Hydraulic Control Valve with Differential Pressure Regulator

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Solution Overview

Problem

Existing hydraulic control arrangements cannot independently control the fluid volume flow to actuators, as they are limited by maximum pump pressure, leading to high energy losses and inefficiencies.

Innovation Solution

A hydraulic control arrangement with a control valve featuring a metering orifice and a differential pressure regulator, which adjusts the flow cross-section between the hydraulic pump and actuator, allowing for independent control of fluid volume flow by maintaining a constant pressure difference across the pilot orifice, thereby reducing hydraulic losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a bypass channel is opened to limit fluid flow rate below maximum pump delivery, then pump pressure increases and check valve opens to supply actuator, but fluid flow rate cannot be controlled independently of load pressure

Engineering Contradiction:
Improvefluid flow rate controlVSAvoidindependence from load pressure
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

A pilot orifice is introduced as an intermediary element between the bypass channel and tank. By controlling the pilot orifice opening, the system mediates between pump pressure and load pressure, enabling independent fluid flow rate control to the actuator while maintaining pressure balance through the differential pressure regulator

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The differential pressure regulator provides feedback control by continuously monitoring the pressure differential across the pilot orifice and adjusting the bypass channel opening accordingly. This feedback mechanism ensures that fluid flow rate to the actuator can be controlled independently of load pressure variations

Inventive Principle:
Principle #23Feedback

2Productivity

If maximum pump pressure is used to achieve maximum fluid flow rate to actuator, then flow rate is maximized, but energy losses increase significantly

Engineering Contradiction:
Improvefluid flow rate to actuatorVSAvoidhydraulic energy losses
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The system changes the pressure parameter distribution by using a pilot orifice with small opening to create a localized pressure drop, rather than relying on maximum pump pressure. The differential pressure regulator maintains a constant pressure differential, allowing maximum fluid flow rate to be achieved at lower overall pump pressure, thereby reducing energy losses

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If a pilot orifice is introduced in the bypass channel, then pressure differential can be controlled, but device complexity increases

Engineering Contradiction:
Improvefluid flow rate controlVSAvoidcontrol arrangement structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The control valve serves multiple functions: it acts as a throttle control valve for the actuator, a differential pressure regulator for the pilot orifice, and a flow controller for the bypass channel. By making the control valve multi-functional, the system achieves precise fluid flow rate control independent of load pressure without adding separate components, thus managing device complexity

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

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 load-independent control of fluid volume flow to actuators, resulting in energy savings and cost reductions by optimizing hydraulic efficiency.

Implementation Method 1

A differential pressure regulator maintains a constant pressure differential across the pilot orifice

Methodology Applied
Scientific EffectPressure differential regulation:

Implementation Method 2

The control valve has a metering orifice for controlling the actuator. The metering orifice allows the flow cross-section between the hydraulic pump and the actuator to be adjusted

Methodology Applied
Scientific EffectOrifice flow control:

Implementation Method 3

If the pump pressure then exceeds the load pressure of the actuated actuator, a check valve associated with the control valve opens, and the actuator is supplied with hydraulic fluid from the pump line

Methodology Applied
Scientific EffectPressure-driven valve operation:

Data Source

PatentEP2891805B1Control assembly and a control valve for such a control assembly
Publication Date: 2020.01.01 ROBERT BOSCH GMBH
  • EP2891805B1 patent drawingFigure 1
  • EP2891805B1 patent drawingFigure 2
  • EP2891805B1 patent drawingFigure 3

AI summary

A hydraulic control arrangement for controlling at least one consumer is disclosed. This control arrangement forms an open-center system. A control valve is provided for the at least one consumer, through which a recirculating flow path extends. This path is connected to a hydraulic pump on one side and to a tank on the other. The recirculating flow path is connected to the hydraulic pump via a pilot orifice, which is thus located between the hydraulic pump and the control valve. When the control valve activates the consumer via a metering orifice, the recirculating flow path is simultaneously activated, and a connection between the recirculating flow path and the consumer downstream of the metering orifice is also established. A differential pressure regulator then maintains a constant pressure differential across the pilot orifice and the metering orifice, thus allowing the fluid flow rate to the consumer to be varied independently of the load pressure via the metering orifice.