Winch Brake Hydraulic Circuit for Air Bleeding Responsiveness

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Solution Overview

Problem

The responsiveness of the brake system in winch units of cranes is compromised due to air being mixed into the hydraulic circuit during the assembly and disassembly process, leading to delays in pressure changes and reduced braking efficiency.

Innovation Solution

A hydraulic circuit design with detachable couplers and throttle valves that effectively discharge air from the positive and negative oil chambers to a low-pressure container, maintaining brake responsiveness by generating a differential pressure and preventing clogging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the winch unit is detachably attached to the machine body for transportation and assembly purposes, then the adaptability and ease of transportation are improved, but air may be mixed into the hydraulic circuit during mounting and dismounting, causing brake responsiveness to deteriorate

Engineering Contradiction:
Improvedetachable attachment capabilityVSAvoidbrake responsiveness
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements a bleeding operation that automatically executes when the winch unit is detached from the machine body. The bleeding valve opens to discharge working oil and air from the specified oil chamber before detachment completes, preventing air accumulation that would compromise brake responsiveness during subsequent reattachment

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces a bleeding valve as an intermediary component between the specified oil chamber and the external environment. This valve serves as a controlled interface that allows air to be discharged while maintaining hydraulic circuit integrity during the detachment process

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If a throttle portion is provided in the sub oil passage to generate differential pressure for air discharge, then the air discharge efficiency is improved, but the device complexity increases due to additional components

Engineering Contradiction:
Improveair discharge efficiencyVSAvoidhydraulic circuit complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The throttle portion is integrated into the sub oil passage as a multi-functional element that simultaneously controls oil flow rate and generates the differential pressure needed for air discharge. This single component performs multiple functions that would otherwise require separate devices

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

Solution Approach 2:

The throttle portion modifies the flow parameters of the working oil by creating a controlled restriction, which generates the necessary differential pressure between the upstream and downstream sides to drive air discharge from the specified oil chamber

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If the brake valve adjusts hydraulic force by generating differential pressure between positive and negative oil chambers, then the brake force control precision is improved, but the device complexity increases due to additional valves and control mechanisms

Engineering Contradiction:
Improvebrake force control precisionVSAvoidvalve and control mechanism complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The brake valve serves multiple functions: it controls the flow of working oil to the specified oil chamber, generates differential pressure between the positive and negative oil chambers, and provides adjustable brake force control. This single valve integrates several control functions that would otherwise require multiple separate components

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

Solution Approach 2:

The brake valve utilizes hydraulic principles to control brake force by regulating the flow and pressure of working oil. By generating differential pressure between the positive and negative oil chambers through hydraulic force adjustment, the system achieves precise brake control without mechanical linkages

Inventive Principle:
Principle #29Pneumatics and hydraulics

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

Stable operability of the braking operation is maintained by ensuring efficient air discharge and preventing pressure delays, even during the mounting and dismounting of the winch unit, thus enhancing the responsiveness of the brake system.

Implementation Method 1

a throttle portion disposed in the sub oil passage and configured to generate a differential pressure in the sub oil passage between an upstream side and a downstream side of the throttle portion

Methodology Applied
Scientific EffectDifferential pressure: Pressure Gradient

Implementation Method 2

a specified oil chamber that is one of the positive oil chamber and the negative oil chamber, and allows a working oil to flow into the specified oil chamber

Methodology Applied
Scientific EffectHydraulic force: Hydraulic Press

Data Source

PatentEP3998225B1Work machine
Publication Date: 2024.07.03 KOBELCO CONSTR MASCH CO LTD
  • EP3998225B1 patent drawingFigure 1
  • EP3998225B1 patent drawingFigure 2
  • EP3998225B1 patent drawingFigure 3

AI summary

Provided is a work machine (100) capable of effectively discharging air from a hydraulic circuit of a winch unit (10) capable of applying braking to a winch drum (1) by receiving a working oil. The work machine (100) includes: a winch unit (10) having a winch drum (1), a winch motor (20), a cylinder portion (3) and a clutch portion (4); a hydraulic sources (24); a braking operating unit (25a); a brake valve (25b); a connecting portion (QC1); and a throttle portion (26A). The throttle portion (26A) includes an opening having an opening diameter that is set so as to hold a pressure in a positive oil chamber (3P) for generating a brake force applied to the winch drum (1) and to discharge a working oil from the positive oil chamber (3P).