Articulated Wheel Loader Rear Kingpin Steering

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Solution Overview

Problem

Existing wheel loaders face limitations in terms of turning radius, lateral stability, and safety against tipping, particularly in confined spaces, due to their steering mechanisms which do not allow for precise transverse direction adjustments without unnecessary driving or reversing.

Innovation Solution

A wheel loader design incorporating a telescopic arm with a lifting cylinder and extension cylinder, combined with an Ackermann steering system that automatically steers the rear wheels in the same direction as the articulation movement, enhancing flexibility and stability by allowing variable lifting heights and ranges, while maintaining the front wheels rigid.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional articulated steering system is used, then the machine can operate in confined spaces, but the turning radius is large and lateral stability is reduced

Engineering Contradiction:
Improveoperability in confined spacesVSAvoidlateral stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent combines articulated steering with Ackermann steering by integrating a steering linkage connected to the rear axle. The steering arrangement actuates both the articulation joint and the rear wheel steering simultaneously, merging two steering mechanisms into one coordinated system that improves lateral stability while maintaining maneuverability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rear wheel steering angle is dynamically adjusted based on the articulation angle through the steering linkage. As the articulation angle changes during turning, the rear wheels automatically deflect at optimized angles, providing dynamic adaptation that enhances lateral stability during articulated motion.

Inventive Principle:
Principle #15Dynamics

2Length of moving object

If the rear wheels are steerable with kingpin steering, then the turning radius is reduced, but the steering system complexity increases

Engineering Contradiction:
Improveturning radiusVSAvoidsteering system complexity
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

The steering linkage integrates the functions of articulation control and rear wheel steering into a single mechanical system. This merging reduces the need for separate steering mechanisms and control systems, thereby reducing overall complexity while achieving reduced turning radius through coordinated rear wheel deflection.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The steering linkage automatically adjusts the rear wheel steering angle based on the articulation angle without requiring additional sensors or active control systems. The mechanical connection enables the rear wheels to self-adjust their deflection angle in response to articulation movements, reducing steering system complexity while maintaining optimized turning performance.

Inventive Principle:
Principle #25Self-service

3Device complexity

If the front wheels are made rigid rather than steerable, then the steering system is simplified, but the ability to navigate tight spaces is reduced

Engineering Contradiction:
Improvesteering system complexityVSAvoidmaneuverability in tight spaces
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The rear wheels provide dynamic steering capability through the steering linkage, allowing the machine to navigate tight spaces despite having fixed front wheels. The rear wheel deflection angle dynamically adapts to the articulation angle, enabling effective maneuvering in confined areas while maintaining a simple front axle design.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3296249B1Articulated work machine
Publication Date: 2020.01.29 LIEBHERR WERK BISCHOFSHOFEN GMBH
  • EP3296249B1 patent drawingFigure 1
  • EP3296249B1 patent drawingFigure 2
  • EP3296249B1 patent drawingFigure 3

AI summary

Working machine (1) with at least one front carriage (3) and with at least one rear carriage (2), wherein the front carriage (3) has at least one front axle (12) of the working machine (1) and the rear carriage (2) has at least one rear axle (5) of the working machine (1), and wherein the front carriage (3) and the rear carriage (2) are articulated to each other by at least one articulating joint (4), and with at least one steering arrangement, wherein the steering arrangement is a steering cylinder which is connected to both the front carriage (3) and the rear carriage (2), wherein the steering arrangement is connected to the front carriage (3) and to the rear carriage (2) such that when the steering arrangement is actuated the articulation angle (A) between the front carriage (3) and the rear carriage (2) changes, wherein the rear wheels (8) arranged on the rear axle (5) have a kingpin steering system which is designed as follows:THAT the rear wheels (8) perform a steering movement in the same direction as the articulation movement, THEREFORE the kingpin steering has at least one steering linkage connected to the front carriage (3), THEREFORE a telescopic arm (13) consisting of at least two segments that can be inserted into and extended apart is arranged on the front carriage (3) AND/OR on the rear carriage (2), to which the working tool (?) of the working machine (1) is attached, THEREFORE at least one lifting cylinder (20) is provided, which is arranged on the telescopic arm (13) and serves to adjust the angle of the telescopic arm (13) relative to the horizontal, and THEREFORE at least one extension cylinder (21) is provided, which is arranged on the telescopic arm (13) and serves to extend and retract the segment(s) of the telescopic arm (13).