Hydraulic Control Valve Actuation for Negative Load Stability

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Solution Overview

Problem

Existing control valve devices for hydraulic cylinders experience vibration issues and power losses when controlling negative loads, leading to unstable behavior and reduced efficiency due to the reliance on inflow-side pressure to actuate outflow-side lowering brake valves.

Innovation Solution

Incorporating a pilot control line with a check valve and throttle devices connected to a drain line, which allows the actuation pressure to be influenced by inlet-side pressure, enabling the lowering brake valve on the outflow side to be actuated by hydraulic control pressure, reducing vibrations and power losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the lowering brake valve on the outflow side is actuated by the inflow-side pressure via pilot control lines, then the valve can be controlled to open into the flow position, but vibration problems occur and power losses increase

Engineering Contradiction:
Improvecontrol of lowering brake valveVSAvoidpower losses
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent extracts the harmful connection between the inflow side and reservoir via pilot control lines. By removing this connection, the system eliminates the power losses and vibrations caused by the pressure-dependent actuation mechanism, while maintaining the essential control function through an alternative actuation path.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a new intermediary mechanism for actuating the lowering brake valve that does not rely on the problematic pilot control lines. This intermediary system allows the valve to be controlled without creating the harmful feedback loop between inflow pressure and reservoir connection that causes vibrations and energy loss.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the lowering brake valve is actuated by inflow-side pressure through throttle devices, then the valve can regulate negative loads, but a high level of coordination effort is required and stable state is not always achieved

Engineering Contradiction:
Improvecontrol stabilityVSAvoidcoordination effort
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the complex coordination requirements by extracting the throttle devices from the actuation path. This eliminates the need for high-level coordination between multiple components while maintaining the valve's ability to regulate negative loads reliably.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using inflow-side pressure to actuate the outflow-side valve (which requires complex coordination), the patent inverts the approach by using a direct actuation method that simplifies the control logic and reduces coordination requirements while achieving the same regulatory function.

Inventive Principle:
Principle #13The other way round (Inversion)

3Ease of operation

If the inlet side is connected to the reservoir via pilot control lines, then the lowering brake valve can be opened, but power losses occur that reduce efficiency

Engineering Contradiction:
Improveactivation of lowering brake valveVSAvoidefficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent extracts the harmful pilot control line connection between the inlet side and reservoir. This removal eliminates the continuous power loss pathway while preserving the essential function of activating the lowering brake valve when needed, thereby improving overall system efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

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 achieves stable control behavior and improved efficiency by reducing vibrations and eliminating power losses during the activation of lowering brake valves, allowing for effective regulation of negative loads on hydraulic cylinders.

Implementation Method 1

a drain line in which a check valve is arranged, which is connected to the inlet-side consumer line, wherein when the inlet-side pressure in the inlet-side consumer line falls below the control pressure, the check valve in the outlet line opens

Methodology Applied
Scientific EffectCheck valve: Valve

Implementation Method 2

with a pilot control line of the lowering brake valve carrying the actuation pressure by means of a drain line in which a check valve is arranged, which is connected to the inlet-side consumer line

Methodology Applied
Scientific EffectThrottle device: Valve

Data Source

PatentEP2503161B1Hydraulic control valve device
Publication Date: 2017.10.04 LINDE HYDRAULICS
  • EP2503161B1 patent drawingFigure 1

AI summary

The invention relates to a hydraulic control valve device (1) for controlling a double-acting hydraulic cylinder (7) with a control valve (2) that throttles in intermediate positions, which is connected to a delivery line (3) of a pump (4), a reservoir line (6) leading to a reservoir (5), and consumer lines (8a, 8b) leading to the hydraulic cylinder (7), wherein the control valve (2) is actuated by a hydraulic control pressure (pA; pB) in the direction of a control position (2b; 2d), in which one consumer line (8a; 8b) forms an inlet side connected to the delivery line (3) and the other consumer line (8b; 8a) forms an outlet side connected to the reservoir (5), and wherein a seat-tight lowering brake valve (15a, 15b) is arranged in each of the consumer lines (8a, 8b) for leak-free shut-off of the hydraulic cylinder (7), which maintains a leak-tight closed position (17a, 17b) and has a flow position (18a, 18b).The object of providing such a control valve device in which stable control behavior is achieved and power losses in the actuation of the lowering brake valves are avoided is solved according to the invention by the fact that the seat-tight lowering brake valve (15b; 15a) arranged in the outlet side can be actuated by the actuation pressure (pA ; pB) of the control valve (2) in the direction of the flow position (18b; 18a).