Steering Actuator Torsion Bar Segmentation Design
Solution Overview
Problem
The existing actuator for steering systems has a low degree of freedom for design change due to its configuration being tied to the hydraulic power steering system, limiting flexibility when the hydraulic power steering system configuration is altered.
Innovation Solution
An actuator design that includes a transmission mechanism, a piston, pressure chambers, an input shaft, an output shaft connected by a torsion bar, a motor rotor, a motor stator, and rotation angle detecting sections, allowing for independent configuration changes without affecting the hydraulic power steering system side, enabling torque detection and improved assembly precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single shaft is used both as a rotary shaft for imparting torque through the motor and as an input shaft of the hydraulic power steering system, then the structure is simplified, but the degree of freedom for design change is reduced
Solution Approach 1:
The patent divides the previously unified shaft into two separate components: a motor shaft that rotates integrally with the motor rotor, and an input shaft that connects to the hydraulic power steering system. These are coupled through a torsion bar, allowing independent design and modification of each component while maintaining functional connection. This segmentation enables design changes on one side without affecting the other, resolving the contradiction between structural simplicity and design flexibility.
2Reliability
If the configuration of the hydraulic power steering system is changed, then the steering system can be improved, but the actuator configuration must also be changed, reducing design flexibility
Solution Approach 1:
By separating the motor shaft from the input shaft and coupling them through a torsion bar, the patent creates an interface that allows independent modification of the hydraulic power steering system without requiring changes to the motor side. The torsion bar acts as a flexible coupling that maintains torque transmission while accommodating design variations.
Solution Approach 2:
The torsion bar serves as an intermediary element between the motor shaft and the input shaft. It transmits torque while allowing independent rotation and design modification of either shaft. This intermediary component enables design changes in the hydraulic power steering system without affecting the motor configuration, thus resolving the contradiction between system improvement and design flexibility.
3Adaptability or versatility
If separate input and output shafts are used with a torsion bar connection, then the degree of freedom for design change is increased, but the device complexity increases
Solution Approach 1:
The motor shaft is designed to perform multiple functions: it rotates integrally with the motor rotor for torque generation, and simultaneously serves as the input to the torsion bar for torque transmission to the hydraulic system. This multi-functionality reduces the need for additional components, offsetting the complexity increase from having separate shafts while maintaining design flexibility.
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
This design enhances the degree of freedom for design change, allows for standalone torque detection, reduces assembly errors, and improves installability within vehicles by decoupling the actuator's configuration from the hydraulic power steering system, while maintaining reliable torque transmission and sealability.
Implementation Method 1
a torsion bar connecting the motor shaft and the input shaft
Implementation Method 2
a motor rotor disposed around an outer periphery of the output shaft within the housing and configured to rotate integrally with the output shaft, a motor stator disposed around an outer periphery of the motor rotor within the housing
Implementation Method 3
a pair of pressure chambers configured to generate a force acting to move the piston
Data Source
AI summary
Provided is an actuator for a steering system, which can be increased in degree of freedom for design change, regardless of a configuration change of a hydraulic power steering side. The actuator for a steering system comprises a transmission mechanism configured to transmit the rotation of a steering shaft to a steered wheel, a piston disposed in the transmission mechanism, and a pair of pressure chambers configured to generate a force acting to move the piston. The actuator for a steering system is disposed between a hydraulic power steering system, which imparts a steering force to the steered wheel along with the movement of the piston, and a steering wheel. The actuator for a steering system includes an input shaft which is rotatably and axially supported by the housing and disposed in the steering wheel side; an output shaft which is rotatably and axially supported by the housing and disposed in the hydraulic power steering system; a torsion bar connecting the input shaft and the output shaft; a motor rotor disposed around the outer periphery of the output shaft within the housing and configured to rotate integrally with the output shaft; a motor stator disposed around the outer periphery of the motor rotor within the housing; and a rotation angle detecting section disposed within the housing and configured to detect the rotation angles of the input and output shafts or a relative angle of the input and output shafts.