Variable Anticavitation Valve for Hydraulic Motor Cavitation Prevention

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Solution Overview

Problem

Hydraulic motors continue to rotate due to inertia, leading to cavitation issues when the main control valve is closed, which existing systems fail to adequately prevent, resulting in inefficiencies and potential damage.

Innovation Solution

A hydraulic system with a variable anticavitation valve and an electronic control unit that controls the pressure relief valve based on vehicle propulsion mode and hydraulic fluid temperature, ensuring fluid flow from one side of the hydraulic motor to the other, even when the main control valve prevents communication between the pump and motor, thereby preventing cavitation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the main control valve is closed to stop fluid communication between the pump and hydraulic motor, then the hydraulic motor rotation is stopped, but cavitation occurs due to inertia forces causing continued rotation

Engineering Contradiction:
Improvecavitation preventionVSAvoidmotor control
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

An anticavitation valve is introduced as an intermediary component between the main control valve and the hydraulic motor. This valve provides a dedicated fluid passage that allows hydraulic fluid to bypass the closed main control valve and reach the hydraulic motor, preventing cavitation while the main control valve remains closed to stop normal operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The fluid control system is segmented into two independent pathways: the main control valve pathway for normal operation control, and the anticavitation valve pathway for cavitation prevention. This segmentation allows each valve to perform its specific function independently without interfering with the other.

Inventive Principle:
Principle #1Segmentation

2Reliability

If an anticavitation valve is added to prevent cavitation, then cavitation is avoided, but the system complexity increases

Engineering Contradiction:
Improvecavitation preventionVSAvoidvalve assembly
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The anticavitation valve is integrated with the main control valve assembly, combining two valves into a single compact unit. This merging reduces space requirements and simplifies installation while maintaining the cavitation prevention function, thereby reducing the overall system complexity despite adding functionality.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a fixed flow resistance is provided by the anticavitation valve, then cavitation is prevented, but operational versatility is reduced

Engineering Contradiction:
Improvecavitation preventionVSAvoidfluid flow control
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The anticavitation valve is designed with variable flow resistance capability, allowing the valve opening to be dynamically adjusted based on operating conditions. This enables the valve to adapt to different flow requirements while maintaining cavitation prevention, thereby preserving operational versatility unlike a fixed orifice design.

Inventive Principle:
Principle #15Dynamics

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

This solution effectively prevents cavitation, enhances operational efficiency, and allows for controlled deceleration modes, such as 'soft' and 'hard' braking, by managing hydraulic fluid flow and pressure, thus improving the overall performance and reliability of the hydraulic system.

Implementation Method 1

an electronically controlled pressure relief valve for variably controlling the hydraulic fluid flow from the first side to the second side of the hydraulic motor

Methodology Applied
Scientific EffectPressure relief: Pressure Drop

Data Source

PatentEP3449158B1Hydraulic system
Publication Date: 2020.01.08 VOLVO TRUCK CORP
  • EP3449158B1 patent drawingFigure 1
  • EP3449158B1 patent drawingFigure 2
  • EP3449158B1 patent drawingFigure 3

AI summary

The present invention relates to a hydraulic system (30) for circulating hydraulic fluid via a pump (26) and a hydraulic motor (28). The hydraulic system (30) comprises a main control valve (36) adapted to be located between the pump (26) and the hydraulic motor (28) as seen in a direction of flow from the pump (26) to the hydraulic motor (28). The hydraulic system (30) further comprises an anticavitation valve (52) adapted to be located between the main control valve (36) and the hydraulic motor (28) as seen in a direction of flow from the pump (26) to the hydraulic motor (28). The anticavitation valve (52) is arranged such that when the main control valve (36) assumes a condition preventing fluid communication between the pump (26) and the hydraulic motor (28), hydraulic fluid may flow from a first side (70) to a second side (74) of the hydraulic motor (28) via the anticavitation valve (52). According to the present invention, the anticavitation valve (52) comprises a variable valve assembly (81) for variably controlling the hydraulic fluid flow from the first side (70) to the second side (74) of the hydraulic motor (28).