Road Milling Machine Steering Linkage for Tight Curve Radii

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Solution Overview

Problem

Existing road milling machines, particularly small ones, face limitations in maneuverability, especially when navigating tight curves and obstacles, due to restricted steering angles and wheel configurations.

Innovation Solution

The design enhances maneuverability by coupling wheel consoles via a connecting part that allows for increased adjustable maximum steering angles, with the center of rotation of front wheels or crawler tracks positioned close to the rear axle, enabling tighter curve radii and precise milling around small obstacles. This is achieved through an offset arrangement of pivot axes and a steering armature with a connecting part and steering cylinder, allowing for larger steering angles and collision-free areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the steering angle is increased to improve maneuverability, then the machine can follow tighter curves, but the structural complexity increases

Engineering Contradiction:
ImprovemaneuverabilityVSAvoidsteering mechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent implements dynamic steering mechanisms where the steering angle is adjustable during operation. The front wheels or crawler tracks can be steered between two steering angle end positions, allowing the machine to adapt its turning radius to the specific work conditions, thereby improving maneuverability without requiring overly complex fixed-geometry steering mechanisms

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The steering system is divided into independent controllable units - each front wheel or crawler track can be steered independently to different angles. This segmentation allows flexible combination of steering angles to achieve various turning radii, improving maneuverability while keeping individual steering components relatively simple

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If the wheelbase is extended to accommodate additional components, then the machine can carry more equipment, but the turning radius increases

Engineering Contradiction:
Improvecomponent accommodationVSAvoidturning capability
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent employs dynamically adjustable steering angles that can be changed during operation. Even with an extended wheelbase for accommodating additional components, the system can increase the steering angle beyond conventional limits to reduce the minimum turning radius, thus maintaining good maneuverability despite the longer wheelbase

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The steering angle parameter is made variable and adjustable to extreme values. By changing the steering angle parameter to exceed conventional end positions, the system compensates for the increased turning radius caused by the extended wheelbase, allowing tight cornering capability to be maintained while carrying additional equipment

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the maximum steering angle is increased, then tighter curves can be followed, but the risk of collision between steering components increases

Engineering Contradiction:
Improvecurve following capabilityVSAvoidcollision avoidance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent employs asymmetric steering configurations where the left and right front wheels or crawler tracks can have different steering angles. This asymmetric arrangement, combined with offset pivot axes, creates collision-free areas that allow extreme steering angles to be achieved without components interfering with each other, thereby enabling tight curve following while maintaining reliability

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent introduces offset in the longitudinal direction between the pivot axes of the front wheels or crawler tracks. This dimensional offset creates spatial separation that prevents collision between steering components even at maximum steering angles, allowing the system to achieve tighter turning radii without compromising component reliability

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP2801664B1Road milling machine for machining road or ground surfaces
Publication Date: 2018.11.21 WIRTGEN GMBH
  • EP2801664B1 patent drawingFigure 1
  • EP2801664B1 patent drawingFigure 2
  • EP2801664B1 patent drawingFigure 3~4

AI summary

In a road milling machine for processing road or soil surfaces, comprising a machine frame (8) supported by a chassis, with a front and a rear axle (6, 7) with wheels (10, 12, 14, 16) or track drives, and a milling drum (20) rotatably mounted on the machine frame (8) between the rear wheels (14, 16), wherein the milling drum (20) is almost flush with a lateral outer surface of the machine frame (8), the so-called zero side (24), in order to enable milling as close as possible to obstacles, wherein at least the wheels (14, 16) or track drives of the rear axle (7) have wheel brackets with lifting columns (48) which are height-adjustable by means of hydraulic cylinders to adjust the milling depth relative to the machine frame (8), wherein at least the wheels (10, 12) or track drives of the front axle (6) have wheel brackets (32) with swivel columns (34),which are steerable about a pivot axis (38) by means of steering levers (36), wherein the steering levers (36) of the wheels (10, 12, 14, 16) or track drives of the front axle (6) are articulated to one another via a rigid connecting part (40) for synchronous adjustment of the steering angles, and wherein at least one steering cylinder (44) articulated to a fixed point (42) relative to the machine frame (8) and directly or indirectly coupled to at least one wheel console (32) adjusts the steering angle of the wheels (10, 12) or track drives, it is provided that the connecting part (40) together with a curved arm (50) projecting from the connecting part (40) forms a steering anchor (30), the arm (50) of which is coupled to the free end of the at least one steering cylinder (44).