Spool Valve Throttle Port for Hydraulic Oil Impact Control
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Solution Overview
Problem
In spool valves for vehicle hydraulic brake apparatuses, the increasing flow rate of working fluid can lead to 'oil impact,' causing adverse effects, which existing designs fail to adequately mitigate.
Innovation Solution
Incorporating a throttle portion in the fluid channel between the valve element and the cylinder, where the opening area remains constant in a throttle valid region and increases in an invalid region, to regulate the flow rate and prevent oil impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the opening area of the supply valve port increases gradually with axial movement of the valve element, then the flow rate of working fluid increases gradually, but this causes oil impact when the hydraulic chamber reaches certain charging level
Solution Approach 1:
The throttle portion is designed with a movable throttle member that dynamically adjusts the throttle opening area based on the axial position of the valve element. When the valve element moves within the throttle valid region, the throttle opening remains constant to prevent oil impact. When the valve element exceeds this region, the throttle opening increases to allow higher flow rates, thus dynamically adapting the flow control to the operational phase.
Solution Approach 2:
The invention changes the parameter of throttle opening area from a fixed value to a variable value that depends on the axial position of the valve element. This is achieved by designing the throttle portion with a movable throttle member whose position is controlled by the valve element's axial movement, thereby transforming the static flow resistance into a dynamic one that adapts to different charging phases.
2Object-affected harmful factors
If a fixed throttle is provided in the fluid channel to reduce flow rate and prevent oil impact, then oil impact is reduced, but the amount of axial movement of the valve element must be increased to secure necessary fluid supply
Solution Approach 1:
The throttle portion transitions from a fixed throttle design to a dynamic throttle design where the throttle opening area changes with the axial position of the valve element. This allows the system to maintain a constant throttle opening during the critical charging phase (within throttle valid region) to prevent oil impact, while allowing the throttle opening to increase when the valve element moves beyond this region, thereby reducing the required axial movement distance.
Solution Approach 2:
The throttle portion is positioned and dimensioned such that it exerts its flow-limiting effect precisely when the valve element is within the throttle valid region, which corresponds to the critical charging phase. This preliminary action of flow control is applied at the right moment to prevent oil impact before it occurs, while allowing unrestricted flow later when the chamber is adequately charged.
3Quantity of substance
If the opening area of supply valve port increases with axial movement, then fluid supply amount increases, but this causes oil impact in the hydraulic chamber
Solution Approach 1:
The system uses a dynamic throttle control mechanism where the throttle opening area is coupled to the axial position of the valve element. During the initial charging phase (valve element within throttle valid region), the throttle opening is maintained constant to limit flow rate and prevent oil impact. When the valve element moves beyond this region indicating adequate charging, the throttle opening increases to allow higher fluid supply amounts.
Solution Approach 2:
The throttle portion acts as a feedback-controlled flow regulator where the axial position of the valve element serves as the feedback signal. The throttle opening area is automatically adjusted based on this position feedback, creating a closed-loop control system that prevents oil impact by reducing flow rate when the chamber is not yet charged and allows increased flow when charging is sufficient.
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 throttle portion effectively reduces the flow rate of working fluid when the hydraulic chamber is fully charged, preventing oil impact and minimizing the overall length of the spool valve by controlling axial movement.
Implementation Method 1
a throttle portion is provided in a fluid channel formed between the supply valve port and the hydraulic pressure source or a fluid channel formed between the supply valve port and the hydraulic chamber
Data Source
AI summary
A spool valve V1 includes a valve element 11 and a cylinder 12 having a bore 12a which accommodates the valve element 11 to be movable in an axial direction. In this spool valve V1, when the valve element 11 in an initial position moves in the axial direction in relation to the cylinder 12, a supply valve port Vi formed between the valve element 11 and the cylinder 12 opens, whereby a working fluid is introduced from a hydraulic pressure source into a hydraulic chamber through the supply valve port Vi. A throttle portion O1 is provided in a fluid channel formed on the hydraulic chamber side of the supply valve port Vi. The throttle portion O1 is configured such that in a throttle valid region which extends from the initial position to a position where the amount of axial movement of the valve element 11 from the initial position becomes equal to a predetermined value, the area of the opening formed between the valve element 11 and the cylinder 12 is constant, and in a throttle invalid region where the amount of axial movement of the valve element 11 exceeds the predetermined value, the area of the opening increases. Thus, it becomes possible to restrain occurrence of oil impact within the hydraulic chamber to which the working fluid is supplied through the spool valve V1.