Wheel Loader Damper Valve Closes During Rap-Out

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Solution Overview

Problem

Existing travel damper control methods for wheel loaders do not account for 'rap-out' actions, leading to acute peak pressures being transmitted to accumulators, which degrades their durability.

Innovation Solution

A travel damper control device with a proximity detecting part and a valve switching part that closes the communication between the boom cylinder and accumulator when the bell crank is in proximity to the cross tube, preventing peak pressure transmission during 'rap-out' actions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the accumulator is coupled to the boom cylinder during rap-out operation, then the vibration of the vehicle body is absorbed, but the acute peak pressure degrades the durability of the accumulator

Engineering Contradiction:
Improvevehicle body vibration absorptionVSAvoidaccumulator durability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The control valve closes the communication between the accumulator and boom cylinder before the rap-out operation occurs. The control unit detects when the bell crank approaches the cross tube (indicating upcoming rap-out) and proactively closes the valve, preventing the acute peak pressure from reaching the accumulator while still allowing vibration absorption during normal operation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The harmful element (acute peak pressure during rap-out) is extracted from the system by selectively closing the communication path between the boom cylinder and accumulator only during rap-out operations, while maintaining the connection during normal vibration conditions

Inventive Principle:
Principle #2Taking out (Extraction)

2Stability of the object's composition

If the open/close valve remains open during rap-out, then the accumulator can absorb vibration, but the peak pressure is transmitted to the accumulator causing durability degradation

Engineering Contradiction:
Improvevibration damping capabilityVSAvoidpeak pressure transmission
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The communication state between the accumulator and boom cylinder is dynamically changed based on operational conditions. The control valve switches between open and closed states according to real-time detection of bell crank position and rap-out operation status, optimizing both vibration absorption and peak pressure protection

Inventive Principle:
Principle #15Dynamics

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

This solution effectively inhibits the degradation of accumulator durability by blocking peak pressure transmission during 'rap-out' actions, ensuring the accumulator's longevity.

Implementation Method 1

the proximity detecting part is configured to detect that the bell crank is in proximity to the cross tube when an inner angle formed by the pair of booms and the bell crank becomes less than or equal to a first angle in a side view of the wheel loader

Methodology Applied
Scientific EffectAngle measurement:

Implementation Method 2

a valve switching part configured to switch the open/close valve into a closed position when the proximity detecting part detects that the bell crank is in proximity to the cross tube

Methodology Applied
Scientific EffectValve closure:

Implementation Method 3

the accumulator communicated with the boom cylinder through an open/close valve

Methodology Applied
Scientific EffectHydraulic pressure absorption: Hydraulic Accumulator

Data Source

PatentEP2543778B1Driving damper control device for wheel loader
Publication Date: 2014.03.12 KOMATSU LTD
  • EP2543778B1 patent drawingFigure 1
  • EP2543778B1 patent drawingFigure 2
  • EP2543778B1 patent drawingFigure 3

AI summary

A travel damper control device includes a proximity detecting part and a valve switching part. The proximity detecting part is configured to detect that the bell crank is in proximity to the cross tube. The valve switching part is configured to switch the open/close valve into a closed position when the proximity detecting part detects that the bell crank is in proximity to the cross tube.