Variable Cross-Section Pistem Stem for Progressive Hydraulic Braking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing pump bodies for hydraulic disk brakes lack the ability to provide a variable hydraulic ratio, resulting in a non-progressive braking action and reduced sensitivity, especially in sports applications where immediate response and modulation of braking are desired.
Innovation Solution
A pump body with a piston having a hollow stem with a variable cross-section, such as a tapered conical shape, which alters the compression chamber volume per unit displacement, allowing for increased fluid displacement in the initial braking step and gradual reduction in the second part, reducing the free stroke amplitude and enabling progressive braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional pump body with constant cross-section piston stem is used, then the structure is simple, but the hydraulic ratio is fixed and the braking response is not immediate
Solution Approach 1:
The piston stem is designed with variable cross-section along its length, creating different local compression chamber volumes. The first portion has a larger cross-section than the second portion, allowing different fluid displacement rates during the braking stroke. This local variation in geometry enables progressive hydraulic ratio change without complex additional components.
2Ease of operation
If a fixed hydraulic ratio is used, then the device structure is simple, but the braking action cannot be modulated progressively
Solution Approach 1:
The hydraulic ratio is made variable by changing the geometric parameter (cross-sectional area) of the piston stem along its length. As the piston moves through its stroke, the varying cross-section of the stem changes the compression chamber volume per unit displacement, thereby modulating the hydraulic ratio and enabling progressive braking action.
3Speed
If the control lever displacement is reduced for faster response, then the braking response is immediate, but the braking action becomes abrupt and difficult to control
Solution Approach 1:
The hydraulic ratio transitions from fixed to dynamic/variable. The variable cross-section piston stem creates a progressive change in fluid displacement during the braking stroke, allowing the system to adapt the braking force application rate. This dynamic characteristic enables both fast initial response and controlled modulation throughout the braking process.
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 reduces the control lever displacement required for braking, achieving faster response and more sensitive control, with a progressive braking action that modulates fluid pressure effectively.
Implementation Method 1
the piston displaces a volume of working fluid present in the cylinder, which is thus compressed and transmitted through a pipe to the piston or pistons of a hydraulic calliper
Implementation Method 2
a piston (2) having a hollow cylindrical stem (3) with a variable cross-section, such as a tapered conical shape, which alters the compression chamber volume per unit displacement
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A pump body for governing hydraulic actuators (6) of disk brakes for bicycles or motorcycles, comprising a cylinder (1) with a chamber for compression of the fluid (5) communicating with the actuator (6), and a piston assembly (2), which is mobile with respect to the cylinder and is provided with a stem (3) and a primary gasket (4), wherein a movement of downstroke of the piston (2) brings about a reduction of the volume of the compression chamber (5) and displacement towards the actuator (6) of a corresponding volume of working fluid (1).