Hydraulic Parking Brake Integration via Switchover Valve
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Solution Overview
Problem
Existing brake systems for motor vehicles require separate mechanical or electromechanical parking brake devices, which are not integrated with the hydraulic system, leading to increased complexity and cost, and do not effectively maintain brake pressure over time due to leakage.
Innovation Solution
A hydraulically operated parking brake device is integrated within the existing hydraulic brake system, utilizing a bistable switchover valve and hydraulic pressure storage device to maintain brake pressure, with a non-return valve to prevent pressure loss and an electric motor for pressure adjustment, allowing for reliable long-term parking brake functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate mechanical or electromechanical parking brake devices are used, then parking brake functionality is achieved, but device complexity and cost increase
Solution Approach 1:
The patent merges the parking brake device with the hydraulic brake circuit by integrating a holding pressure generator directly into the hydraulic system. This eliminates the need for separate mechanical or electromechanical parking brake devices, reducing overall system complexity while maintaining parking brake functionality through hydraulic pressure maintenance.
Solution Approach 2:
The holding pressure generator serves multiple functions: it maintains parking brake pressure, compensates for hydraulic leakage, and integrates with the existing brake circuit infrastructure. This multi-functionality allows a single component to replace what would traditionally require separate dedicated systems.
2Reliability
If separate mechanical or electromechanical parking brake devices are used, then parking brake functionality is achieved, but manufacturing cost increases
Solution Approach 1:
By combining the parking brake function with the existing hydraulic brake system components, the patent eliminates the need for separate mechanical or electromechanical parking brake assemblies. This integration reduces the total number of parts that need to be manufactured and assembled, thereby lowering manufacturing costs while maintaining functional reliability.
3Ease of manufacture
If conventional wheel brakes are used without integrated parking brake, then manufacturing cost is reduced, but parking brake functionality is lost
Solution Approach 1:
The holding pressure generator is designed to work with conventional wheel brakes without requiring integrated parking brake mechanisms. It provides universal parking brake functionality across different brake types by maintaining hydraulic pressure, allowing conventional brakes to gain parking brake capability without modification.
Solution Approach 2:
The patent uses hydraulic principles to maintain parking brake pressure through the holding pressure generator. By utilizing the existing hydraulic brake fluid system, the patent provides parking brake functionality without mechanical or electromechanical components, thereby maintaining compatibility with conventional wheel brakes.
4Ease of operation
If switchover valve is normally open, then manual braking is possible during power dropout, but brake pressure cannot be maintained for parking
Solution Approach 1:
The switchover valve is designed to be dynamically controllable, switching between normally open and normally closed states based on operational requirements. During manual braking operations, it remains open to allow pressure transfer; during parking brake operations, it closes to isolate the brake circuit and enable pressure maintenance by the holding pressure generator.
Solution Approach 2:
The system performs preliminary actions by pre-positioning the switchover valve in the appropriate state before parking brake activation. The holding pressure generator is pre-configured to maintain pressure, and the switchover valve is closed in advance to prevent pressure escape, ensuring reliable parking brake functionality from the outset.
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 simple, cost-effective integration of parking brake functionality within the hydraulic system, ensuring reliable maintenance of brake pressure even with leakage, enhancing safety and operational efficiency.
Implementation Method 1
a hydraulic pressure storage device which is connected to the brake circuit and which provides a hydraulic pressure that also acts on the brake circuit if the switchover valve is closed
Implementation Method 2
with a non-return valve to prevent pressure loss
Data Source
AI summary
A brake system for a motor vehicle includes a master cylinder, an actuatable switchover valve, and at least one parking brake device. The master cylinder includes at least one brake circuit which has at least one hydraulically actuatable wheel brake. The actuatable switchover valve is configured to separate and connect the brake circuit from/to the master cylinder. The parking brake device is paired with the wheel brake and configured as a hydraulically actuatable parking brake device. For this purpose, the parking brake device has a hydraulic pressure store which is configured to be operatively connected to the brake circuit. The switchover valve is configured to be closed in at least one first de-energized state in order to separate the brake circuit from the master cylinder.