Tensioner Oil Recirculation via Segmented Pressure Adjustment
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Solution Overview
Problem
Conventional tensioners face issues with oil leakage and vibration of transmission chains due to lack of damping force after long periods of inactivity, requiring high oil supply pressure and complex sealing mechanisms.
Innovation Solution
A tensioner design with a plunger, housing, check valve, main biasing unit, oil storage chamber, and pressure adjustment mechanism that recirculates oil efficiently using a piston and cylinder to maintain oil pressure, reducing dependency on oil pumps and eliminating the need for high-precision sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oil is supplied through a housing oil supply hole to maintain damping force, then damping force is maintained, but oil supply pressure must be designed to be high
Solution Approach 1:
The patent segments the oil supply path into two separate channels: a plunger oil supply hole that supplies oil to the pressure oil chamber, and a housing oil supply hole that supplies oil to the oil storage chamber. This segmentation allows independent control of oil supply pressure for each function, enabling the plunger to receive high-pressure oil for damping while the housing receives lower-pressure oil for storage replenishment.
Solution Approach 2:
The oil storage chamber acts as an intermediary between the housing oil supply hole and the pressure oil chamber. Oil flows from the housing through the oil storage chamber to the pressure oil chamber, allowing pressure reduction and buffering. The storage chamber mediates the pressure transition, enabling low-pressure supply from the housing while maintaining high-pressure damping in the pressure chamber.
2Reliability
If a check valve is used to prevent oil from flowing out, then oil is retained, but oil must be replenished from the oil pump side
Solution Approach 1:
The oil storage chamber enables the tensioner to replenish its own oil supply internally. When oil leaks from the pressure oil chamber, it flows into the oil storage chamber through the communication adjustment groove, and new oil is supplied to the storage chamber from the housing oil supply hole. This self-service mechanism eliminates the need for external oil pump replenishment systems.
Solution Approach 2:
The patent recovers leaked oil by directing it from the pressure oil chamber into the oil storage chamber through the communication adjustment groove. Instead of discarding leaked oil, the system recovers it for potential reuse, maintaining oil quantity and reducing the need for external replenishment.
3Reliability
If oil leaks out of the pressure oil chamber, then damping force is lost, but recirculation path increases device complexity
Solution Approach 1:
The communication adjustment groove serves multiple functions: it acts as a seal between the pressure oil chamber and oil storage chamber, provides a recirculation path for leaked oil, and enables pressure adjustment. This multi-functionality reduces the need for separate components, maintaining damping force without significantly increasing device complexity.
Solution Approach 2:
The patent merges the recirculation path with the existing communication adjustment groove structure. Instead of adding a separate recirculation channel, the groove is utilized to guide leaked oil back to the storage chamber, combining sealing and recirculation functions in a single structural element.
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 design improves oil recirculation efficiency, reduces oil consumption and power requirements, stabilizes chain tension, and eliminates the need for high-precision sealing, lowering costs and maintaining chain stability.
Implementation Method 1
a check valve that divides a space between the housing and the plunger into a pressure oil chamber and an interior space and allows oil to flow into the pressure oil chamber while preventing oil from flowing back into the interior space
Implementation Method 2
a pressure adjustment mechanism that adjusts an oil pressure in the oil storage chamber... a liquid-tight state is maintained between the cylinder portion and the piston in all positions
Implementation Method 3
as the plunger 520 reciprocates, the oil flows through a very small gap between the plunger 520 and the plunger housing hole 531, and due to flow resistance, a damping effect for damping the reciprocation of the plunger 520 is obtained
Data Source
AI summary
Provided is a tensioner with which efficiency of recirculation of oil can be improved and dependency on oil supplied from an oil pump or the like can be reduced. The tensioner includes a pressure adjustment mechanism, wherein the pressure adjustment mechanism includes a cylinder portion and a piston that is disposed in the cylinder portion so as to be capable of moving in a front-rear direction and that divides an interior space into an oil storage chamber and an adjustment space, and a liquid-tight state is maintained between the cylinder portion and the piston in all positions between a position of the piston where the piston has moved closest to the oil storage chamber side and a position of the piston where the piston has moved closest to the adjustment space side.