Master Cylinder Piston Segmentation for Sealing and Pressure Equalization
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Solution Overview
Problem
Existing master cylinders face challenges in secure sealing of the cylinder chamber from the outside and reliable flow of hydraulic medium into the chamber, particularly in manufacturing efficiency and maintaining sealing functionality over multiple actuations.
Innovation Solution
The piston is designed with two sections, one having a cylindrical surface and the other with a radially inward set-back area, allowing for sealing contact in the actuation position and pressure equalization through gaps in the pressure equalization position, eliminating the need for a radial bore and enabling easy manufacturing, particularly from plastic materials. This design includes a transition section with a gradually increasing outer diameter for gentle application and minimized wear on sealing elements, along with securing sealing elements like O-ring or X-ring seals to prevent hydraulic medium escape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a radial bore is provided in the piston for pressure equalization, then hydraulic medium can flow into the cylinder chamber, but the piston becomes more complex and harder to manufacture
Solution Approach 1:
The piston is divided into two functional sections: a first section with a cylindrical lateral surface for sealing contact, and a second section with a radially inward set-back area that creates a gap for hydraulic medium flow. This segmentation eliminates the need for radial bores while maintaining pressure equalization functionality.
Solution Approach 2:
Different regions of the piston are given different geometries to serve different functions. The first section has a cylindrical surface for sealing, while the second section has a set-back area for fluid communication, allowing each region to optimize its local function without compromising the whole.
2Ease of manufacture
If the piston has a simple cylindrical shape, then manufacturing is easy, but secure sealing and reliable hydraulic medium flow cannot be achieved
Solution Approach 1:
The piston is divided into two functional sections: a first section with a cylindrical lateral surface for sealing contact, and a second section with a radially inward set-back area that creates a gap for hydraulic medium flow. This segmentation eliminates the need for radial bores while maintaining pressure equalization functionality.
Solution Approach 2:
The piston design creates a dynamic gap between the set-back area and the main sealing element that opens during pressure equalization and closes during actuation, allowing the structure to adapt its sealing characteristics based on operational phase without mechanical complexity.
3Reliability
If the piston applies strong force to the main sealing element for secure sealing, then sealing is improved, but wear on the sealing element increases
Solution Approach 1:
The piston design creates a dynamic gap between the set-back area and the main sealing element that opens during pressure equalization and closes during actuation, allowing the structure to adapt its sealing characteristics based on operational phase without mechanical complexity.
Solution Approach 2:
The radial position of the piston surface changes between two states: a first radial position during actuation for sealing contact, and a second radially inward position during pressure equalization for gap formation. This parameter change enables the system to switch between sealing and fluid communication modes.
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 ensures a simple, reliable, and secure sealing of the cylinder chamber, allowing hydraulic medium to flow effectively into the chamber during pressure equalization, while facilitating easy manufacturing and reducing wear on sealing elements, thus enhancing the overall performance and durability of the master cylinder.
Implementation Method 1
the main sealing element in the first section of the piston is in sealing contact with the piston
Implementation Method 2
hydraulic medium for pressure equalization can flow along the piston from the follow-up space into the cylinder chamber
Implementation Method 3
a transition section of the piston, which is arranged between the first section and the second section of the piston, has an outer diameter that increases along the piston from the outer diameter of the second section to the outer diameter of the first section
Data Source
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AI summary
In order to provide a master cylinder, in particular for a clutch system, activation system or brake system of a vehicle, which master cylinder can be manufactured at low cost and permits reliable sealing of a cylinder chamber towards the outside and reliable flowing on of hydraulic medium into the cylinder chamber, it is proposed that a piston of the master cylinder comprises a first section which has a cylindrical lateral surface and that the piston comprises a second section which has at least one region which is offset radially towards the inside with respect to the cylindrical lateral surface of the first section, wherein at least one set?back region extends as far as an end side of the piston facing the cylinder chamber, and wherein the first and the second sections are arranged on the piston in such a way that in an activation position of the piston a main sealing element in the first section of the piston bears in a seal?forming fashion against said section, and in a pressure?equalisation position of the piston at least one gap is formed in the second section of the piston between the piston and the main sealing element, through which gap hydraulic medium can run on along the piston into the cylinder chamber from a run?on space in order to equalize the pressure.