Direction Control Valve Pressure Loss Reduction

Solution Overview

Problem

Hydraulic circuits for construction machines experience increased pressure loss and larger spool sizes due to multiple bleed openings in direction control valves, complicating the center bypass passage and making manufacturing difficult.

Innovation Solution

A direction control valve group with a first internal passage that maintains a consistent passage area regardless of spool position, eliminating the need for bleed openings and allowing pressure oil to flow directly to the center bypass passage, reducing pressure loss and simplifying the center bypass passage shape.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple bleed openings are provided in the spool of a direction control valve to enable bleed-off control, then bleed control functionality is achieved, but pressure loss increases and the spool size becomes larger

Engineering Contradiction:

Improvebleed control functionalityVSAvoidpressure loss

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The invention extracts the bleed-off control function from the direction control valve spool by removing the bleed openings from the spool structure. Instead, a separate bleed control valve is introduced to perform the bleed-off control, thereby eliminating the pressure loss and size increase associated with multiple bleed openings in the spool while preserving the bleed control functionality.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention segments the control functions by separating the direction control valve from the bleed control valve. The direction control valve handles only direction control without bleed openings, while the bleed control valve independently manages the bleed-off control. This segmentation allows each valve to be optimized for its specific function, reducing overall system complexity and pressure loss.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If multiple bleed openings are provided in the spool of a direction control valve to enable bleed-off control, then bleed control functionality is achieved, but the spool size increases making manufacturing more difficult

Engineering Contradiction:

Improvebleed control functionalityVSAvoidspool manufacturing

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The invention extracts the bleed-off control function from the direction control valve spool by removing the bleed openings from the spool structure. Instead, a separate bleed control valve is introduced to perform the bleed-off control, thereby eliminating the pressure loss and size increase associated with multiple bleed openings in the spool while preserving the bleed control functionality.

Inventive Principle:

Principle #2Taking out (Extraction)

3Adaptability or versatility

If multiple bleed openings are provided in the spool of a direction control valve to enable bleed-off control, then bleed control functionality is achieved, but the center bypass passage becomes more complex

Engineering Contradiction:

Improvebleed control functionalityVSAvoidcenter bypass passage complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention segments the control functions by separating the direction control valve from the bleed control valve. The direction control valve handles only direction control without bleed openings, while the bleed control valve independently manages the bleed-off control. This segmentation allows each valve to be optimized for its specific function, reducing overall system complexity and pressure loss.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention extracts the bleed-off control function from the direction control valve spool by removing the bleed openings from the spool structure. Instead, a separate bleed control valve is introduced to perform the bleed-off control, thereby eliminating the pressure loss and size increase associated with multiple bleed openings in the spool while preserving the bleed control functionality.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS10443213B2Hydraulic circuit for construction machine

Publication Date: 2019.10.15 SUMITOMO CONSTRUCTION MACHINERY

AI summary

A direction control valve group for a construction machine that controls an amount of pressure oil supplied to a hydraulic actuator from a hydraulic pump that discharges the pressure oil is provided. The direction control valve includes a cylinder port that supplies the pressure oil to the hydraulic actuator, a bridge passage that is switchably connected and disconnected to the cylinder port according to a change in position of a first spool, and an internal passage that supplies the pressure oil discharged from the hydraulic pump to the bridge passage. The first spool is provided in the internal passage.