Helical Rubber Lining Extrusion for Composite PCP Stators
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Solution Overview
Problem
Existing methods for manufacturing composite PCP stators face challenges in accurately forming a helical rubber lining with precise control and without adhesive or cohesive elements, leading to defects such as voids and distortion during the curing process.
Innovation Solution
A modified crosshead over mandrel extrusion technique is employed, where a helical mandrel is used in conjunction with a die plate, allowing for kinematic correlation of axial and rotational movements to form a helical rubber hose, which is then inserted into a stator tube and cured with thermoset resin, ensuring precise control and adhesion without adhesives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional extrusion methods are used to form rubber lining, then the manufacturing process is simpler, but the helical shape precision and uniformity deteriorate
Solution Approach 1:
The patent implements dynamic coordination between mandrel axial movement and die plate rotation through a kinematic correlation mechanism. The mandrel moves axially while the die plate rotates, with their motions precisely coordinated to extrude rubber in a perfect helical pattern. This dynamic system transforms the extrusion process from static to dynamically controlled, achieving high helical shape precision while managing device complexity through synchronized motion control.
Solution Approach 2:
The patent introduces a kinematic correlation mechanism as an intermediary between the mandrel and die plate. This intermediary component coordinates the axial movement of the mandrel with the rotation of the die plate, ensuring precise helical geometry without requiring complex direct coupling. The intermediary mechanism simplifies the overall system by providing a dedicated interface for motion coordination.
2Strength
If adhesive elements are used to bond rubber to metal, then bonding strength improves, but material purity and structural simplicity deteriorate
Solution Approach 1:
The patent extracts and eliminates adhesive elements from the bonding system. Instead of using adhesives to bond rubber to metal, the invention relies on direct mechanical interlocking through the helical geometry and friction-based adhesion during the extrusion and curing process. This extraction of adhesives simplifies the structure to just rubber and metal components while achieving sufficient bond strength through the helical configuration and curing process.
Solution Approach 2:
The patent creates a composite structure where rubber and metal components are directly bonded through the helical configuration and curing process without adhesives. The composite nature arises from the intimate contact and mechanical interlocking between the rubber lining and metal stator, forming a unified structure that leverages the properties of both materials while maintaining structural simplicity.
3Manufacturing precision
If rubber lining is formed without kinematic correlation, then the extrusion process is simpler, but the uniformity and precision of helical shape deteriorate
Solution Approach 1:
The patent replaces simple mechanical extrusion with a kinematically correlated system that coordinates mandrel movement and die plate rotation. This substitution introduces precise motion control mechanisms that ensure uniform helical geometry while maintaining production efficiency. The mechanical system is enhanced with correlation mechanisms that automatically synchronize movements, eliminating the need for complex manual coordination while preserving productivity.
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 method enables the fabrication of a composite PCP stator with a uniformly shaped rubber lining, preventing defects and ensuring a strong bond between the rubber and metal components, enhancing the structural integrity and performance of the stator.
Implementation Method 1
The material can be a thermoset resin. The method can further include curing or vulcanizing the thermoset resin to solidify and bond the material to the helical hose.
Implementation Method 2
moving a helical mandrel through the crosshead assembly and die plate outlet port while extruding the melted elastomer about the mandrel
Implementation Method 3
heating the rubberized mandrel and shell to cure the rubber
Data Source
AI summary
Techniques for forming a helical rubber hose are provided. Such techniques include modified crosshead extrusion techniques in which an elastomer is melted, fed into a crosshead assembly, and extruded on a helical mandrel fed through the crosshead assembly to form a hose. In techniques described herein, relative axial and rotational motion of the mandrel and a die plate at or on the outlet or output of the crosshead assembly are kinematically matched such that the distance of relative axial movement of the mandrel per one revolution equals one pitch of the mandrel.