Work Vehicle Brake Control System for Slope Parking

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Solution Overview

Problem

The negative-type parking brake system experiences a time lag between the output of a parking brake instruction and its full operation, which can be inconvenient for operators, especially when operating on slopes, as they need to continuously press the brake pedal until the parking brake is fully engaged.

Innovation Solution

A control system that automatically operates the service brake device upon receiving a parking brake instruction from the operator, regardless of pedal operation, until the parking brake force reaches a predetermined value, incorporating features like oil temperature detection to adjust the operation time and vehicle speed detection to prevent sudden braking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the operator continuously presses the brake pedal until the parking brake is fully engaged, then the vehicle can be reliably stopped, but the operation becomes cumbersome and time-consuming

Engineering Contradiction:
Improveparking brake engagement reliabilityVSAvoidbrake operation convenience
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The service brake is activated automatically and preliminarily when the parking brake switch is operated, providing immediate braking force before the parking brake is fully engaged. This preliminary action ensures the vehicle is secured during the time lag period without requiring the operator to continuously press the brake pedal.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control device acts as an intermediary between the parking brake switch and the service brake device. It detects the parking brake instruction and automatically activates the service brake, mediating the time lag between the operator's input and the parking brake's full engagement.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the service brake operates concurrently with the parking brake for an extended period, then the vehicle remains securely stopped, but gear backlash may occur in the transmission

Engineering Contradiction:
Improvevehicle stopping reliabilityVSAvoidtransmission gear backlash
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The control device continuously monitors the brake release pressure and detects when the parking brake has been fully engaged. Upon detecting full engagement, it automatically deactivates the service brake, providing feedback-based control that prevents excessive concurrent operation and potential gear backlash.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The service brake operation duration is dynamically adjusted based on the actual engagement status of the parking brake. The control device extends or shortens the service brake activation period according to the detected brake release pressure, optimizing the transition between brakes to minimize transmission stress.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2116435B1Control device for work vehicle
Publication Date: 2013.09.04 HITACHI CONSTRUCTION MACHINERY CO LTD
  • EP2116435B1 patent drawingFigure 1
  • EP2116435B1 patent drawingFigure 2
  • EP2116435B1 patent drawingFigure 3(a)~3(b)

AI summary

A control system for a work vehicle includes: a negative-type parking brake device that starts operating in response to a parking brake instruction; an output device that outputs the parking brake instruction; a service brake device that operates in response to an operation of a brake pedal by an operator; and a brake control device that operates the service brake device regardless of a pedal operation by the operator when the parking brake instruction is output from the output device.