Hydraulic Lash Adjuster Air Separation Design
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Solution Overview
Problem
Hydraulic lash adjusters require additional components, such as guide tubes, to prevent air bubbles from entering the high pressure chamber, increasing the number of parts and complexity.
Innovation Solution
A hydraulic lash adjuster design with a low pressure chamber extending continuously through the plunger and an oil supply hole oriented outward in the radial direction, generating a swirl flow that separates air bubbles and prevents them from entering the high pressure chamber without the need for a guide tube.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a guide tube is added to prevent air bubbles from entering the high pressure chamber, then air separation effectiveness is improved, but device complexity increases
Solution Approach 1:
The invention extracts and eliminates the guide tube component from the traditional hydraulic lash adjuster structure. Instead of using a separate guide tube to prevent air bubbles from entering the high pressure chamber, the patent redesigns the low pressure chamber and oil supply hole configuration to achieve air separation through the main oil supply passage itself, thereby removing the need for the additional guide tube part.
Solution Approach 2:
The invention merges the air separation function previously performed by the separate guide tube into the main oil supply passage system. By configuring the oil supply hole to face the bottom surface of the low pressure chamber and the low pressure chamber to extend to the bottom surface of the plunger, the oil supply passage itself performs both oil supply and air bubble removal functions, combining multiple functions into a single integrated structure.
2Reliability
If the low pressure chamber extends continuously through the plunger with radially outward oriented oil supply hole, then air bubble separation is improved, but manufacturing complexity increases
Solution Approach 1:
The invention implements preliminary action by configuring the oil supply hole to face the bottom surface of the low pressure chamber before oil enters the chamber. This pre-orientation of the oil supply hole creates immediate upward flow that pushes air bubbles toward the head section from the start of oil injection, preventing air bubbles from traveling deep into the chamber toward the high pressure chamber before they can be separated.
Solution Approach 2:
The invention changes the orientation parameter of the oil supply hole from a conventional configuration to one that faces the bottom surface of the low pressure chamber with a specific inclination angle. This parameter change in hole orientation fundamentally alters the oil flow pattern, creating a upward-directed flow that naturally separates air bubbles from the oil stream and directs them toward the head section for removal.
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 swirl flow effectively coarsens and separates air bubbles, preventing them from entering the high pressure chamber, reducing the number of parts required and maintaining damping force functionality.
Implementation Method 1
generating a swirl flow that separates air bubbles and prevents them from entering the high pressure chamber
Implementation Method 2
the air bubbles are moved through the swirl flow toward a radial central region of the swirl flow... the air bubbles collide (integrate) with each other and the volume expansion of the air bubbles is promoted
Implementation Method 3
the valve mechanism opening to allow the oil to flow from the low pressure chamber into the high pressure chamber when the plunger performs a stretching motion based on a restoring force of the biasing means
Implementation Method 4
when the plunger receives an input load from the rocker arm with an oil pressure in the high pressure chamber and performs a contracting motion, a damping force can be generated
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Air is restrained from flowing into a high pressure chamber while the number of parts is reduced. A plunger (14) is slidably fitted into a body (13) ; a reservoir (24) is formed in the plunger (14) with a communication hole (25) formed in a head section (19) thereof to allow communication between an inside and an outside; a high pressure chamber (28) is formed in the body (13) between the body (13) and the plunger bottom section (20); an oil supply hole (40) is formed in a plunger circumferential wall section (21); a return spring (41) is interposed between the body (13) and the plunger (14) ; a valve mechanism (42) is disposed on the plunger bottom section (20) ; the reservoir (24) is set such that a space continuously extends; and the oil supply hole (14) is oriented outward in the radial direction as compared to an axis (O) of the plunger (14).