Hydraulic Boost Valve Seat Geometry for Low-Hysteresis Flow Boost
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Solution Overview
Problem
Current boost valves in hydraulic systems suffer from significant pressure hysteresis, leading to different opening and closing pressures, and provide a constant flow boost rate that is primarily dependent on valve geometry, resulting in noise, vibration, and harshness issues.
Innovation Solution
A hydraulic boost valve design featuring a housing, valve seat, and piston with a protrusion that engages the valve seat along a contact line to obstruct or allow fluid communication, reducing pressure hysteresis by maintaining a constant active flow force area and adjusting orifice sizes for varying flow rates, eliminating side loads and frictional resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional boost valves are used to increase fluid flow rate, then the flow rate through the hydraulic system is improved, but significant pressure hysteresis occurs causing different opening and closing pressures
Solution Approach 1:
The valve seat is designed with a cam-shaped profile that changes the contact point between the piston and valve seat during operation. As pressure increases, the contact point moves along the cam surface, dynamically adjusting the effective orifice area. This dynamic geometry compensation eliminates pressure hysteresis by ensuring consistent opening and closing pressures while maintaining high flow rate capability.
Solution Approach 2:
The cam-shaped valve seat profile changes the geometric parameters of the flow passage during operation. By varying the contact point position along the cam surface, the effective flow area is dynamically adjusted to compensate for pressure differences, eliminating hysteresis while preserving high productivity.
2Productivity
If constant flow boost rate is provided by conventional boost valves, then the flow rate is improved, but noise, vibration, and harshness issues occur
Solution Approach 1:
The cam-shaped valve seat enables dynamic adjustment of the effective orifice area based on operating conditions. This dynamic geometry allows the valve to provide higher flow boost rates when needed while smoothly modulating flow to eliminate NVH issues, replacing the constant flow rate limitation with adaptive flow control.
Solution Approach 2:
The cam profile is designed to create periodic variations in the effective flow area that synchronize with the operating cycle, providing high flow boost when required while using controlled periodic modulation to eliminate noise and vibration through smooth flow transitions.
3Device complexity
If piston design is simplified, then device complexity is reduced, but side loads and frictional resistance increase
Solution Approach 1:
The cam-shaped valve seat creates a dynamic contact geometry where the contact point moves along the cam surface during operation. This dynamic arrangement naturally guides the piston movement and eliminates side loads without requiring complex piston features such as recesses or grooves, achieving low friction with simple piston design.
Solution Approach 2:
The cam-shaped valve seat acts as an intermediary element that mediates between the piston and the fluid pressure. By providing a guided contact surface, it eliminates side loads and frictional resistance without modifying the piston structure, keeping the device simple while reducing harmful forces.
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 design achieves negligible pressure hysteresis, quick flow boost when line pressure exceeds a threshold, and adjustable flow rates without inducing noise, vibration, or harshness, ensuring smooth operation with minimal NVH issues.
Implementation Method 1
Boost valves are utilized to increase a flow rate of fluid through a hydraulic system
Data Source
AI summary
A hydraulic boost valve includes a housing, a valve seat, and a piston. The housing defines an axially extending internal cavity, a slot that extends radially outward from the internal cavity within the housing, and an outlet port that establishes fluid communication between the slot and a fluid output circuit. The valve seat is secured to an end of the housing. The valve seat defines first and second orifices. The first orifice establishes fluid communication between a fluid input circuit and the outlet port via the slot. The second orifice establishes fluid communication between the fluid input circuit and the fluid output circuit. The piston is disposed within the internal cavity such that the slot is positioned between the piston and an external wall of the housing.