Bicycle Brake Master Cylinder Layout for Tolerance Control
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Solution Overview
Problem
Existing bicycle control devices are costly and have tolerance variations between the master cylinder and primary seal, relying on separate locating features for the piston assembly, which complicates manufacturing and assembly.
Innovation Solution
The control device integrates the bleed port and timing ports into the master cylinder, allowing independent design and material selection for each component, and locates the piston assembly directly on the master cylinder to reduce tolerance variations and simplify manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separate locating features are used for the piston assembly, then manufacturing and assembly are simplified, but tolerance variations between the master cylinder and primary seal increase
Solution Approach 1:
The patent combines the locating features directly into the master cylinder body, eliminating the need for separate locating components. The master cylinder is made as a single integrated piece that includes built-in locating features, which simultaneously simplifies manufacturing and assembly while ensuring precise positioning and minimizing tolerance variations between the master cylinder and primary seal.
2Ease of manufacture
If the control device uses integrated components, then manufacturing costs are reduced, but material selection flexibility decreases
Solution Approach 1:
The patent employs composite material construction, specifically using glass-filled Nylon or carbon-filled Nylon for the master cylinder body. This allows the integrated component to maintain both cost-effectiveness and material performance flexibility, as the composite materials provide desirable properties such as strength, stiffness, and dimensional stability while remaining economical to manufacture.
3Manufacturing precision
If the piston assembly is located on the master cylinder, then tolerance variations are minimized, but assembly complexity increases
Solution Approach 1:
The locating features are merged directly into the master cylinder body as integral elements rather than separate components. This integration ensures precise positioning of the piston assembly with minimized tolerance variations while actually simplifying assembly, as the built-in locating features guide the piston assembly into correct position during a single assembly operation without requiring additional locating components.
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 configuration reduces manufacturing costs and assembly complexity while ensuring precise hydraulic pressure application for efficient braking, with minimized lever movement for immediate braking feedback.
Implementation Method 1
Some of these braking systems utilize a mechanism including a brake lever to generate pressure in a hydraulic fluid. This pressure is transferred through a hydraulic line or conduit to a brake assembly, such that the hydraulic pressure is applied to pads of the brake assembly
Implementation Method 2
The piston assembly is movable relative to the master cylinder portion. At least part of the piston assembly is disposed within the master cylinder portion... the piston assembly is configured to translate in a first direction relative to the master cylinder portion... such that the seal moves towards the timing port and pushes a portion of the fluid out of the master cylinder portion
Data Source
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AI summary
A control device mountable to a handlebar of a bicycle includes a housing, a lever coupled to and pivotable relative to the housing, and a master cylinder portion supported by the housing. The master cylinder portion has a fluid cylinder. The fluid cylinder has a first end and a second end opposite the first end with a cylindrical wall therebetween. An opening extends through the master cylinder portion, from the first end to the second end. The control device also includes a plug removably connected to the master cylinder portion via the opening at the first end of the fluid cylinder, and a piston assembly supported by the housing. The piston assembly is movable relative to the master cylinder portion. The fluid cylinder is accessible from outside the housing when the plug is removed from the fluid cylinder. The brake control device has a fluid path (FP) between the first end of the fluid cylinder and the second end of the fluid cylinder, via the fluid chamber (196) of the housing.