Plastic Double Piston Pump for Weight Reduction

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Solution Overview

Problem

Conventional piston pump devices with double pistons are heavy and large due to their steel or dimensionally stable metal construction, making them unsuitable for mobile applications where weight and space savings are essential.

Innovation Solution

The piston pump device uses plastic materials for the double piston and/or second housing part, specifically unreinforced plastics like polyamide or fiberglass-reinforced plastics, to reduce weight while maintaining stability, and incorporates a stabilizing sleeve and annular space to manage high pressures, along with a pot-shaped design and ventilation system for efficient operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If steel or dimensionally stable metal is used for the piston pump device, then high pressure resistance is achieved, but weight and size increase significantly

Engineering Contradiction:
Improvepressure resistanceVSAvoiddevice weight
Core Design Contradiction:
Stress or pressureVSWeight of moving object

Solution Approach 1:

The patent employs composite material construction by combining plastic components (piston, second housing part) with metal stabilizing elements. This allows the main body to be lightweight plastic while metal reinforcement provides the necessary pressure resistance, resolving the contradiction between weight reduction and pressure capability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Instead of making the entire device from heavy metal, the patent applies metal stabilizing sleeves and reinforcement elements only in specific high-stress areas where pressure resistance is critical. The majority of the device uses lightweight plastic, achieving local optimization of strength-to-weight ratio.

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If steel or dimensionally stable metal is used for the piston pump device, then structural stability is maintained, but space requirements increase

Engineering Contradiction:
Improvestructural stabilityVSAvoiddevice volume
Core Design Contradiction:
Stability of the object's compositionVSVolume of moving object

Solution Approach 1:

The combination of plastic and metal stabilizing elements creates a composite structure that achieves structural stability without the bulk required by solid metal construction. The plastic components provide the basic structural framework while metal reinforcements add stability only where needed, reducing overall device volume.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The device is segmented into plastic components and metal stabilizing elements that can be separately optimized. The plastic parts provide the main structure with minimal volume, while discrete metal elements add stability only in critical zones, avoiding the need for throughout metal construction that would increase volume.

Inventive Principle:
Principle #1Segmentation

3Weight of moving object

If unreinforced plastic is used for the piston and housing parts, then weight is reduced, but pressure withstanding capability decreases

Engineering Contradiction:
Improvecomponent weightVSAvoidpressure withstanding capability
Core Design Contradiction:
Weight of moving objectVSStress or pressure

Solution Approach 1:

Unreinforced plastic components are combined with metal stabilizing sleeves and reinforcement elements. The plastic provides lightweight construction while the metal elements provide the necessary pressure withstanding capability, allowing the use of unreinforced plastic without sacrificing pressure resistance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Metal stabilizing sleeves act as intermediary elements between the unreinforced plastic components and the high-pressure environment. These sleeves transfer and distribute pressure loads, protecting the plastic components from direct pressure exposure while maintaining the lightweight plastic construction.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Stability of the object's composition

If reinforced plastic is used for the housing, then dimensional stability improves, but sealing surface quality deteriorates

Engineering Contradiction:
Improvedimensional stabilityVSAvoidsealing surface quality
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The housing is constructed with differentiated local qualities: reinforced plastic is used for sections requiring dimensional stability and pressure resistance, while unreinforced or differently finished plastic sections provide smooth sealing surfaces. This local differentiation allows both dimensional stability and sealing quality to be optimized in their respective areas.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The housing combines reinforced plastic sections with smooth-finish sections, potentially using different plastic compositions or surface treatments in different areas. This composite construction allows the housing to provide both dimensional stability from the reinforced sections and high-quality sealing surfaces from the smooth sections.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP2884104B1Piston pump device
Publication Date: 2018.05.23 SKF LUBRICATION SYST GERMANY
  • EP2884104B1 patent drawingFigure 1~2
  • EP2884104B1 patent drawingFigure 3~5

AI summary

The present invention relates to a piston pump device (1), in particular for a lubricant pump, with a double piston (8) comprising a working piston (8a) and a delivery piston (8b) connected to each other via a piston rod (20), wherein the working piston (8a) is arranged sealingly in a first housing part (10; 12) and the delivery piston (8b) is arranged sealingly in a second housing part (10; 12), such that the working piston (8a) and the first housing part (10; 12) define a working chamber (16) for a working medium and the delivery piston (8b) and the second housing part (10; 12) define a delivery chamber (34) for a delivery medium, wherein the double piston (8) and/or the first and/or the second housing part (10; 12) are made of plastic, and a lubricant pump (100) with such a piston pump device (1).