Electro-Hydraulic Brake Actuator With Solenoid-Free Pilot Pressure Control
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Solution Overview
Problem
Existing electro-hydraulic actuators rely on solenoid valves for controlling hydraulic fluid flow, which can malfunction due to power outages or electrical interference, leading to increased maintenance costs and power consumption, and heat generation affects hydraulic fluid viscosity, making them less efficient and difficult to miniaturize.
Innovation Solution
An electro-hydraulic actuator design that uses a hydraulic circuit without solenoid valves, employing a motor, pump, reservoir, and a hydraulic circuit with a pressurizing, pressure reducing, and pilot flow paths, along with a pilot pressure generating mechanism and check valve to control fluid flow based on hydraulic pressure, ensuring reliable discharge and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If solenoid valves are used to control hydraulic fluid flow, then the hydraulic circuit can switch flow paths quickly and precisely, but the system requires electricity which increases power consumption and maintenance costs
Solution Approach 1:
The patent removes solenoid valves from the hydraulic circuit entirely, extracting the electrical control component that causes power consumption and maintenance issues. The system replaces electrical valve control with a purely hydraulic control mechanism using a pilot pressure generating mechanism and check valves to achieve flow path switching without electrical components.
Solution Approach 2:
The patent replaces the electrical-mechanical solenoid valve system with a purely hydraulic-mechanical control system. The pilot pressure generating mechanism uses hydraulic pressure differential to control check valve opening and closing, substituting electrical actuation with hydraulic actuation to eliminate power consumption associated with electromagnetic coils.
2Measurement precision
If solenoid valves are used for high-speed flow path switching, then operational precision is improved, but reliability decreases due to susceptibility to power outages and electrical interference
Solution Approach 1:
The hydraulic control system is self-regulating through hydraulic pressure differential. The pilot pressure generating mechanism automatically controls the check valves based on the pressure differential between the pilot chamber and reservoir, eliminating dependence on external electrical power sources and improving system reliability through self-service operation.
Solution Approach 2:
The patent uses hydraulic pressure control instead of electrical control. The pilot pressure generating mechanism utilizes hydraulic pressure differential to actuate check valves, leveraging the inherent reliability of hydraulic systems that are immune to electrical interference and power outages while maintaining precise flow path control.
3Ease of operation
If the pump operates continuously to maintain hydraulic pressure, then the actuator is ready for immediate operation, but heat generation increases causing hydraulic fluid viscosity changes
Solution Approach 1:
Instead of continuous pump operation, the system uses periodic action where the pump operates only when hydraulic pressure needs to be restored. The check valves maintain system pressure during idle periods, allowing the pump to cycle on and off rather than running continuously, thereby reducing heat generation while maintaining actuator readiness.
Solution Approach 2:
The check valves provide continuous pressure maintenance without continuous pump operation. By trapping hydraulic fluid under pressure in the actuator chamber, the check valves ensure the actuator remains ready for immediate operation while allowing the pump to stop, maintaining useful pressure without the continuous energy input that generates heat.
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 enables reliable hydraulic fluid discharge without solenoid valves, reducing maintenance needs, minimizing power consumption, and preventing heat-related viscosity issues, resulting in a more efficient and compact actuator design.
Implementation Method 1
a check valve disposed within the pressurizing flow path for allowing the hydraulic fluid to pass only in a forward direction from the pump to the hydraulic actuator
Implementation Method 2
a pressure reducing flow path that connects the hydraulic actuator and the reservoir via an unloading valve in an openably closable manner
Implementation Method 3
a pilot pressure generating mechanism that generates the pilot pressure... during operation of the pump, the pilot pressure is generated
Implementation Method 4
the hydraulic circuit hydraulically controls operation of the hydraulic actuator
Data Source
AI summary
An electro-hydraulic actuator includes a pump powered by a motor, a hydraulic actuator biased to a first state that reciprocates between the first state and a second state, a reservoir, and a hydraulic circuit. The hydraulic circuit includes a pressurizing flow path that supplies fluid from the pump to the hydraulic actuator, a discharge flow path that discharges fluid from the hydraulic actuator to the reservoir via an unloading valve, a pilot flow path that branches off midway through the pressurizing flow path and supplies fluid pressurized to a pilot pressure to the unloading valve, a mechanism that generates pilot pressure while the pump is operating, and a check valve that allows fluid to pass only from the pump to the hydraulic cylinder. The hydraulic circuit transitions to the second state when the pump is operating, and returns to the first state and when the pump is stopped.