Work Vehicle Steering Lever Control Unit Malfunction Prevention

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Solution Overview

Problem

The complexity of enabling and disabling steering lever operations in work vehicles leads to operator confusion due to complicated conditions, despite increased types of switches, which do not effectively suppress malfunctions.

Innovation Solution

A work vehicle equipped with a steering lever, engine, main switch, rear frame, front frame, steering actuator, lever switch, and lever steering control unit, where the lever switch allows selection of enabled or disabled states for the steering actuator motion, and the lever steering control unit disables the actuator motion upon engine start instruction, simplifying malfunction suppression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple types of switches are provided to prevent steering lever malfunctions, then the reliability of steering lever operation is improved, but the device complexity increases and operator confusion occurs due to complicated enabling conditions

Engineering Contradiction:
Improvesteering lever malfunction preventionVSAvoidnumber of switches and enabling conditions
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the essential function from multiple complex switches and reduces it to a single main switch that detects engine start state. This eliminates the complexity of multiple switches while maintaining the core safety function of preventing steering lever operation during engine start.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The main switch serves multiple functions: it controls engine start, triggers the control unit to disable steering lever operation, and provides a unified control interface. This multi-functionality replaces what previously required multiple specialized switches, simplifying the overall system.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If multiple types of switches are provided to prevent steering lever malfunctions, then the reliability of steering lever operation is improved, but the ease of operation deteriorates because the operator cannot understand the reason for disabled lever operation

Engineering Contradiction:
Improvesteering lever malfunction preventionVSAvoidoperator understanding of lever operation status
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The control unit provides feedback to the operator by displaying the reason why steering lever operation is disabled (e.g., 'engine start in progress'). This feedback mechanism maintains reliability while improving ease of operation by making the system state transparent to the operator.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control unit preliminarily determines the disabled state of the steering lever based on engine start detection and prepares the appropriate display message before the operator attempts operation. This preliminary preparation ensures clear communication of system status.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the steering actuator motion is disabled during engine start, then the reliability is improved by preventing malfunctions, but the ease of operation worsens by restricting steering lever functionality

Engineering Contradiction:
Improvemalfunction suppression during engine startVSAvoidsteering lever operability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The steering lever operation is periodically enabled and disabled based on engine state: disabled during engine start (temporary restriction), then enabled after start completion. This periodic control ensures safety during critical phases while maintaining operability during normal operation.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The steering lever operability dynamically changes based on engine start state. The control unit adjusts the enabled/disabled status in real-time according to whether the engine is starting, providing automatic adaptation without operator intervention.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3199425B1Work vehicle
Publication Date: 2020.01.15 KOMATSU LTD
  • EP3199425B1 patent drawingFigure 1
  • EP3199425B1 patent drawingFigure 2
  • EP3199425B1 patent drawingFigure 3

AI summary

A controller (10) disables the motion of a steering cylinder (9) brought about by a steering lever (22) when an enabled state is selected via a lever switch (22a) and an instruction to start an engine (7) is issued via a main switch (23).