Internal Check Valve Piston for Faster Hydraulic Tensioner Response
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Solution Overview
Problem
Conventional hydraulic tensioners with external check valves have a delayed response time due to the distance between the oil reservoir and the high pressure chamber, which affects the piston's reaction force against dynamic loads from chains or belts.
Innovation Solution
A hydraulic tensioner with a piston containing an internal check valve assembly placed within the transition diameter of the piston, comprising a disk seat, a moveable disk, and a check valve spring, allowing fluid flow between the internal reservoir and the high pressure chamber, enhancing the piston's response time by reducing the distance between the oil reservoir and the high pressure chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If an external check valve is used in conventional hydraulic tensioners, then the structure is simpler, but the response time is delayed due to the distance between the oil reservoir and the high pressure chamber
Solution Approach 1:
The check valve assembly is nested within the piston structure itself. The piston contains an internal reservoir and the check valve assembly is positioned within the transition diameter of the piston bore, creating a compact integrated structure where the oil reservoir is moved closer to the high pressure chamber, thereby reducing response time while maintaining structural simplicity
Solution Approach 2:
The invention merges the check valve assembly with the piston structure by placing it within the transition diameter of the piston bore. This integration combines the oil reservoir and check valve functions into a single compact unit, eliminating the need for separate external components and reducing the distance between the reservoir and high pressure chamber
2Loss of time
If the oil reservoir is moved closer to the high pressure chamber, then the response time is improved, but the piston structure becomes more complex
Solution Approach 1:
The check valve assembly is nested within the transition diameter of the piston bore, with the moveable disk positioned between the internal reservoir and the high pressure chamber. This nested arrangement allows the oil reservoir to be located close to the high pressure chamber while maintaining a compact piston structure that does not require additional external components
Solution Approach 2:
The piston structure is designed with a transition diameter region that specifically accommodates the check valve assembly. This localized structural feature is created only where needed within the piston bore, rather than redesigning the entire piston, thereby minimizing the increase in overall structural complexity while achieving the goal of reduced response time
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 internal check valve assembly improves the response time of the piston's reaction force, effectively countering dynamic loads from chains or belts by optimizing fluid pressure distribution within the tensioner.
Implementation Method 1
a check valve spring received between the moveable disk and the check valve retainer
Implementation Method 2
fluid can flow from the internal reservoir to the high pressure chamber adjacent to the disk seat and within the piston
Implementation Method 3
the disk is biased against the retainer by the force of the oil flowing between the disk seat and the internal bulge
Implementation Method 4
increasing the fluid pressure within the high pressure chamber, exerting an outward force on the piston, opposing an inward force of the dynamic load from the chain or belt
Data Source
AI summary
A hydraulic tensioner for an internal combustion engine for tensioning a span of a chain or a belt has a piston with an internal reservoir connected to a high pressure chamber through a check valve assembly. The check valve assembly has a disk seat formed by an internal bulge within the piston; a check valve retainer within the piston, and a moveable disk that is received between the disk seat formed by the internal bulge and the check valve retainer and is moveable between a first position and a second position, and a check valve spring that is received between the check valve disk and the check valve retainer.