Wheel-Based Steering Drive with Speed Superposition Control
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Solution Overview
Problem
Existing wheel side steered vehicles require complex designs and mechanical forces for steering control, lacking a simple and reliable operation.
Innovation Solution
A steering drive system with a coupling element, variably adjustable electric machines, and a power summation/branching unit that allows for low-loss, stepless steering through precise control of superposition rotational speeds, eliminating the need for mechanical forces and enabling a 'steer-by-wire' concept.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional steering drive system with mechanical components is used, then steering control can be achieved, but the device complexity and mechanical forces required increase
Solution Approach 1:
The patent replaces the traditional mechanical steering control system with an electric motor-driven system. The electric machine (29) directly controls the coupling element (20) to superimpose rotational speed on the output drives (14, 15), eliminating the need for complex mechanical steering components such as steering clutches, hydrodynamic couplings, and mechanical control linkages. This substitution reduces device complexity while maintaining steering functionality.
Solution Approach 2:
The system utilizes the kinetic energy from the vehicle's forward motion to automatically generate the power needed for steering. The travel drive system (10) inherently provides the base rotational speed, and the electric machine only needs to add or subtract superposition rotational speed to achieve steering. This self-service approach reduces the need for separate power sources and mechanical energy transmission components.
2Power
If hydrodynamic steering clutch or mechanically controllable powershift clutch is used, then power transmission can be achieved, but energy loss and device complexity increase
Solution Approach 1:
The patent replaces hydrodynamic steering clutches and mechanically controllable powershift clutches with an electric motor-driven coupling element. The electric machine (29) directly drives the coupling element (20) to superimpose rotational speed, eliminating the need for hydrodynamic fluid coupling or mechanical friction-based power transmission. This substitution reduces energy loss by avoiding hydrodynamic inefficiencies and mechanical friction while maintaining effective power transmission for steering control.
3Ease of operation
If mechanical forces are used for steering control, then steering can be achieved, but the ease of operation and precision are reduced
Solution Approach 1:
The patent replaces mechanical force-based steering control with electric motor-driven rotational speed superimposition. The electric machine (29) controls the coupling element (20) to add or subtract rotational speed from the output drives (14, 15), creating a torque difference that produces steering motion. This eliminates the need for direct mechanical forces applied to steering mechanisms, improving ease of operation through electrical control while reducing reliance on mechanical force transmission.
Solution Approach 2:
The system changes the control parameter from mechanical force to rotational speed superimposition. By controlling the speed of the electric machine (29) and the resulting superposition rotational speed at the coupling element (20), the system precisely controls the torque difference between output drives (14, 15). This parameter change from force to speed control enables more precise and easier steering operation.
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 provides low-loss, stepless steering over the entire range with reduced mechanical complexity, independent energy operation, and enhanced steerability, reducing the need for external energy sources and mechanical components.
Implementation Method 1
at least a first electric machine (29), the speed of which is variably adjustable or controllable
Implementation Method 2
a superposition rotational speed to be superimposed on the basic rotational speed at the output drives (14, 15)
Data Source
AI summary
A steering drive system for a wheel side steered vehicle includes a coupling element couplable to output drives of the vehicle in order, when an amount of a superposition rotational speed of the coupling element is greater than zero, to provide at the output drives, which are driven at a basic rotational speed on the basis of a travel drive system of the vehicle, for steering the vehicle a superposition rotational speed which is to be superposed on the basic rotational speed. The system further includes at least one first electric machine whose rotational speed can be variably set or controlled, with a power summation and/or power branching unit, wherein a first connection of the power summation and/or power branching unit is coupled to a shaft which can be coupled, in particular via a defined transmission ratio, to a shaft of the travel drive system. A second connection of the power summation and/or power branching unit is coupled to the at least one first electric machine, and a third connection of the power summation and/or power branching unit is coupled to the coupling element, in particular via at least one defined transmission ratio.