Hydraulic Brake Piston Wear Detection Without Clip-On Sensors
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Solution Overview
Problem
Traditional hydraulic brake wear detection systems, including clip-on sensors, are not robust, costly, and require frequent replacement, while newer brake-by-wire systems still rely on these sensors for pad wear detection, lacking effective solutions for reliable and cost-efficient wear monitoring.
Innovation Solution
A hydraulic brake wear detection apparatus and method that utilizes a caliper piston and internal piston within a caliper cavity, responsive to pressurized hydraulic fluid, to detect brake pad wear by isolating a predetermined volume of fluid and using negative pressure to rebalance and measure wear-induced changes, allowing for accurate pad wear status determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If clip-on sensors are used for brake pad wear detection, then wear monitoring capability is provided, but the system becomes costly and requires frequent replacement
Solution Approach 1:
The brake pad wear detection system utilizes the existing hydraulic brake system components (caliper piston, brake fluid, caliper cavity) to perform wear detection functions. The system self-monitors by measuring the volume of hydraulic fluid required to move the caliper piston, eliminating the need for external clip-on sensors that require replacement.
Solution Approach 2:
The hydraulic brake system's existing components are made multi-functional. The caliper piston serves both its primary function of applying brake pressure and a secondary function of detecting pad wear through volume displacement measurement. The brake fluid serves both pressure transmission and wear detection medium functions.
2Reliability
If clip-on sensors are used for brake pad wear detection, then wear monitoring is enabled, but the system becomes costly
Solution Approach 1:
The system uses existing hydraulic components to perform wear detection, eliminating the need for additional expensive sensor hardware. The brake system itself provides the detection capability through its inherent hydraulic fluid volume displacement characteristics when the piston moves.
Solution Approach 2:
Instead of using physical clip-on sensors that contact the brake pad, the system creates a hydraulic copy or representation of the wear condition by measuring fluid volume displacement. This indirect measurement approach eliminates the need for physical sensors while maintaining detection capability.
3Measurement precision
If a predetermined volume of pressurized hydraulic fluid is isolated in a closed hydraulic loop, then the internal piston can be reciprocated to detect wear, but the system requires complex valve control
Solution Approach 1:
The system uses periodic reciprocating motion of the internal piston to detect wear. The piston moves back and forth in a controlled cycle, allowing measurement of fluid volume displacement over time. This periodic action enables accurate wear detection through cumulative volume measurement while using simple on/off valve control.
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 provides a robust, cost-effective method for detecting brake pad wear, reducing the need for frequent sensor replacements and enhancing the reliability of wear monitoring in both traditional and brake-by-wire hydraulic brake systems.
Implementation Method 1
The internal piston is reciprocated by a predetermined volume of pressurized hydraulic fluid responsive to wear of the brake pad
Implementation Method 2
the internal piston is retracted longitudinally away from the brake rotor into a detection piston position by the provision of negatively pressurized hydraulic fluid to the caliper cavity
Implementation Method 3
The normally open venting valve is selectively closed to isolate the predetermined volume of pressurized hydraulic fluid from the reservoir of brake fluid and thus provide a closed hydraulic loop
Data Source
AI summary
A hydraulic brake wear detection apparatus and a method for detecting a degree of pad wear of a brake pad of a hydraulic brake includes a caliper piston located at least partially within a caliper cavity and attached to the brake pad. The caliper piston includes a piston cavity extending from a caliper piston rim into a caliper piston body at a location longitudinally opposite, and spaced from, the brake pad. An internal piston is located at least partially within the piston cavity and is entirely enclosed in an internal space defined cooperatively by the piston cavity and the caliper cavity for reciprocal longitudinal motion with respect to the internal space. The internal piston is reciprocated by a predetermined volume of pressurized hydraulic fluid responsive to wear of the brake pad.