Joystick Pilot Valve Boot and Drainage Structure
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Solution Overview
Problem
Joystick pilot valves in construction equipment, such as excavators, experience oil leakage and contamination due to foreign substances entering the hydraulic system, leading to malfunction and undesired operation of equipment.
Innovation Solution
The implementation of a joystick pilot valve structure featuring a boot to prevent alien material penetration and a drain hole system that directs leaked oil back into the inner portion, combined with a check valve in the drain hole to ensure hydraulic fluid does not leak externally, enhancing operational reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a boot is added to prevent alien material penetration and oil leakage, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent employs a boot (flexible shell) that covers the guide hole and push rod assembly. This boot is made of flexible material that can accommodate the movement of the push rod while effectively sealing the guide hole to prevent alien materials from entering and hydraulic oil from leaking outward, thus improving reliability without requiring complex mechanical sealing mechanisms
Solution Approach 2:
The patent introduces an intermediary drainage system with drain holes and check valves. The drain holes provide a controlled pathway for leaked oil to enter the inner portion of the joystick, while the check valve acts as a one-way gate to prevent oil from flowing back outward. This intermediary system manages oil leakage systematically rather than attempting complete prevention, resolving the contradiction between reliability and complexity
2Reliability
If drain holes are created to redirect leaked oil, then reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The drainage system is designed to be self-regulating through the check valve mechanism. The check valve automatically opens to allow oil flow from the outer portion to the inner portion when oil leaks through the guide hole, and automatically closes to prevent reverse flow. This self-service mechanism reduces the need for precise manual adjustment of drain hole parameters during manufacturing
Solution Approach 2:
The patent extracts the oil redirection function into a separate, dedicated drainage system with check valves. By isolating this function from the main valve body structure, the drain holes can be positioned and sized with standard tolerances rather than requiring high-precision integration with the spool and guide hole assembly, thereby reducing manufacturing precision requirements
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
This solution effectively prevents oil leakage and contamination, maintaining equipment functionality and preventing malfunctions by ensuring hydraulic fluid remains within the system, thus enhancing the reliability of the joystick pilot valve.
Implementation Method 1
the check valve for making the leaked oil flow into the joystick valve is set up in the drain hole and wherein the operation oil (hydraulic fluid) collected in the operation oil chamber of the valve body may not be again leaked to the outer portion of the valve body
Data Source
AI summary
A joystick pilot valve equipped with the structure for preventing oil leakage comprises: a valve body; spool installed in the valve body to be moved between the supply port and the hydraulic fluid chamber; spool hole installed in the valve body; pushing cam connected to the upper portion of the valve body by joint; joystick lever connected to the pushing cam to make the pushing cam move like seesaw by the operation and make the spool move in the spool hole forward and backward to make the supply port connected or disconnected to the hydraulic fluid chamber; outer boot provided at the valve body to cover the outer periphery of the valve body, the pushing cam and the joystick lever; inner boot arranged inside of the outer boot and forming oil leak storage chamber sealed from the outer side at the upper portion of the guide hole.