Semi-Trailer Castor Wheel Steering Control via Powered Slide
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Solution Overview
Problem
Current steering systems for semi-trailers with castor pivot steered wheel sets lack controlled steering capabilities, particularly at low speeds and during maneuvering in confined areas, and are prone to unintended steering due to centrifugal force, which compromises stability and maneuverability.
Innovation Solution
A device that allows controlled steering of castor pivot steered wheel sets via an operator interface, utilizing hydraulic power to move a slide along a guiding element, with steering rods and an air spring mechanism for automatic return to neutral position, and a speed sensor to prevent steering above a predefined speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a castor pivot steered wheel set is used to provide steering through centrifugal force, then the trailer can follow curved paths, but unintended steering occurs on sideways sloping roads due to gravity
Solution Approach 1:
A slide mechanism acts as an intermediary between the operator's control input and the wheel set, providing controlled steering intervention. The slide moves along a guiding element and connects to the steering arm through steering rods, mediating the steering action to override unintended steering while maintaining controlled maneuverability
Solution Approach 2:
The spring mechanism provides self-service by automatically returning the slide to its neutral position when the operator releases control, thereby automatically returning the wheels to straight-ahead position without requiring continuous operator input or additional active control systems
2Reliability
If a non-steered axle is added to ensure stability in straight ahead driving, then steering stability is improved, but the device complexity increases
Solution Approach 1:
The invention transforms the static, passive steering system into a dynamic, controllable one. The slide mechanism can remain stationary (providing stability like a non-steered axle) or move along the guiding element (providing active steering when needed), allowing the system to adapt its steering characteristics based on operational requirements without adding physical axles
Solution Approach 2:
The controlled steering device provides multiple functions: it can provide no steering (maintaining stability), provide controlled steering for maneuvering, or provide maximum steering for tight spaces. This single device replaces the need for separate non-steered and steered axle configurations, reducing overall system complexity
3Ease of operation
If additional steering is applied to a castor pivot steered wheel set to improve low speed maneuverability, then maneuverability is improved, but unintended steering interference occurs
Solution Approach 1:
The guiding element provides feedback constraints on the slide's movement, ensuring the slide moves only in the intended steering direction along a predetermined path. This feedback mechanism prevents unintended steering interference while allowing controlled steering input to be effectively transmitted to the wheels
Solution Approach 2:
The slide and steering rods act as intermediaries that translate the operator's control input into precise wheel steering angles. This intermediary mechanism provides mechanical advantage and control amplification, allowing the operator to easily maneuver the trailer at low speeds while maintaining accurate steering control
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
Enables controlled steering of semi-trailer axles under driver input, improving maneuverability and stability by allowing additional steering beyond centrifugal force, with automatic return to neutral position and safety features to prevent excessive speed steering.
Implementation Method 1
with an air spring mechanism for automatic return to neutral position
Implementation Method 2
utilizing hydraulic power to move a slide along a guiding element
Implementation Method 3
The steering action is then created by centrifugal force when the trailer is following a curved path
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a device for applying a steering angle to a wheel set of a semi-trailer wherein the wheel set belongs to one axle and is steerable by a castor pivot steering arrangement. The device comprises a base (3) attached to the chassis, a powered slide (5) connected to the base (3), two steering rods (6) that each connect the slide (5) to one end of a steering arm (7), control means to control power supplied to the slide (5), and an operator interface to enable input by a driver concerning the amount of steer to be applied in magnitude and direction.