Hydraulic Control Valve Using Pilot Load-Sense for Secondary Functions
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Solution Overview
Problem
Hydraulic machines face challenges in maintaining a high standby pressure level for secondary functions when primary functions are not actuated, as the pump reduces pressure to a minimal level, preventing the operation of secondary functions that require elevated pressure.
Innovation Solution
A hydraulic control valve system that uses a pilot signal as a substitute load-sense signal to maintain a high pressure level, allowing the pump to provide pressurized fluid even when primary functions are not actuated, by comparing the pilot fluid pressure with the load-sense pressure and communicating the higher pressure to the load-sensing source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the pump reduces pressure level to minimal standby level when primary functions are not actuated, then energy consumption is reduced, but the ability to drive secondary functions is lost
Solution Approach 1:
The system pre-establishes a standby pressure level above the minimal level by using the pilot signal from the spool valve to maintain pressure in the standby line. This preliminary pressure maintenance enables secondary functions to be actuated immediately when needed, without requiring the pump to continuously operate at high pressure.
Solution Approach 2:
The patent introduces a standby line with a standby pressure relief valve as an intermediary mechanism. This standby line receives a portion of the pump output and maintains a predetermined pressure level independently of the primary function demands. The pilot signal from the spool valve acts as a mediator to control the standby pressure relief valve, ensuring the standby line maintains sufficient pressure for secondary functions while the pump operates at reduced pressure for energy savings.
2Adaptability or versatility
If the pump maintains high pressure level continuously, then secondary functions can be actuated, but energy consumption increases
Solution Approach 1:
The system pre-establishes a standby pressure level above the minimal level by using the pilot signal from the spool valve to maintain pressure in the standby line. This preliminary pressure maintenance enables secondary functions to be actuated immediately when needed, without requiring the pump to continuously operate at high pressure.
Solution Approach 2:
Instead of maintaining full high pressure continuously, the system applies partial pressure maintenance only to the standby line. The standby pressure relief valve is configured to maintain a predetermined pressure level that is sufficient for secondary functions but lower than the full operating pressure. This partial action approach provides the necessary pressure for auxiliary functions while avoiding the energy consumption of continuous high-pressure operation.
3Loss of energy
If the pump operates at minimal standby pressure, then energy is saved, but auxiliary functions requiring elevated pressure cannot operate
Solution Approach 1:
The system pre-establishes a standby pressure level above the minimal level by using the pilot signal from the spool valve to maintain pressure in the standby line. This preliminary pressure maintenance enables secondary functions to be actuated immediately when needed, without requiring the pump to continuously operate at high pressure.
Solution Approach 2:
The patent introduces a standby line with a standby pressure relief valve as an intermediary mechanism. This standby line receives a portion of the pump output and maintains a predetermined pressure level independently of the primary function demands. The pilot signal from the spool valve acts as a mediator to control the standby pressure relief valve, ensuring the standby line maintains sufficient pressure for secondary functions while the pump operates at reduced pressure for energy savings.
4Ease of operation
If the pump maintains elevated pressure continuously, then auxiliary functions can operate, but energy efficiency decreases
Solution Approach 1:
The system pre-establishes a standby pressure level above the minimal level by using the pilot signal from the spool valve to maintain pressure in the standby line. This preliminary pressure maintenance enables secondary functions to be actuated immediately when needed, without requiring the pump to continuously operate at high pressure.
Solution Approach 2:
Instead of maintaining full high pressure continuously, the system applies partial pressure maintenance only to the standby line. The standby pressure relief valve is configured to maintain a predetermined pressure level that is sufficient for secondary functions but lower than the full operating pressure. This partial action approach provides the necessary pressure for auxiliary functions while avoiding the energy consumption of continuous high-pressure operation.
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 the operation of secondary functions by maintaining a sufficient pressure level in the hydraulic system, ensuring that the pump provides fluid flow capable of driving auxiliary functions even when primary functions are not in use.
Implementation Method 1
a pilot check valve configured to allow the pilot fluid signal to pass through when a pressure level of the pilot fluid signal exceeds a pressure level of a load-sense pressure signal
Implementation Method 2
a spool axially movable in the bore; a load-sense passage traversing the at least one worksection and configured to communicate a load-sense pressure signal having a first pressure level and representing a load-induced pressure of the actuator; a plurality of pilot fluid passages configured to communicate a pilot fluid signal having a second pressure level to the at least one worksection so as to move the spool in the bore
Data Source
AI summary
An example valve assembly is configured: generate a valve load-sense pressure signal indicative of a pressure level at a workport of an actuator; generate a pilot fluid signal to be communicated to a worksection of a valve assembly to enable shifting a spool in the worksection; compare a first pressure level of the valve load-sense pressure signal to a second pressure level of the pilot fluid signal; and communicate the pilot fluid signal to a load-sense port fluidly coupled to a load-sensing source of pressurized fluid when the second pressure level of the pilot fluid signal exceeds the first pressure level of the valve load-sense pressure signal.