Double-Acting Drive Piston for Hydraulic Lubrication Pump

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Solution Overview

Problem

Existing automatic lubrication pumps for hydraulic percussion tools face challenges in ensuring continuous lubrication over extended periods, as they rely on mechanically sensitive components like return springs and one-way clutches, which lead to wear and require frequent maintenance.

Innovation Solution

A double-acting drive piston with a progressive distributor that alternates between two drive chambers, driven by hydraulic pressure, eliminating the need for mechanically sensitive components and ensuring continuous lubrication through hydraulic actuation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanically sensitive components like return springs and one-way clutches are used in automatic lubrication pumps, then the pump can achieve continuous lubrication delivery, but the device complexity increases and reliability decreases due to wear

Engineering Contradiction:
Improveservice lifeVSAvoidmechanical components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes mechanically sensitive components (return springs, one-way clutches) from the lubrication pump system. Instead, it uses a double-acting drive piston with two drive chambers that are alternately pressurized by hydraulic pressure through a progressive distributor, eliminating the need for mechanical resetting mechanisms and reducing wear-prone parts.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces mechanical systems (springs, clutches) with a hydraulic system. The double-acting drive piston is actuated by hydraulic pressure applied alternately to two drive chambers through a progressive distributor, converting mechanical wear-prone components into a hydraulic actuation system that reduces friction and wear.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If a single drive chamber is used in the lubrication pump, then the device complexity is reduced, but the productivity decreases because the delivery piston cannot perform multiple conveying movements continuously

Engineering Contradiction:
Improvecontinuous lubrication deliveryVSAvoiddrive mechanism
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent divides the drive mechanism into two separate drive chambers (first and second drive chambers) that are alternately pressurized. This segmentation allows the delivery piston to perform multiple conveying movements continuously as one chamber pressurizes while the other resets, effectively doubling the productivity without proportionally increasing complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements periodic action through the progressive distributor that alternately applies hydraulic pressure to the first and second drive chambers in a cyclic manner. This periodic pressurization ensures continuous reciprocating motion of the delivery piston, maintaining constant lubrication delivery without idle periods.

Inventive Principle:
Principle #19Periodic action

3Reliability

If complex control devices are added to ensure continuous lubrication over long periods, then the reliability improves, but the device complexity and ease of operation worsen

Engineering Contradiction:
Improvecontinuous operation capabilityVSAvoidmaintenance requirement
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent implements self-service through the progressive distributor that automatically alternates hydraulic pressure between the two drive chambers based on the cyclic pressure increases in the hydraulic circuit. The system self-regulates and maintains continuous lubrication delivery without external control devices, batteries, or complex timing mechanisms, reducing maintenance requirements.

Inventive Principle:
Principle #25Self-service

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 significantly reduces wear and ensures a longer service life by using hydraulic actuation, allowing for continuous lubrication without the need for complex mechanical components, thus improving the reliability and longevity of the lubrication system.

Implementation Method 1

designed to be connectable to a pressure line of a hydraulic circuit with repeatedly rising or constant hydraulic pressure

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 2

driven by hydraulic pressure, eliminating the need for mechanically sensitive components

Methodology Applied
Scientific EffectHydraulic actuation: Hydraulic Press

Implementation Method 3

a switchover element which can be switched into the hydraulic circuit and actuated by the hydraulic pressure and comprises a progressive distributor, through which the drive chambers alternate during operation can be connected to the pressure line

Methodology Applied
Scientific EffectFluid flow alternation: Fluid Spray

Implementation Method 4

a feed chamber that can be filled with lubricant and is connected to at least one lubricant outlet of the automatic lubrication pump

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP2024140B1Automatic lubricating pump with double-acting drive piston
Publication Date: 2010.08.04 SKF LUBRICATION SYST GERMANY
  • EP2024140B1 patent drawingFigure 1
  • EP2024140B1 patent drawingFigure 2~3
  • EP2024140B1 patent drawingFigure 4

AI summary

The invention relates to an automatic lubricating pump (1) for a machine having a hydraulically actuated percussion tool (4), such as a hydraulic hammer for example. The lubricating pump (1) is designed such that it can be connected to a pressure line (P) of the hydraulic circuit (2). The lubricating pump (1) has a drive piston (8), designed such that it can be driven by the hydraulic circuit, and a feed piston, connected to the drive piston in a motion-transmitting manner, of a feed pump (9), by means of which lubricant is fed to a lubricating point. The service life of the lubricating pump can be prolonged compared with conventional pumps if the drive piston (8) is designed to be double-acting with two drive chambers (8c, 8d) and a hydraulically operable changeover member (16) is provided which can be connected in the hydraulic circuit and by means of which the drive chambers (8c, 8d) can be alternately and automatically connected to the pressure line (8) during operation.