Axle Steering Linkage for High-Angle Differential Wheel Steering
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Solution Overview
Problem
Existing steering arrangements for working machines with four-wheel steer and short wheelbases are limited in providing differential steer angles, often requiring complex components and assemblies to achieve smooth travel.
Innovation Solution
A compact steering arrangement using a single non-linear linkage and actuator connected directly to the linkage, allowing for high steer angles and efficient pivoting of wheel mounts, which includes a linear actuator and a unitary steering linkage positioned above the axle to protect components from impacts and dirt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single actuator and non-linear linkage are used for steering, then the steering arrangement becomes compact and requires fewer components, but achieving high steer angles and differential steering becomes more difficult
Solution Approach 1:
The patent employs a non-linear (curved) linkage geometry instead of a straight linkage. The linkage follows a curved path that enables the wheel mounts to achieve high steer angles while maintaining a compact arrangement. This curvature in the linkage path is essential for providing the required angular displacement without increasing component count or overall system size.
Solution Approach 2:
The patent positions the linkage and actuator in a three-dimensional configuration above the axle, utilizing vertical space rather than only horizontal space. This spatial arrangement allows the steering components to be compact while still achieving the necessary range of motion and differential steer angles between inner and outer wheels.
2Object-affected harmful factors
If wheel mounts are positioned above the axle, then components are protected from impacts and dirt, but assembly and maintenance become more difficult
Solution Approach 1:
The steering system is divided into modular components including the actuator, linkage, and wheel mounts that can be assembled separately and then integrated. This segmentation allows for easier manufacturing and assembly of individual components before final installation, reducing the overall assembly difficulty despite the elevated positioning above the axle.
3Device complexity
If a single linear actuator is used to actuate the steering linkage, then the steering arrangement becomes more compact, but providing differential steer angles between inner and outer wheels becomes limited
Solution Approach 1:
The non-linear linkage geometry translates the linear motion from a single actuator into differential angular movements at the wheel mounts. The curved path of the linkage ensures that the inner and outer wheels can achieve different steer angles simultaneously, enabling Ackermann steering geometry to be realized with only one actuator.
Solution Approach 2:
The patent combines the functions of multiple potential actuators into a single linear actuator that controls both wheel mounts through the non-linear linkage. This merging of actuation functions into one component maintains compactness while the linkage geometry ensures proper differential steering is achieved.
Data Source
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AI summary
An axle assembly is provided for a working machine. The axle assembly includes an axle having first and second ends, the first end having a first wheel mount for pivotably mounting a first wheel to the axle and the second end having a second wheel mount for pivotably mounting a second wheel to the axle. The assembly has a steering arrangement for pivoting the first and second wheel mounts relative to the axle, the steering arrangement having a linkage connected to the first and second wheel mounts and configured to pivot the first and second wheel mounts relative to the axle. The steering arrangement also includes an actuator configured to actuate the steering linkage in order to effect pivoting of the first and second wheel mounts, and the actuator is directly connected to the steering linkage.