Hydraulic Plunger Pump Valve Core Stability

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Solution Overview

Problem

Existing hydraulic plunger pump control structures face challenges with instantaneous pressure drops affecting valve core thrust, leading to instability and reduced control accuracy.

Innovation Solution

A hydraulic plunger pump variable control structure that includes a valve body, main valve core, and valve sleeve, where the valve sleeve is fitted with the main valve core to define a valve throttling port, and the structure reduces the effect of instantaneous pressure drops on valve core thrust by controlling relative displacement between the main valve core and valve sleeve.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If pressure oil is used to push the variable piston through a valve opening, then the control structure is simple with few parts, but the instantaneous pressure drop of the pilot oil source affects the force on the valve, reducing responsiveness and control accuracy

Engineering Contradiction:
Improvecontrol structure complexityVSAvoidcontrol accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent divides the control system into two independent parts: a pilot control device that controls valve opening/closing, and a variable control device that controls piston movement. The pilot control device uses pressure oil to control the valve core, while the variable control device uses a separate feedback mechanism (lever and spring) to control the variable piston, preventing pressure drops from affecting control accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a lever mechanism as an intermediary between the valve sleeve and variable piston. The lever converts the movement of the valve sleeve into opposite movement of the variable piston, providing mechanical feedback without requiring pressure oil to directly push the piston through the valve opening.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If a lever mechanism is used to drive feedback of the valve sleeve, then the structure is simple with few parts, but pressure oil must flow through a valve opening to push the variable piston, causing instantaneous pressure drops that affect responsiveness

Engineering Contradiction:
Improvestructure complexityVSAvoidresponsiveness
Core Design Contradiction:
Device complexityVSSpeed

Solution Approach 1:

The patent separates the feedback function (handled by the lever mechanism) from the pressure control function (handled by the pilot control device). This segmentation allows the lever to provide immediate mechanical feedback without waiting for pressure oil to flow through the valve opening, improving responsiveness.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If the valve core and valve sleeve are integrated with a three-position two-way valve structure, then the number of parts is reduced and structure is simplified, but the instantaneous pressure drop affects the thrust on the valve core, reducing stability and control accuracy

Engineering Contradiction:
Improvenumber of partsVSAvoidvalve stability
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The patent divides the control functions into separate devices: the pilot control device handles valve opening/closing stability, while the variable control device handles piston position stability through the lever feedback mechanism. This segmentation prevents pressure drops from affecting both functions simultaneously, maintaining overall system stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a feedback mechanism where the lever is hinged to the valve body and connected to the variable piston. When the variable piston moves, the lever rotates and drives the valve sleeve to move in the opposite direction, providing mechanical feedback that stabilizes valve position without relying on pressure oil flow through the valve opening.

Inventive Principle:
Principle #23Feedback

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

The solution enhances valve stability and improves control accuracy by mitigating the impact of instantaneous pressure drops on valve core thrust.

Implementation Method 1

the valve core is pushed to move due to an area difference between the two diameters, such that the throttling port is opened and the oil fluid enters the Pp chamber from the P chamber

Methodology Applied
Scientific EffectPressure difference: Pressure Gradient

Implementation Method 2

The function is based on a lever principle, such that the movement direction of the variable piston is opposite to the movement direction of the valve sleeve, so as to realize a process of mechanical feedback

Methodology Applied
Scientific EffectLever principle: Lever

Data Source

PatentEP3580457B1Hydraulic plunger pump variable control structure and control method for the same
Publication Date: 2025.03.05 JIANGSU HENGLI HYDRAULIC TECH CO LTD
  • EP3580457B1 patent drawingFigure 1~2

AI summary

A hydraulic plunger pump variable control structure (100) and a control method for the same are provided. The hydraulic plunger pump variable control structure (100) includes a valve body (1), a main valve core (2) and a main valve sleeve (3). The main valve core (2) has a first end provided with a spring loaded assembly (4), and a second end provided with a pilot valve core (6). The spring loaded assembly (4) is configured to provide a reverse preloading force. The main valve sleeve (3) is connected with a feedback rod (5) that is connected with a variable piston pump. A valve sleeve (7) is disposed outside the main valve core (2). The pilot valve core (6) is pushed by hydraulic oil to overcome the preloading force of the spring loaded assembly (4), so as to drive the main valve core (2) to move. A throttling port between the main valve core (2) and the valve sleeve (7) is achieved by controlling relative displacement between the main valve core (2) and the valve sleeve (7) after aforementioned moving. The hydraulic oil that flows into the throttling port controls the movement of the variable piston pump. The movement of the variable piston pump drives the main valve sleeve (3) to move along the opposite moving direction of the main valve core (2).