Steering Control Apparatus Integrating Self-Locking Worm Gear
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional variable gear ratio steering (VGRS) apparatuses are large in size due to the separate provision of a lock mechanism for fixing the steering ratio, which is not integrated with the gear mechanism.
Innovation Solution
A steering control apparatus that integrates a differential gear mechanism with a worm gear having a self-lock function, where the worm gear includes a worm wheel and a worm, and an electronic control unit to monitor and prevent self-lock failures, thereby reducing the overall size and preventing idling of the steering device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate lock mechanism is provided to fix the steering ratio, then the steering ratio can be reliably fixed, but the overall size of the apparatus becomes large
Solution Approach 1:
The lock mechanism is merged with the differential gear mechanism by integrating the lock pin and latch member into the existing gear structure. The lock pin is positioned within the differential gear assembly and works in conjunction with the pinion gear teeth, eliminating the need for a separate lock mechanism and reducing overall apparatus size while maintaining reliable steering ratio fixation.
Solution Approach 2:
The differential gear mechanism serves dual functions: it varies the steering ratio during normal operation and simultaneously provides the locking function when the latch member engages the lock pin. This multi-functionality eliminates the need for a dedicated lock mechanism, reducing the apparatus size while ensuring reliable steering ratio fixation when needed.
2Volume of moving object
If the worm gear self-lock function is used to fix steering ratio, then the apparatus size is reduced, but self-lock failure may cause steering device idling
Solution Approach 1:
A sensor detects the steering angle and provides feedback to the control unit. The control unit monitors whether the steering angle returns to the neutral position after steering input, which would indicate self-lock failure. When idling is detected, the control unit activates the motor to apply corrective torque, preventing unsafe steering device idling while maintaining the space-efficient worm gear self-lock design.
Solution Approach 2:
The control unit continuously monitors steering angle feedback and detects potential self-lock failures before they result in dangerous steering device idling. By taking preliminary corrective action through motor activation when abnormal steering behavior is detected, the system prevents the harmful effect of steering idling while maintaining the compact worm gear design.
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 integrated design reduces the overall size of the steering control apparatus and ensures safe and efficient steering operations by preventing idling and enhancing safety through self-lock failure detection and suppression.
Implementation Method 1
The worm gear has a lead angle for providing a self-lock function, by which the worm wheel is enabled to rotate by rotation of the worm and the worm is disabled to rotate by rotation of the worm wheel
Data Source
AI summary
In a steering control apparatus, a worm gear is configured to have a lead angle for a self-lock operation, by which a worm wheel is allowed to rotate by rotation of a worm but the worm is not allowed to rotate by rotation of the worm wheel. Thus, a lock mechanism need not be provided separately from a gear mechanism and the apparatus is reduced in entire size. A VGRS control part checks whether the worm gear has a self-lock failure, which disables the self-lock operation. If the worm gear has the self-lock failure, idling suppression processing is performed to suppress idling of a steering wheel. Thus, even when the self-lock failure arises, the steering wheel is suppressed from idling.