Master Cylinder Bore Segmentation for Brake Feel
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Solution Overview
Problem
In hydraulic brake systems, existing master cylinders for X-split type vehicles face challenges in maintaining consistent braking force due to pressure differences between hydraulic pressure chambers, leading to degraded initial brake feel and increased hydraulic oil demand, which is not effectively addressed by increasing initial flow rate structures.
Innovation Solution
A master cylinder design featuring a cylinder body with joined first and second bores, each with large and small diameter portions, and corresponding pistons with different cross-sectional areas, including check valves to control oil flow and prevent backflow, allowing increased initial flow rate while maintaining balanced pressure distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the caliper brake is arranged to increase the amount of rollback to reduce drag during braking, then drag of the caliper is reduced, but an excessively large amount of hydraulic oil is needed at the initial stage of braking, resulting in degradation of initial brake feel
Solution Approach 1:
The first bore is segmented into a large diameter portion and a small diameter portion along the moving direction of the first piston. This segmentation allows different sections of the bore to serve different functions: the large diameter portion accommodates greater piston displacement for rollback reduction, while the small diameter portion maintains appropriate hydraulic pressure for initial brake feel.
Solution Approach 2:
Different sections of the bore have different diameters to provide local quality variations. The large diameter portion is located where greater volume is needed for rollback accommodation, while the small diameter portion is positioned to maintain pressure characteristics. This local differentiation resolves the contradiction between reducing drag and maintaining brake feel.
2Productivity
If a structure is adopted to increase an initial flow rate in the first hydraulic pressure chamber, then initial flow rate is increased, but pressure difference between the two hydraulic pressure chambers occurs, resulting in difference in braking force among the wheels
Solution Approach 1:
Both the first bore and second bore are segmented into large and small diameter portions, creating corresponding large and small hydraulic pressure chambers. This segmentation allows each chamber to have optimized volume characteristics while maintaining pressure balance through the communication passage between small diameter portions.
Solution Approach 2:
A communication passage is provided between the first small hydraulic pressure chamber and the second small hydraulic pressure chamber. This intermediary passage acts as a mediator to balance pressure between the two main hydraulic pressure chambers, preventing pressure difference while allowing increased initial flow rate through the segmented bore structure.
3Productivity
If the first piston applies pressure to increase flow rate, then initial flow rate increases, but pressure difference between first and second hydraulic pressure chambers occurs, leading to inconsistent braking force
Solution Approach 1:
The segmentation of bores into large and small diameter portions creates a pressure balancing mechanism. When the first piston moves, it experiences different pressure characteristics in different sections, which naturally balances the pressure between the two hydraulic pressure chambers through the communication passage, ensuring consistent braking force.
Solution Approach 2:
The bore diameter is changed as a parameter along the piston moving direction, creating large and small diameter portions. This parameter change modifies the pressure-volume relationship in each chamber, allowing increased flow rate while maintaining pressure balance and braking force consistency through the communication passage between small diameter chambers.
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 design enhances brake feel by increasing initial flow rate and reducing pressure differences between hydraulic pressure chambers, ensuring consistent braking force and improved brake performance for X-split type vehicles.
Implementation Method 1
each of the first and second bores may include a large diameter portion expanded to an inside of the cylinder body to increase flow rate at an initial stage of braking
Implementation Method 2
including check valves to control oil flow and prevent backflow
Implementation Method 3
a master cylinder serves to generate hydraulic pressure and transfer the generated hydraulic pressure to a caliper brake installed at each wheel
Implementation Method 4
When the first piston 3 of the master cylinder moves forward, the first piston 3 applies pressure to the oil in the first hydraulic pressure chamber 5, and in turn the oil pressure in the first hydraulic pressure chamber 5 presses the second piston 4
Data Source
AI summary
Disclosed is a master cylinder for brake systems including a cylinder body including a first cylinder having a first bore therein and a second cylinder having a second bore therein, the first and second cylinders being joined together by fastening members to allow the first and second bores to communicate with each other, a first and second piston installed to move forward and backward in the first and second bores, a first hydraulic pressure chamber adapted to be pressed by the first piston arranged in the first bore, and a second hydraulic pressure chamber adapted to be pressed by the second piston arranged in the second bore. Each of the first and second bores comprises a large diameter portion expanded to an inside of the cylinder body to increase a flow rate at an initial stage of braking and a small diameter portion narrowed from the large diameter portion.