Steering Mechanism for Tight Turns via Servomotor Actuation
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Solution Overview
Problem
Existing steering mechanisms for short vehicles, such as wheelchairs and small tractors, face challenges in achieving a reduced turning radius without excessive wear and noise, with prior solutions being fragile, complex, or requiring complex motor control electronics.
Innovation Solution
A steering mechanism using fewer parts with only rotating components, including a servomotor and linear actuator, allowing for independent control of wheel angles through electronic actuation, enabling simultaneous rotation of wheels at different angles for tight turns, and avoiding fragile translational movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a cam system is used to achieve a very small turning radius, then the turning radius is reduced, but the calculation and machining becomes complex and the wear of moving parts becomes rapid
Solution Approach 1:
The patent replaces the complex cam-based mechanical steering system with an electric motor-driven system. The servomotor (5) controls the linear actuator (4) which moves the rudder bar (1), eliminating the need for complex cam calculations and machining while reducing moving part wear through fewer contact points and simpler mechanics.
2Length of moving object
If cables are used to connect wheels to the center of the vehicle, then the turning radius is reduced, but the assembly becomes fragile and requires a large space under the vehicle
Solution Approach 1:
The patent replaces the cable-based mechanical connection system with an electric motor and linear actuator system. The servomotor (5) and linear actuator (4) provide direct mechanical control of the rudder bar (1), eliminating fragile cables and reducing the space required under the vehicle while improving reliability through more robust electrical-mechanical components.
3Length of moving object
If connecting rods with rectilinear slides are used, then the turning radius is reduced, but the mechanism becomes fragile and sensitive to sand or earth projections
Solution Approach 1:
The patent replaces the connecting rods and rectilinear slides with an electric motor-driven linear actuator system. The servomotor (5) controls the linear actuator (4) which moves the rudder bar (1) through a more sealed and protected mechanism, reducing sensitivity to sand and earth projections while maintaining the reduced turning radius capability.
4Ease of manufacture
If wheels are steered by accelerating outer wheels without correct steering, then the mechanism is simple to produce, but the motor control electronics become more complex and tires wear quickly
Solution Approach 1:
Instead of controlling wheel speed differentials to achieve steering (which complicates motor control electronics), the patent inverts the approach by using a single servomotor (5) to control the steering angle of all wheels through the linear actuator (4) and rudder bar (1). This simplifies motor control electronics while maintaining mechanical effectiveness and reducing tire wear through proper wheel orientation.
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
This solution provides a robust, cost-effective steering mechanism that allows for precise control of wheel angles, reducing tire wear and noise, and enabling tight turns without the need for complex calculations or fragile components.
Implementation Method 1
The movements of the four wheels are mechanically linked together, so that the rotation of one wheel necessarily causes the orientation of the other three wheels to change. The steering mechanism with the two pedals 1, 1' of the invention makes it possible to control these rotations.
Implementation Method 2
The linear actuator 4, the translations of which are immediately converted into rotation by the rudder bar 1
Data Source
Figure 1
Figure 2
AI summary
A steering mechanism comprising a first swing bar (1), said swing bar comprising a first link (12) designed to allow the swing bar (1) to pivot about an axis of rotation (z). A second link (13) designed to be able to collaborate via a second pivot (23) with a first member (33) collaborating with a first wheel (43) connected to the steering mechanism, and a third link (14) designed to be able to collaborate via a third pivot (24) with a second member (34) collaborating with a second wheel (44) connected to the steering mechanism. The second link and the third link are positioned symmetrically in relation to the longitudinal axis of the steering mechanism when the wheels are straight. A fourth link (15) is designed to be able to collaborate via a fourth pivot (25) with a linear actuator (4). The fourth link is offset from said central axis when the wheels are straight so that actuation of the linear actuator (4) causes the swing bar to rotate in relation to the chassis, and causes a rotation of the wheels (43, 44) via the first and second members.