with conventional power steering systems. The control assembly (20) includes a shaft (26) subject to rotational resistance via a torsion bar (62). A valve assembly (22) has a first hydraulic circuit (76) that is interchangeable from an unassisted condition (36) to an assisted condition (34) for providing supplementary steering force to a steering gear after the rotational resistance of the torsion bar (22) is overcome by rotating the shaft (26). An actuator (38) includes a second hydraulic circuit (86) interchangeable from an unengaged condition (42) to an engaged condition (40) applying circumferential force on the shaft (26) to overcome the rotational resistance of the torsion bar (62) and rotate the shaft (26) from a non-rotated position thereby activating the supplementary force of the first hydraulic circuit (76).