Dual-Action Right-Angle Pilot Actuator for Compact Electrohydraulic Valves
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Solution Overview
Problem
Conventional electrohydraulic valves are complex, expensive, and bulky due to the use of multiple pilot valves and components, which increases component count, cost, and assembly difficulty, and often lack adequate force feedback, with stepper motors lacking durability for some applications.
Innovation Solution
A dual-action, right-angle pilot actuator with a cage, pilot spool, and a follower connected by springs, which selectively directs pressurized fluid and receives mechanical force feedback, reducing component count and length while providing durable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple pilot valves are used to control the spool, then the valve can function properly, but the component count increases and the valve block consumes more space
Solution Approach 1:
The patent combines multiple pilot valve functions into a single integrated pilot valve assembly. The pilot valve body incorporates multiple pilot spools (first and second pilot spools) that work together to control the main spool, eliminating the need for separate pilot valves and reducing overall component count while maintaining proper valve function.
Solution Approach 2:
The single pilot valve assembly performs multiple functions that would traditionally require separate valves. It controls both the extension and retraction of the main spool through its dual pilot spool configuration, and also provides centering functionality, making one component do the work of multiple components.
2Strength
If conventional metering valves are made massive for durability, then they can handle heavy loads, but they require significant energy to move quickly between positions
Solution Approach 1:
The valve system is segmented into a main spool for load handling and a separate pilot spool for control. The pilot spool is lightweight and requires minimal energy to move, while the main spool remains robust for handling heavy hydraulic loads. This segmentation allows the control element to be optimized for speed and energy efficiency while the power element maintains strength.
3Device complexity
If a single pilot valve is used to reduce component count, then cost and assembly difficulty decrease, but the valve assembly length increases
Solution Approach 1:
The pilot spools are arranged in a compact, space-efficient configuration within the pilot valve body. Rather than extending linearly, the first and second pilot spools are positioned to utilize three-dimensional space effectively, with their control ports and passages arranged to minimize the overall length of the valve assembly while maintaining all necessary functions.
4Ease of operation
If stepper motors are used to control the pilot spool, then precise control is achieved, but durability is insufficient for some applications
Solution Approach 1:
The patent replaces the stepper motor mechanical drive system with a hydraulic pilot control system. Instead of using an electric motor to directly drive the pilot spool, pressurized pilot fluid is used to move the pilot spool through hydraulic pressure differential. This substitution eliminates the mechanical wear and durability issues of stepper motors while maintaining precise control through fluid pressure regulation.
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 results in a low-cost, high-performance, compact valve configuration with improved force feedback and durability, enabling efficient control of hydraulic actuators with reduced complexity and size.
Implementation Method 1
The pilot spool is movable to selectively connect the supply port and the drain port with one or the other end of the control spool. As the pilot spool moves, the control spool is fluidly connected with either the pressurized pilot fluid or the tank pressure, thereby causing the control spool to move.
Implementation Method 2
The follower is separate from the cage and disposed at the tip end of the cage, and at least one spring operatively connects the follower to the cage and to the pilot spool... providing force feedback
Data Source
AI summary
A pilot actuator is disclosed for use with a valve. The pilot actuator may have a cage with a base end and a tip end, and a pilot bore formed in the cage. The pilot actuator may also have a supply port, a drain port, a first end port, and a second end port each formed in the cage and intersecting with the pilot bore. The pilot actuator may further have a pilot spool slidingly disposed in the pilot bore and movable to selectively connect the supply port and the drain port with the first and second end ports, a follower separate from the cage and disposed at the tip end of the cage, and at least one spring operatively connecting the follower to the cage and to the pilot spool.