Fast Fill Tandem Master Cylinder with Segmented Piston
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current braking systems experience a delay in pressure buildup and unsettling pedal feedback during initial actuation due to the lack of physical contact between brake pads and the rotor, requiring a larger piston diameter for fast fill, which increases the force needed and necessitates a larger boost system.
Innovation Solution
A fast fill braking system with a master cylinder featuring a primary pressure chamber with a larger diameter portion and a smaller diameter portion, and a primary piston with complementary diameters, allowing for rapid pressure increase in downstream braking circuits without the need for a larger boost system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a larger diameter piston is used to quickly fill downstream braking circuits, then the fast fill function is improved, but the force required to move the piston increases
Solution Approach 1:
The primary pressure chamber is segmented into two portions with different diameters: a first chamber portion with a larger diameter for fast fill operation, and a second chamber portion with a smaller diameter for normal operation. This segmentation allows the system to achieve both fast fill capability and reduced force requirements by using the appropriate chamber portion at different times
Solution Approach 2:
The system dynamically switches between different piston diameters by moving the primary piston between two positions: a first position where the larger diameter first piston portion engages the larger diameter first chamber portion for fast fill, and a second position where the smaller diameter second piston portion engages the smaller diameter second chamber portion for normal operation. This dynamic switching resolves the contradiction between fast fill performance and force requirements
2Productivity
If a larger diameter piston is used to displace larger quantity of fluid, then the pressure buildup speed is improved, but the boost system size must increase
Solution Approach 1:
The primary pressure chamber is divided into two portions with different diameters, allowing the system to use a larger diameter first chamber portion for rapid pressure buildup when needed, and a smaller diameter second chamber portion for normal operation. This eliminates the need for a larger boost system while maintaining fast fill capability
Solution Approach 2:
The system changes the effective piston diameter parameter dynamically by switching between two positions: using the larger diameter first piston portion with the larger diameter first chamber portion to achieve rapid pressure buildup, and switching to the smaller diameter second piston portion with the smaller diameter second chamber portion for normal operation, thereby avoiding the need for an oversized boost system
3Loss of time
If a larger diameter piston is used to quickly take up the gap, then the braking response time is improved, but the pedal feedback difference becomes more pronounced
Solution Approach 1:
The system dynamically switches between two operational modes: a fast fill mode using the larger diameter first piston portion and first chamber portion that quickly takes up the gap between brake pads and rotor, and a normal operation mode using the smaller diameter second piston portion and second chamber portion that provides consistent pedal feedback. This dynamic switching resolves the contradiction between response time and feedback consistency
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 system minimizes the delay in braking and reduces unsettling pedal feedback by rapidly increasing pressure, achieving the desired fast fill function with potentially smaller forces required, thus potentially reducing the need for a larger boost system.
Implementation Method 1
a first annular seal mounted on the first large diameter portion and configured to sealingly engage the second substantially cylindrical chamber when the first large diameter portion is within the second substantially cylindrical chamber and the primary piston is moving in a forward direction
Implementation Method 2
the master cylinder generates fluid pressure in downstream braking circuits and displaces fluid in order to place friction members of the braking system against complementary surfaces
Data Source
AI summary
A fast fill braking system includes a master cylinder, a primary pressure chamber having a first chamber portion located forwardly of a second chamber portion, the first chamber portion having a diameter larger than a diameter of the second chamber portion, and a primary piston including a first piston portion positioned within the primary pressure chamber and a second piston portion extending out of the primary pressure chamber, the first piston portion having a diameter (i) larger than a diameter of the second piston portion, and (ii) complementary to the diameter of the second chamber portion.