Pneumatic Disc Brake Ramp Geometry for Stable Self-Reinforcement
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Solution Overview
Problem
Pneumatically actuated disc brakes face challenges in achieving self-energization due to their 'soft' actuating characteristics, leading to uncontrollable brake vibrations and limited restoring forces, which cannot be controlled like electromechanical brakes, and require a design that optimizes ramp geometry for safe automatic release and energy efficiency.
Innovation Solution
A pneumatically actuated disc brake with a self-energizing mechanism featuring degressive ramp curves, where the ramp geometry is optimized to adapt to operating conditions, minimizing brake cylinder size and energy requirements, and a method to determine and set the optimal ramp course based on friction coefficient scatter analysis, ensuring reliable and fast release behavior even under ABS control processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a degressive ramp angle design is used to maximize self-boosting and minimize actuation energy, then the required actuation energy is reduced, but the brake produces uncontrollable vibrations and cannot be safely restored due to the soft actuating characteristics of pneumatic systems
Solution Approach 1:
The patent applies dynamics by making the ramp angle variable rather than constant. The ramp angle changes dynamically during the braking process, starting with a larger angle to overcome clearance and then transitioning to a smaller angle for stable self-boosting. This dynamic adjustment resolves the contradiction between maximizing self-boosting and maintaining control stability in pneumatic brake systems.
Solution Approach 2:
The patent changes the geometric parameter of the ramp angle from a constant value to a variable value that changes with piston displacement. By adjusting the ramp angle parameter according to the braking phase (larger angle initially, then smaller angle), the system achieves both energy efficiency and operational reliability, overcoming the limitations of fixed ramp angle designs in pneumatic systems.
2Speed
If a larger ramp angle is used in the initial phase to quickly overcome brake clearance, then the actuation response is faster, but the coefficient of friction fluctuations cause violent reactions and brake vibrations
Solution Approach 1:
The patent implements periodic action by dividing the braking process into distinct phases with different ramp angles. The first phase uses a larger ramp angle for rapid clearance overcoming, then transitions to a second phase with a smaller ramp angle for stable self-boosting. This phased approach eliminates violent reactions while maintaining fast initial response.
Solution Approach 2:
The dynamic adjustment of ramp angle during the braking process allows the system to adapt to different operational phases. The ramp angle is larger when needed for fast response (overcoming clearance) and becomes smaller when stability is needed (preventing vibrations), thus resolving the contradiction between speed and vibration control.
3Force
If the ramp angle is optimized for maximum self-boosting with tan(α) = μ, then the actuation force requirement is minimized, but the brake cannot be safely and automatically restored due to limited restoring forces in pneumatic systems
Solution Approach 1:
The patent uses dynamic ramp angle adjustment to ensure safe restoration. By reducing the ramp angle in the later phase of braking, the system maintains adequate restoring forces while still achieving energy efficiency. The variable ramp angle design prevents the restoration problems that would occur with a constantly optimized (minimum angle) design.
Solution Approach 2:
The patent prepares for restoration issues in advance by designing the ramp geometry to maintain larger angles during phases where restoration may be needed. This beforehand cushioning approach ensures that even with pneumatic systems' limited restoring forces, the brake can be safely and automatically restored without requiring excessive actuation force.
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 solution reduces compressed air requirements, minimizes brake cylinder size and weight, enhances response time, and ensures safe and automatic brake release with reduced energy consumption, maintaining the same braking effect as conventional brakes at maximum pressure.
Implementation Method 1
an actuating device with a brake cylinder that can be pressurized with at least compressed air as a brake force generator
Implementation Method 2
the coefficient of friction μ and the desired ideal state caused by fluctuations in the coefficient of friction
Data Source
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AI summary
A pneumatically actuable disc brake is provided, with a brake caliper, at least one brake pad on the application side and at least one brake pad on the reaction side, and a brake disc, at least one brake pad which is on the application side and is moveable both in a direction parallel to an axis of rotation of the brake disc and parallel to the friction surface of the brake disc, an actuating device with a brake cylinder, which is acted upon at least with compressed air, as a braking force generator which acts upon an applicator for applying the brake pad, and at least one self-reinforcing device with ramps, wherein the ramps each have a degressive ramp curve (22) which is produced according to the formula h = G -1 (u). In this case, h=the curve profile of the ramp and u=the peripheral travel.