Master Cylinder Piston Indentations for Auxiliary Brake Fluid Tapping
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Solution Overview
Problem
Existing master cylinders face challenges in providing a high flow rate of brake fluid to auxiliary braking devices like E.S.P. and A.B.S. without causing fluid leaks or pressure drops, and increasing duct passage cross-sections can lengthen piston dead travel, while machining helix channels increases manufacturing costs.
Innovation Solution
The piston is hollowed radially to create indentations upstream of the port, allowing brake fluid to be stored and tapped off efficiently, reducing air bubble formation and seal extrusion during return to rest position, and maintaining seal collaboration with the master cylinder wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the passage cross section of the duct is increased to obtain a sufficiently high flow rate, then the flow rate of brake fluid is improved, but the dead travel of the piston is lengthened
Solution Approach 1:
The invention segments the brake fluid supply path by creating a separate tap in the piston that directly communicates with the chamber, bypassing the need for increased duct cross-section. This segmentation allows the main duct to maintain its original dimensions while providing an alternative high-flow path through the piston tap, thus resolving the contradiction between flow rate and dead travel length.
Solution Approach 2:
The piston tap acts as an intermediary element that directly connects the chamber to the auxiliary braking device. This intermediary path eliminates the bottleneck created by the duct passage, allowing high flow rate without requiring increased duct dimensions that would otherwise lengthen the piston dead travel.
2Productivity
If machining channels along the wall of the master cylinder is done to tap off brake fluid, then the flow rate is improved, but the manufacturing cost is increased
Solution Approach 1:
The invention merges the auxiliary braking device tap directly into the piston structure, combining multiple functions (piston movement, sealing, and fluid tapping) into a single component. This integration eliminates the need for separate machined channels in the master cylinder wall, thereby maintaining high flow rate capability while significantly reducing manufacturing complexity and cost.
Solution Approach 2:
The piston is designed with multi-functionality, serving not only its primary function of generating braking pressure but also providing a direct tap for the auxiliary braking device. This universal design approach allows the piston to fulfill multiple roles without requiring additional machined channels, thus improving flow rate while keeping manufacturing costs low.
3Productivity
If an opening is made through the reservoir to tap off brake fluid, then the flow rate is improved, but brake fluid leaks or pressure drop occurs
Solution Approach 1:
The invention extracts the fluid tapping function from the reservoir structure and relocates it to the piston. By taking the tap out of the reservoir and placing it in the piston, the system maintains high flow rate capability while preserving the integrity of the reservoir sealing system, thereby preventing leaks and pressure drops associated with reservoir openings.
Solution Approach 2:
The piston serves as an intermediary structure that provides access to the chamber for the auxiliary braking device without compromising the reservoir seal. This intermediary approach allows fluid extraction while maintaining the closed, pressure-tight environment of the reservoir, thus resolving the contradiction between flow rate and sealing reliability.
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 design ensures a high flow rate of brake fluid to auxiliary braking devices, minimizes air bubbles and seal extrusion, and reduces manufacturing costs by optimizing piston travel and seal interaction, thereby enhancing braking performance and efficiency.
Implementation Method 1
The primary piston and the secondary piston comprise a primary port and a secondary port respectively. Each of these ports opens via a first end facing a wall delimited by the bore of the master cylinder and via a second end into a corresponding chamber. The primary seal and the secondary seal control the flow of brake fluid from the primary reservoir and the secondary reservoir to the primary chamber and the secondary chamber respectively via the primary port and via the secondary port.
Data Source
AI summary
The invention relates to a motor vehicle master cylinder (1). More specifically, the invention relates to a piston (4, 5) of the master cylinder which has a first indentation (24) and a second indentation (27), which indentations are formed upstream of a port (13, 14) of the piston. The first indentation and the second indentation delimit a space within which hydraulic brake fluid can be stored so that it can be tapped off by an auxiliary braking device of the E.S.P. type.