Fluid Pressure Loop Valve Spool Design for Lubrication
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Solution Overview
Problem
Conventional fluid pressure loops for automatic transmissions face challenges in maintaining fluid state and controlling flow rates in lubrication loops, leading to potential air contamination and fluid quality issues.
Innovation Solution
A fluid pressure loop design incorporating a second control valve with a spool and recessed portions to manage fluid flow rates, including a sub-flow path and annular sub-port to prevent air mixing, along with an orifice and chamfered edges to mitigate flow rate changes and reduce oil vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a flow rate control mechanism is provided in the lubrication loop to control fluid flow rate, then the flow rate can be adjusted, but the fluid state cannot be satisfactorily maintained due to air contamination
Solution Approach 1:
The lubrication loop is divided into two separate loops: a main lubrication loop for flow rate control and a sub-lubrication loop for fluid state maintenance. The second control valve separates these loops, allowing independent control of flow rate (main loop) and fluid quality (sub loop with air separator), thus resolving the contradiction between flow adjustment and fluid state maintenance.
Solution Approach 2:
An air separator is introduced as an intermediary device in the sub-lubrication loop to remove air bubbles from the fluid before it reaches the lubrication points. This mediator ensures that even when flow rate is adjusted in the main loop, the fluid maintaining its proper state through the sub loop, preventing air contamination issues.
2Productivity
If the fluid flow rate in the lubrication loop is increased, then lubrication effectiveness improves, but air may be drawn into the system causing fluid contamination
Solution Approach 1:
The air separator is positioned in the sub-lubrication loop to preemptively remove air bubbles from the fluid before it is distributed to lubrication points. This preliminary anti-action prevents air contamination from affecting the lubrication system, allowing high flow rates to be maintained without the harmful effect of air ingress.
Solution Approach 2:
The air separator acts as an intermediary barrier between the fluid supply and the lubrication points, intercepting and removing air bubbles. This mediator allows the system to operate at higher flow rates for improved lubrication effectiveness while preventing air contamination from reaching the critical lubrication areas.
3Ease of operation
If a second control valve is added to control flow rate in the lubrication loop, then flow adjustment is improved, but device complexity increases
Solution Approach 1:
The second control valve is designed with multi-functionality, serving both as a flow rate control mechanism and as a separator between the main and sub-lubrication loops. By combining these functions in a single component, the system achieves improved flow adjustment capability while minimizing the increase in overall device complexity.
Solution Approach 2:
The control valve structure merges the flow rate control function with the loop separation function. The valve body integrates both the main flow path control and the sub-loop connection, combining multiple functions into a single component to reduce the number of separate parts and simplify the overall system architecture.
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
Effectively controls fluid flow rates, prevents air contamination, and maintains fluid quality by allowing fluid to flow through both main and sub-flow paths, ensuring stable operation even under varying conditions.
Implementation Method 1
the spool is moved to one end side of the valve housing chamber against a biasing force of the spring by applying a pressure of the fluid equal to or higher than a predetermined pressure to the spool control chamber
Implementation Method 2
a spring disposed at one end of the valve housing chamber and configured to bias the spool to the other end
Implementation Method 3
an orifice formed in the main flow path
Implementation Method 4
the edge of the first recessed portion of the spool is chamfered so as to mitigate sudden changes in a flow rate
Data Source
AI summary
A lubrication loop includes a main flow path connected to a lubrication flow path, a control valve connected to the main flow path, a return flow path connected to the control valve and configured to return the fluid to the fluid pump, and a sub-flow path branching off from the main flow path. The control valve includes a discharge port at a distance from a supply port of a valve housing chamber and connected to the return flow path, an open port formed at one end of the valve housing chamber to discharge the fluid, an annular recessed portion formed on an outer circumferential surface of the spool has a width extending from the supply port to the discharge port, and a sub port annularly formed between the discharge port and the open port on an inner circumferential surface of the valve housing chamber and connected to the sub-flow path.