Hydraulic Brake Control System with Independent Valve Segmentation
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Solution Overview
Problem
Existing hydraulically actuated braking devices for agricultural and construction vehicles face reliability issues, particularly in emergency braking scenarios, due to the risk of electro-hydraulic actuation failures and unintentional brake activation, which can lead to unsafe driving conditions.
Innovation Solution
A control system for a hydraulically actuated braking device featuring a second valve unit, such as a 3/3-way valve, actuated by an auxiliary device to ensure a reliable emergency braking function independently of the primary valve unit, with an actuating device like a hand lever or foot switch for manual operation, and a brake actuation valve designed to remain stable in its switching positions to prevent unintended changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single valve unit is used for brake actuation, then the device complexity is reduced, but the reliability of emergency braking function deteriorates due to potential actuation failures
Solution Approach 1:
The braking system is divided into two independent valve units: a first valve unit for normal parking brake operation and a second valve unit for emergency braking. This segmentation allows each valve unit to perform its specific function independently, ensuring that failure of one does not compromise the other, thereby improving reliability while maintaining manageable complexity through functional separation.
Solution Approach 2:
The system changes the operational parameter of valve independence by transitioning from a single-valve configuration to a dual-valve configuration where the second valve unit can operate independently of the first. This parameter change enables alternative braking pathways, ensuring emergency braking functionality remains available even when the primary valve unit fails.
2Ease of operation
If the brake actuation valve is made sensitive to external forces, then the response to actual braking needs is improved, but the risk of unintended switching due to external forces increases
Solution Approach 1:
The brake actuation valve is designed with inherent stability characteristics that pre-counteract the harmful effect of external forces causing unintended switching. The valve maintains its last switching position without requiring continuous energy input, effectively preventing external disturbances from altering the braking state, thus ensuring reliability while maintaining operational responsiveness when intentionally actuated.
3Reliability
If the actuating device is made fixable, then the braking position is maintained reliably, but the risk of locked braking position that cannot be released increases
Solution Approach 1:
Instead of designing the actuating device to be inherently fixed or locked, the system inverts the approach by making the actuating device non-fixable with inherent stability. The valve maintains its position through passive stability mechanisms rather than active locking, allowing natural return to neutral position or easy release while still maintaining the desired braking position reliably during operation.
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 enhances the functional reliability of the braking device, particularly the emergency braking function, by ensuring reliable and safe braking operations even if the primary valve unit fails, reducing the risk of unintentional brake activation and external force-induced switching errors.
Implementation Method 1
a pressure source designed as a pressure accumulator
Implementation Method 2
a spring element arranged in a spring-loaded brake cylinder in order to generate a braking torque
Implementation Method 3
This braking torque can be canceled out in that a pressure acting against the force of the spring element is built up in a pressure chamber of the spring brake cylinder
Data Source
Figure 1
AI summary
A control system (30) for a hydraulically actuated braking device (1) for an agricultural or construction vehicle, wherein the braking device (1) has a spring-applied brake cylinder (2) with a pressure chamber (4) that can be pressurized with pressure medium, which can be connected via a first valve unit (16) in the form of a brake actuating valve (16) and a second valve unit (13) to a pressure source designed as a pressure accumulator (9). The first valve unit (13) can be actuated by means of an actuating device (14) when the first valve unit (13) is switched in a flow position. According to the invention, the second valve unit (13) can be actuated by means of an actuating device (14) to actuate the braking device (1).