Hydraulic Brake Piston Reset via Negative Pressure
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Solution Overview
Problem
Hydraulically acting brake systems experience a residual braking effect due to insufficient restoring forces, leading to increased CO2 emissions and longer braking distances, which existing solutions fail to adequately address without causing pedal travel loss or additional expenditure.
Innovation Solution
The introduction of a negative pressure mechanism in the hydraulic supply line to actively reset the brake piston, allowing for a defined brake clearance adjustment, which can be adaptive and diagnosed, using either the master brake cylinder or an additional unit, with valves controlling the flow to achieve minimal residual braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a roll back seal is used to move the brake piston away from the brake disc, then the brake lining clearance is improved, but the residual braking effect is not fully compensated and the brake piston travel is limited
Solution Approach 1:
The patent applies hydraulic principles by using negative pressure (vacuum) in the hydraulic supply line to actively reset the brake piston. The central control unit generates negative pressure that acts on the brake piston through the hydraulic fluid, pulling the piston and brake lining away from the brake disc by a defined distance to create optimal clearance and eliminate residual braking effects.
Solution Approach 2:
The patent changes the pressure parameter in the hydraulic system by introducing negative pressure (vacuum condition) to the brake piston. This parameter change allows the piston to be pulled back beyond what traditional roll back seals can achieve, enabling precise control of brake lining clearance and complete elimination of residual braking effects.
2Speed
If additional units for generating negative pressure are provided, then the brake piston reset speed is improved, but the device complexity increases
Solution Approach 1:
The patent makes the master brake cylinder multi-functional by enabling it to generate both positive pressure during braking and negative pressure during brake lining clearance adjustment. The central control unit controls the master brake cylinder to switch between these functions, eliminating the need for separate negative pressure generation units and reducing system complexity.
Solution Approach 2:
The patent merges the negative pressure generation function with the existing master brake cylinder. Instead of adding separate units, the master brake cylinder is integrated to perform both traditional braking (positive pressure) and brake lining clearance adjustment (negative pressure) functions, simplifying the overall hydraulic system.
3Duration of action of stationary object
If brake clearance is set to compensate for contamination and ageing, then the brake lining durability is improved, but pedal travel loss occurs and braking distances become longer
Solution Approach 1:
The patent makes the brake lining clearance dynamic rather than static. The central control unit actively adjusts the brake lining clearance by generating negative pressure when needed (e.g., after braking operations or when contamination is detected) and eliminates this clearance before subsequent braking operations. This dynamic adjustment optimizes both brake lining durability and braking performance throughout the service cycle.
Solution Approach 2:
The patent implements periodic adjustment of brake lining clearance based on operational conditions. The central control unit monitors braking operations, contamination levels, and wear indicators, then periodically generates negative pressure to adjust clearance as needed. This periodic action ensures optimal clearance is maintained without creating permanent pedal travel loss or extended braking distances.
4Reliability
If negative pressure is generated in the hydraulic supply line, then the residual braking effect is minimized, but the risk of air entrainment increases
Solution Approach 1:
The patent uses feedback control through the central control unit, which monitors pressure conditions in the hydraulic system during negative pressure generation. The control unit detects pressure drops that may indicate air entrainment and adjusts the negative pressure generation accordingly, stopping or reducing vacuum application when air intake risk is detected, thus maintaining reliable residual braking effect elimination while preventing air entrainment.
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 solution effectively minimizes residual braking effects, reducing CO2 emissions and braking distances, while being cost-effective and compatible with both electro-pneumatic and electro-hydraulic systems, and eliminates the need for brake lining wear sensors.
Implementation Method 1
a brake clearance may be generated and/or adjusted by means of negative pressure in the hydraulic supply line of a wheel brake
Data Source
AI summary
The invention relates to a hydraulic brake system comprising a master brake cylinder the at least one working chamber of which is connected to the wheel brakes of the vehicle via at least one hydraulic line, the brake piston of at least one wheel brake being adjustable by a negative pressure in the hydraulic lines to produce a brake clearance.