Rack-and-Pinion Steering Drive for Large-Angle Paving Machine Steering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Self-propelled construction machines, particularly slipform paving machines, face challenges in achieving quick and large steering angles for their travelling devices, with existing steering drives prone to mechanical self-locking and limited adjustability.
Innovation Solution
The implementation of a steering drive system utilizing a first toothed rack movable by a linear drive means, which engages with a toothed wheel, allowing for rapid adjustment of steering angles and preventing mechanical self-locking through hydraulic or pneumatic drive means, and optionally using a second toothed rack with a parallel linear drive for kinematic freedom from play.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a worm drive is used for steering, then mechanical self-locking occurs providing stability, but quick adjustment of steering angle and large steering angles are prevented
Solution Approach 1:
The patent replaces the traditional worm drive mechanical system with a toothed rack and toothed wheel mechanism. This substitution eliminates the self-locking characteristic of worm gears while enabling quick steering adjustment and large steering angles through the linear-to-rotational motion conversion of the rack-and-pinion system.
Solution Approach 2:
The patent introduces a linear drive means (hydraulic or pneumatic) to actuate the toothed rack. This allows for rapid, controlled movement of the rack to achieve quick steering angle changes while maintaining reliability through fluid pressure control rather than mechanical self-locking.
2Reliability
If mechanical self-locking is present in steering drives, then stability is maintained, but damages occur when travelling devices pivot slightly due to inability to follow movement
Solution Approach 1:
The patent replaces the self-locking worm drive with a toothed rack and toothed wheel system actuated by linear drive means. This new mechanism can dynamically follow slight pivots of the travelling device without generating damaging forces, as the hydraulic or pneumatic actuation can adapt to movement demands without mechanical binding.
Solution Approach 2:
The patent introduces dynamic control through linear drive means (hydraulic or pneumatic) that can rapidly adjust steering angle in response to movement demands. This dynamic response capability prevents the buildup of damaging forces that occur in static, self-locking mechanical systems when subjected to unexpected movements.
3Adaptability or versatility
If traditional steering drives are used, then mechanical simplicity is maintained, but large steering angles and quick steering are limited
Solution Approach 1:
The patent segments the steering function into distinct components: a linear drive means for generating linear motion, a toothed rack for converting linear motion to rotational motion, and a toothed wheel for achieving the steering angle. This segmentation allows each component to be optimized for its specific function, enabling large steering angles and quick response while managing overall system complexity through modular design.
Solution Approach 2:
The toothed rack acts as an intermediary element between the linear drive means and the toothed wheel. It converts linear displacement from the hydraulic or pneumatic actuator into rotational motion of the toothed wheel, thereby enabling large steering angles and quick steering while maintaining a manageable level of mechanical complexity through this intermediate conversion mechanism.
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 quick and precise steering with large angles, avoiding mechanical self-locking and ensuring smooth operation even under high loads, with the ability to detect and adjust steering speed dynamically.
Implementation Method 1
The at least one first linear drive means may be a first hydraulic or pneumatic drive means
Data Source
AI summary
In a self-propelled construction machine (1), in particular slipform paving machine, comprisinga machine frame (2),at least three travelling devices (14),wherein the travelling devices (14) are each connected to the machine frame (2) by means of lifting columns (12),wherein at least two of the at least three travelling devices (14) are steerable by means of one each steering drive (6), wherein the respective steering drive (6) comprises at least one first part (10), which is connected to the respective travelling device (14), and one second part (16), which is connected to the respective lifting column (12),it is provided that the steering drive (6) comprises at least one first toothed rack (22), wherein the first toothed rack is movable by means of at least one first linear drive means (26), wherein teeth of the at least one toothed rack engage with teeth of at least one toothed wheel (17), and the toothed wheel is thus rotatable by means of the movement of the toothed rack.