Sealing Piston Lip Geometry for Wear-Resistant Hydraulic Chucking
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Solution Overview
Problem
Hydraulic expansion chucking devices face challenges in maintaining tightness due to the wear and tear of sealing pistons during repetitive movement, leading to decreased sealing effectiveness over time.
Innovation Solution
A sealing piston with a long and blunt sealing lip, composed of a rigid pin and an elastic seal, provides enhanced sealing by creating an interference fit with the bore, reducing leakage and wear, and is designed for improved durability and resistance to pressure changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the sealing piston is made movable to enable clamping and unclamping operations, then the operational functionality is improved, but the sealing tightness deteriorates over time due to wear
Solution Approach 1:
The sealing lip is designed with specific dimensional parameters (length L ≥ 1.5×(Rd-Rs) and radius Rd ≥ 1.05×Ri) to optimize the interference fit. These parameter changes ensure sufficient sealing pressure is distributed over a larger area, compensating for wear during repetitive movements while maintaining operational functionality.
Solution Approach 2:
The sealing lip is designed with excessive length and blunt shape beforehand to create a cushioning effect. The additional material length compensates for wear that occurs during operation, ensuring the sealing effectiveness is maintained throughout the service life of the sealing piston.
2Reliability
If a traditional seal design is used, then the initial sealing effect is achieved, but the sealing effectiveness decreases over time due to repetitive movement and wear
Solution Approach 1:
The sealing lip dimensions are specifically changed: length L ≥ 1.5×(Rd-Rs) and radius Rd ≥ 1.05×Ri. These parameter modifications create a more robust seal that maintains effectiveness over time by distributing wear across a larger contact area and providing material reserve.
Solution Approach 2:
The sealing piston combines a rigid pin (metal) with an elastic seal (rubber or plastic). This composite structure provides both structural integrity for movement and elastic sealing properties that accommodate wear and maintain tightness throughout the operational duration.
3Manufacturing precision
If the sealing lip is made sharp and thin for precise sealing, then the initial sealing contact is improved, but the resistance to damage and wear is reduced
Solution Approach 1:
The sealing lip is designed with asymmetric geometry: blunt overall shape with specific length and radius proportions. This asymmetric design prioritizes durability and damage resistance while maintaining sufficient sealing precision through the controlled interference fit dimensions.
Solution Approach 2:
The sealing lip parameters are specifically changed from traditional sharp designs: length L ≥ 1.5×(Rd-Rs) and radius Rd ≥ 1.05×Ri. These parameter changes create a blunt, robust sealing surface that is resistant to damage while maintaining effective sealing contact.
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 sealing piston maintains high tightness and reliability over long periods, effectively preventing fluid leakage and ensuring secure clamping of tools or workpieces, even with repeated use.
Implementation Method 1
a seal (18) that directly adjoins the pin (16) and likewise extends in said axial direction A... The seal (18), on the other hand, faces the inside of the expansion chucking device and is in particular in contact with the fluid in the pressure chamber
Implementation Method 2
A fluid is disposed in the pressure chamber, which in turn presses on a wall, e.g. an expansion sleeve, in which a tool or workpiece can be clamped
Data Source
AI summary
The invention relates to a sealing piston, which is designed for use in a hydraulic expansion chucking device. The sealing piston comprises a pin that extends in an axial direction (A), and a seal that adjoins the pin and likewise extends in said axial direction (A). The seal comprises a sealing shaft that adjoins the pin and has a shaft radius (Rs). The seal further comprises a sealing head that adjoins the sealing shaft, wherein the sealing head comprises a circumferential sealing lip, which has a sealing radius (Rd) that is greater than the shaft radius (Rs). The sealing lip forms a contact surface in radial direction (R) for abutment and sealing against an inner wall of a bore in the expansion chucking device, and, measured in axial direction (A), has a sealing length (Ld) that is greater than the difference between the sealing radius (Rd) and the shaft radius (Rs). The invention further relates to a corresponding expansion chucking device.