Engine Tensioner Segmented Oil Chambers for Pressure Stability
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Solution Overview
Problem
Existing tensioner designs face issues with oil leakage and unstable oil pressure when the engine is at a standstill, leading to chain slippage or noise, and excessive oil pressure buildup when the plunger is pushed back by the chain, resulting in chain flapping.
Innovation Solution
A tensioner with a plunger, housing, check valve, inner sleeve, and relief unit, where a second high oil-pressure chamber is formed in the housing, and a relief unit is provided outside to manage oil pressure, using a gap between the plunger and inner sleeve as an oil flow passage to prevent leakage and maintain stable oil pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an orifice member is provided at the front end of the plunger to discharge oil, then oil pressure can be maintained at appropriate levels, but oil leaks from the relief hole when the engine is at a standstill with the plunger oriented vertically downward
Solution Approach 1:
The patent divides the single high oil-pressure chamber into two separate chambers: a first high oil-pressure chamber (11) for maintaining tension on the chain, and a second high oil-pressure chamber (34) for oil discharge control. The relief unit is positioned to discharge oil from the second chamber, separating the tension maintenance function from the pressure relief function, thereby preventing oil leakage while maintaining appropriate oil pressure levels.
2Stability of the object's composition
If the relief unit discharges oil easily to prevent excessive pressure buildup, then the plunger can move back smoothly, but the chain may flap due to insufficient tension
Solution Approach 1:
The patent segments the oil pressure management into two independent chambers with different functions. The first chamber maintains high pressure for chain tension, while the second chamber allows controlled discharge. This segmentation enables the plunger to move back smoothly without causing chain flapping, as the tension-maintaining oil in the first chamber is not discharged.
3Reliability
If a relief valve mechanism is provided to discharge oil when pressure rises, then oil pressure can be controlled, but there is temporarily no oil inside the chamber after discharge when the plunger is pushed back hard
Solution Approach 1:
The patent creates two independent high oil-pressure chambers, where the first chamber serves as a backup oil supply. When the plunger is pushed back hard and oil is discharged from the second chamber, the first chamber maintains oil pressure and can quickly replenish the second chamber through the communication passage, eliminating the temporary oil loss period.
4Reliability
If oil is supplied to the high oil-pressure chamber to maintain plunger tension, then the chain can be held firmly, but flow resistance creates damping that slows down plunger reciprocal movement
Solution Approach 1:
The patent segments the oil flow paths into two separate passages: one for supplying oil to maintain tension (through the check valve) and another for discharge control (through the relief unit in the second chamber). This segmentation allows the tension-maintaining oil flow to provide necessary damping while the discharge passage efficiently removes excess pressure without interfering with the reciprocal movement speed.
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
Prevents oil leakage and maintains stable oil pressure in the first high oil-pressure chamber, ensuring the chain is held firmly without excessive oil discharge, reducing noise and chain flapping.
Implementation Method 1
a coil spring (not shown in FIG. 6) that biases the plunger 120 toward the front side
Implementation Method 2
oil is supplied to a high oil-pressure chamber 111 formed between the plunger accommodation bore 131 and the plunger 120, so that the plunger 120 is biased toward the front side by the oil in the high oil-pressure chamber 111
Implementation Method 3
As the plunger 120 reciprocates, oil flows through the small gap between the plunger 120 and the plunger accommodation bore 131, and the flow resistance provides the damping effect of slowing down the reciprocal movement of the plunger 120
Data Source
AI summary
A tensioner with a simple structure is provided, which is capable of keeping oil pressure in a first high oil-pressure chamber stable and holding a chain favorably. The tensioner includes a plunger, a housing, a check valve, an inner sleeve, and a biasing member. In the housing, a second high oil-pressure chamber and a unit setting part are formed. In the unit setting part, a relief valve unit is set. A gap between an inner circumferential surface of a plunger hole and an outer circumferential surface of the inner sleeve functions as part of an oil flow passage that connects the first high oil-pressure chamber and the second high oil-pressure chamber.