Electric Steering Gear Reduction for Compact Power Assist
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Solution Overview
Problem
Conventional hydraulically operated steering systems are bulky, complex, expensive, and inefficient, requiring a large amount of power, necessitating a more compact and efficient power assist steering system for vehicles.
Innovation Solution
A power assist steering system incorporating a drive motor with a first and second gear reduction stage, featuring a helical gear mesh and strain wave gearing, ovular coupler, flexible coupling, and bearing members, which provides a high gear reduction ratio in a compact design, reducing power consumption and space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a hydraulic steering system is used, then steering assistance is provided, but the system becomes bulky and space-consuming
Solution Approach 1:
The patent replaces the hydraulic system with an electric motor-driven system. The electric motor (120) directly drives the pinion gear (114) through a gear reduction mechanism, eliminating the need for hydraulic pumps, fluid reservoirs, hoses, and control valves. This substitution of hydraulic mechanics with electric-mechanical actuation achieves steering assistance while dramatically reducing system volume and eliminating fluid-related components.
Solution Approach 2:
The patent extracts and removes the hydraulic components (pump, fluid reservoir, hoses, control valves) from the steering system. By taking out these bulky hydraulic elements and replacing them with a compact electric motor and gear reduction mechanism, the system achieves the same steering assistance function with significantly reduced volume and simplified architecture.
2Power
If a hydraulic steering system is used, then steering assistance is provided, but the system becomes complex and expensive
Solution Approach 1:
The patent replaces the complex hydraulic system with a simpler electric-mechanical system. The electric motor (120) with integrated gear reduction (including strain wave gear mechanism) provides steering assistance through direct electromagnetic actuation, eliminating the need for hydraulic pumps, fluid management components, pressure control valves, and associated plumbing. This substitution reduces both structural complexity and manufacturing cost while maintaining the steering assistance function.
3Power
If a hydraulic steering system is used, then steering assistance is provided, but a large amount of power is required
Solution Approach 1:
The patent changes the actuation parameter from hydraulic pressure to electrical torque. The electric motor (120) converts electrical energy directly to mechanical torque through electromagnetic fields, driving the pinion gear (114) and rack (116). This parameter change from hydraulic to electric actuation improves energy efficiency by eliminating the inefficiencies of hydraulic fluid compression, leakage, and thermal losses, while providing precise torque control through electronic means.
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 achieves a 10% improvement in efficiency over hydraulic systems, is more compact, and requires less power, while maintaining reliability through sacrificial bearing members that allow continued operation in failure modes, enhancing overall vehicle performance.
Implementation Method 1
The flexible coupling is elastically deformable by the ovular coupler during rotation
Data Source
AI summary
A steering system for a vehicle includes a drive motor having a motor shaft. The steering system also includes a first gear reduction stage for receiving a first rotational input from the motor shaft and providing a first rotational output. The steering system further includes a second gear reduction stage for receiving the first rotational output from the first gear reduction stage and providing a second rotational output. The second gear reduction stage may include at least one of a strain wave gearing, a worm drive, and a planetary gearing. The steering system includes an output shaft for receiving the second rotational output from the second gear reduction stage.