Split Flow Pump Lower Pressure Selection Circuit

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Solution Overview

Problem

In working machines like hydraulic excavators, using a split flow pump requires complex configurations to adjust discharge flow rates between multiple circuit systems, necessitating the detection and adjustment of operation valves and actuators, which can be cumbersome.

Innovation Solution

A working machine control system that includes a split flow type fluid pressure pump, two circuit systems with operation valves, and a lower pressure selection circuit to adjust the discharge flow rate by selecting and communicating with the working fluid of lower pressure, allowing for increased flow rates without the need for pressure sensors or controllers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If pressure sensors and controllers are used to detect and adjust discharge flow rates, then accurate flow rate control is achieved, but the system configuration becomes complex and costly

Engineering Contradiction:

Improveflow rate detection accuracyVSAvoiddetection and control system

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces electronic sensors and controllers with a purely mechanical feedback system. The neutral passages and internal pump mechanisms provide automatic flow rate adjustment based on pressure differentials and flow conditions, eliminating the need for electronic detection and control components while maintaining accurate flow rate regulation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system uses its own operational parameters (pressure, flow) to automatically regulate discharge flow rates without external measurement devices. The mechanical feedback loop enables the pump to self-adjust based on the actual needs of each circuit system.

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 simple adjustment of discharge flow rates in working machines, ensuring minimal flow when actuators are not activated and increasing flow as needed when actuators are operated, without the use of pressure sensors or controllers.

Implementation Method 1

a lower pressure selection circuit configured to select and communicate with a working fluid of lower pressure among a working fluid on the downstream of the first operation valve of the first neutral passage, and a working fluid on the downstream of the second operation valve of the second neutral passage

Methodology Applied

Scientific EffectPressure differential selection: Pressure Gradient

Data Source

PatentUS10273983B2Working machine control system and lower pressure selection circuit

Publication Date: 2019.04.30 KYB CORP

AI summary

A working machine control system includes a split flow type fluid pressure pump configured to discharge a working fluid from a first discharge port and a second discharge port, and a lower pressure selection circuit configured to select and communicate with a working fluid of lower pressure among a working fluid on the downstream of a first operation valve of a first neutral passage in a first circuit system to which a working fluid discharged from the first discharge port is supplied, and a working fluid on the downstream of a second operation valve of a second neutral passage in a second circuit system to which a working fluid discharged from the second discharge port is supplied. The fluid pressure pump is adjusted in such a manner that the lower the pressure of the working fluid selected by the lower pressure selection circuit is, the more a discharge flow rate is increased.