Work Vehicle Controller Direction Switching Brake Logic

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Solution Overview

Problem

Existing work vehicle controllers face issues with transmission shock and reduced clutch lifetime due to improper deceleration methods when switching between forward and reverse travel directions, particularly during shuttle operations, leading to uncomfortable operation feelings and inefficiencies.

Innovation Solution

A controller that determines the vehicle's travel direction based on clutch oil pressure and vehicle speed, activating the brake only when the selected travel direction differs from the actual direction and the vehicle speed exceeds a threshold, preventing unnecessary brake activation until the final operation position is established.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the reverse clutch is connected gradually to decelerate the vehicle, then the vehicle speed is reduced, but the reverse clutch is subjected to significant thermal load reducing its lifetime

Engineering Contradiction:

Improvevehicle speedVSAvoidreverse clutch lifetime

Core Design Contradiction:

SpeedVSDuration of action of stationary object

Solution Approach 1:

The patent introduces a brake device as an intermediary element to assist in decelerating the vehicle during direction switching. The brake device shares the deceleration burden with the reverse clutch, reducing the thermal load on the clutch while achieving the same speed reduction effect. This is accomplished by controlling the brake device to apply braking force during the clutch connection process.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the operational parameters of the brake device during the direction switching process. By activating the brake device at specific moments and controlling its braking force, the system optimizes the deceleration process to minimize thermal load on the reverse clutch while maintaining effective speed reduction.

Inventive Principle:

Principle #35Parameter changes

2Duration of action of stationary object

If the reverse clutch connection operation is performed in a short period of time to reduce thermal load, then the thermal load on the reverse clutch is reduced, but the vehicle is decelerated abruptly causing significant transmission shock

Engineering Contradiction:

Improvereverse clutch thermal loadVSAvoidtransmission shock

Core Design Contradiction:

Duration of action of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The brake device serves as a mediator that absorbs the shock of abrupt deceleration. By coordinating the brake device activation with the reverse clutch connection, the system achieves rapid clutch engagement without transmitting abrupt deceleration forces to the transmission, thus reducing transmission shock while maintaining short operation time.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The brake device provides beforehand cushioning by being activated in anticipation of the reverse clutch connection. This pre-positioned braking force cushions the deceleration process, allowing the clutch to engage rapidly without causing transmission shock.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Duration of action of stationary object

If the brake is activated whenever the operation lever is switched, then the thermal load on the clutch is reduced, but the brake may be unnecessarily activated during shuttle operations reducing operational efficiency

Engineering Contradiction:

Improveclutch thermal loadVSAvoidoperational efficiency

Core Design Contradiction:

Duration of action of stationary objectVSProductivity

Solution Approach 1:

The controller uses feedback from the operation lever position and vehicle state to intelligently determine when to activate the brake device. By monitoring whether the vehicle is in a shuttle operation mode or performing a genuine direction change, the system activates the brake only when necessary, avoiding unnecessary activations during shuttle operations while still protecting the clutch during actual direction changes.

Inventive Principle:

Principle #23Feedback

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 reduces thermal load on the clutch, minimizes transmission shock, and enhances operational efficiency by ensuring the brake is only activated when necessary, aligning with the operator's intentions.

Implementation Method 1

brake means for reducing the vehicle body speed

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

determines a current travel direction of the vehicle body based on an operation position selected by the travel operation lever, a clutch oil pressure of the forward clutch or the reverse clutch, and a vehicle body speed

Methodology Applied

Scientific EffectPressure detection: Pressure Gradient

Data Source

PatentUS7946404B2Work vehicle controller

Publication Date: 2011.05.24 KOMATSU LTD

AI summary

A device for a work vehicle eliminates uncomfortable operation feeling, improves the working efficiency, and reduces thermal load on a clutch and transmission shock. It is determined whether the current travel direction of the vehicle body is a forward travel direction F or a reverse travel direction R based clutch oil pressure of the forward clutch or reverse clutch. Braking force of a brake device is controlled such that the brake device is activated on the conditions that the travel direction position selected by the travel operation lever and the travel direction determined by a travel direction flag are opposite to each other, and the detected vehicle body speed is equal to or greater than a predetermined threshold value.