Excavator Hydraulic Generator Coupling Without Case Drain Lines

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Solution Overview

Problem

Existing high-pressure hydraulic attachment tools for excavators face challenges in generating DC power without the need for electrical wiring or additional hydraulic lines, which are prone to damage and require complex setup, and existing hydraulic power generation solutions are inefficient due to back pressure issues and the necessity of case drains.

Innovation Solution

A boom-mountable high-pressure hydraulic tool with an electric power generation assembly that includes a sealed hydraulic motor and generator, where the motor output shaft is enclosed within a sealed housing, eliminating the need for a case drain or separate low-pressure return line by using a non-contact magnetic coupling to transmit power, allowing the tool to operate at full rated pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If electrical wiring is run down the boom from the high pressure hydraulic attachment, then DC power can be supplied to the attachment, but the wiring is subject to damage from materials contact, flexing at pivot joints, and contacts at connection points and swivels

Engineering Contradiction:
ImproveDC power supply to attachmentVSAvoidwiring integrity
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent replaces the electrical wiring system with a hydraulic power transmission system. Instead of running electrical cables down the boom, the invention uses hydraulic fluid under pressure to drive a hydraulic motor that generates electricity at the attachment end. This substitution eliminates the mechanical wiring system that is prone to damage from flexing, contact, and connection issues.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces hydraulic fluid as an intermediary medium to transmit power from the boom to the attachment. The hydraulic fluid carries energy through the hydraulic circuit, enabling power transmission without direct mechanical or electrical connections that would be vulnerable to damage during operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Use of energy by moving object

If high pressure hydraulic fluid is used to run a hydraulic motor that generates electricity at the boom, then DC power can be generated at the attachment, but a case drain line would be required down the boom which adds complexity and maintenance requirements

Engineering Contradiction:
ImproveDC power generation at attachmentVSAvoidhydraulic line configuration
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent merges the hydraulic motor housing with the existing hydraulic circuit architecture. The motor's sealed housing incorporates internal case drain ports that connect directly to the return line, eliminating the need for a separate external case drain line down the boom. This integration reduces the number of hydraulic lines and connection points required.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The hydraulic motor serves multiple functions: it acts as both a power actuator for the attachment tool and simultaneously as a generator for DC power production. The sealed housing design with integrated case drain capability allows the same hydraulic motor to handle both mechanical work and electrical generation without requiring separate dedicated lines for each function.

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

3Use of energy by moving object

If a hydraulic motor is used for electrical power generation, then DC power can be generated, but the motor cannot handle the back pressure from the return line and would require an additional low pressure return line

Engineering Contradiction:
Improveelectrical power generationVSAvoidback pressure handling
Core Design Contradiction:
Use of energy by moving objectVSStress or pressure

Solution Approach 1:

The patent designs the hydraulic motor with a sealed housing that replicates the pressure handling capabilities of high-pressure hydraulic actuators. By copying the robust sealed housing design from standard hydraulic motors rated for high pressure, the generator motor can withstand the back pressure from the return line without requiring a separate low-pressure return line architecture.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent changes the pressure handling parameters of the hydraulic motor by selecting or designing a motor with a sealed housing rated for the full system pressure range. This parameter change allows the motor to operate effectively in the high-pressure return line environment, eliminating the need for dual-pressure line configurations.

Inventive Principle:
Principle #35Parameter changes

4Use of energy by moving object

If existing hydraulic power generation devices are used, then DC power can be generated, but they require high-quality relatively low pressure hydraulic circuits or an additional case drain line

Engineering Contradiction:
ImproveDC power generationVSAvoidhydraulic circuit requirements
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The hydraulic motor with sealed housing serves itself by incorporating internal case drain ports that manage its own hydraulic fluid circulation. The sealed housing design allows the motor to self-regulate its internal pressure and fluid flow without requiring external case drain lines or special low-pressure circuit configurations, making it self-sufficient in handling its hydraulic fluid requirements.

Inventive Principle:
Principle #25Self-service

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

Enables efficient DC power generation for high-pressure hydraulic tools without the need for additional hydraulic lines or electrical wiring, reducing maintenance and damage risks, while handling high back pressure and full-rated hydraulic pressures effectively.

Implementation Method 1

A motor non-contact coupling can be mounted on the motor output shaft within the sealed housing. A generator non-contact coupling can be coupled to the generator input shaft and positioned entirely outside the sealed housing. The motor non-contact coupling can be drivingly coupled to the generator non-contact coupling.

Methodology Applied
Scientific EffectMagnetic coupling: Magnetic Field

Data Source

PatentEP3818217B1Excavator boom mountable high pressure hydraulic tool including a hydraulic motor driven generator
Publication Date: 2023.12.13 STANLEY BLACK & DECKER INC
  • EP3818217B1 patent drawingFigure 1
  • EP3818217B1 patent drawingFigure 2
  • EP3818217B1 patent drawingFigure 3~4

AI summary

An output shaft of a hydraulic motor is enclosed within a sealed housing and coupled to an input shaft of an electric generator using non-contact couplings. Tool electrical components are electrically coupled to the electric generator. A high pressure hydraulic tool circuit includes a hydraulic tool load and the hydraulic motor of the electric power generation assembly coupleable between a hydraulic boom inlet line and a hydraulic boom return line. Both the hydraulic tool load and the hydraulic motor of the electric power generation assembly can be designed to input hydraulic fluid up to the full rated pressure of the tool. The sealed housing of the hydraulic motor of the electric power generation assembly can be designed to retain hydraulic fluid within the interior up to the full rated pressure of the tool so that no case drain or separate low pressure return line for the hydraulic motor is necessary.