Rotational Speed Superposition Device for Steering Systems
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Solution Overview
Problem
Existing vehicle steering systems with rotational speed superposition devices face challenges such as high energy consumption, increased mass and inertia, and complex structural requirements, leading to impaired responsiveness and reliability.
Innovation Solution
A rotational speed superposition device with a harmonic drive gearing system, where the input and output shafts are independently rotatable and supported by a stationary support configuration, allowing for variable rotational speed superposition with reduced mass and energy consumption, and incorporating a simple locking mechanism for safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the housing is connected with the steering shaft and rotates jointly with it to implement rotational speed superposition, then the rotational speed superposition function is achieved, but the moved masses increase and handling becomes more difficult and inert
Solution Approach 1:
The patent extracts the rotating housing from the system by connecting only the necessary components (input shaft, output shaft, harmonic drive gearing) to the steering shaft, while the housing remains stationary and is connected to the vehicle body. This separation removes the unnecessary rotating mass while preserving the rotational speed superposition function.
Solution Approach 2:
The system is segmented into stationary and rotating components. The housing and stator are stationary, while only the rotor and essential transmission elements rotate with the steering shaft. This segmentation reduces the total moved mass while maintaining functional integrity.
2Reliability
If a locking mechanism is activated to connect the input shaft with the output shaft in case of error, then the control safety is ensured, but the device complexity increases
Solution Approach 1:
The locking mechanism is designed to activate automatically upon detection of errors such as power supply failure or rotor malfunction. The system self-locks without requiring external intervention, ensuring control safety while minimizing the need for complex control systems.
3Adaptability or versatility
If the entire device with housing for rotational speed superposition is set into motion during steering, then the rotational speed superposition is achieved, but the responsiveness of the control is impaired
Solution Approach 1:
The stationary housing is extracted from the rotating mass, allowing the rotor and essential components to accelerate and respond more quickly to steering inputs. The housing remains fixed to the vehicle body, eliminating its inertial resistance to rapid steering maneuvers.
4Adaptability or versatility
If a large number of structural elements is necessary for the realization of rotational speed superposition, then the functional requirements are met, but the production costs increase and operating reliability decreases
Solution Approach 1:
The patent merges the housing with the stator of the harmonic drive gearing, and integrates the locking mechanism within the existing structural framework. This consolidation reduces the total number of separate components while maintaining all necessary functions.
Solution Approach 2:
The housing serves multiple functions: it provides structural support, houses the stator, and acts as a mounting structure for the locking mechanism. This multi-functionality reduces the need for additional dedicated components.
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 solution simplifies energy coupling, reduces system inertia, and enhances control behavior with improved responsiveness and reliability, while minimizing additional steering force and frictional losses, allowing for efficient and responsive steering without perceivable counterforces.
Implementation Method 1
the rotational number superposition takes place with a strain wave gearing... the device therein is implemented integrally and rotationally with the steering shaft driven by the steering wheel and comprises a drive motor whose driving rotational speed is adjustable for the purpose of attaining the desired rotational speed superposition
Data Source
AI summary
A rotational speed superimposing device for a vehicle steering system has an input shaft with an output shaft, which is oriented toward the input shaft in the axial direction thereof, and has a supporting arrangement, which positions the input shaft and the output shaft so that they are at least, in part, rotationally mounted. An auxiliary drive provided with a rotor, which is connected in a rotationally fixed manner to a wave generator, such as an oval disk on whose periphery an external toothed flexible ring is directly or indirectly mounted, this external toothing engaging in an internal gear at least at two opposite peripheral points. The supporting arrangement is fixed to the vehicle body. The output shaft is connected in a rotationally fixed manner to the internal gear, and the input shaft is connected in a rotationally fixed manner to the external toothed flexible ring. The input shaft and the output shaft are mounted so they freely rotate independently of one another.