Worm Gear Auto-Adjustment to Prevent Steering Play and Backlash
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Solution Overview
Problem
Existing adjusting devices for worm gears in electromechanical auxiliary power steering systems fail to maintain stable gearing without play, leading to wear and potential rattling or jamming, especially under separating forces during operation.
Innovation Solution
An adjusting device comprising a spring, guide linkage, pressure piece, and clamping device that exerts a spring force radially onto the worm, with a resilient element and wedge mechanism to prevent reverse movement, ensuring continuous adjustment and secure alignment despite wear and separating forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spring is used to exert radial adjusting force onto the worm, then the worm can be automatically adjusted to compensate for wear, but the guide linkage may move back away from the worm due to separating forces during operation
Solution Approach 1:
The guide linkage is designed with dynamic capability to move in the adjusting direction towards the worm to compensate for wear, while the clamping device dynamically engages to prevent reverse movement. This dynamic design allows the system to adapt between adjustment mode and stable positioning mode.
Solution Approach 2:
The clamping device acts as an intermediary mechanism between the spring force and the guide linkage. It receives the adjusting force and translates it into unidirectional movement capability, mediating between the continuous spring force and the discrete adjustment needs of the worm position.
2Reliability
If the guide linkage is allowed to move freely for adjustment, then wear compensation is possible, but the adjusting path increases relatively over time
Solution Approach 1:
The clamping device is pre-configured to engage the guide linkage and prevent reverse movement. This preliminary constraint ensures that each adjustment movement is permanent and cumulative wear compensation is achieved without increasing the overall adjusting path required.
Solution Approach 2:
The wear that would normally be harmful is converted into a beneficial adjustment mechanism. As wear occurs, the spring force automatically pushes the guide linkage to compensate, and the clamping device ensures this compensation is permanent, transforming the harmful wear effect into a self-correcting mechanism.
3Device complexity
If a simple spring mechanism is used for adjustment, then the device complexity is reduced, but the system cannot prevent reverse movement under separating forces
Solution Approach 1:
The adjusting mechanism is segmented into two independent functional components: the spring for generating adjusting force and the clamping device for preventing reverse movement. This segmentation allows each component to be simple in design while collectively achieving reliable unidirectional adjustment and positioning.
Solution Approach 2:
The spring mechanism and clamping device are merged into a single integrated adjusting assembly where the spring provides continuous force and the clamping device provides directional control. This combination achieves reliable reverse movement prevention without significantly increasing overall device complexity.
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 device allows for automatic radial adjustment of the worm on the worm wheel, maintaining a stable gear alignment and preventing play, even after wear, thus reducing noise, vibration, and harshness while ensuring precise control.
Implementation Method 1
The spring is shaped so as to exert a spring force on the guide linkage, in order to radially push the guide linkage towards the worm
Implementation Method 2
Such a resilient element can absorb in a resilient manner distortion of the gearing partners and thus prevent rattling and jamming during the operation of the worm gear
Data Source
AI summary
An adjusting device for automatically adjusting a worm on a worm wheel of a worm gear for an electromechanical auxiliary power steering system for a vehicle, includes a spring, a guide linkage, and a pressure piece. The spring is shaped so as to exert a spring force onto the guide linkage in order to radially push the guide linkage towards the worm. The guide linkage is designed to transmit the spring force onto the pressure piece. The pressure piece, which is connected to the guide linkage, is designed to contact a worm section of the worm in order to exert an adjusting force, which is produced by the spring force, onto the worm. The adjusting device additionally has a clamping device which is designed to prevent the guide linkage from moving back away from the worm.